MALARIA CONTROL IN WAR AREAS MALARIA CASES IN UNITED STATES 1942-43 1915 1920 1925 1930 1935 1940 FEDERAL SECURITY AGENCY > U. S. PUBLIC HEALTH SERVICE ATLANTA, GEORGIA JUNE 1943 PERSONNEL AND PAYROLL PROCUREMENT AND SUPPLY VOUCHERS AND ENCUMBRANCES PROPERTY ACCOUNTING DIVISION OF ADMINISTRATION UNITED STATES PUBLIC HEALTH SERVICE MALARIA CONTROL IN WAR AREAS ORGANIZATION CHART - HEADQUARTERS OFFICE W. S. PUBLIC HEALTH SERVICE DISTRICT OFFICES TRAINING AND EDUCATION STATES RELATIONS DIVISION MEDICAL OFFICER IN CHARGE EXECUTIVE OFFICER STATE DEPARTMENTS OF HEALTH THE SURGEON GENERAL WAR AREAS PROJECT OPERATION | N, I. M, OFFICE OF MALARIA INVESTIGATIONS K. S. P. H. 5, LIAISON OFFICE REPORTS AND STATISTICS DIVISION OF OPERATIONS MEDICAL SECTION ENTOMOLOGICAL SECTION ENGINEERING SECTION AEDES AEGYPTI SECTION ATLANTA, GEORGIA MALARIA CONTROL IN WAR AREAS 1942 - 43 The program Malaria Control in War Areas, a joint under- taking by the Public Health Service and the several State Health Departments, is designed to control production of malaria mosqui- toes and reduce potential malaria transmission in extra- cantonment zones of military and essential war industrial areas. Operation of the projects is by the State Health Departments utilizing re- sources of the Public Health Service. Policy direction is exer- cised by the Atlanta office of the Public Health Service in collaboration with the Public Health Service Districts involved. FEDERAL SECURITY AGENCY U. S. PUBLIC HEALTH SERVICE ATLANTA, GEORGIA TABLE OF CONTENTS PART I Page PICTORIAL PRESENTATION OF MALARIA CONTROL IN WAR AREAS 1 PART II INTRODUCTION 34 OPERATIONS DIVISION 36 MEDICAL SERVICES 38 Blood Slide Surveys 39 ENTOMOLOGICAL SERVICES 41 Effectiveness of the MCWA Program 47 Special Entomological Survey Work 48 ENGINEERING SERVICES 51 Larvicidal Operations 52 Major Drainage 55 Insecticidal Control 64 MCWA IN PUERTO RICO 66 ADMINISTRATIVE DIVISION 67 PERSONNEL AND ACCOUNTS 69 PROCUREMENT AND SUPPLIES 70 SPECIAL PROJECTS AND COOPERATIVE ENTERPRISES 71 AEDES AEGYPTI CONTROL PROGRAM 71 DOG FLY CONTROL IN FLORIDA 78 BLOOD SLIDES FOR THE ARMY 79 TRAINING AND EDUCATION 79 COMMUNITY EDUCATION PROGRAM 80 PART III STATE SECTION 83 PART I The program Malaria Control in War Areas, inaugu- rated in March 1942, is designed to control production of disease- bearing anopheline mosquitoes, and to reduce potential malaria transmission in extra-cantonment zones of military establishments and essential war industries. During the 1942 mosquito season, control operations were promulgated in areas contiguous to 900 Army, Navy, and war- connected establishments. By June 30, 1943, the number of war establishments increased to 1161, embracing work in 317 counties of 21 States, the District of Columbia and Puerto Rico. Working through State health departments, full use was made of coordi- nated medical, entomological, and engineering sciences to obtain maximum control with mini mum expenditures of manpower and materials. Where medical opinion and entomological evidence indicated that the malaria problem of a war area was of minor import, epidemiologic and mosquito-density surveillance replaced costly engineering operations. Community education has been used to stimulate voluntary control programs through individual and community efforts, thus multiplying the measurable effects of the appropriation dollar. At present, malaria in the United States is at a low point. This is the result of the cyclic nature of the disease, and control work carried on by community, state, and federal agencies. The purpose of the present MCWA program is to maintain the existing low incidence throughout the period of war mobilization. It is an enterprise of preventive medicine. The descriptive material of the report is pictorially reviewed in the following pages. Here is depicted the enormity and complexity of the malaria problem, the method of attack, and the accomplishments of the past year. COORDINATION WITH ARMY AND NAVY PUBLIC HEALTH SERVICE The program of Malaria Control in War Areas functions primarily as an extension of military anti-malaria work. It operates in those areas where military jurisdiction does not extend, but where exposure of military or war personnel to malaria-carrying anophelines might occur. In- cluded are zones contiguous to military canton- ments or adjacent to essential war industries, and recreational areas for military personnel, and housing developments for war workers. ARMY AND NAVY SURGEON GENERAL SURGEONS GENERAL MCWA HEADQUARTERS DISTRICT AND STATE OFFICES Joint planning and field study together with exchange of epidemiological, entomological and engineering information between the Army Serv- ice Command and Naval District Offices; and the State Health Department and Public Health Serv- ice Offices effects close correlation of anti- malaria effort. SERVICE COMMAND AND NAVAL DISTRICT OFFICES PHS LIAISON OFFICERS AREA SUPERVISORS Local liaison is maintained between the area supervisors and the malaria control officers on military posts to coordinate parallel field operations inside and outside of reservations* POST MALARIA CONTROL OFFICERS MCWA CONTROL WITHIN A ONE MILE ZONE,(FLIGHT RANGE OF ANOPHELES QUADHIMACULATUS) SURROUNDING THE MILITARY RESERVATION. malacia THE NUMBER ONE DISEASE OF WORLD WAR II MALAWI NDMBER 0NE DISEASE OF THE WORLD! COUB-Tfiy OF UFe MAC»IlHt GEOGRAPHIC DISTRIBUTION - MALARIA HIGHLY ENDEMIC AREAS MODERATELY ENDEMIC AREAS LOW ENDEMIC AREAS MALABIA DISEASE OF CYCLES MALARIOUS AREA OF THE UNITED STATES IN THE UNITED STATES * possible UPSWING IN THE MALARIA CYCLE CONSTITNTES A POTENTIAL THREAT TO THE WAR EFFORT BY EN0AN6ERING THE HEALTH OF FIGHTIHG MEH & WAR WORKERS PROTECTION FMM MALARIA IS INSURED BI the control work of military forces inside reservations, the control work of civilian health agencies in the surrounding civil area but the immensity of the task has required the support and expansion of the normal local and state health depart- ment facilities hy the United States Public Health Service* M.C.W.A. FUNCTION TO WORK WITHIN THE ONE MILE MOSQUITO FLIGHT RANGE IN EXTR A - CANTONMEN ZONES, IN AND ABOUT WAR INDUSTRIES, RECREATIONAL ZONES, HOUSING FACILITIES ANO ACCESS HIGHWAYS. 'HE RESPONSIBILITY HAS BEEN PLACED IN THE OFFICE OF MALARIA CONTROL IN WAR AREAS M.C.W.A. IS THE SUPERSTRUCTURE BUILT UPON THE SOLID FOUNDATION OF STATE AND LOCAL HEALTH AGENCIES FOR THE PROTECTION OF FIGHTING MEN ANO WAR WORKERS. MALARIA IS A COMPLEX PROBLEM INVOLVING The infinite variety of relationships between the complicated life histories, habits, and behaviors of three living organisms- MALARIA PARASITE ANOPHELES MOSQUITO MAN BREAK THE MALARIA CHAIN ATTACK ATTACK ATTACK ATTACK THE PARASITE ATTACK IGNORANCE DRUGS INFORMATION ITECHNICAL MAN MOSQUITO MAN ATTACK ADULT MOSQUITOES MOSQUITO - PROOFING SPRAYING REPELLENTS ATTACK MOSQUITO LARVAE OILING DUSTING DRAINING ATTACKING THE PARASITE WITH DRUGS by treating clinical cases carriers reduces the danger of malaria transmission. THE ATTACK ON THE ADULT MOSQUITO is in some cases dependable and is employed where practical, but THE PRINCIPAL ATTACK selected because it is the most effective, practical, and reliable method available for the emergency use is AGAINST THE AQUATIC STAGES OF MOSQUITOES All other attacks may be supported ty the ATTACK ON IGNORANCE, which may well be the hope for eradication. THE ATTACK REQUIRES MEN DOCTORS, ENTOMOLOGISTS ENGINEERS ADMINISTRATIVE PERSONNEL 8f LABORERS AND MATERIALS EQUIPMENT AND SUPPLIES MEN AND MATERIALS PERSONNEL Each figure represents 25 people COMMISSIONED TECHNICAL SUB-TECHNICAL CLERICAL LABOR EQUIPMENT Each figure represents 50 unite AUTOMOTIVE BICYCLES HAND SPRAYERS POWER SPRAYERS AND OUSTERS IARVICIDi *•* «*u»e nfNMM 100,000 eol*» mmI (twring Rxal ytw 1043 OR (GALLONS) PARIS GREEN (LBS.) July 1, 1943 THE DOCTOR APPRAISES THE MALARIA HAZARD The most effective attack requires a shift of emphasis from treatment to prevention. Planning prevention requires predicting where cases may occur. Consider- ation is given past and present direct measurements in light of the many variable factors affecting transmission. REPORTS OF CASES AND DEATHS form the largest source of unrefined direct measurements. These reports reach the MCWA office from the practicing physician after they have been compiled by the state health department. They must be kept as current as possible and carefully studied in relation to the need for control work. BLOOD SLIDE SURVEYS WERE MADE IN THE FALL OF 1942. In 16 states and the District of Columbia, 120,000 blood smears were taken, of which 104,000 have been reported examined,revealing 0.2156 positive. The extensive control efforts of community, state, and federal health agencies during the past decade have been largely responsible for this low incidence. THE CYCLIC HISTORY OF MALARIA INDICATES A RISE IN INCIDENCE IF PROPER CONTROL MEASURES ARE NOT EFFECTIVELY EMPLOYED* LEGEND SCHEMATIC SEASONAL VARIATION MALARIA CASES UNITED STATES ESTIMATED TREND OF * MALARIA RATES MAP SHOWING POINTS AT WHICH BLOODSLDES WERE TAKEN IN SOUTHEASTERN UNITED STATES. FALL — 1942 TREND OF MALARIA IN THE UNITED STATES Because of the low incidence of malaria at the present time, EVALUATION of the effectiveness of the control program in keeping rates low cannot be done directly but REQUIRES INDIRECT MEASUREMENT BY ENTOMOLOGICAL METHODS." MANY WAR ESTABLISHMENTS ARE IN MALARIOUS AREAS PHOTO BY U. S. ARMY SIGNAL CORPS THE ABSOLUTE PROOF OF MALARIA IS THE OCCURENCE OF CASES. IN POTENTIALLY MALARIOUS AREAS A PREVENTIVE PROGRAM MUST NOT AWAIT THE DISCOVERY OF GASES BEFORE BEGINNING CONTROL WORK. THE POTENTIAL DANGER DEPENDS ON THE DENSITY OF THE MALARIA VECTORS - ANOPHELINE MOSQUITOES. THE ENTOMOLOGIST LOCATES BREEDING PLACES AND ESTIMATES THE DENSITY OF THE ANOPHELINE MOSQUITOES He also evaluates the effectiveness of control measures. In studying a new project, the entomologist discusses the malaria situation with the doctor, usually a health officer. After a conference with the doctor, the entomologist visits mosquito resting places in the vicinity of the war establishment. ANOPHELES QUADRIMACULATUS THE VECTOR OF MALARIA * is sometimes found in large nusbers* THE ENTOMOLOGIST OBTAINS THE BEST HAP of the locality from the County Engineer. *The control program is concerned with only three species of ANOPHELES> QUADRIMACULATUS in the eastern United States, ALEIMANUS in Texas and Puerto Rico, and FREEBORNI in the western United States. THE ENTOMOLOGIST MAKES A RECONNAISSANCE SURVEY in the vicinity of the war establishment, which, for simplicity, let us call "CAMP QUAD". He DIPS FOE LARVAE and places these in a vial for identification in the laboratory He MAPS THE LARVAL STATIONS by numbering each in a triangle symbol. He INSPECTS A NUMBER OF ADULT STATIONS near Camp Quad and maps each by a number in a circle symbol. He IDENTIFIES THE SPECIES OF ANOPHELINE larvae with the aid of the microscope. BREEDING PLACES ARE INSPECTED. Larvae and adults are identified. Notes are made and forms filled out. THESE DATA ARE INDICATED ON A MAP OF CAMP QUAD. The schematic map shows the entomological index stations for larvae and adults. SCHEMATIC MAP SHOWING ENTOMOLOGICAL INDEX STATIONS OA AONULATIO AAtA LEGEND ADULT CATCH'US STATION MALARIA CONTROL IN WAR AREAS ■ ••NIHaTON COWMTT. I1D»LI JACKSON BREEDING AREAS NEAR CAMP QUAD When the entomologist has gathered and analyzed the data, he discusses the problem with the engineer. THE ENGINEER AND ENTOMOLOGIST MAKE A JOINT RECONNAISSANCE SURVEY around Camp Quad. THE ENGINEER DETERMINES THE MOST EFFECTIVE CONTROL METHOD AND SETS IT IHTO OPERATION Making the best use of available man-power and equipment, HE DECIDES ON THE MOST PRACTICABLE AND ECONOMICAL METHOD OF CONTROL. He also supervises the control work so that it functions efficiently and effectively. IHE ENGINEER SURVEYS THE AREA. WAR AREA #2 WORK SHEET WAR AREA II WORK SHEET RELATIVE COSTS OF COHTHOL g UHVKIDnC OH «HMOE aaATIVI COOTS OF COITOPL BT UiWgOPC Og Baffin EXTENT OF BREEDING SURFACE 210 ACRES LENGTH OF BREEDING SEASON 24 WEEKS BREEDING AREA CONDITION: RELATIVELY OFF* PONDED AREAS. ALL PARTS REACHABLE BY BOAT OR MAN WEARING BOOTS. EXTENT OF BREEDING SURFACE 1190 ACRES LHC IB OF RRKKnnr. SEASON 24 WEEKS BREEDING AREA CONDITION! EXTENSIVE MARSH! AND INTHIUITIENTLI WOODED AREA. BOTTCM VERT SOFT SO AS TO BE UNSAFE FOR WADING AND GENERALLY TOO SHALLOW AND OVERGROWN FOR BOAT. IARVICIDING 1. IN OREER TO TREAT ENTIRE AREA AT WEEKLY INTERVALS WITH PARIS GREEN DUST WILL REQUIRE 6 DUSTERS AND 1 FOREMAN. 6 LABORERS FOR 24 WEEKS • $29.16 PER WEEK $4,199.04 1 FOREMAN FOR 24 WEEKS • $39.74 PER WEEK I 953.76 TOTAL $5,152.80 2. LBS. PARIS GREEN • 20 CENTS PER LB. PER WEEK FOR 24 WEEKS $1,006.00 1,890 LBS. LIME 6 $9.00 PER TON PER WEEK TOR 24 WEEKS - - $ 204.12 TOTAL $ 1,212.12 COST OF IARVICIDING $ 6.364.92 mi m^r.R I. TO ELIMINATE BREEDING SUR- FACE BY DRAINAGE WILL REQUIRE EXCAVATION OF 40,000 CU. YDS. OF EARTH IN ALL. APPROX- IMATELY ONE-HALF CAN EE DUG WITH DRAG-LINE AT 35 CENTS PER CU. YD. $ 7,000.00 OTHER HALF CAN EE HAND EXCAVATED t $1.00 PER CU. ID. I^OOPiQO COST OF DRApUgE Mm™,99 ABOVE INCLUDES CLEARING OF IEAVY STUMP AGE, EXCAVATING, MOV DO SHIPMENT, ETC. QUESTIONABLE WHETHER DRAGLINE CAN EE OBTAINED IN THIS AREA AT THIS TIME. URVICXDING 1. AIRPLANE DUSTING AT WEEKLY INTER- VALS ONLY FEASIBLE METHOD. 2. AVERAGE DUSTING TIME PER WEEK 6 HOURS tt $55 PE& HOUR FOR 24 WEEKS | 7,920.00 AVERAGE STANDBY TIME PER WEEK 10 HOURS t $20 FER HOUR FOR 24 WEEKS $ 4,800.00 FERRYING MILEAGE 200 MILES PER WEEK t $.70 PER MILE FDR 24 WEEKS — $ 3,360.00 3. MIXING, TRANSPORTING AND SERVICING: 4 LABORERS AND 1 FORrMAN FOR 24 WEOS - - $ 3,753.12 4. 1,190 LBS. PARIS GREEN • 20 CENTS FEE LB. PER wm FOR 24 WEEKS $ 5,712.00 43 TONS LIME t $9 PER TCN I. JSU22 COST OF LARVICIDPIG DRAINAGE 1. AREA SUITABLE FOR DYNAMITE DITCHING. 2. COMPLETE DRAINAGE WILL REQUIRE EXCAVATION OF 30,000 CU. IDS. OF EARTH. APPROXIMATELY THREE-FOURTHS TO BE BLOWN WITH DYNAMITE fe 30 CENTS PER CU. YD. $ 6,750.00 APPROXIMATELY ONE-FOURTH HAND EXCAVATED « #1.00 PER CU. YARD S 7.500.00 ysuuatam hi*m«g> &L£.£L> /9?l61 %-R 1/3 So0 PsoroPAerj t-B Pru r o BM>M quad. erne. pa net. Tool Quid MPMFM|,M>MrMF »■■- L Z-^fc.S&^jjjE Z-A NRP L L . . A-R NRP J_ Z \A. %txanj ae U.-A AJRP 0_ Q_ c' i~-g. AL&£. 1 2ll to ITV.TA** C-/\ BRP L I 7~ff NRP 2L 1 Z P- c«lmv'bis k. (Namo) c, xJ&jruzs. Form 3206 (M-7) . (Title) F. S. A.r-P. H. S.—Jan. 1943 ' opo 16—32877-1 MCWA-107 Type of project (check one): Control and inspection Inspection only Figure 7 forms are forwarded each week to Army Service Command headquarters for infor- mation and comment. No attempt nas been made to establish arbitrarily a definite thresh- old of quadrimacnlatus density as determined by numbers occurring in natural resting places, by which to judge the adequacy of control work. Rather, the effectiveness of the work in any area is gauged by conditions inside a control zone compared to those in similar environments outside. An exception to this is in Puerto Rico where uniform animal bait traps are used and where collec- tions of more than five adults per trap per night are considered indicative of inadequate control. In determining the need for anopheline control around war areas in the States which comprise the malaria belt, the presence of even moderate numbers of Anopheles quadrimaculatus in and about the war establishments is taken as justification for control, whereas, in areas outside the malaria belt, the presence of the same or even greater numbers of this species is not considered cause for alarm. Under the latter conditions it is usually recommended that the area be kept under close observation but that no con- trol work be undertaken unless there is evidence of malaria transmission or a notable increase in quadrimaculatus prevalence. A number of places are under surveillance at present where, on ac- count of previous malaria history, there is a possibility that malaria may become epidemic. There is also the possibility that new strains of the parasite may be introduced by returning troops or war workers. In cases of this kind, careful surveys are made in order to have information avail- able for immediate use if control work should become necessary. Effectiveness of the MCWA Program Entomological records received during the 1942 breeding season indi- cate that MCWA control work was effective in satisfactorily reducing the densities of Anopheles quadrimaculatus in approximately 92 percent of the war establishments protected by the MCWA program. The remaining 8 percent showed periods during the season when anopheline densities were considered to be sufficiently high to create a potential malaria hazard. This 8 percent was distributed generally throughout the malaria belt in 12 of the 19 states in which work was undertaken, which indicates that the failures were caused by local difficulties rather than by general mis- understanding or technical failures in any one State. Furthermore, the stand- ard of satisfactory control is based on the scarcity of anophelines through- out the entire protected area, and therefore dangerous densities in any one portion would cause the entire zone to be designated as unsatisfactory. In the main, the failures fell into two categories: (1) Poor tech- nique such as inefficient larviciding and inspection, and (2) unavoidable cases such as (a) overwhelmingly large breeding areas involving difficult control problems, e.g., rice fields, extensive impoundments, and flooded areas caused by abnormal rains; (b) delay in starting of control, and (c) the necessity for major drainage operations for adequate control. Quadrimaculatus densities throughout the 1942 season, in those zones where continuous comparable records are available to indicate conditions out- side as well as inside or adjacent to the protected war activities, are il- lustrated in figure 8. Here it is shown that at the beginning of the season the densities were higher inside the protected areas than outside, but that as the control work progressed and all the troublesome breeding spots were located, the Inside densities were maintained at a low level for the remain- der of the season. It is particularly significant that inside densities did not reflect the considerable rise which occurred outside during the late summer. Reports received to date for the 1945 mosquito season (May-June) in-* dlcate somewhat higher average vector densities in control areas than during the corresponding months in 1942. The percentage of zones in which satisfac- tory control is being maintained, however, stands at about 94 percent, or slightly higher than for the 1942 season. The same observations as made on DENSITIES OF MALARIA VECTORS’* INSIDE PROTECTED ZONES COMPARED TO ADJACENT UNPROTECTED TERRITORY 1942 *Anoohslss ouodrimaculotui (Southsrn States) A.moculioswnis freeborni jtWest Coast) olblwonus (South Texas) Figure 8 the 1942 records concerning the distribution of unsatisfactory zones and the reasons for the high densities of mosquitoes present apply equally well to these early 1945 season records. Special Entomological Survey Work At the request of various war agencies special entomological surveys were made during the year at war establishments in various parts of the corn try. The chief purpose of this work was to determine the abundance of the malaria vector, quadrimaculatus, and whether or not it was advisable for MCf to institute control. Further work of this nature around a number of north- ern war locations is planned for the coming summer, particularly at Amy an< Navy hospitals where troops returning from tropical countries are quartered, In New England during 1942, at the request of the Surgeon General of the Army, such surveys were made at Portland and Presque Isle, Maine; Chicopee Falls and Ayer, Massachusetts; Portsmouth, New Hampshire; and Narragansett, Rhode Island. In all of these areas very little evidence of hazardous densities of quadrimaculatus was found, the mosquitoes causing concern being of the pest varieties. Ayer, Massachusetts, is reported to have a malaria history, and because of the importance of this war area, and the presence of an Army general hospital, further survey work will be under- taken during the 1945 season. At the request of the Surgeon General of the Navy, detailed mosquito surveys, including plans and estimated costs for control work, were made around the following places; Potomac River Naval Command (Md. and Va.) New River Marine Base (N.C.) Banana River Naval Air Station (Fla.) Parris Island Marine Base (S.C.) Corpus Christi Naval Air Station (Texas) Philadelphia Navy Yard (Pa.) Cherry Point (N.C.) Key West (Fla.) Charleston Navy Yard (S.C.) New Orleans (La.) July 1, 1943 MALARIA CONTROL IN WAR AREAS Airplane Dusting Dragline Ditching Dynamite Ditching Aedes Aegypti Cor LEGEND U. S. PUBLIC HEALTH SERVICE TYPES OF PROJECTS Inspection Lorviciding Minor Drainage Major Drainage Vertical Drainage ENGINEERING SERVICES The malaria control engineer, utilizing entomological and medi- cal data, decides on the method of attack, puts it into effect, and furnishes the technical supervision necessary for the successful conduct of the work. In the MCWA program, the functions of the Engineering Section are: 1. To make the necessary engineering surveys. 2. To decide on the most feasible and economical plan of operation. 3. To initiate control work. 4. To guide the control operations so that they function efficiently and effectively. 5. To handle, at the area and State level, the operational and executive details necessary to the smooth functioning of the program. During the fiscal year 1943 the methods generally used for con- trol of malaria in territories adjacent to Army, Navy, and industrial war establishments were: (1) Destruction of mosquito larvae by larvicides; (2) elimination of mosquito breeding areas by drainage or filling; and, (3) killing of adult mosquitoes by spraying. Project proposals, originated by State health departments, covered three types of activities: 1. Larvicidal and minor drainage projects which utilized periodic larvicidal applications to control production of the malaria vector. Minor drainage and clearing operations incidental to, and necessary for, the efficient operation of the larvicidal program were performed as part of these projects. Where insecticidal spraying for the control of engorged adults was utilized, it was included under this type of project. 2. Major drainage and clearing projects which depended on drainage, clearing, or filling as the major factor in achieving control of anopheline breeding. 3* Inspection projects in which no larvicidal or drainage work was indicated at the time but for which entomological and/or medical observation were deemed necessary to determine whether control should be instituted. Inspectional services varied from regular routine inspection at weekly intervals to occasional inspections. The application of larvicides is the primary method of control used in this program. Although this is somewhat contrary to the usual practice in normal malaria control operations in which main reliance is placed on control by drainage and filling, the emergency nature of this program and the temporary character of most of the war establishments being protected, made it advisable to use larvicides to control anopheline production where effective control could be achieved by such measures. Larvicidal Operations Petroleum oil and parts green were the two larvicides most commonly used, although some pyrethrum emulsion and phenol were employed. During the year 1,376,607 gallons of oil and 152,267 pounds of paris green were used. Since paris green dusted on the water is toxic only to anophelines, while oil kills all mosquito larvae, oil was more generally used. Table 2 presents data on the amounts of larvicides used and the extent of cumulative water surface treated by individual States. KN ~=t ON rH « Man E 2 KNrH NKNON CM CM VO .U O CM (\l OiOjvp rH VO O KN ONrH CM O KNKNON O) ovduxu UN UNdvO f-CM t^-uNr-vo-d On • M CM o r-u- OnO l^-ON CM 3 -d g IT O\0 rH rH CO ONKVdr^ f— KN rH CO ifNCM CM ON CM rHVO_dO UN CM KNrH LT UN CO CM KN ON VO UNO KNO.Jt VO UNrH t~-o ONt^- U~-fM ON O' w -d- «r V TJ to &, CO h (0 «1 e o os vO KN_drH£-- rH_ctvO UN trv CM CM _d’_d’KNvO KN ON KNrH vO -d- cu unS rH_d o_d e*-KN o 3 CO rH =e tis bo c „ ONvO _d CTNUN -CtCN--3- KN OH CM CM-dt*- UN ONrH KNO On r~- knvo r- OnvO rH k* £ o CO rH o r-H ON CM rH VO KN Zc ON vO 0> o rH CM rH 1=5 g» . ifXU rH GO-d iJqN? r? 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c • *h 3 o c O KNvo *H O rH IT CM _d VO CM KN CM On CM IT. O CO rH VO rH KNCM if rH O ON CM O if KNU- Kv. vO t •o • p •H U 1 X! p p _ZfKNrH KNrH NO VO rH OJ ON vOHOJOn if-CM U'.CM vO rH H CM CM rH ON CM OvO S'U rH vO a O m -H a) f- fc W rH E a, rH I £ rl S | 01 c tj _d-|>-_c; *H CM HH CM rH rH ON-dPjj’C'-KN UNrHONKNO CM rH -dvo vO CM CM rH C c C _ K c o M K %H • £ E g O C-* The larvicides were applied by means of hand sprayers or dusters or by power equipment. Approximately 3.377 hand sprayers, 801 hand dusters, 2$ power dusters, 13 power sprayers, and 19 water-oil units were in use. The use of power equipment (figure 9) was advocated wherever feasible to expand control operations without increasing manpower. The effectiveness of larvicidal operations increased during the year as the expert.ence and training of the personnel progressed. Special investigations were made when control work did not effect reductions in density. For example, when "quad” counts in a certain war area continued to rise despite regular and pro pear larviciding, the oil was found to have poor spreading qualities and very little odor. A toxicity test made with culicine and anopheline larvae resulted in practically no mortality after an hour, indicating non-compliance with the specifications under which the oil was purchased. Because of the present oil shortage, it was found in many instances that the oil supplied did not conform to the specifications for an efficient larvicide. Precautions are now being taken to check all larvicidal oils secured through Treasury Department procurement schedules and other contracts to insure satisfactory larvicidal qualities. Late in August 1942 it became necessary to larviclde approximately 3,500 acres of prolific A. quadrimaculatus breeding area wltliin flight range of important war establish- ments near Washington, D.C. This breeding occurred in the water-cbestnut infested areas of the Potomac River and its tributaries. The dense growth of this plant Fig. 9 Power Duster in Operation (5 H.P.) precluded power spraying or dusting from boats. It was therefore decided to control this area ty means of airplane dusting with paris green. Operations were conducted at Pohick Bay, Accotink Bay, Dogue Bay, Gunston Cove, and Holloway Point. Dusting was started on August 20 and completed on September 26. During this period a total of 19 tons of paris green mixture vas used. MAP SHOWING REGIONS FOR AIRPLANE DUSTING AND AREAS OF OPERATION © ARFAS OF OP F R ATI O N NEWPORT, ARK. WALNUT RIDGE,ARK. NEW ORLEANS,LA. GREENVILLE , MISS. MEMPHIS , TENN . POTOMAC RIVER Fig. 10 Airplane Dusting Regions After the inauguration of this control work, quadrimaculatus densities rapidly declined. Preparations have been made to use airplane dusting more extensively during the 1943 season. The malarious areas of the United States have been divided into four regions and contracts made with commercial airplane dusting companies for work in three of the four regions (figure 10). No bids were received for work in region 2, but the States included are on the northern fringe of the malarious belt where there is less likelihood of need for airplane dusting. Fig. 11 Airplane Dusting on Wolf River Backwater, Memphis, Tennessee By June 30, 194-3* four airplane dusting projects were in operation* These were located near New Orleans, Louisiana; Newport, Arkansas; Walnut Ridge, Arkansas; and Greenville, Mississippi. Operations will begin during the first week of July, 1943* in the Potomac River water chestnut area and on another project near Memphis, Tennessee. Minor drainage and clearing operations incidental to the prosecution of larvicidal control were carried on with the same personnel used for spraying and dusting. Breeding areas were kept under close inspection and only places actually breeding ’’quads11 were larvicided. A variable number of man-hours not needed for larvicidal or clearing work was available each week and was utilized for the digging of relatively small, open earth ditches which served to reduce the magnitude of the breeding area. During the fiscal year 1943, 1,090 miles of minor ditching were completed, resulting in the eli- mination of 5,441 acres of breeding surface. The substantial saving of manpower and critical materials resulting from this work enabled MCWA to undertake control measures without increased appropriation in the many new or enlarged areas which required protection. In addition, 3,975 miles of stream and ditch banks were cleared and 11,671 surface acres were cleared of aquatic vegetation. Data concerning the minor drainage work done in the various States during the year is presented in Table 2. Major Drainage Major drainage projects are classified as follows, in order of priority* Class A. Projects in areas where drainage is necessary for adequate control. Class B. Projects in areas where larvicidal control may be adequate but Is expensive, and where drainage is more economical. Class C. Projects in areas where larvicidal control is adequate and economical but where drainage is part of the long- range control program and where local conditions warrant drainage work. Major drainage was limited to those areas where effective control could not be achieved by larviciding and where the cost of effective larvlciding was so great that drainage was obviously more economical. Such work was not undertaken where it would result in competition for essential industrial and agricultural labor, or for critical equipment. Before major drainage projects could be instituted, it was necessary that project proposals (figure 13) be submitted supported by a plan and profile (figure 15), a quantity estimate (figure 14), a statement of status of easements, a concise project narrative, and clearance from other Governmental agencies involved. MALARIA CUNWOl ilN WAR AREAS P UBL4 C*HL\ LTHJISXVICB 60) Volunteer Building ATLANTA, GEORGIA State SHS? Ate. JilSfcaoB _ Project (Key) —.711) From SCT.1 to Mgr 13 . l»OL PROGRESS REPORT—LARVICIDING AND MINOR DRAINAGE SURFACR TWUriP I Amount Bridies Ditches. Pood*. Man-Hours 4‘ or Ira etc., over 4 1. Larvicidmg | 45 379,300 ' 115 (4) Paris green dusted, lb*. (not mixed) . . — .= .--4==^^=- D.1«M orod _1S3U_ It.. U5 5,125,000 ISO (f) Other jmttoa 6*i*V<>n 50* 532,720 JO Total 479.724 I 9,225,916 619 2. Entomological Inspection Service, man-hours r w ~i Cu. Yo. Amount Man-Houss i. Minor Drainage and Clearing . (a) Ditching, lineal feet 210 HOP 816 (*) Ditch cleaning, lineal feet . . . . (f) Clearing, square feet 41»5PP 175 (i) Other • • • Total Lyn | 4. General Supervision (including General Foremen, Aides, and Engineers, excluding Inspectors), man-hours | 160 j 5. Total Man-Hours (Total 1-4 inclusive) | 2120 | 6. Miscellaneous (a) Total number of men employed (average) men. (h) Field time lost because of rain 3Q. man-hours. (r) Water surface eliminated by incidental ditching —.25LrQPO *q. ft. (i) Maximum period between larvicidal applications days. (#) Zones larvicided 3i is 5 (/) Zones minor drainage -ls..3 (g) Zones inspection only , 7L — Nors.-TTra Iona a w b* f- ALL «rt CHRTIFIID CORRECT Arm Sm firm tor. Pig. 12 Sample Progress Report Larviciding and Minor Drainage Job Description: This job consists of the construction of 600 lin. ft. of French drain together with considerable clearing. The swamp is located at the south end of Camp Quad and the ditch runs through part of the reservation. That portion of the ditch which runs through the reservation aajacent to the barracks is to be lined. It is estimated that this ditch will drain a 20 acre swamp into the Chicago Creek and thus entirely eliminate larvicidlng operations. The swamp is located approximately 400 feet from the barracks area. Easements: All necessary easements have been secured an are on file in the State Health Department. 1. New Ditching: A. Hand 100 Lin. Ft. 200 Cu. Yds. B. Machine Lin. Ft. Cu. Yds. C. Dynamite ....... 500 Lin. Ft. 780 Cu. Yds. 2. Ditch Lining: A. Monolithic 100 Lin. Ft. B. Pre-cast Lin. Ft. C. Masonry ....... Lin. Ft. 5. Underground Drains: A. Tile Lin. Ft. B. French ........ 200 Lin. Ft. John Doe (Signed) Pig. 14 Sample Quantity Estimate Sheet Malaria Control in War Areas O.S. Public Health Service QUANTITIES ESTIMATE FOR MAJOR DRAINAGE PROJECT PROPOSAL State .. Pro j ec t-Albeay #4 Date of Proposal - Jan. 1. 1945 Unit No. 1 )—Non-Labor Costs: (a) Equipment Cars 2 (g) |4/day $0 days $—JjOCUQO Trucks @ $j/day dSJTS 2#1lQQ Concrete Mixers 1 @ $4/day 10 CiSJTS li0-?-QQ Rubber Boot* 2Q..@ 15/pair lQQ*-00- Small Tools _30 .men @ ff/nun _aSD..J?.Q Total Equipment Cost $ ffljO >00 (b) Materials and Supplies Cement—270—-*x. @ $ l.Oj&x. $ - Sand 30-—c. y. @ $1 » #/c. y. li5L».,Q.Q Gravel-30 c. y. @ $2.2f/c. y. Gas and Oil (Lump Scm) 1QQ0_.,00 Office Supplies (Lump Sum) .00. Contingency Fund 30_ - men @ )l/man —30 aQQ- Total Cost Materials and -Sup. $1607.#) (c) Other Non-Labor Cost* OAA Care and Maintenance of Equipment $ Total Other Non-Labor Cost* $ 200 .00 (,) + (b) + (c) TOTAL NON-LABOR COST $27i|7.#) 9—Estimated duration of project months. Page 2 of 2 Fig. 13 Sample Portion of Project Proposal (0 0) C P •H CO P 'gW ? P< P rH tfl At H S 03 O h cr £ o -q At ra tj p o> <5 c x x o oo °a-d a) -P t -5 CO 0} rH fi. rH cO cO cO S B -H cO {>> o *H c3 cd O to B CO eooa) rH O O CO JC .H BP S O 0) ja to 2*8 «*5 to Wherever available, WPA labor and other resources were uti- lized for major drainage work. An average of 2,205 WPA employees were engaged in this work under the tech- nical supervision of MCWA personnel. A considerable number of drainage projects were completed; a few, not finished when WPA ceased operations, were completed with MCWA personnel. Hand labor, dynamite, and draglines were used for drainage work. Generally, drainage was effected by means of open earth ditches. This method was used because the work was of an emergency nature and required a minimum of labor and materials. Furthermore, many of the war establishments are of a temporary character. The use of concrete, brick, or masonry inverts was restricted. Such durable ditch linings were used only where: MALARIA control in war areas 60) Volunteer Building * ATLANTA GEORGIA State . ■>apla Area M*»0O Propel (key) D 5 ttllt 3 Fmm marl minor 15s Mtt,. PROGRESS REPORT—MAJOR DRAINAGE AND CLEARING Amount NM-Nnn 1. Clearing or Brushing, acres X.15 107 2. Channel or Ditch Cleaning, lineal feet 7656 275 3. New Ditching (main ditches and laterals, excluding lining) : a. Hand Lineal feet 776 1218 Cubic yards 3® b. Machine Lineal feet HP- r-T Cubic yarda 2985. Machine-hours 60 C. Dynamite .... Lineal feet WPP .25.— Cubic yards 12Q0 4. Precast Ditch Lining Prepared (not placed) (thickness in.) Square feet completed 1160 68. 3. Ditch Lining Placed ... a. Concrete, square feet .780 b. Masonry, square feet 3QQ c Other, square feet d. Ditch lining placed, lineal feet .* 225 25 6. Underground Drainage a Tile drain, lineal feet b. French drain, lineal feet . . . . . . . «5 ' ZmZ~ZZ 7. Fill Urea 13*000 sq. ft) a Cubic yards 3136 69 b. Truck-hours c. Machine-hours H 8 Sodding or Seeding ... a. Sodding, square feet 150. 16 b. Seeding, square feet 9 Miatellaneoui Work Done . R**OTll* rtw**, #»ch Jt XJ7 b. 1’ L.1 ’’"!!! 10. General Supervision (including engineers, aides, general foreman), man-hours 115 11. Total man-hours (1 to 10, inclusive) VM a Total men employed (professional, subprofeasional, and custodial) . ,. 26 men. b. Field time lost because of rain 21 man hours. c. Water surface eliminated by major ditching and fill 35 ecrea REMARKS* 150 Uo.ft. Of troeMt eoocroto and 75 Uc.fl. 9t tdiSml.JffiTte mtoarj. Doll idtUa coo oonth of eoaelaUen. Nora.—Submit Mfwnic report for each major dum*gt unit. wwijmra^mTOi CERTIFIED CORRECT: Mb Do#, P. 1, .iMlMgE Fig. 16 Sample Progress Report Major Drainage and Clearing. a. The grade was so flat that a smoothly lined ditch was necessary for proper functioning, b. The grade was so steep that ditch lining was necessary to prevent erosion or scouring. c. The ditches formed part of the control system of a permanent establishment, town, or other community where malaria control will be required after the war and where the materials for the ditch lining were contributed locally. On a number of major drainage projects, machinery and power equipment were used for construction of main outlet channels, in most instances, draglines Pig. 17 Dragline Ditching and other heavy construction machinery were employed on a rental basis. Some equipment of this type was secured by transfer from other federal agencies. In some instances the War Department supplied heavy equipment for digging the main outlet canal in extra-cantonment zones. During the spring of 1942 a disastrous tornado hit the Pryor, Oklahoma, war area, destroying houses and uprooting trees, many of which were blown into Pryor Creek. Subsequent heavy rains flooded the area and floated many more trees and much debris into the stream, thereby causing many small impoundments and creating "quad" breeding places within the town of Pryor. Attempts to control breeding through the application of larvicides during the 1942 season were not completely effective. Power equipment was utilized on this project. By using snatch blocks, the largest logs were removed from the stream bed. Many of the stumps and other debris were removed by dynamite. The length of the stream was approximately 8.6 miles, from which a total of 49,000 cubic yards of drift was removed and burned. The breeding places were eliminated. Dynamiting is known to be an economical method of ditch con- struction in suitable situations. The use of this material in the IOTA program has been encouraged wherever applicable, because of the speed and econony with which it can be utilized. Dynamite is readily available and little skilled labor is needed for its use. Depending on soil conditions, a crew of 3 to 10 men can blast from 750 to 3,000 linear feet of ditch per day. It is expected that dynamite will be used even more extensively during the next fiscal year. The efficiency and economy of dynamite ditching is clearly illustrated by the following examples: In July, 1942, the first MCWA dynamite project for construct- ion of ditches was started at Pine Bluff, Arkansas. The project involved the construction of 12,000 linear feet of dynamite ditching and 1,500 linear feet of hand ditching. Approximately 18,000 pounds of 50 percent nitro-glycerine dynamite were used on the project. The cost break-down at the completion of this project showed a unit price of 3B cents per linear foot of ditch and 29.2 cents per cubic yard of excavation. A considerable amount of clearing and incidental work which is not ordinarily encountered made these unit costs somewhat higher than usual. The cost of hand ditching would have been about one dollar per cubic yard. Fig. 18 Dynamite Ditching An interesting example of malaria control drainage was provided by a situation at Jerome, Arkansas. Directly across the highway from the Japanese Relocation Center was a 233-acre impoundment known as Ward’s Brake. The entire area was a potential quadrimaculatus breeding ground. Due to the unusual condition of the lake (shown in figures 19 and 20) it was extremely difficult, if not impossible, to control breeding by larvi- cidal measures. The only feasible methods of control were by airplane dusting or drainage. Investigation indicated that drainage was the most practical method of control. The project was started on January 18 and completed on May 3 by the use of a dragline and dynamite. The job consisted of removing 53>774 cubic yards of earth by dragline at a total cost of $16,362, and the construction of approximately 15,OCX) linear feet of dynamite ditch at a cost of approximately $3,665. Figure 20 is a picture of Ward’s Brake completely drained. At Miami, Oklahoma, a ditch 4,650 linear feet long, 3 feet deep, 6 feet wide at the top and 2 feet wide at the bottom, was constructed with dynamite in only two days. An average of 1.33 cubic yards of earth were moved per pound of dynamite. A major drainage project was started by the WPA at Walterboro, South Carolina, in November, and in January a dragline was assigned to this project. By the end of March only lj miles of ditch had been completed. Test shots indicated the feasibility of completing the project with dynamite, and blasting was started in April. " Two months later the project was completed. It would have required about eighteen months to finish the job with the small dragline available. Another drainage project for the control of about 1,500 acres of breeding area located near Norfolk, Virginia, was completed with dynamite at a total cost of approximately $8,000. The cost of doing this job with power equipment had previously been estimated at $80,000. During the year 448,800 pounds of dynamite costing $55,671 have been used on projects operating in Florida, Alabama, Arkansas, Kentucky, South Carolina, North Carolina, Virginia, and Oklahoma. Prior to November 1942, underground drainage was rather loosely included under the general term ’’drainage” in drainage progress reports. Since that time this activity has been reported separately. From January 1 to June 30, 1943, 7,005 linear feet of underground drains were con- structed. With the increasing shortage of manpower for larvicidal work and ditch maintenance, it is expected that underground drainage will become a considerable factor in the program for the fiscal year 1944* Underground or French drains are easily constructed and well adapted to the MCWA program. Satisfactory drains may be constructed of tile, brickbats, rock, gravel, or poles, all of which are covered ty a layer of leaves, straw, or other filter material and backfilled with earth (figures 21 and 22). Properly constructed drains of this type are Fig. 19 Ward’s Brake - 233 acres of Anopheles quadrimaculatus breeding area located 600 feet from the main entrance of a Japanese Relocation Area - Jerome, Arkansas Fig, 20 Ward’s Brake - three months later after completion of a combination dragline and dynamite major drainage project inexpensive to install and requiri little or no maintenance. Some systems of this type have been reported to give satisfactory service after more than 30 years of use. These systems are parti- cularly efficient in eliminating swamps and marshes produced by seepage outcrops, for subdraining concrete inverts and open earth ditches, stabilizing ditch banks, draining marshes caused by- springs, and providing outlets fo: overflowing artesian wells. Also they are often more acceptable to property owners than are large open-type ditches. Elimination of mosquito breeding places by filling has been effectively utilized in the MCWA program. In several in- stances municipalities have assisted MCWA crews in this work. Street sweepings, tin cans, garbage, and other refuse can be used to great advantage for this work when utilized in conjunction with major or minor drainage projects. For example, the Fig. 21 Underground Tile Drain Fig, 22 Underground Pole Drain lowest portions of swamps and ponds can be filled to ditch elevation, thus making it possible to drain the area effectively. At Jefferson Barracks, Missouri, when efforts to drain a six-acre sink hole just outside the reservation failed, written permission to attempt vertical drainage was secured from the Sanitary Engineer of the State health department. A vertical shaft was sunk and in a relatively short period of time effective drainage was secured. The cost of this project to MCWA was only $770, The military authorities furnished approxi- mately $1,000 in cash, material, and labor. At Jerome, Arkansas, during the construction of the ditch to drain Ward's Brake, it became necessary to lower the elevation of a monolithic culvert since its Fig. 23 Hydraulic Jack and Deadman - Jerome, Arkansas Fig. 24 Cofferdam on Culvert Jacking Project - Jerome, Ark, Pig. 25 Culvert Jacking Project Completed - Jerome, Ark. flow line was 5.8 feet above the proposed grade. Because it was not possi- ble to dig up the roadbed, it was decided to use a hydraulic jack to force a 2411 x 42’ steel culvert through the roadbed underneath the monolithic culvert. A concrete headwall was constructed on both sides of the culvert. Although flood waters and the presence of old concrete under the floor of the culvert added to the difficulty of the job, the total cost of the operation was $54-8, of which $370 was for labor and $178 for material. Figures 23, 24, and 25 show steps during construction. During the fiscal year 1943, 68 major drainage projects were in operation in 13 States and Puerto Rico. About 184 miles of new ditch were constructed, 77 percent by hand, 18 percent through the use of dynamite, and 5 percent with draglines, A total of 1,257,104 man hours of labor were expended on major drainage projects. A tabular summary on the major drainage program by States is presented in Table 3» TABtF) III VCWA MAJOR DRAIHAOK PROJECTS FT?CAL YEAR, 1945 S'l'ATFl Maximum No. of Projects Clearing Channel or Ditch Cleaning Lln.rt. New Dltci Lin. Ft Ing Fill Ditch Pie Lir.!ng ced T7ndr. "ground Drains Total Man Acres Hand Machine Dynamite Cu.Yds. Eq.Ft. Lin.Pt. Lin.Ft. Hours Alabama Arkansas 1 2 49 12? 21 7,85S 50.159 24,600 55,968 26.865 10,0014 60,295 145,000 2,610 502 ::: ::: 62 102,£62 24,624 26,986 Illinois 5 19 59,019 15,825 ... — — —- 15,^05 Kentucky Mississippi Missouri Morin Carolina 4 5 I 10 I 454 9,000 6,P6o 1,160 1,0^7,297 29.525 112,000 5,990 211,^16 59,000 1,625 244 574 10,542 96 20,966 7,642 564 1.514 126 1.890 257 56.c50 52,958 7,574 252,512 5 7,274 10,657 2?. ,c76 166 — — ... 17,442 2BB.4j,R 595.794 fuerto Rico 2 19 , ?7 475 15,290 l4.96.Bil5 10,600 170,512 1*5,567 6,100 52,740 595 22,594 16,562 6,241 4.642 I’e nnessee 5 U2 10,700 — — 967 1 , 1,275 27.765 10 5 54,610 50,106 5,689 1,595 ... ... 6 45.646 Virginia 5 17 56,692 15,297 1)4,960 — 10,960 5.576 l66 21,597 Total 08 1,269 1,6214,602 755,666 144,769 197.644 60,009 57.026 12.554 ■7,005 1,257,104 Insecticidal Control Throughout the 1942 malaria transmission season, a program for destruction of adult Anopheles quadrimaculatus was conducted at Stuttgart, Arkansas, where this vector was breeding abundantly in the extensive rice fields. Since ordinary control methods applied to this large area would have been excessively expensive in relation to the number of people to be protected, it was determined to institute a program of house-to-house spraying on an experimental basis. The houses were sprayed twice weekly with a pyrethrum spray. The aim of the program was to kill engorged mos- quitoes during the parasite development period, thus preventing possibility of malaria transmission. This project is being repeated during the 1943 breeding season. MALARIA CONTROL IN WAR AREAS AREA NO. I BAY CITY ZONES 2 a 3 AIRFIELD S BAY CITY JAN 1943 SUFFOLK COUNTY, STATE Pig. 15 Sample Plan and Profile For Major Drainage Project FEDERAL OR STATE ROADS SWAMP OR FRESH HARSH * R OVERPASS (R R OVER RO.) - R R UNDERPASS (R R UNDER RO> WOODED AREA SALT MARSH SECONDARY ROADS LEVEE LEGEND CONTROL LIMITS — - - • STATE OR COUNTY RIVER OR WIDE STREAM NARROW STREAM OR OiTCM - INTERMITTENT STREAM UNCO DRAINAGE DITCH UNDERGROUND DRAIN LAKE OR POND ( INTERMITTENT POND BORROW-PIT SPRING MCWA IN PUERTO RICO The administration of the MCWA program in Puerto Rico was estab- lished under the direction of the Public Health Service District No. 6 in collaboration with the Insular health department. MCWA integrates with the Array and Navy in the joint planning of intra- and extra-reservation control activities. Through this cooperation there is available to the MCWA program the military equipment, materials, office space, quarters and mess facilities The WPA operated drainage projects in the extra-reservation areas under MCWA supervision. Larviciding at some of the military bases was started by the Insular health department as far back as 1940. The equipment and some personnel' of that department were assigned to the MCWA early in the program. The malaria problem in Puerto Rico is more complex than it is in the States. The mortality rate for 1941 was 124.9 per hundred thousand population. The principal vector. Anopheles albimanus, has considerably different habits from Anopheles quadrimaculatus. It transmits malaria throughout the year. It breeds in almost all types of habitats not only in ponds, swamps, marshes and ditches, but also in the edges of running streams, hoof prints, cart tracks, seepage areas, ground pools, brackish waters, and even artificial containers. Consequently, the scope of control work against Anopheles albimanus is much greater within similar sized areas than is necessary against Anopheles quadrimaculatus. Because it has a greater flight range, the areas under larvicidal control extend 2-| to 3 miles beyond pro- tected areas and are at least 4 times as large as in the States, Tactical and strategic considerations rather than environmental health hazards determine the locations of military bases. At present there are IX) MCWA projects operating in Puerto Rico for the protection of 21 military and naval establishments. Although the majority of military popu- lation is protected against the malaria hazard, a minority has temporary duty in many unprotected places. It is within this minority that most of the residual malaria occurs among the military population. The anticipated life of some of the reservations is temporary or uncertain. Accordingly, larviciding, the chief method of control, is supplemented by major and minor drainage, where adequate reduction of anopheline density cannot be obtained by other means, Paris green has been the principal larvicide. In some cases it was necessary to resort to air- plane dusting. Since natural resting places have not proved suitable for determining Anopheles densities in Puerto Rico, animal baited traps were used primarily. Experiments were conducted which show that suction light traps are adaptable to this purpose and may be used where electric current is available. The density of Anopheles albimanus during 1943 was only 3 percent of that recorded for the 1942 season. For June 1943, at four of the more important military establishments, the incidence of malaria, in- cluding relapses, was only about 20 percent of the same period for 1942. ADMINISTRATIVE DIVISION ADMINISTRATIVE ORGANIZATION ADMINISTRATIVE OFFICER PROCUREMENT ANO SUPPLY SECTION MISCELLANEOUS ACCOUNTS SECTION GENERAL SECTION PERSONNEL ANO ACCOUNTS SECTION PRIORITIES SUPPLIES PROCUREMENT AUTOMOTIVE VOUCHER UNIT ENCUMBRANCE ANO COST ANALYSIS PROPERTY UNIT REPORTS PAYROLL UNIT PERSONNEL UNIT TRAVEL UNIT MAIL AND RECORDS A PROPERLY COORDINATED ADMINISTRATIVE ORGANIZATION MADE POSSIBLE EFFECTIVE MALARIA CONTROL OPERATION 4,000 MEN RECRUITED AND TRAINED OVER 90,000 ITEMS OF SUPPLIES AND EQUIPMENT PURCHASED APPROXIMATELY f 6,500.000 EXPENDED Administration of the MCWA program is under the control of the Executive Office, which is responsible to the States Relations Division of the Public Health Service. Besides the headquarters office of MCWA in Atlanta, Georgia, there are 20 additional offices in the United States which handle MCWA administrative matters for the individual States. In addition, there is an office in Puerto Rico. Men and materials must be provided when and where necessary, and without delay. During the year the Administrative Division of the head- quarters office was charged with the responsibility of recruiting more than 4.000 men and procuring more than 60,000 items of equipment and supply, in addition to more than 500 tons of lime, 140 tons of paris green, and 1.900.000 gallons of larvicides. The shortage of manpower and the problem of priorities added to the difficulties of these tasks. Adequate location records of all property, classified as to types, were kept to insure proper maintenance, usage, and control. Approx- imately 500 automotive vehicles, mostly trucks, were in use during the year. The administrative task of keeping these vehicles operating was increased by the application of gasoline and tire rationing. The accounting system for the control of all funds, except pay- rolls and travel, was simplified during the latter part of the year to insure adequate encumbrance records, monthly cost analysis statements, and prompt payment of vouchers. TABLE IV MCTJA EXPENDITURES FOR FISCAL YEAR 1943 (Pro-rated to the nearest thousand)* BY STATES BY BUDGE! OBJECTS Name of State Amount % Total No. and Name of Object Amount % Total Alabama $188,000 3.0 01 Personal Services $5,092,000 83.0 Arkansas 371,000 6.1 California & Oregon 67,000 1.1 02 Travel 228,000 3.7 District of Columbia 49,000 0.6 Florida 619,000 10.1 05 Transportation 35,000 0.5 Georgia 254,000 4.1 Illinois & Indiana 93,000 1.5 04 Communications 12,000 0.2 Kentucky 137,000 2.2 Louisiana 898,000 14.6 05 Rents, Utilities etc. 29,000 0.5 Maryland 55,000 0.9 Mississippi 268,000 4.4 06 Printing, Binding 12,000 0.2 Missouri & Oklahoma 179,000 2.9 North Carolina 557,000 9.1 07 Other Contractual Services 64,000 1.0 South Carolina 922,000 15.0 Tennessee 179,000 2.9 08 Supplies and Materials 425,000 6.9 Texas 691,000 11.3 Virginia 294,000 4.8 09 Equipment 245,000 4.0 Puerto Rico 319,000 5.2 Totals $6,140,000 100.0 $6,140,000 100.0 Transferred to EH &SA 327,000 327,000 Totals $6,467,000 $6,467,000 * The amounts shown above Include costs of the following, pro-rated proportionately: Headquarters and Districts, Departmental Personal Services, Community Health Education, Blood Slide Survey. EXPENDITURES FOR THE FISCAL YEAR , 1943 PERSONNEL AND ACCOUNTS The Personnel and Accounts Section, composed of the Personnel, Payroll, and Travel Units, controls the flow of men and money for the MCWA program. Through its relationship with State administrative offices, this section handles administration relating to recruitment, appointment, and promotion of personnel; controls travel authorizations; and directs the preparation and handling of payrolls. During the year expansion of this section was necessary to do the increased work in connection with payroll allotment plan for War Bonds, personnel ceilings, and income tax deductions. High labor turnover in the most critical war areas also was a major problem. Approximately $6,000,000 was expended during the year for the pay- ment of salaries, and about $200,000 for travel and the movement of house- EMPLOYEES ON DUTY AND SALARY DISBURSEMENTS BY MONTHS NUMBER OF EMPLOYEES hold effects. The trend of personnel and salary expenditures ty months dur- ing the fiscal year 1945 is indicated on the above graph. Employees were encouraged to continue and increase their partici- pation in the War Savings Bond Campaign. Reports indicate that 77 percent of MCWA employees are allotting 7.6 percent of their earnings to the pur- chase of War Savings Bonds* PROCUREMENT AND SUPPLY The Procurement and Supply Section is responsible for the acqui- sition of supplies, materials, and services other than personal services. Approximately $900,000 was expended during the year for these items. In view of the magnitude of the program, strict control over the flow and distribution of supplies and materials to locations in the field was imperative. A reserve stock of the more common items of equipment and tools was procured during the year from curtailed Federal agencies and lo- cated in the central warehouse in Atlanta for allocation to the States as needed. The Automotive Unit of this section was responsible for the ad- ministrative work in connection with the MCWA fleet of over 600 vehicles. A.'aong the tasks involved were assignment and maintenance of vehicles, gaso- line rationing, accident reports, and issuance of courtesy cards. SPECIAL PROJECTS AND COOPERATIVE ENTERPRISES AEDES AEGYPTT CONTROL PROGRAM Yellow fever, the dreaded "Yellow Jack" of the tropics, becomes an ever-increasing menace in the southern United States with the return of military personnel from fever-ridden areas. A large portion of these service men disembark from planes rather than ships. This gives rise to the com- plicating factor of speedy travel in relation to the incubation period of the disease and the additional hazard of plane-carried living Aedes aegypti mos- quitoes which may be infected. Military planes which land at airports where quarantine services are maintained receive attention equivalent to that INSPECTION CORRECTION given commercial airliners; but many planes land at military airbases where quarantine services are lacking. The history of dengue fever in this coun- try is characterized by in- termittent sudden outbreaks of considerable extent with almost complete prostration of the affected communities. Two of the most recent outbreaks were the epidemic in southern Florida in 1934 which in- volved several thousand cases, and the epidemic in Hidalgo County, Texas, in 1941 in which an esti- mated two thousand cases occurred. Undoubtedly, the disease simmers in areas close to our southern borders and shores where there is a year-round breeding of the insect vector, Aedes aegypti. Dengue, too, could easily be introduced by military personnel returning from endemic sections of the world. EDUCATION Aedes aegypti mosquito control, there- fore, is a most important public health measure. It is especially important from the standpoint of successful prosecution of the war. South Atlantic and Gulf Coast ports of entry daily receive the influx of homeward bound men returning from infected areas. These ports are also centers of heavy military concentration and vital industrial activity. If complete eradication of the infestation cannot be attained economically in these places, the least that should be done is to lower the aegypti population to a level of relative safety. The Aedes aegypti index, a figure indicating the percentage of inspected premises oh which breeding was found, is used as the criterion of aegypti Incidence and as a guide to control operations. Multiple breeding places on a single premise may contribute to a heavy mosquito population in the immediate vicinity, but because of the limited flight range of aegypti. (75-100 yards), wide geographical distribution, as evi- denced by a high index on many premises, is much more dangerous from the epidemic standpoint. Five percent is the empirical threshold which has received general acceptance as the point above which there is a danger of individual cases of disease serving as epidemic foci. Prior to the establishment of the MCWA program, title VI funds were allotted through the Public Health Service and the State health departments to a few municipalities for the control of Aedes aegypti. In order to consolidate all mosquito control programs of the Service under one direction, responsibility for the existing aegypti control programs was assigned to Malaria Control in War Areas. In addition to the programs which were already being conducted at Charleston, South Carolina, and Miami, Florida, and which served as nuclei out of which operations were subsequently extended to other places, a demonstration eradication program was instituted at Key West, Florida. Key West was chosen because of its high aegypti population, its past history of yellow fever, its military importance, and its isolated position which augured well for its protection from re-infestation should eradication prove practical. Four areas in Texas — Houston, Galveston, Corpus Christ!, and Brownsville — were originally selected, and small additional control units were later added at San Antonio and in Hidalgo County. Here the emphasis was placed chiefly on public education. In addition, spot surveys were made at Beaumont, Orange, and Port Arthur, which showed such low indexes that no further activity, other than a lat©-season survey (194-3)> is contemplated. Savannah, Georgia, was selected as a site of operations for a mobile unit. Two mobile units were assigned to New Orleans for a short survey and incidental correction. Eleven municipali- ties were under survey and incidental control at the end of the fiscal year. Except for the Florida cities, public education plays a large part in the control fro gram. Aegypti Control Through Public Education There are two main schools of thought in aegypti control, both of which are predicated on the presence of tropical conditions. Both agree that the only solution to the aegypti problem is eradication, the practicability of which has been demonstrated in the principal cities of Brazil. One school believes, however, that the only method of accomplish- ing elimination is by a concerted, simultaneous attack on every possible type of breeding place in the community from roof gutters to cellar sumps. The other group would first concentrate on the "mother foci", searching out every cistern, shallow well, fire barrel, sump, and similar containers which hold water throughout the entire year. This school would ignore, until the concentrated attack on mother foci has been accomplished, such breeding places as roof gutters which will eventually be flushed out by storms, tin cans which will rust out, flower vases which will be emptied, and other temporary breeding places. They believe that as the mother foci are eliminated "seed" for the non-permanent places will be cut off and incidental breeding in tin cans and flower vases will decrease in direct proportion to the elimination of the mother foci. In fact, continued breeding in vases, cans, and similar containers in an area is considered to be an indication that a mother focus in that immediate area still remains. Observations to date are wholly in accord with this latter procedure as a routine, efficient manner of approach. Under epidemic conditions, where the quickest possible elimination or reduction of adult females is the ultimate goal and where expense and manpower are of secondary importance, the all-out or "shot- gun" procedure is, of course, the only one to adopt. When it is considered that the adult female aegypti seldom travels on her own power more than 100 yards from the con- tainer in which she lived as a larva, it becomes apparent at once that practically everyone breeds his own household supply. Control is an individual problem, or at most a community problem, which can be solved by individual effort without the need for expensive equipment or large appropriations of public funds. All that is needed is a desire on the part of every individual to do his share in making his community a safer and healthier place in which to live. In the Texas, South Caro- lina, and Georgia projects, emphasis has accordingly been placed on the educational phases of the program. Epidemic-Type Control at Key West In Florida, the Key West project is being carried on with all the services that would be inaugurated in the event of an epidemic. Inspectors visit each room of every dwelling and business establish- Personnel - 45 A complete aegvcti program, including interior and exterior inspections and special crews for each supplementary service, such as laryielding, distri- bution of gambusia minnows, roof gut- ter inspections, clean-up and mari- time inspections. The inspection cycle his averaged about twelve days; hence, the index follows the actual aegyptl incidence very closely. ment in the city approximately once a week; every potential mother focus in the city is numbered and visited once a week for appro- priate treatment; all roof gutters are in- spected and cleaned at least once a month; all boats in the harbor are inspected at weekly intervals; vacant lots overgrown with vegetation are cleaned and search is made for breeding containers, hidden wells, and cisterns; tin cans are methodically collected; and the discovery of indoor breeding is followed immediately by aerosol spraying of the premises. When the Key West project was started in June 1942, the index of breeding was 38 percent of the properties inspected. Looking back on this original survey, the men who made it are confident that if they Personnel - average 10 Very small staff doing spot check in- spection-corrections only. Emphasis on public education and cooperation. Summer indices reflect exterior indices; winter indices reflect interior indices. Em- phasis pieced on elimination of perma- nent "mother foci’ breeders during winter months. had known the city as well then as they do now the index would have been well over 50 percent* By late summer, when breeding should have been high, the index had fallen to less than 3 percent and by June 1943 it was hovering around 1 percent, with few if any adults escaping to perpetuate the breed. It is hoped that by late summer it can be announced that aegypti mosquitoes have been eliminated from Key West. If such is the case, it will be the first instance of aegypti elimination from a North American by control methods. Six Projects in Texas The results of the educational work supplemented by expert inspection and the incidental correction that accompanies Personnel - average 6 Small staff for inspectorial duty. Indices reflect ex- terior breeding only. In- spectorial activities sus- pended during winter months to concentrate on eliminat- ing permanent "mother foci" breeders. Emphasis on pub- licity and public education. the inspections, has been surprisingly gra- tifying. For instance, in Houston, a city of 450,000 people, the paid inspection staff during the 1942 season consisted of only six inspectors. If operations in Houston had been conducted on the same basis as in Key West, with interior and ex- terior inspection of each premise on a schedule approaching complete coverage of the city each week, and with all the inci- dental special services of an anti-epidemic campaign, the task would have required 800 employees. By interesting school children, luncheon clubs, firemen, and other organized groups, and by press releases, radio, and movie contacts, the index of premises breeding aegypti was held at a figure con- Personnel - average 6 Small inspectorial staff j making exterior inspections I only except during winter | months when interior inspec- tions were made. Elimina- •on of permanent 'mother foci* breeders during win- ter months. Extensive pub- lic education program. Personnel - 4 Small inspectorial staff; general public cooperation. Summer indices reflect ex- terior breeding only, win- ter indices reflect in- terior breeding only. sistently below 5 percent. All of the other projects in Texas — Galveston, Corpus Christ!, Brownsville, San Antonio, and Hidalgo County — are being conducted on this basis. Major emphasis is on education and public cooperation through individual effort. This is augmented by the efforts of an other- wise entirely inadequate staff of inspectors. During the winter months the personnel on the Texas projects transferred their energies to elimination of permanent mother foci such as cisterns, and eliminated more than a thousand of them by sealing, screening, or filling. Cooperative Project at Miami Miami, Miami Beach, and some of the surrounding territory are critical areas from the quarantine standpoint because of the key air fields in the vicinity. Before the war, the Public Health Service supple- mented the appropriations of the Dade County Anti-Mosquito District with title VI funds allocated through the State health depart- ment to aid in the control of aegypti mosquitoes. With the inauguration of aegypti control by MCWA, most of the financial responsibility for the aegypti portion of the Miami program was assumed by MCWA in cooperation with theFlorida State Board of Health as in the case of Key West. The staff was augmented and the director of the Dade County district continued to direct the local work. The inspection and correction program was limited to outside premises except in the case of establishments open to the public. The average breeding index for the calendar year of 1942 was 4.4 per- cent for the entire area. Judging from experience in other cities it is probable that this figure would have been nearly doubled if interior inspections in the residential areas had been included. Such an index is too high for safety, but the encouraging note is that five special areas including four important air fields, their surrounding communities, and the extensive military establishments, all of which were inspected both inside and out, showed an index of only 1.07 percent. Furthermore, by May 1$, 1943, the gross index, includ- ing about 13 percent of premises inspected inside and out, had fallen to barely more than 1 percent. Personnel - 25 City-wide program of exterior inspec- tions on six weeks cycle. Special military areas, both interior and ex- terior inspections, on ten day cycle. Charleston Program Augmented Charleston, too, had been receiv- ing title VI fluids through the South Caro- lina State Board of Health to aid in the con- trol of aegypti mosquitoes. In August 19-42 this project was included in the MCWA pro- gram and two entomologists were assigned to direct the local inspection staff. For the period August 1 to November 30 the average index for outside inspections only was 2.5 percent. From December 1 to June 30, 1943 the index was consistently below 1 percent, reflecting the fact that Charleston is near the northern limit of the natural range of the species. A little work at Charleston pays surprisingly large dividends. Careful inspection under skilled supervision such as is now being carried on may very well pro- duce elimination at this point even though the inspectional staff of 15 men is probably much too small to cover adequately as large a city as Charleston. _ Personnel - average 20 Eitprlor Inspections only * on jslx weeks cycle. Spot chicks on interior breeding. Mobile Units at Savannah and New Orleans In March, 1943y a survey and incidental correction program was instituted at Savannah with headquarters at the Henry Rose Carter Memorial Laboratory, Control here is more difficult than in Charleston because of the lack of previous work and the increased biological problem incident to location of the area. Winter breeding apparently is present in Savannah, with approximately twice as much interior as exterior breed- ing. At both Charleston and Savannah, an organized educational effort is being developed in the school system to utilize the program of the Victory Corps curricula. The aegypti campaign lends itself particularly well to this program as there Ii~ah Almost perfect opportunity for edu- cation to be translated into constructive action. The effort is being watched with interest as an experiment in the training and utilization of students in intelligent participation in community health programs. During April a group of 20 inspectors initiated a survey of New Orleans, historic gateway of yellow fever into the United States. During the next fiscal year this project will continue as an inspection- correction program with considerable reliance on public education and cooperating groups. So far, the New Orleans public has shown exceptional interest in the undertaking. A well-devised plan has been developed for utilization of the 10,000 OCD block wardens for inspection and educational activities in case of an actual outbreak of the disease. Operation of the aegypti program has demonstrated in a number of representative municipalities the possibility of achieving effective control and possibly even of eliminating this species. In every case, except Key West, the work has been kept within a financial range that will permit its continuation by the municipality. Men and Materials for Epidemic Control It can easily be seen from the above that the MCWA Aedes aegypti program, which is designed to protect only war projects, cannot assume responsibility for protecting continental United States from the appear- ance of yelloYf fever or dengue by eliminating aegypti mosquitoes or reducing them to a point below the ’’threshold of sanitary importance” at all places where the viruses may possibly be introduced. In fact, the chances are that if either of these diseases does become epidemic it will be at some point where the MCWA program has not been put into effect. As a result of this program there is now a trained force of personnel with full working equipment capable of being marshalled at the request of local or State authorities at any point in the southern States within twenty-four hours after either of these diseases is reported. Working outward in expanding circles from centers of infection, there is no reason why there should be an aegypti mosquito left within seven blocks of the focus at the end of the first day’s operations. The existence of this unit, along with medical precautions such as vaccination, early diagnosis and adequate care of the sick, and an educational campaign to advise the lay public of the necessary pre- cautions, makes it likely that any outbreak of yellow fever or dengue would be brought under control quickly and efficiently. DOG FLY CONTROL IN 7.rAR AREAS OF FLORIDA FLORIDA COUNTIES IN WHICH DOG FLY CONTROL PROJECT WAS IN OPERATION DURING 1942 SEASON Fig. 27 Extent of Control Area Fig. 28 Spraying Breeding Grounds The Bureau of Entomology and Plant Quarantine of the United States Department of Agriculture and the Public Health Service, in accordance with a "memorandum of understanding" dated August 1942, cooperated in conduct- ing a dog fly control program for the protection of military activities in northwestern Florida. Funds for the operation of the project were allocated by the United States Array Air Forces. The area covered by con- trol activities is shown in figure 27. Dog flies (Stomoxys calcitrans), known in most parts of the country as "stable flies" breed from August to November in this area in deposits of marine grasses on the shores of bays and sounds. At military bases in this region many of the activities are conducted in the open and in places where great numbers of flies may be concentrated by land breezes. If many flies are present it is impossible to conduct normal outside activities because of severity of the insect’s bite. Control was effected by treating the grass deposits with 25 per- cent creosote in sea water. The mixture was applied at high pressure from spray machines mounted on small barges and towed near the shoreline (figure 28). Spraying operations began on August 18 and ceased on November 5, 1942, during which period 1,222,950 gallons of spray were applied to 605 miles of grass distributed along a shoreline of 922 miles. Eight major military establishments and numerous smaller ones such as Civil Air Patrol fields and recreation camps were protected by this project. Incidental to the military value of the program was the inestimable benefit to civilian activities throughout the area, many of which’ are devoted to the war effort. The total cost of the program, including the purchase of a large part of the equipment, was approximately $155,000. The success of the project is demonstrated by the low dog fly counts obtained during the course of the control activities. Additional evidence is afforded by statements by officials of various military bases who affirm that the program accomplished its objective and that military activities functioned without interruption throughout the dog fly season. BLOOD SLIDES FOR THE ARM! At the outbreak of the war, very few medical schools in this country were well equipped for laboratory study of parasitological diseases. Therefore, under the leadership of several groups, a center was established at the Army Medical School in December 1942 to assemble parasitological materials and redistribute them to all medical schools and other professional training schools in the country. Malaria materials were so scarce that it was feared months would elapse before adequate collections would be made. In collaboration with the Malaria Investigations Laboratory in Columbia, South Carolina, men and materials were supplied to make enough positive blood smears to relieve the shortage. Approximately 28,000 slides of the three species of malaria plasmodia were furnished to the Army Distributing Center for Parasitological Materials. Most of these slides have been sent to schools where they were urgently needed to train medical men for the armed forces. TRAINING AND EDUCATION With the tremendous turn over in personnel (60% during the fiscal year), it became increasingly obvious that one of the bottle- necks of the MCWA program would be trained personnel. The only solution was the development of a sound in-service training program, utilizing the facilities of MCWA for training new personnel and for continuing the training of certain persons already employed. Plans were developed under the guidance of the Medical, Engineering, and Entomological Sections, Phis training program is administered by the Executive Office in order that it may combine all three professional points of view and thus serve ill sections equally. The training course which was developed presents basic malaria Problems and MCWA methods of control by means of a one-week classroom course equally suitable for any of the professional or sub-professional trainees. Field training to supplement the basic course is provided in iccordance with specific needs which are determined by an analysis of the rork the individual will perform and the type of knowledge and skill that Ls necessary. With the decrease in experienced manpower available for teach- ing and with a marked increase in the number of trainees, the need for devising efficient training techniques became more and more apparent. The obvious answer was the use of more visual and auditory materials since these are recognized as better substitutes for personal teaching than the printed page. An attempt to collect sufficient materials of this type revealed an extreme shortage and made it necessary to develop means of producing such essential training aides. This was done through the various production units of the Division of Sanitary Reports and Statistics. Similar materials were also produced for the Community Edu- cation Program. Care has been taken to utilize all available materials and to avoid duplication. To this end, meetings were held with other agencies interested an the production of visual materials concerning malaria. These agencies agreed to keep one another informed about their activities. ' The well-equipped photographic laboratory in the Malaria Investigations Laboratory in Columbia, South Carolina, was, with little added expense, turned into a photographic production unit. The Tennessee Authority had several thousand feet of unedited film which con- tained much basically valuable technical material. Through a coopera- tive agreement facilities were set up for editing some of this film into concise units which could be used for instructing the MCWA technical staff. Similar types of cooperative enterprises with other organizations are contemplated. Scripts were written for several motion picture films and film strips. Field shooting of two films has been completed and a third is in progress. The Graphics Section of the Division of Sanitary Reports and Statistics, cooperating with MCWA, is preparing a series of drawings to be used in a film strip. The production schedule calls for making sound and silent films in black-and-white and technicolor. A library of slides, film strips, and photographs for in-service training and lay education is being assembled. COMMUNITY EDUCATION FOR MALARIA CONTROL Complete protection of either troops or war workers is im- possible if they spend much time in uncontrolled malarious areas. Even- ing walks in areas five to ten miles from cities and camps are common. War workers and military personnel sometimes live alone or in small groups away from protected zones. The need for reducing or keeping low the endemic malaria reservoir in these wider areas led to the development of the Community Education Program. The effects of such a program — the action of residents of the broader zones in fighting malaria — is a safeguard against rising rates which will influence the immediate control zone. In a lesser degree it is similar in effect to the main job. An experimental program in 1942 was planned in collaboration with the Division of Sanitary Reports and Statistics and several State so health officers. The experimental program was limited to twenty-six counties in seven States, Assistants in health education, principally school teachers, were recruited on recommendations of local health officers. The twenty- six persons employed received a ten-day intensive training course in malaria and in the techniques of community education, effective methods of leading people to face, study, and solve their own problems. They returned to their respective communities to carry on malaria education as regular members of the local health department. Since ths effective- RESULTS OF COMMUNITY EDUCATION PROGRAM -1942 PEOPLE LEARNED ABOUT MALARIA THEY DID SOMETHING ABOUT IT MEETINGS 1,050 ATTENDANCE 38,648 I PERSONAL CONTACTS 10,487 1 DISPLAYS AND EXHIBITS 83 > NEWS ARTICLES 362 RADIO PROGRAMS 63 HOUSES SCREENED 468 HOUSES - SCREENS REPAIRED 1,529 PONDS OR DITCHES CLEANED 139 PLACES SPRAYED, DUSTED, OR OILED 796 of the MCWA control program is judged by vector control, the community education must be judged by how much the people themselves do to control mosquitoes. These results are indicated bn the accompanying chart. The contributions made by the educational program reach beyond the immediate observable effects. Among them ares A firmer entrench- ment of the position of the County health department, a better cooperation of schools and health departments, and cariy-over into the schools by the teachers when they return. The effect of this program on establishing comprehensive health education programs in several health departments and many school systems; the demonstration of what can be done in health edu- cation in counties with small budgets; stimulating people to face their own problems and do something about them; the increased likelihood that local groups will continue malaria control programs after emergency funds are withdrawn; and the successful demonstration of democracy at work in the realm of communities facing their health problems—are all contribut- ions which in broad perspective may be as important as the direct contri- bution to malaria control efforts. Since State and County health officials were generally enthusi astic about the results, this year 92 educators were employed in as many counties in 13 States. Following the 1942 plan they were given their training and began their work Just as the fiscal year closed. COMMUNITY EDUCATION FOR MALARIA CONTROL IN WAR AREAS ORGANIZATION OF 1942 PROGRAM U. S. PUDL1C HEALTH SERVICE STATES RELATIONS DIVISION RimiOH OF SAHIT ART REPORTS A STATISTICS RATIONAL IRSTITITE OF REALTN MALARIA CONTROL IN WAR AREAS , FIELD ACTIVITIES IN HEALTH EDUCATION MALARIA IRVESTMATIORS STATE M.C.W.A. OFFICE STATE HEALTH DEPARTMENT STATE HEALTH EDUCATION SECTION LOCAL M.C.W.A. OFFICE LOCAL HEALTH DEPARTMENT INTENSIVE PRELIMINARY TRAINING COURSE HEALTH EDUCATOR FUTURE SCHOOL HEALTH EDUCATION PROGRAMS HEALTH DEP'T CLINICS EDUCATIONAL GROUPS COMMERCIAL GROUPS WELFARE GROUPS OTHER MEETINGS RELIGIOUS ORGANIZATIONS WOMEN'S ORGANIZATIONS YOUTH ORGANIZATIONS FARM ORGANIZATIONS INTERESTED INDIVIDUALS FRATERNAL SOCIETIES SOCIAL CLUBS ClviC CLUBS THEATERS INDIVIDUAL AND COMMUNITY DEMOCRATIC ACTION FACING AND STUDYING LOCAL MALARIA PROBLEMS GROUP AND INDIVIDUAL MALARIA CONTROL ACTIVITIES PROTECTION OF HEALTH OF MILITARY PERSONNEL AND WAR WORKERS MALARIA CONTROL IN WAR AREAS 1942 - 43 PART III SMd «— MC WA OPERATES IN EACH STATE AS A COOPERATIVE ENTERPRISE BETWEEN THE PUBLIC HEALTH SERVICE AND THE STATE HEALTH DEPARTMENT. L E G E N D INSPECTION LARVICIDING a MINOR DRAINAGE AIRPLANE DUSTING MAJOR DRAINAGE DYNAMITE DITCHING MACHINE DITCHING VERTICAL DRAINAGE AEDES AEGYPTI CONTROL \/ WAR ESTABLISHMENTS PROTECTED AS OF JUNE 30,1943 ” (INCLUDING 17 IN KANSAS AND 1 IN OREGON) Note Symbols on state maps in this section are arranged on a county basis STATE OF ALABAMA DEPARTMENT OF PUBLIC HEALTH MONTGOMERY B. F. AUSTIN. M. D. STATE HEALTH OFFICER In the vicinity of war estab- lishments in the State of Alabama approximately 24 miles of hand ditching were completed by MCWA during the past year. This, with about two miles of dynamited ditch, resulted in the permanent elimina- tion of many mosquito breeding areas. Completion of major drainage work in one War Area eliminated need for further control there and in other areas reduced necessary control op- erations very radically. A total of 472 acres of water surface was treated with an average of 25 gal- lons of oil per acre, and small scale vegetation clearing operations were carried out. In all 188,105 man-hours of labor were expended for both major drainage and larviciding. state health officer BURTON F AUSTIN M.D. BUREAU OF SANITATION STATE OFFICE M.C.W.A. 14 WAR AREAS 64 WAR ESTABLISHMENTS PROTECTED B. F. Austin, M. D. State Health Officer. W. B.G RAYS ON,M.D. STATE HEALTH OFFICER BOARD MEMBERS E .D.McKNIGHT.M.D J.G. GLADDEN, M.D. M.E.McCASKILL.M.O. F.O.MA HON V, M.D. W.G.H O D G E S, M.D. THOS.WILSON.M.D. L.D. DUNCAN, M.D. Little Rock Achievements by MCV.A in Arkansas during the past year included the economical construction of 12 miles of dynamited ditch. In one War Area a small crew using dynamite removed 20,000 cubic yards of excavation and constructed 6,000 lineal feet of ditch at a total cost of $8,000. The use of a dragline, if such had been possible in the swamp, would have cost about $20,000. One major drain- age project involving the use of a dragline was completed and A6 miles of ditch were excavated by hand. Wa- ter surfaces totaling 9,650 acres in the vicinity of war establishments were treated with paris green and oil. The clearing of over 1,000 a- cres was accomplished to facilitate larviciding. Recently airplane dusting with paris green of large rice field areas near Walnut Ridge and Newport was started. The MOW A work was accomplished with the ex- penditure of only 324,045 man-hours of labor. STATE HEALTH OFFICER W.B. GRAYSON M.D. BUREAU OF SANITARY ENGINEERING STATE OFFICE MCW.A. 17 WAR AREAS 63 WAR ESTABLISHMENTS PROTECTED W. B. Grayson, II. D. State Health Officer STATE OF CALIFORNIA department of Healtl} DIRECTOR OF PUBLIC HEALTH WILTON L.HALVERSON M.D BUREAU OF SANITARY ENGINEERING STATE OFFICE NICW.A. 4 WAR AREAS H WAR ESTABLISHMENTS PROTECTED In the State of California the campaign against Anopheles freeborni. the vector of malaria in that state, involved the treatment with oil of 2,5H acres of water surface and the construction by hand of over 9 miles of ditch. A total of 1A7 acres of water surface was eliminated and a nearly equal extent cleared of vege- tation. Air fields at Porterville, Vi- salia and Merced and a congregating center at Marysville for troops from Gamp Beale were included in the pro- gram. Inspection at Hammond General hospital at Modesta returned data that indicated the necessity for con- trol next year. Director of Public Health GOVERNMENT OF THE DISTRICT OF COLUMBIA OFFICE OF THE HEALTH DEPARTMENT The District of Columbia shares with Virginia and Maryland the problem of controlling mosquitoes in the water chestnut growth in the Potomac River, Last year 3,500 acres of water chestnut were dusted with paris green by airplane and the same means of control will con- tinue to be utilized, since it is the only practicable method of effecting control. The work was performed at a very low unit cost per acre. Other control work around the Capital of the Ration included about 22 miles of hand ditching and the oiling or clearing of small water surface acreages. The above work was performed with 41,883 man hours of labor. HEALTH OFFICER GEORGE C. RUHLAND M.D EPIDEMIOLOGIST AREA PROJECTS I WAR AREA 23 WAR ESTABLISHMENTS PROTECTED \ \ \ George C. Ruhland, M. D. \1 Health Officer WILLIAM PARR, PH. G. , MEMBER TAMPA HERBERT L. BRYANS, M. D., PRESIDENT PENSACOLA ROBERT B. MclVER, M. D.. MembCi JACKSONVILLE Unarh nf Hralltj POST OFFICE BOX 210 HENRY HANSON. M.D., STATE HEALTH OFFICER JACKSONVILLE STATE HEALTH OFFICER HENRY HANSON M.O BUREAU OF MALARIA CONTROL STATE OFFICE M.CW.A. 22 WAR AREAS 91 WAR ESTABLISHMENTS PROTECTED In the State of Florida over 182 miles of hand ditching was accomplished in the past year—the greatest amount done in any State on the IICWA program. Florida also led the states in the extent of breeding water surface permanently eliminated, which has already ef- fected a significant reduction in man power required to continue con- trol in these areas. Dynamite was used in the construction of about 9 miles of ditch, and 9,365 acres of water surface were treated with mosquito larvicldes. At Key West the campaign against the Yellow Fever mosquito reduced the Aedes aegyptl index from 29 percent to only one percent. At Miami, Aedes aegyptl control was concentrated around military zones• Henry Hanson, M. D., State Health Officer. STATE OF GEORGIA DEPARTMENT OF PUBLIC HEALTH T. F ABERCROMBIE, M. D , DIRECTOR ATLANTA In Georgia A- mtiliffla.Cttlatug was controlled primarily through the use of paris green as a larvi- cice. A highly perfected and integrated system of entomological and operational reports is in use in this state. In all, during the past year over 15,120 acres of water surface were dusted. In addition over 42 miles of ditching was accomplished by hand, and over 352 acres were cleared of aquatic vegetation. Altogether 257 man-hours were expended in work around war establishments. In Savannah, headquarters for the AflAMLAMaPlI control unit were set up in the Henry Rose Carter Memorial Laboratory, named for the Public Health Service pioneer in the study of Yellow Fever. STATE HEALTH OFFICER TF ABERCROMBIE M.D. DIVISION OF PUBLIC HEALTH ENGINEERING STATE OFFICE M.C.WA. 17 WAR AREAS 93 WAR ESTABUSHMENTS PROTECTED T. F. Abercrombie, M.D. Director STATE OF ILLINOIS DWIGHT H. GREEN, GOVERNOR DEPARTMENT OF PUBLIC HEALTH SPRINGFIELD ROLAND R. CROSS, M. D. DIRECTOR H. L. PSTTITT, M. O. ASSISTANT DIRECTOR ADDRESS ALL CORRESPONDENCE TO THE DIRECTOR Illinois lies on the border of the malarious section, but the A. guadrimaculatus population was high and the malaria hazard in cer- tain war areas was deemed sufficient- ly great to justify control work. Last year over 5 miles of hand ditch- ing was accomplished and approximate- ly 600 acres of water surface was treated with oil or paris green. In one area in close proximity to an Army air field on which pilots were being trained, a small amount of ex- cavation (only about 70 cubic yards) resulted in the elimination of the greater part of a prolific quad breeding place. In addition about 84 acres were cleared of aquatic vegetation. The above operation en- tailed the expenditure of 36,821 man-hours of labor. DIRECTOR OF HEALTH ROLAND R. CROSS M.D. DIVISION OF SANITARY ENGINEERING STATE OFFICE M.CWA. Director 14 WAR AREAS 94.WAR ESTABLISHMENTS PROTECTED State of Indiana STATE BOARD OF HEALTH Indiana is one of the states lying on the border of the malar- ious portion of the United States, and the MCWA program in that state consisted mostly of inspection to detect any outbreak of malaria or malaria mosquitoes. In the single operational area in the state, how- ever, over a mile of hand ditching was accomplished, and breeding sur- faces totaling 101 acres were treat- ed with larvicides. A total of 21,920 man hours of labor were ex- pended. STATE HEALTH COMMISSIONER THURMAN B. RICE MD. BUREAU OF SANITARY ENGINEERING STATE OFFICE M.C.W.A 9 WAR AREAS WAR ESTABLISHMENTS PROTECTED 1s (£- Thurman B. Rice M.D. State Health Officer THE HEALTH OF THE PEOPLE IS REALLY THE FOUNDATION UPON WHICH ALL THEIR HAPPINESS AND ALL THEIR POWERS AS A STATE DEPEND. —DISRAELI. We Want a League,Offensive and Defensive,With Every W ell-W isher of Kentucky and Her People State Department of Health of Kentucky A. T. McCORMACK, M. D., Stale Health Commissioner. 620 South Third Street. LOUISVILLE, KENTUCKY, In the campaign against Anopheles quadrimaculatus in Kentucky during the year just past, MCWA larvicided about 2,000 acres of water surface, 23,138 gallons of oil being used. In addition about 10 miles of hand ditching was ac- complished, and 2,350 pounds dyna- mite was used in the excavation of 1,800 linear feet of ditch. A total of 155,555 man-hours of labor was required to conduct the MCWA operations around war establish- ments in Kentucky last year. STATE HEALTH COMMISSIONER A T. McCORMACK M.D. BUREAU OF SANITARY ENGINEERING STATE OFFICE M.C.W.A. 6 WAR AREAS 48 WAR ESTABLISHMENTS PROTECTED A. T. He Co mack State Health Comrriissloner DAVID E. BROWN, M. D. STATE HEALTH OFFICER DEPARTMENT OF HEALTH CIVIL COURTS BUILDING Nrfai (Drirons PRESIDENT STATE BOARD OF HEALTH DAVID E. BROWN MD. During fiscal year 1943* MCWA treated a total of 61,946 acres of breeding water in Louisiana with oil. This constituted the great- est acreage larvicided by any state included in the program and more than three-quarters of a million gallons of oil were used for this purpose. In addition large breed- ing places were eliminated by al- most 105 miles of ditching and a considerable amount of vegetation and debris was removed* Recently an airplane dusting project was initiated at New Orleans and two more will be begun in the near future. 2,000 acres of breeding surface in close proximity to war establishments will be treated with paris green in this manner* During the year an Aedes aegypti unit started control in New Or- leans, the historic gateway of Yellow Fever* DIVISION OF PUBLIC HEALTH ENGINEERING STATE OFFICE M.CW.A. 9 WAR AREAS 56 WAR ESTABLISHMENTS PROTECTED 4k*u it,m tatP IBoarft of Health of &o«tlj (Carolina (Colombia, fc. <5. state health officer JAMES A. HAYNE M.D, Malaria control around war establishments in South Carolina involved the treatment of about 12,29S acres of water, both oil and paris green being used as lar- vicides* The MCWA program coraplet- ed more than 100 miles of hand ex- cavated ditch and blasted an addi- tional 9 miles with dynamite. In one case the drainage of a large prolific quad, breeding area in close proximity to an air field which would have required IS months to drain with a dragline was finish- ed in about 60 days through the use of dynamite. Durable lining was installed in more than a mile of ditch, the most of any state in the MCWA program, and 6,100 linear feet were ditched with machinery. Over acres of water surface was eliminated by major and minor drainage and veg- etation was cleared from 2,636 acres. An Aedes aegypti control program was initiated in Charles- ton and no exterior breeding was found in March or April. DIVISION OF PREVENTABLE DISEASES STATE OFFICE M.C.W.A. 23 WAR AREAS' 101 WAR ESTABLISHMENTS PROTECTED f / JAMES A. HAYNE. M.D., DR.P.H. ( / Secretary and state Health officer JOHN M. LEE. M.D., CHAIRMAN. NASHVILLE OREN A. OLIVER. D.D.8., VICK CHAIRMAN. NA8HVILLK J. R. THOMPSON. JR.. M.D., SECRETARY. JACKSON L. F. MITCHELL. PH.6.. NASHVILLE R. B. WOOD. M.D., Knoxville W. K. VANCE. JR.. M.D., BRISTOL MRS. FERDINAND POWELL. JOHNSON CITY T. R. RAY. M.D., SHKLBYVILLK W. L. RUCKS. M.D., MEMPHIS PUBLIC HEALTH COUNCIL W. C. WILLIAMS. M.D. COMMISSIONER OF PUBLIC HEALTH DEPARTMENT OF PUBLIC HEALTH NASHVILLE STATE OF TENNESSEE During the year the MCV«A pro- gram in Tennessee controlled A.quad- rimaculatus production by oiling waters totaling 3,310 acres in ex- tent, A considerable acreage of water was eliminated by 27 miles of hand ditching, and 387 acres were cleared of vegetation. 1,275 feet of durable ditch lining was placed. The above efforts involved 168,328 man-hours of work by MCWA personnel. A project for the control of breed- ing in flooded areas near war es- tablishments north of Memphis by means of airplane dusting of paris green was recently initiated. COMMISSIONER OF PUBLIC HEALTH W.C.WILLIAMS M.D. DIVISION OF PREVENTABLE DISEASES STATE OFFICE MQW. A. y\(^XJt^JJULAJubJ Commissioner 10 WAR AREAS 69 WAR ESTABLISHMENTS PROTECTED ——■ ■ ———, ■ i '-fiulJ&S S'-fATS iiPAill) Di‘ Geo w Cox , m d State: health ofticer AUSTIN) Texas is unique among the states included in the MCWA pro- gram in that it is necessary to control two dangerous malaria vectors. In addition to Anopheles quadrimaculatus. a second species. Anopheles albimanus« is found in numbers in the lower Rio Urande valley. During the past year in Texas, 13,143 acres of water sur- face were treated with larvicides. Over 325,000 gallons of oil and 1,500 pounds of paris green were used, hand ditching of 156 miles was completed permanently eliminat- ing well over 1,200 acres of mos- quito breeding waters, and clear- ing of vegetation from about 1,070 acres was accomplished. In all 641,127 man-hours of work were ex- pended, Aedes aegyptl control was initiated in the lower Rio Grande valley and near Corpus Christi, Houston and Galveston. Through public education and cooperation notable Aedes aegypti population reduction was accomplished STATE HEALTH OFFICER GEORGE W. COX M.D. BUREAU OF SANITARY ENGINEERING STATE OFFICE M.C.WA 14 WAR AREAS 140 WAR ESTABLISHMENTS PROTECTED ,L Geo, V. Cox( M. Dr~ State Health Officer Commonwealth of Virginia Department of Health Richmond I C. Riggin, M D Commissioner Virginia, with Maryland and the District of Columbia, is concerned with the prevention of quad breeding in growths of water chestnut in the vicinity of war establishments along the Potomac River, During the past year it was.necessary to control 3,500 acres by airplane application of paris green. Other work by MCWA in Virginia was concentrated in the Norfolk-Portsmouth, Virginia Beach and Peninsula areas and included 10? miles of hand ditching. A notable achievement was the dynamite drain- age of a series of heavily breeding marshy areas at Dam Neck. Hie use of dynamite resulted in a saving of $72,000 as compared with the esti- mated cost for use of a dredge. More than 21,280 acres of water surface were treated with oil and paris green and over 976 acres were cleared of vegetation. COMMISSIONER OF HEALTH I.C. RIG6IN M.D BUREAU OF SANITARY ENGINEERING STATE OFFICE M.CW.A 6 WAR AREAS 83 WAR ESTABLISHMENTS PROTECTED State Health^o^^ssioner NFORMATION IjECHNICAL CT RAINING ATTACK MOSQUITO LARVAE OILING DUSTING DRAINING ATTACK IGNORANCE BREAK THE MALARIA CHAIN ATTACK MAN MOSQUITO ATTACK ATTACK THE PARASITE ATTACK ADULT MOSQUITOES MOSQUITO - PROOFING SPRAYING REPELLENTS ATTACK MAN DRUGS MALARIA CONTROL IN WAR AREAS 1943-44 FEDERAL SECURITY AGENCY U S. PUBLIC HEALTH SERVICE MAP SHOWING OPERATIONS OF MALARIA CONTROL IN WAR AREAS U S. PUBLIC HEALTH SERVICE OFFICE OF MALARIA CONTROL IN WAR AREAS ATLANTA, GEORGIA SCALE OF MILES LEGEND AREAS WHICH HAVE CONTROL ACTIVITIES IN OPERATION AREAS HAVING LIMITED SEASONAL CONTROL OR SURVEILLANCE AEOES AEOYPTI CONTROL PROJECTS MALARIA CONTROL IN WAR AREAS 1943.44 The Malaria Control in War Areas program, established in March, 1942, is a joint undertaking fay the U. S. Public Health Service and State Health Departments de- signed to reduce the hazard of malaria transmission in extra-cantonment zones of military areas and around essential war industries. It complements similar acti- vities of military authorities within reservation limits. Operations are di- rected against the malaria moscruito. Malarious areas are determined by epidemi- ologists, vectors are surveyed and their breeding areas located fay entomolo- gists, and control methods are decided upon by engineers. This orofessional team is served by a group of administrators. The result is a coordinated attack against malaria, the number one disease of World War II. FEDERAL SECURITY AGENCY U. S. PUBLIC HEALTH SERVICE TABLE OF CONTENTS The Malaria Problem 1 Malaria Control Operations 5 Malaria, the Disease 7 Malaria Vectors 12 naiaria Control 18 * Imported Malaria 28 Dengue - Yellow Fever Mosquito Control 32 Dengue Control in the Hawaiian Islands . 39 Other Mosquito-borne Diseases and Insect Pests 43 In-Service Training 45 Education 47 Administration 54 Malaria Control in the States 58 THE MALARIA PROBLEM GEOGRAPHIC DISTRIBUTION - MALARIA HIGHLY ENDEMIC AREAS MODERATELY ENDEMIC AREAS LOW ENDEMIC AREAS Malaria is no stranger to war. It has plagued the armies of the world from ear- liest times and has lingered in postwar civilian populations far from its endemic areas. The present war is unique in its world-wide scope. A map of malarious areas of the world shows that the training areas and the battle fronts of World War II coincide with the endemic areas of ma- laria. Early in the war emphasis was placed on training. Millions of men were moved from non-malarious areas to the malarious South where the climate would permit year around maneuvers. War industries were expanding rapidly and calling for thousands of mi- grant workers. America responded to this call in the face of dire predictions from epidemiologists. No mass migration of this kind into a malarious area has ever occurred without serious consequences. That no serious outbreak occurred is prob- ably due to a number of factors, not the least of which were the all-out efforts of Army and Navy sanitarians within military reservations and of the M.C.W.A. program outside the reservations. The record is clear and spectacular; Army malaria admis- sions per 1000 men in the continental United States were not only a fraction of those for the years of World War I but they actually decreased from 1941 to 1943. During the same period malaria continued its downward trend in the civilian popula- tion. It is now at the lowest point in his tory. 1 MALARIA, ADMISSIONS PER THOUSAND MEN PER YEAR ARMY IN THE CONTINENTAL U S. WORLD WAR I - WORLD WAR H RATES FOR 1943 ARE PROVISIONAL, BASED ON WEEKLY STATISTICAL REPORTS, AND EXCLUDE CASES RESULTING FROM OVERSEAS EXPOSURE. But the malaria battle is not over. We have won the first round but new and un- precedented hazards lie ahead. Men are fighting in spi te of malaria in many hyper- endemic areas where, without control mea- sures, practically everyone becomes in- fected. A few of these men have returned home, back to farms and cities, back to every crossroad and corner of the country. As the tide of battle turns it is estimat- ed that perhaps two or more million men will return with foreign malaria parasites in their blood. These will profoundly up- set the balance of malaria transmission unless an all-out attack is made to com- pensate for the overwhelming increase of carriers. METHODS OF ATTACK The methods of attacking malaria are few and are for the most part direct. They are aimed at breaking the chain of malaria transmission at one of its weak points. The three links in this chain are a mala- ria carrier or person sick with the di- sease, a mosquito vector, and a healthy person. Interwoven in this simple se- quence are the life cycle of the malaria parasite and the life cycle of the mos- quito. The result is a vicious circle with several vulnerable points. The first segment of the circle is the man sick with malaria. Parasites are circulating in his blood, reproducing, destroying red blood cells and causing chills and fever at re- gular intervals. Then there is the adult female Anopheles mosquito, penetrating in- to the blood system of the diseased person, sucking sexual forms of the parasite which combine in the mosquito’s stomach to pro- duce myriads of new parasites for injec- tion into the third segment of the malaria cycle, a susceptible person. Finally there is the mosquito life cycle, the fe- male laying eggs after her blood meal and thus starting hundreds of new potential vectors on their way. Anti-malarial drugs. The oldest method 2 of attack is against the first segment of the circle - the victim of malaria. The art of healing preceded the science of medicine, and cinchona bark was known to relieve the symptoms of malaria lorig be- fore the parasite or its vector were dis- covered. Quinine is still one of the best drugs but must be used sparingly since the main sources of supply fell into enemy hands. Fortunately, atabrine, a synthetic drug, is as good or better than quinine but no anti-malarial drug does more than lower me death rate and suppress the more formed of them. Education, then, becomes a positive and far-reaching method of ma- laria control. People have improved hous- ing and drainage in their communities as they have become increasingly enlightened concerning malaria and its transmission. As civilization has advanced, malaria has completely disappeared from large areas of the world. Mosquito control. The third point of attack is the mosquito vector. Recent knowledge enables vis tc concentrate on the obiective, save time and money and in- Tha Cycle of Malaria Transmission acute symptoms of the disease. The search continues in hundreds of private and State laboratories throughout the world- for a drug which is prophylactic and also capa- ble of freeing the patient of malaria par- asites. Education. Another vulnerable point for attack is the ignorance of mankind. Malaria is clearly a social disease, in- separably connected with poverty and ig- norance. Individual methods of fighting malaria such as mosquito proofing, spray- ing and the use of repellents mean nothing if the affected populations are not in- crease the efficiency of malaria control work. In some instances destruction of adult mosquitoes is particularly effective in malaria control since infected mosqui- toes may be killed before they have a chance to spread the disease. Preventive measures are usually direct- ed at the larval stages of the mosquito in water. Mosquito wrigglers may be killed by poison dusts which are swallowed with their food, or by oil sprays which pene- trate their respiratory systems. These agents are effective for only a tew days; therefore the regular application of lar- 3 Air Traffic Incrsases the Possibility of Introducing Yellow Fevar from Existing Foci vicides is of prime importance in an emer- gency program. Complete elimination of breeding places by drainage is more perma- nent and, in the long run, more economical in many places, especially when integrated with other water uses such as conservation programs, flood control and irrigation. Anti-mosquito measures have been so perfected in recent years that complete eradication has been achieved in the case of two immigrant South American disease vectors. Unfortunately, this is not yet economically feasible for native species, but it has been clearly demonstrated that effective control can be obtained wherever expenditure of the required amount of mon- ey is justified. It is not necessary to kill every mosquito vector to control ma- laria. With a given number of carriers, there is a threshold of sanitary impor- tance below which mosquitoes are so scarce that their chances of becoming infected and transmitting the disease to suscepti- ble people become infinitesimal. If mos- quitoes are so few and far between that they do not find malaria patients during their lifetime, the disease will die out. DENGUE AND YELLOW FEVER The same basic principles apply to den- gue - yellow fever mosquito control. Den- gue has already struck in Honolulu and in the South Pacific. It could paralyze any southern city and disrupt war activities if control measures were not carried on. Even more tragic would be the re-introduc- tion of yellow fever. These possibilities are not so remote as they once were be- cause of the new internationalism of the air. With no spot in the world more than 60 hours distant from our doorsteps, new mosquito vectors and diseases or more vir- ulent strains of existing diseases may ar- rive any day. The answer to these new challenges must not be a feeble one. The words "too lit- tle,, too late" are tragic reminders of un- preparedness. These new threats must be met with an all-out effort at home. If dengue-yellow fever vectors are reduced and malaria is traced to its deep endemic reservoirs and overwhelmed, the danger from mosquito-borne diseases will be prac- tically eliminated. 4 MALARIA CONTROL ORGANIZATION MALARIA CONTROL IN WAR AREAS LINES OF AUTHORITY AND INTERRELATIONS SURGEON GENERAL BUREAU OF MEDICAL SERVICES BUREAU OF STATE SERVICES NATIONAL INSTITUTE OF HEALTH DIVISION OF FOREIGN QUARANTINE DIVISION OF PUBLIC HEALTH METHODS DIVISION OF STATES RELATIONS DIVISION OF COMMISSIONED OFFICERS MALARIA INVESTIGATIONS PUBLIC HEALTH SERVICE LIAISON OFFICES MALARIA CONTROL IN WAR AREAS PUBLIC HEALTH SERVICE DISTRICT OFFICES STATE HEALTH DEPARTMENTS WAR AREAS 1800 WAR ESTABLISMENTS GENERAL ORGANIZATION Malaria Control in War Areas was orga- nized, with lines of authority from the office of the Surgeon General through the Bureau of State Services and the States Relations Division. It operates as an in- dividual unit through its Headquarters Of- fice in Atlanta, Georgia. Autnority is exercised and responsibility discharged by the Headquarters Office in cooperation with the District Offices of the Public Health Service. Operation of the program is by the State Health Departments under policy and administrative direction of the Atlanta Office. Full use is made of the Public Health Service Liaison Offices in coordinating the effort of MCWA, the State Health Departments, and military authori- ties. The operational unit is the “war area.” Approximately 1800 war establishments are protected and these are grouped according to location, nature and extent of opera- tions, so as to form 250 "war areas. " The "area supervisor" is generally an engineer. He is in complete charge of his area and works closely with the sanitary officers in adjacent military establishments and with the local health officer. MCWA personnel includes about 200 com- missioned officers, 60 non-commissioned professional employees and 415 sub-profes- sional, 138 clerical and 2400 custodial employees. MCWA activities are closely related to other work of the U. S. Public Health Ser- vice. The Division of Public Health Me- thods has been helpful in publishing tech- nical articles and has prepared numerous posters, hand bills, and other informa- 5 EQUIPMENT UNIT OFFICER IN CHARGE EXECUTIVE OFFICER COMMISSIONED OFFICERS UNIT RECORDS AND STATISTICS MAPPING AND DRAFTING TRAINING DIVISION MEDICAL DIVISION ENTOMOLOGY DIVISION ENGINEERING DIVISION AEDES AEGYPTI DIVISION ADMINISTRATIVE DIVISION IN SERVICE TRAINING SECTION PERSONNEL AND PAYROLL SECTION MEDICAL INVESTIGATIONS OPERATIONAL INVESTIGATIONS REPORTS SECTION IMPORTED MALARIA IMPORTED VECTORS PROCUREMENT AND SUPPLY SECTION PHOTOGRAPHIC SECTION EPIDEMIOLOGICAL SURVEYS CONTROL SURVEYS VOUCHERS AND ENCUMBRANCES SECTION TRAINING MATERIALS SECTION LABORATORY SERVICES FIELD AND LABORATORY TESTS PROPERTY RECORDS SECTION Headquarters Organization of the Office of Malaria Control in War Areas tional materials needed in the course of in-service training and field work. In cooperation with the National Insti- tute of Health, investigations relating to returning malaria carriers are pursued to determine exotic strain virulence and transmission efficiency of local malaria vectors. Operational investigations are employed to develop and measure efficien- cies of new insecticides and to increase the effectiveness of control techniques. Foreign quarantine is vital to our na- tional safety at all times, but the danger of importation of foreign diseases or vec- tors has never been greater than during the present emergency. Exotic disease vectors will certainly be introduced un- less extraordinary measures are taken. MCWA entomologists have been detailed to the Foreign Quarantine Division for sur- veillance at major airports of entry. HEADQUARTERS ORGANIZATION The Headquarters organization of MCWA includes the Executive Office with six supporting divisions: Medical, Entomologi- cal, Engineering, Administrative, Aedes aegypti, and Training. Balanced coordina- tion of modern medical, entomological, and engineering sciences is employed to pro- duce effective protection for war person- nel with a minimum expenditure of manpower and materials. This associated partner- ship, serviced by an administrative divi- sion, has demonstrated its effectiveness. The Medical Division determines endemicity, locates foci of infection, and studies trends of the disease; entomologists de- termine densities and breeding areas of vectors and check control measures; engi- neers, analyzing these data, apply the mechanics of engineering science to ac- complish effective and economical control. The Training Division, primarily a ser- vice division, is responsible for the in- doctrination and training of all new per- sonnel, the production of training and operational materials, and for reporting progress. Supporting service units as in- dicated are attached to the Executive Of- fice. Sections under the Administrative Division and Training Division perform the functions indicated by their respective names. 6 MALARIA, THE DISEASE Malarious Area of the United States 1882 Malarious Area of the United States 1834-5 The map of malarious areas of the United States for 1882 shows that the dis- ease was prevalent in 38 States from the Mexican to the Canadian border. In 1935 malaria was a significant problem in only 15 States, mostly in the southeastern part of the country, and today the disease has reached the lowest point in its history. What has happened in the last half cen- tury? No comprehensive program of malaria eradication was attempted and anopheline mosquitoes still abound in nearly all parts of the country. Probably the answer lies in the advance of modern agriculture and drainage of the land, in the continued application of mosquito control measures by local, State, and federal agencies, and in the advance of education, with better housing and screening and the populariza- tion of sprays for adult mosquitoes. The downward trend of malaria is not so simple as it would appear from a compari- son of the maps of 1882 and 1934-1935. Malariologists have shown that the disease fluctuates in the United States. With each upswing malaria increases in marginal areas where large numbers of susceptible persons are endangered. In alternate pe- riods it decreases and practically disap- pears except in certain endemic foci or permanent pools of infection where it smolders quietly like a volcano between eruptions. We are now at a critical point in the history of malaria in the United States. Although the disease has reached an all- time low, the return of large numbers of malaria carriers may upset this favorable situation. A rational approach to this problem appears to be supplementation of the present MCWA program. Vigorous anti- malarial measures must be applied in areas where factors are conducive to malaria transmission. Such a program requires precise answers to several questions: where are these areas; how extensive are they; if found, can the malaria hazard be neutralized by the methods of control available at the present time? The last question may be answered in the affirma- tive insofar as the vectors are concerned. The first two questions are more diffi- cult because potential foci and endemic foci are as elusive as individual malaria cases MALARIA SURVEYS Existing information on the prevalence of malaria is inadequate. Reporting is notoriously poor and most cases are not confirmed by a blood smear. Self-treat- ment for alleged malaria has made chill tonics one of the South’s most popular home remedies. Out of the morass of ill- defined malaria records, mortality data may be selected as a convenient and more 7 or less reliable starting place to deter- mine the existing foci of malaria in the United States. A record of deaths from malaria for the period 1938-1942 was ob- tained from the Bureau of the Census and from State health departments. On the ba- sis of death rates per 100,000 population and per 1,000 square mile area, 120 coun- ties with the greatest malaria problem were.selected. Since these are apparently the most malarious areas in the country 4. Information about previous surveys and other data from State and local health agencies, private physicians, hospi- tals, agricultural agencies, indus- tries, druggists, and residents. Evaluation of effect of physiographic features, housing, education, and other socio-economic factors on malaria. 6. Spleen surveys through schools. A serologic test (complement fixation) for malaria may soon be available for LEGEND COMBINED RANK AS DETERMINED BY (I) RANK ACCORDING TO MALARIA DEATHS PER 100,000 POPULATION AND (2) RANK ACCORDING TO MALARIA DEATHS PER 1,000 SQUARE MILES 120 COUNTIES HAVING HIGHEST COMBINED RANK ACCORDING TO MALARIA DEATH RATES BY POPULATION AND BY AREA IN 16 STATES 1938- 1942 MORTALITY STATISTICS FROM BUREAU OF THE CENSUS AND STATE HEALTH DEPARTMENTS FIRST FORTY COUNTIES SECOND FORTY COUNTIES THIRD FORTY COUNTIES UNITED STATES PUBLIC HEALTH SERVICE OFFICE OF MALARIA CONTROL IN WAR AREAS ATLANTA,GEORGIA the spotlight has been focused on them in t order to determine the malaria incidence, the local foci, and the factors that con- tribute to the perpetuation of malaria in each county. Several methods of approach have been used by epidemiologists in the field: 1. Analysis of mortality and morbidity s tatis tics. 'I. Supplementary morbidity data from phy- sicians, diagnostic laboratories, and questionnaires distributed through the schools. 3 Parasitemia surveys by thick film technique. field surveys. Mortality Surveys. Mortality statis- tics were selected as the most obvious starting point for the survey of malaria incidence. At first sight these records would appear to be positive and fool-proof since most of them are official records submitted by physicians. Actually, expe- rience has shown that such data should be used with caution. Interviews with physi- cians indicate that the great majority of cases are not confirmed in the laboratory. Yet, in most cases, mortality records have been a useful guide in spotting areas of endemicity. In some counties, mortality 8 data coincide with the findings of the school morbidity survey. On the other hand, there was a striking variance in the two sets of findings in one county, where it was possible to interpret the school morbidity survey results more intelligibly in terms of what is known about physiogra- phic factors and housing. Morbidity Surveys. Records of reported malaria are another useful source of in- formation but are even less reliable than mortality records. Many cases of malaria are never seen by % physician and, if seen, are not always reported. In one in- stance, doctors had reported only 25 cases in a county for 1943; but, when interview- ed personally, they estimated that more than 1,000 cases had actually occurred. There is a striking racial difference, too, in reporting malaria cases. In one small town almost all the reported cases from 1939 to 1943 were white, whereas al- most all the deaths were Negro. Additional morbidity information is-ob- tained by various means such as private laboratory records, medical records of in- dustries, Farm Security Administration, and house to house canvasses. In one county, people in every third house were interviewed for a history of malaria. It was concluded that, under the conditions of the survey, house-to-house interviews were too time-consuming to justify the questionable information obtained. Surveys by questionnaires distributed through schools proved to be a useful method of gathering morbidity data repre- senting all parts of a county. Despite the crudity of this method, it has helped materially in evaluating the extent of the malaria problem in each community, and es- pecially in determining the distribution of the disease. Qjestionnaires requested the following information: 1. How many persons, children and grown-ups, lived in your home during all of 1943? 2. Did any of these have ma- laria or chills and fever in 1943? 3. Did anyone in your home have malaria or chills and fever before 1943? 4. Location of house you lived in at end of 1943. 5. If you moved during 1943, how many miles did you move? Teacher Distributes Morbidity Forms Pupils Take tna Forms Homs Parents Fill in Desired Information 9 Surveys based on a single slide for each person examined reveal at best only 50% of the actual number of malaria vic- tims. Nevertheless, thick film surveys are the most reliable method now available for obtaining an index of the prevalence of malaria in the United States. Because of the progressive increase in the number of malaria cases throughout the season, more than twice as many new cases of malaria are reported in the fall as in the spring. Considering the seasonal va- riation in malaria occurrence, the compar- ison of a 1942 fall survey and a 1934 spring survey gives a good indication of the decrease in malaria during those eight Making Blood Smear Parasite Surveys. The thick film tech- nique for examining blood to determine presence or absence of malaria parasites has been widely used. To the diagnosti- cian a "positive" slide is final evidence of malaria infection. However, he does not consider that a "negative" slide ex- cludes the possibility of malaria. Sever- al factors might cause a negative report even though malaria is present. Perhaps the parasites were so few that no para- sites were found on the slide examined. Perhaps the person examined had been tak- ing anti-malarial drugs which decrease the number of parasites in the circulating blood. If additional tests were made in cases where negative slides result, there would be a better chance of discovering malaria parasites in the blood. Microscopic Bxaminat ion of Si idss years. In the spring of 1934 blood smears collected in 15 southeastern States showed 5.8% positive; whereas in the fall of 1942 only .27% showed positive. About 90 000 smears were collected in eight States during the fall of 1943. As of June 30, 1944, 25,408 of these had been examined with 28 positives (0 11%). The striking difference between the 1934 spring and recent fall surveys clear- ly indicates a tremendous decrease in ma- laria. This decrease is confirmed by a marked though proportionately smaller de- crease in reported malaria deaths. Blood Slide Survey Laboratory at Memphis 10 palpable spleens. The real significance lies in the group with spleens larger than PDI (palpable only on deep inspiration). Many more children showed spleen sizes of 1, 2, or 3 in Arkansas than in the North. Even so, 1.2% for Massachusetts and 3.9% for New York are high figures in the ab- sence of malaria and show a significant difference that is difficult to explain. Judging from these surveys, splenomega- ly must be interpreted with caution as a guide to the prevalence of malaria in areas of low endemicity. The complement fixation test for mala- ria has recently been developed to the point where it shows promise. Utilizing the parasites of chicken or monkey malaria for the antigen, this technique may become a valuable survey method. Unfortunately it is not yet ready for field use, but tests are continuing in an effort to elim- inate certain technical difficulties. Splann Survey in a Grammar School Spleen surveys have been conducted by a medical officer specially trained in the technique of spleen examination. The surveys included comparable data from malarious areas in Arkansas and from non- malarious sections of New York and Massa- chusetts. The surveys were confined to school children under 14 years of age be- cause the spleen is easier to palpate in young children, school groups are easily approached, and the size of the spleen is more significant in childhood than in later life when chronic infections or varying degrees of immunity may have de- veloped. Each child examined was ques- tioned to detect any unusual disease his tory. Results are shown in the table below. In Arkansas 24% of the children examined were found to have palpable spleens. Such figures would appear to be significant but for the fact that 14.7% of the children in New York and 12.3% in Massachusetts had Spleen Examination. Classification According to Mark F. Boyd SPLEEN SURVEY - SPRING. 1944 White Children Who Arrived in County of Present Residence before March, I94d. In the search for the elusive malaria focus all known methods of surveying have been tried. Results must be evaluated by malariologists in cooperation with State and local health officers, because local conditions are all important in epidemio- logical work. There is still no really satisfactory criterion for quantitatively estimating the "malariousness" of an area. Mortality statistics, morbidity data, parasite surveys and spleen surveys ail have their limitations. The best current procedure is to utilize a combination of all epidemiological methods. State Exam. Number Positive * Pos i t i ve Tota 1 PDI 1 2 3 Tota 1 PDI I.2&3 Arkansas 1,048 253 137 1 12 4 0 24. 1 13. 1 1 1. 1 Massachusetts 838 103 93 9 0 1 12.3 1 1. 1 1.2 New York 2,406 354 259 88 4 3 14.7 10.8 3.9 11 MALARIA VECTORS The anopheline mos- quito is one of the most vulnerable links in the chain of mala- ria transmission. In malarious areas anophe- line abundance is the most useful indication of where to concentrate control measures. Once the malaria problem is defined, whether it be in the 120 most malarious counties, in poten- tially malarious mili- tary areas, or else- where, the first step toward control is to locate all sources of the vector mosquitoes. This task would be difficult if all species of mosquitoes were involved and only "shotgun" control methods were available. However, advance- ment has been made far beyond that stage in applying anti-mosquito measures for ma- laria control, and cure-all methods are no more efficacious here than in the treat- ment of human ills. ANOPHELES SPECIES CONTROL The principle of Anopheles species con- trol or "species sanitation" was first enunciated by Darling in Panama in 1910. Da rling noticed that for any given area there is usually but one important malaria vector even though other species of Anoph- eles may be present in abundance. Subse- quent work throughout the world has proved the soundness of this principle . There are 12 species of anopheline mos- quitoes in the United States, all of which are capable of transmitting malaria, as proved by laboratory tests. Fortunately, only three of these are important malaria vectors in nature and in general each of these reigns supreme in its own territory: Anopheles quadrimaculatus Say in the East- ern and Southern States,* Anopheles albimanus Wied. in tlie lower Rio Grande Valley; and Anopheles freeborni Aitken in the Western States. One factor that de- termines the impor- tance of a malaria vector is, of course, the degree of suscep- tibility of the mos- quito to each of the types of malaria para- site. However, this is not the most impor- tant factor. Above all else, the habits of the mosquito spe- cies in relation to the habits of the nu- man population within its range must be considered. What does it matter that a species is capable of transmitting malaria if it never bites human beings? This sit- uation occurs in Europe, where it has been called “Anophelism without malaria.” It has been known for a long time that in some parts of Europe apparently good vec- tors abound in the absence of malaria, while in others the vectors are scarce where the disease is endemic. Rice and Barber investigated the situation by test- ing the blood meals of 37,000 anophelines by precipitin tests. It was shown that Anopheles maculipennis Mieg. is not a homo- geneous species but is divisible into six races. Three of the races proved to be cattle feeders and thus were not concerned with malaria transmission, whereas the other three fed principally on humans in Spain, the Mediterranean, and the Balkans. The feeding habits of Anopheles in this country are being investigated at the MCWA Carter Memorial Laboratory in Savannah, Georg ia. Recently engorged female anophe- lines are collected during the routine in- spection of adult stations throughout the Anopheles quadrimaculatus Say 12 Precipitin tests of anopheline blood meals. Blood sarrqples (1) are soaked in saline (2) and than drawn into capillary tubes with human, equine, bovine, porcine, and avian anti- sera (3). Blood source is determined by viewing (4) precipitate (5) in one of the tubes. MCWA program. The Fice and Barber tech- nique of mass precipitin testing is used to determine the source of the blood. Essentially, this technique involves soaking the blood from filter paper on which it is originally collected, and bringing the resulting mixture (antigen) into contact with prepared human, equine, bovine, porcine, and avian antisera in five capillary tubes. In the appropriate tube, a precipitate appears at the point of contact between antigen and antiserum, indicating the source of the original blood meal. Results of tests of 13,139 satisfactory samples from 21 different States are shown in the chart below. Many more samples will be required to insure significant re- sults, but these preliminary figures bear out the fact that six of our commonest anophelines feed largely on bovine blood. Alhimanus shows the greatest preference for human blood, based upon a very small series of tests. It is expected that future tests will show regional differ- ences in preference for human blood and consequently have a direct bearing on control practices. RESULTS OF PRECIPITIN TESTS SHOWING NUMBER AND PER CENT OF TESTED SPECIMENS OF SIX SPECIES OF ANOPHELES FEEDING ON SPECIFIED HOSTS - TO JUNE 30,1944 Species Humon Equine Bovine Porcine Avion No reaction Total No. No. Per cent No. Per cent No. Per cent No. Per cent No. Per cent No. Per cent Tested quodrimaculo tus 366 4.2 1479 16.9 4646 53.0 1041 11.9 228 2.6 997 11.4 8757 punctipennis 39 3.0 240 18.4 756 57.8 154 11.7 25 1.9 94 7.2 1308 freeborni 27 4.4 70 11.3 384 62.1 25 4.1 5 .8 107 17.3 618 crucians 6i 3 9 146 9.4 870 56,1 194 12.5 88 5.7 191 12.4 1550 pseudo punctipennis 21 3.8 33 6.0 401 73.0 25 4.6 12 2.2 57 10.4 549 oibimanus 30 8.4 19 5.3 243 68.1 15 4.2 8 2.2 42 11.8 357 13 Examining a Larval Breading Place Examining an Adult Heating Place ANOPHELINE SURVEYS When control work is requested, the en- tomologist first makes a thorough survey to determine the density of anopheline adults. This is done by collecting adults from a series of natural and artificial resting places during the daytime and from light traps and bait traps at night. Ad- ditional data are obtained from biting records. If adult densities are high enough to constitute a malaria hazard, a survey is made of possible breeding areas within flight range of the place to be protected. The mere presence of anophelines, even though they are abundant, is not suffi- cient to justify a malaria control program. The information must be evaluated in terms of the local situation. What is the his- tory of malaria in the area? What is the present malaria hazard? How important is it to the war effort or to the public health to prevent or control malaria in the area? Answers to these questions must come from local health officers in confer- ence with trained malariologists. Practi- cal considerations, such as availability of funds for control purposes and the eco- nomics of'the control problem must be tak- en into consideration. If it is decided that a control program is necessary, or that the locality should be kept under surveillance, a control zone is set up. The procedure in this case is to locate all breeding areas within flight range of the area to be protected and to select representative adult stations. For convenience in evaluation of records, the zone i,s divided into "A". "B", *t", or "Dn sections indicating successive quarter- mile distances from the protected territo- ry. nEn stations are located more than one mile distant and serve as an index to anopheline populations under uncontrolled conditions. Inspectors sample all sta- tions regularly. Particular attention is paid to the number of adults in the criti- Mosquito Light Trap 14 cal nAn stations, i.e., those nearest the protected area. When significant num- bers of Anopheles mosquitoes are found in adult stations, the source of breeding usually is revealed by high counts at one or more larval stations. Continued high adult counts in nA" stations may be due to ineffective larvicidal work, undiscovered breeding places, formerly non-breeding areas coming into production, or unusual flights from extensive breeding areas out- side the control zone. HABITS OF MALARIA VECTORS The malaria vector of the western United States, Anopheles freeborn!, is usually associated with seepage areas adjacent to irrigation canals and favors clear, shallow, sunlit water with some growth of algae. Recent surveys along the coast show that it also breeds in brackish waters with a saline concentration equiva- lent to 17% sea water. The flight range is very great because of fall "pre-hiberna- Conference with Health Officer tion" flights and spring "emergence" flights during which the species migrates distances of 10 or 15 miles. The main malaria vector in the South- ern and Eastern States, Anopheles quadri- maculatus, breeds chiefly in permanent fresh water pools, ponds, and swamps that contain aquatic vegetation or floating de- Diagram of a Control Zona Showing Successive Distances from War Establishments 15 Anopheles quadrimaculatus Breeding Place Anopheles albimanus Breeding in Hoof Printe bris. It does not normally fly more than one mile, so this distance has been taken as a standard in planning control. The Neotropical Anopheles albimanus in- vades the Rio Grande Valley from Mexico and is the principal malaria vector in Puerto Rico, Jamaica, and other Antillean islands. It occurs commonly amid mats of floating vegetation in large bodies of water such as ponds or lakes but is also found in ground pools with algae. The larvae thrive in fresh water fully exposed to the sunlight and in brackish water as well. Adults may fly as much as 2XA miles, so control zones must embrace a larger area than in the case of quadrimaculatus. Generalizations on the habits of anoph- elines are valuable. However, it has been said that mosquitoes are i11iterate--that they have not read the books and hence do not know how they are expected to act. There is endless variety in the habits and idiosyncrasies of mosquitoes. Therefore, it is important that careful entomological work precede the inauguration of control and that inspection be maintained in order to determine any unusual habits in the specific locality concerned. EVALUATION OF CUNIROL MEASURES Results of malaria control operations expressed in terms of gallons of oil spray- ed, tons of paris green dusted, miles of ditches cleaned or dug, or man hours ex- pended are unsatisfactory for evaluating the effectiveness of control. The real results of malaria control work in any community can only be measured by a de- crease in incidence of the disease. This criterion is not applicable at present be- cause there are so few malaria cases. However, the effectiveness of anti-mosqui- to measures can be gauged by the decrease brought about in density of the vector species and this decrease indicates the extent to which potential malaria trans- mission has been reduced. During 1943, the densities of malaria vectors in areas included in the MCWA pro- gram were maintained at a satisfactory level in 86% of the protected zones. A zone is considered satisfactory if no "a" station shows an adult count of more than 10 for three consecutive weeks. The 14% of unsatisfactory zones were distributed in 17 of the 21 States under control, so no 16 general failure occurred in any one State. Results of the control work as a whole during 1943 show that average densities inside the control areas did not exceed counts of 10, whereas average outside den- sities reached 22 at the peak of the sea- son. Highest single station counts inside protected areas are compared to those in adjacent unprotected zone. This compari- son is based on averages of the highest single counts from each control area, not on averages of all station counts. Thus, areas are rated by their worst conditions with respect to "quad" densities. Though perhaps a rather severe criterion, this measurement was adopted because average figures for an entire area might mask un- satisfactory conditions in a particular section of the area. One of the chief functions of the en- tomologist is to obtain the information that will make it possible to limit opera- tions to areas which show a definite need for anopheline control. Preliminary sur- veys or routine inspections (Entomological Surveillance) have prevented two-thirds as many (257) projects being inaugurated as the number of actual projects in operation. RESULTS OF CONTROL WORK IN WAR AREAS DENSITIES OF MALARIA VECTORS * INSIDE COMPARED TO OUTSIDE WAR ESTABLISHMENTS 1943 * ANOPHELES QUA0RIMACULATU9 (SOUTHERN STATES) A FREEBORNI (WEST COAST) A ALBIMANUS (SOUTH TEXAS) About 80 professional entomologists and general biologists are employed to carry on entomological phases of the MCWA pro- gram. They are assisted in routine survey work by sub-professional employees who serve as area inspectors. The entomolo- gist is an integral part of the "malaria team. " He supplies the information on which an efficient program can be planned and prosecuted. SAVINGS IN CONTROL THROUGH ENTOMOLOGICAL SURVEILLANCE ZONES UNDER CONTROL ZONES UNDER SURVEILLANCE 17 MALARIA CONTROL LEGEND I ACRE TREATMENTS 1 MAN HOURS Snmnary of Larvicidal Operations The duties of the engineer in the mala- ria control team are to determine control methods, to direct mosquito control opera- tions, to survey and design proposed drainage construction, and to prepare maps which guide field project activities. Heavy construction is imoortant on larger or more permanent projects, with larvicid- ing, clearing, and temporary drainage as the more frequently employed emergency measures. MCWA engineering is primarily a management enterprise. Since MCWA is a war emergency program, temporary larvicidal control measures are used wherever they accomplish the desired objectives, thus saving both money and critical equipment needed in combat areas. Drainage is utilized where larvicidal con- trol is inadequate or when the cost of drainage may be amortized in five years or less in terms of the annual larvicidal cost. Special local conditions have ne- cessitated the use of such other methods as dredging, hydraulic fill, flood gate installation, cleaning, sanitary fill, diking, vertical drainage, ditch flushing, ditch grading, and destruction of adult mosquitoes. Careful analysis of the prob- lem in any area is necessary before decid- ing on the type of control measures to be applied. Project activities are planned insofar as possible to avoid seasonal peaks in la- bor and supervisory requirements. This aim has been accomplished in the past by concentrating on drainage construction, heavy clearing, stream channeling, map- ping, and drainage surveys during the cold months and on larviciding and other recur- rent work during the malaria season. By distributing work in this manner it has been possible to conserve manpower and tc maintain a seasoned field organization, LARVICIDING During the year the basic control oper- ation of the MCWA program was the applica- tion of larvicides to Anopheles mosquito breeding areas. In Puerto Rico, southern Florida, and southern Louisiana, larvicide was applied throughout the year. Proceed- ing northward the larviciding season was progressively reduced to as little as two months in some of the marginal States 18 The average larvicidal crew consisted of a foreman and four oilers or dusters, equip- ped with a truck and the necessary tools and supplies. Oil Spraying. The majority of the lar- yicidal acre applications were made with paris green but oil was used exclusively in many zones and accounted for the bulk of the financial and labor expenditures. The rate of application varied in differ- ent types of breeding plaqes from 12 to 50 gallons per acre, with 18.9 gallons per acre as the average.* Eighty thousand seven hundred and five acre applications of oil were made during the year at a unit labor cost of 8.07 man-hours ‘per acre ap- plication . Oil larviciding was performed princi- pally by hand, using approximately 3,000 knapsack and compressed air sprayers. "Die use of power equipment was increased dur- ing the year, wherever possible, in order to conserve manpower and to reach breeding places inaccessible to hand labor. Power equipment employed included several oil- water centrifugal pimps and 50 high-pres- sure sprayers which were installed either on trucks or in boats. power units were found to be particularly effective in oil- ing water surfaces covered with heavy flotage or dense vegetation. The average acre application cost of oil larvicidine Hand Duster in Operation was $9.55 by hand and $2.26 by power meth- ods, including cost of labor, larvicides, and equipment. Paris Green Dusting. Paris green was employed extensively as a larvicide in areas where oiling was impracticable, in- effective, or unduly expensive. Hand dusting was the most common method of application for breeding areas of rela- tively small size and readily accessible to men on foot. Approximately 1500 rotary blower dusters were used. The effective radius of application by hand dusting ranged from 50 feet in the tropics, where air turbulance is greater, to 150 feet in some of the more favorable areas of the continental United States. During the year 187,799 acre treatments of paris green were made, 45% by hand, 21% by power duster, and 34% by airplane. Re- spective costs per acre application were $2.98. $0.65, and $1.06. Dust mixtures varied from 4% to 10% paris green by weight for hand and power dusting, and 15% to 25% for airplane dusting. Rates of ap- plication varied from one-half pound of paris green per acre in relatively clear areas to two pounds per acre in densely vegetated areas or in high-flying airplane operations over swamps. The average rate of application of paris green was 1.3 pounds per acre and 1.7 man hours were ex- pended per acre application. Knapsack Sprayers in Operation 19 Some of the most prolific malaria mos- quito breeding areas in Arkansas, Louisi- ana and coastal Texas are irrigated rice fields which are best controlled by air- plane dusting. Since the possibility of damage by paris green to the rice crop was an important consideration, an experimen- tal project was established at Stuttgart in cooperation with the Rice Branch Experi- ment Station of the University of Arkansas. A two-acre section of Arkansas Fortuna rice was dusted at weekly intervals for several weeks during the growing season. As a result of the experiment it was con- cluded that paris green mixtures, at con- centrations utilized for larvicidal pur- poses, had no appreciable effect on the yield of rice grain or straw. This finding confirmed studies made in other parts of the world where the irrigation of rice creates a major malaria hazard. Paris green was used almost exclusively on the MCWA program in Puerto Rico. Peak monthly consumption of paris green was 4.5 tons. About 340,000 gallons of oil per month would be required to larvicide the same acreage. The full-time use of a tank- er to transport oil to Puerto Rico and of many trucks for its local distribution would be necessary to supply this demand. Forty power dusters and numerous power mixers were utilized on the MCWA program. Most of this equipment was mounted on motor-boats or trucks. Application by boat was found preferable in navigable streams and lakes having breeding areas along the margins. Power dusting from trucks is particularly suitable where access trails are available or easily constructed; where trees grow over the entire watered area favoring extensive breeding and preventing boat navigation; and where the most remote breeding place in the area is within dust- ing radius of the shore line (approximate- ly 600 feet). In Puerto Rico, ox carts have been used to power-dust breeding places which were inaccessible even to four-wheel drive military vehicles. Large shallow water marshes, which are inacces- sible even to carts, have been power-dust- ed by two laborers carrying a 3/4 horse- power duster on a hand barrow. The prin- cipal advantage of power dusting over other methods of larviciding is the Power Ousting to Control Shoreline Breeding 20 Airplane Ousting on the Potomac River Airplane Dusting Unit in Puerto Rico greater radius of application obtained. The airplane was used in the States of Virginia, Mississippi, Arkansas, Louisiana, Tennessee, and in Puerto Rico for dusting areas which were too large or inaccessible for power dusting. About 350,000 pounds of 25% paris green mixture were ap- plied in 64,780 acre applications on nine airplane dusting projects. The ef- fectiveness of airplane dusting has varied widely, being lowest in wooded swamps with trees of widely varying height. Optimum results were obtained in large water chestnut areas of the Potomac River. This low-growing, imported aquatic plant was so dense that power dusting by boat was im- possible, and airplane dusting was the on- ly alternative. Planes dusted parallel strips 40 feet wide at a flying height of 10 to 15 feet above the water and at a speed of 70 miles per hour. Over-all lar- val reductions of 97% were accomplished. Cost per hour for plane and pilot was $75.00, but the average over-all cost was low since even a small plane can dust up to 200 acres per hour. Organic Larvicides. On water supply impoundments and in other special situa- tions where there was some objection to the application of paris green or oil, both the original and a modified New Jer- sey larvicide were ettectively utilized. This larvicide was prepared with a commer- cial mixture of pyrethrurr in oil. In the Norfolk-Portsmouth area it was applied on water supply lakes with a power pressure sprayer. Phenol larvicide was used in a few areas. This larvicide is quite toxic to animal and vegetable life and also has the undesirable characteristic of quickly per- meating water. It therefore must be ap- plied according to the volume rather than the surface area of water treated. A promising new insecticide, dichloro- diphenyl-trichloroethane, or DDT, has been under investigation during the past year. When it becomes available in sufficient quantity for use on the MCWA program, a considerable revision of control proce- dures may be necessary. Field tests are being conducted at Memphis in cooperation with the Division of Malaria Investiga- tions of the National Institute of Health and at the Savannah MCWA laboratory. DDT shows unusual possibilities as a larvicide in oil, and as a residual spray for killing adult mosquitoes. It is also being test- ed as a larvicide to be added to irriga- tion water in rice fields, at Stuttgart, Ark. 21 Earth Removal in Relation to Man-Hours DRAINAGE Drainage is generally the most satis- factory method of malaria control; but on an emergency program, especially in tempo- rarily inhabited war areas, it is seconda- ry in extent to larviciding. On the emergency MJJWA program,breeding places are drained if they cannot be larvicided ef- fectively; if the cost can be amortized within five years or less through savings realized in larvicidal expenditures; or if critical manpower shortages coincide with the mosquito breeding season and winter drainage will materially reduce summer manpower requirements. During the winter a maximum of 63 major drainage projects were in operation in 46 areas of 13 States and Puerto Rico. Since a majority of the malaria mosquitoes in the continental United States do not fly more than one mile, drainage was usually concentrated within this radius. Where excessive breeding did not occur between the one-half mile and one mile radius, control of this area by larviciding was, in most cases, sufficient. In a few in- stances it was necessary to install drain- age works past the one-mile radius in or- der to obtain satisfactory outlets. On MCWA projects in the West Indies, where A. albimanus is the vector, it was often ne- cessary to perform extensive drainage as far as two miles from the protected popu- lation, due to the longer flight range and more intensive breeding habits of this species. While practically all of the less ex- pensive drainage enterprises have been completed, a number have not been under- taken due to costliness which would far exceed MCWA appropriations. These com- prise projects requiring the hydraulic filling of hundreds or thousands of acres of river marsh or swamp, or levee con- struction and pumping to dewater other areas of similar size and character. In some instances the estimated cost of indi- vidual projects of this type exceeds a million dollars. Although nearly all drainage work orig- inally projected around the older military establishments has been completed, many new areas have been added recently. These consist mainly of newly established pris- oner-of-war camps and military hospitals. Major drainage is seldom justifiable around prisoner-of-war branch camps because of their temporary nature. However, larvicid- al work has been supplemented by drainage at some of the more permanent base camps. Plain Earth Ditches. On small ditches 22 the bulk of construction has been accom- plished by hand labor. The life of this type of drainage has been designed to con- form to the duration of occupancy of the protected site. In most instances plain earth ditches have been dug without lin- ing, sodding, erosion control, or appurte- nant structures. The average cost for rhi s type of excavation where performed by hand labor was $1.46 per cubic yard. One thousand fifty-nine miles of hand ditching were completed during the year, involving over 6Q0,000 cubic yards of excavation. Dynamite Blast Dynamite ditching was used extensively by MCWA- Most of the larger ditches were in swamps and low areas where soil conditions and the high ground water table favored propagation-dynamiting but impeded satisfactory mechanical or hand excavation. Under these conditions dynamite is more economical and more rapid. After the right-of-way is cleared, a crew of three to ten men can blast 750 to 3000 feet of channel per day. An example of economical dynamite ditch construction is an 18,000 foot ditch which was blasted in eight days at Round Pond, within one mile of Newport, Arkansas, at a cost of $4,707. The cost of larviciding this 200-acre pond was es- timated at $4,705 for a single season. A total of 192 tons of dynamite was used on the MCWA program to blast 60 miles of ditch at a cost'of 27t per cubic yard (rough excavation only). Dragline drainage has been performed principally by contract, although some work has been carried on with MCWA owned equipment. Twenty miles of this type of ditch were dug. Sub-sur face drainage has been practiced in lieu of open drainage wherever it was practicable and more economical. This type of drainage is particularly suitable for the interception of underground seep- age, drainage of waterholding streams and ditches, and the dewatering of wet pasture lands. Twenty-six thousand eight hundred and four feet of sub-surface drains have been constructed. Resourceful use was made of locally Surveying a Ditch Dragline Ditching 23 job by the dry mix process, or furnished by local agencies. Ditch Lining. Approximately 60,000 linear feet of permanent ditch lining were installed by MCWA operations. This work was limited in the United States to a few permanent establishments where materials were furnished by -property owners or local governments. The use of lining was more extensive in the tropics where malaria mos- quito production is more difficult to con- trol and where the malaria hazard is greater; but even there, installation of MCWA-produced ditch lining has been con- fined to the vicinity of permanent milita- ry establishments. Under an exchange agreement with the Army and Navy in Puerto Rico, pre-cast ditch lining was produced by MCWA at its central concrete products plant for installation in various posts and bases throughout the Island. Perpetu- al easements were obtained by the U. S. Engineers at all locations where lining was installed. Most of the lining was precast. Ditch banks were stabilized with Bermuda grass, planted generally by the "stolon" method. Culverts. Highway and railway fills across swamps frequently contribute to malaria mosquito breeding. Right-of-ways Subdraining with Poles available materials on the smaller sub- drainage projects. Many French drains were constructed with poles cut on the jobsite and covered with a filter of pine needles. On the more extensive sub-drain- age projects, hard-burned terra cotta ag- ricultural tile and butt-joint cement mor- tar pipe were most commonly used. Lateral lines were generally four to six inches in diameter, with intercepter and outfall lines ranging from 6" to 15" in diameter. All cement mortar pipe was produced on the Old Ditch before Lining Ditch Sodded with Bermuda after Lining 24 Before Vertical Drainage After Vertical Drainage cleared through swamps on either side of a roadbed expose water surfaces to sun- light, thereby encouraging-the growth of "quad-favorable" aquatic vegetation. When earth is excavated from a low area to pro- vide material for the fill, a permanent water hole is created, especially when culverts have been installed too high for residual drainage. In a number of cases these problems have been corrected by low- ering cross-drainage culverts or "jacking through" smaller culverts at lower eleva- tions. Special types of drainage were used where they offered the best solution to the control problem. At Jackson Barracks, La., a levee and a manually-operated flood gate were constructed. At Macon, Ga., and in Puerto Rico pumps were used for drain- age. An inverted siphon was installed at Macon, Ga. Hydraulic dredging was utiliz- ed effectively at Leesburg, Fla., and Macon, Ga., and vertical drainage at Jef- ferson Barracks, Missouri. OTHER METHODS OF CONTROL Fill ing. Filling provides permanent elimination of mosquito breeding places. About 80,000 cubic yards of fill were placed during the year at a cost of $0.61 Constructing Vertical Drain 25 per cubic yard. The following methods of filling were employed on MCWA projects: Filling by Bulldozer- This method is economical where the length of haul is short. If the bulldozer is followed by a highway grader, no hand labor finishing is necessary. This system was used with ex- cellent results in Memphis, Tenn, and thf coastal areas of South Carolina. Filling by the diversion of stream carrying a heavy load of silt has been usecl in low swampy areas adjacent to g raised stream bed. Roadside ponds wen filled by diverting into them the flow ol si1t-carrying roadside ditches. The cost of this type of filling is negligible, but its use is limited to special situations. Successful projects of this type were op- erated at Valdosta, Ga. and Tallahassee, Fla. Sanitary Fill. This method was used to eliminate a breeding area at Paducah, Ky. When used, mixed garbage was covered at the end of each day’s work with earth. Filling by Hydraulic Dredge Drainage Maintenance. Cleaning and maintenance of drainage ditches are important elements in MCWA operations. They serve the joint purpose of preventing breeding in the ditches themselves, and of maintaining hydraulic functions in order to avoid the re-establishment of breeding conditions in the areas drained. Some use was made of free crankcase oil and of worn cutting oil from machine industries as an herbicide to kill vegetation in drainage ditches and along their banks. A wide ditch in Missouri was choked with emergent vegetation providing ideal breed- ing places for "quads." The situation was corrected by cutting a longitudinal trench through the vegetation along the bottom of the ditch, thus producing a dinette where summer flow of water was confined. Ap- proximately 1320 miles of ditch cleaning was accomplished during the year. Clearing. Routine clearing is necessa- ry in larvicidal and drainage maintenance work. During the year heavy vegetation was removed from about 8,000 acres of con- trolled area. Clearing around the shore lines of swamps and ponds is carried on in order that laborers may apply larvicide uniformly; trails are cut to provide access to the breeding areas; ditch banks are cleared preparatory to larviciding or drainage maintenance; channels are snagged to facilitate small boat navigation; and Result of Stream Diversion Fill Other fills were made with uncovered trash and ashes. Filling by Dragline. Spoil excavated by dragline in the construction of drainage canals was used to fill low places within reach of the machine. A small amount of miscellaneous filling was accomplished by dump trucks, drag pans, hand labor with wheel barrows, and hy- draulic dredges. 26 pver-hanging tree 1 intis are cut to prevent flotage collection. Care is exercised in carrying out this work to prevent in- creased malaria mosquito breeding as a re- sult of shade removal. Large scale clearing of water chestnut in the Potomac River to effect permanent elimination was begun. This aquatic plant is an annual with a growing season that coincides with the mosquito breeding sea- son The plants are cut when they become dense- near the end of May, before the chestnuts mature. Cutting was partially financed by MCWA and was carried on by the Corps of Engineers, U- S. Army. Clearing of aquatic vegetation is also important in resacas near Brownsville, Texas. Large hinged rakes mounted on the front of boats were used. Vegetation is gathered, pushed toward the shore and lifted by the rake. Adult Mosquito Destruction Among the adult destruction methods, greatest progress has been made in the de- velopment of aerosol sprays. Pyrethrum or thiocyanates are mixed with liquid freon and are dispersed by releasing the gas. Release of the gas for four seconds from a standard pyrethrum-freon bomb is sufficient to kill all mosquitoes in a space of 1000 cubic feet. Adult spraying was used in the Stutt- gart area in Arkansas, where an advanced pilot training school is located in the midst of a large rice-growing area. The 2800 acres of breeding area within flight range of the school could have been con- trolled partially by airplane dusting but the cost per capita would have been prohi- bitive. Under these circumstances an in- tensive adult spraying program seemed the most practical approach to malaria control. Each building in the protected area was sprayed twice a week. This gave four or more chances of killing the mosquito be- tween its first blood meal and its final development as a malaria transmitter. The control area consisted of 19 farm establishments with a total of 119 build- ings. A power spray unit mounted on a jne-half ton truck was used to spray out- buildings. For interior spraying, the pressure sprayers or hand-operated sprayers were used. The cost of the program was $1.23 per building application. The cost per square mile for this type of control was approxi- mately the same as the State average for larviciding, $1,070. Raking Flotage from Breedino Area Destruction of Adult Mosquitoes. Mala- ria control operations have been directed principally against the larval stage of the mosquito. However, recent work in India and South America has demonstrated that the spray killing of adult mosquitoes around habitations under certain condi- tions is an effective means of malaria control. Although this method has little effect on the density of the malaria mos- quito population in an area, it does kill mosquitoes that are in the process of be- coming infective. 27 IMPORTED MALARIA IMPORTED MALARIA STUDIES The U. S. Army, Navy, and Public Health Service, recognizing that malarias con- tracted in foreign countries are being brought into this country by soldiers and that relapses are occurring in these sol- diers, set up a ioint program to study the public health significance of imported malarias. This program is called "import- ed Malaria Studies. " The principal objectives of the program are (1) to determine the ability of the imported malarias to infect American ano- phelines and to be transmitted by them; (2) to gather information on parasitology and other characteristics, and to distin- guish, if possible, between strains; (3) to evaluate the findings and to suggest their implications upon control measures. The divisions of the Public Health Ser- vice which are cooperating in this work are the Office of Malaria Control in War Areas and the National Institute of Health. The Office of Malaria Control in War Areas has made available funds for carrying on the work, and supplies all the personnel with the exception of the Officer in Charge. The National Institute of Health furnishes the Officer in Charge and is responsible for the direction of the in- vestigation. The Army makes available troops relapsing with inported malaria and has provided space for the two branch la- boratories. The headquarters laboratory of Import- ed Malaria Studies is located in the Na- tional Institute of Health Malaria Re- search Laboratory at Columbia, S. C. , where the regular personnel and equipment of the Institute are used when needed. This laboratory has access to four Army hospitals and one Navy hospital in North Carolina, South Carolina, and Georgia. The branch laboratories are located at Letter- man General Hospital, San Francisco, Cali- fornia, and Harmon General Hospital, Long- view, Texas. At each laboratory an insec- tary is maintained, with Anopheles quadri- Laboratory Mosquito Colony Mosquitoes Biting Malaria Patient Attemp ting Transmission 28 The techniques involved in the work are those which have been worked out during the past few years in the Columbia labora- tory. Large colonies of mosquitoes are maintained. At the optimum age, these mosquitoes, preferably about 200:, are fed upon the relapsing malaria patients. At regular intervals the mosquitoes are dis- sected to determine the degree of infec- tion and distinguishing characteristics. Batches of infected mosquitoes are fed up- on mental patients who need malaria for therapeutic reasons. This tests the trans- mission of these strains. So far over 11,000 mosquitoes brave been tested on nearly 100 cases of relapsing imported malaria. The results indicate that these imported malarias are a defi- nite threat to the public health of this country inasmuch as they are transmitted by American anophelines. Studies are un- der way now to evaluate this hazard. MOBILE UNITS As a precaution against imported mala- ria, eight mobile malaria control and in- spection units have been organized. Each Examination for Malaria Parasites maculatus Say or Anopheles Aitken as the standard testing species. Other suspected species are tested as they are available. LEGEND ARMY GENERAL HOSPITALS NAVAL HOSPITALS PRISONER OF WAR INTERNMENT CAMPS PRISONER OF WAR BRANCH CAMPS Location of Army and Navy Hospitals and Prisonsr-of-War Camps 29 unit consists of a passenger vehicle and a ll/4 ton truck, fully equipped for inspec- tion, larviciding, interior adult mosquito control, and incidental hand drainage work. The officer in charge of the unit has a small crew of two to five men to do the control work and to assist with inspec- tions. The units are assigned to the district offices to be used where needed and are directly responsible to the district MCWA personnel The mobile units were designed primari- ly for malaria control and inspection around prisoner-of-war camps and Army gen- eral hospitals in Public Health Service districts outside the malarious belt. En- tomological inspections are made around all POW camps and hospitals and control is undertaken when the inspections indicate the necessity. Twenty seven control zones and 37 inspection zones have been esta- blished. If the problem in any zone be- comes too extensive for adequate control by the mobile unit crew a separate resi- dent control project is set up. The mobile units are available for im- mediate service on an explosive epidemic of malaria, irrespective of location with regard to war establishments. It is felt that such localized outbreaks can be stamped out within a short time by concen- trated work in the immediate vicinity of the malaria cases. QUARANTINE It is not enough to stand guard against the importation of new strains of malaria. Malaria of an endemic type is already pre- sent in this country and could reach epi- demic proportions if new and highly effi- cient vectors’ should be imported. Such a condition occurred in northeastern Bra- zil when Anopheles gambiae, one of the most efficient malaria vectors, was acci- dentally introduced from Africa in 1930 By 1938 northeastern Brazil had become "the scene of epidemic malaria equal in severity if not in extent to that of the worst out- breaks described in the literature of the disease" (Soper and Wilson, 1943). This is a clear warning at a time when world barriers are disappearing. Few mosquitoes Equipment Included in Mobile Unit Mobile Unit Crew at Work were able to overcome the hazards of long sea voyages on surface vessels but the new clipper ships of the air provide ideal transportation for insect hitch-hikers. The unprecedented air travel during the war has increased the chances of importing new disease vectors tremendously. It is likely that more chances of introducing a foreign mosquito now occur in a single month than occurred during preceding cen- turies . This threat is being anticipated by rigid quarantine plus constant surveil- lance in the vicinity of airports of entry in an effort to catch any immigrant di- sease vector that may have slipped past guards. This work is a function of the Foreign Quarantine Division of the Public Health Service. Seven MCWA entomologists have been assigned to the Quarantine Divi- sion to assist during this period of 30 Passenger Plane Approacning Florida Coast Precautionary Spraying before Plane Lands greatly increased hazard. These men are located at Miami, West Palm Beach, New Orleans Brownsville, and Ft. Worth. The disinsectization program involves spraying of the planes while in flight by either airline or military personnel and further spraying upon arrival after pas- sengers have disembarked but before the baggage and freight are removed. Following this last spraying a search is made for insects, both dead and alive. During the past year approximately 25,000 insects were recovered from the hundreds of planes inspected. Eleven hundred and five mos- quitoes are included in this total of which 30 were tropical anophelines. All of the latter had been killed before recovery. The recovery of the tropical malaria vector, Anopheles albimanus, on two occa- sions in the vicinity of Florida airports indicates that mosquitoes can and do enter the country in spite of the rigid quaran- tine. In one case a female albimanus was found in a natural resting place adjacent to Morrison Army Air Field at West Palm Beach. The specimen was dead when found and there seems to be no explanation for its presence other than that it arrived by plane. In the other case an Army Sanitary Corps Officer found a single larva of al- bimanus adjacent to the Army airport at Boca Raton, Florida. An exhaustive follow- up failed to reveal further specimens but these two instances show the importance of the surveillance program. Quarantine Officer Checking Tenperafuree Searching Plane for Mosquitoes 31 DENGUE - YELLOW FEVER MOSQUITO CONTROL HISTORIC OCCURRENCE OF DENGUE AND YELLOW FEVER DENGUE FEVER YELLOW FEVER Yellow fever was once the scourge of' two continents. Deeply rooted in the tro- pics, it invaded temperate cities in the United States during the humid, hot sum- mers. Seldom did a year pass without an epidemic in one or more southern cities. New Orleans, vlemphis, Mobile, Savannah, Charleston, and even New York and Phila- delphia were visited on several occasions. Since Walter Reed’s dramatic mosquito transmission experiments at the turn of the century, there has been a steady in- crease in knowledge and decrease in inci- dence of the disease. Greatest achieve- ments of the past half century are the de- velopment of a technique for eradication of the mosquito vector and the development of an effective vaccine. Greatest dis- appointment is the discovery of endemic yellow fever in the monkeys of South Amer- ican and African jungles. Greatest threat for the future is the vast expansion of air travel, which trans.cends all barriers and brings South American jungles within a few hours flying time of door steps in the United States. Less spectacular, but more imminent, dengue or nbreak-bonen fever has already struck in the Pacific and could paralyze southern cities now, when we can least af- ford it. Although not fatal, dengue is a painful, debilitating disease and is espe- cially dangerous to a country at war be- cause of its explosive potentialities. Cases were counted in thousands in Florida during the 1930’s and in hundreds of thou- sands in Texas during the 1920’s. To meet these threats the United States Public Health Service conducted surveys prior to the war, and since 1941 32 it has operated an emergency program for the control of the mosquito vectors. As a division of the Office of Malaria Control in War Areas, this work is conducted through State and local health departments. The job is so overwhelming that a new concept of control has been reauired to fit conditions in the United States. In South America, before the war, eradication was found to be cheaper than control. A large initial expenditure of funds and manpower proved to cost less in the long run than a less expensive but continuous program. It woujd be unjustifiable at this time to divert sufficient manpower from war activities to eradicate dengue- yellow fever mosquitoes from the principal aegypti (Linn). A closely related mosqui to, Aedes albopictus (Skuse), is important in Hawaii and the Orient, and Aedes scutella- ris (Walker) is dominant in the South Pa- cific. Although less susceptible to era- dication measures, albopictus and scutel- laris may be considered as similar to aegypti for all practical control purposes. Experience with malaria shows that the habits of a mosquito species are most critical in determining its importance as a disease vector. Aedes aegypti has the most domesticated habits of all mosquitoes. In fact, it seems to be inseparably asso- ciated with mankind, preferring to feed on human blood, breed in man-made containers, and live in cities. Larvae have been found thriving in an inverted bottle cap, half an egg shell, an old shoe, and in the shallow well of a sticker-tape machine on the counter of a downtown store. More typical breeding places are temporary or permanent water containers in and around houses. Seventy-six per cent of the con- tainers found breeding during the summer season of 1943 were receptacles such as tin cans, bottles, old tires and other typical components of a junk pile. Twen- ty-five per cent of the breeding was in tin cans alone. This is no great techni- cal problem, but a problem of individual and municipal sanitation prompted by edu- cation. Aedes aegypti (Linn.) cities of the southern United States. In place of eradication, a comprehensive pro- gram of mosquito control in critical cities where military installations and war industries create the greatest hazards is offered: together with disinsectization of planes in cooperation with the Foreign Quarantine Division of the Public Health Service; vaccination of air passengers and ground crews in cooperation with the Army, Navy, and Rockefeller Foundation; notifi- cation of air passengers; and an epidemic program prepared for action on 24-hour no- tice. DENGUE-YELLOW FEVER VECTORS The principal vector of dengue and yel- low fever throughout the world is Aedes Percentage of Types of Breeding Containers 33 AEDES AEGYPTI INSPECTIONS The Aedes aegypti inspector in a proj- ect city is a combination of door-to-door salesman, super mosquito sleuth, and effi- cient mosquito control operator. His is the job of selling himself and the project to a housewife who may be busy or unsympa- thetic, and at the same time inspecting every nook and cranny of the premises for possible mosquito breeding places. Breed- ing places are corrected by eliminating containers or by larvicidal treatment. It is- recognized that constant repeti- tion *and careful checking are necessary in this type of work. In fact, routine erad- ication procedure calls for a 10-day in- spection cycle, so that each premise is visited within the period of development of a generation of mosquitoes. This ex- haustive approach to aegypti control was tried on the Key West project as a demon- stration and training program, but is nei- ther possible nor desirable for the rest of the projects, considering the critical manpower shortage. Objectives of the Aedes aegypti control program are; (1) reduction of the mosqui- to vectors of dengue and yellow fever be- low the danger point; (2) training of per- sonnel for possible epidemics; and (31 ed- ucation of householders to be their own inspectors so that they can carry on mos- quito control after our emergency program is over. Results of most aegypti control proj- ects are now available for a complete breeding season and winter season. These results are as varied as the cities and the people of the various sections of the Aegypti Breeding in House Plant country. Projects have been deliberately made more or less autonomous, headquarters supervision being restricted to technical advice, suggestions as to policy, and ad- vice on procedure. Detailed operations must be made to fit the local situation. For example, Key West has many abandoned cisterns which are bad permanent breeders; Honolulu has no cisterns but has many tropical garden plants that hold water and breed mosquitoes. Cities vary in their racial composition, and each race presents special problems to the mosquito inspector. The Negroes of the Southeast leave three tin cans in the back yard as a foundation for their laundry kettle, the Cubans in southern Florida hide their house plants from the inspector, the Mexicans in Texas store water for drinking purposes, and the Jaoanese in Honolulu raise tropical plants with cup-like leaves that hold water. THE AEGYPTI BREEDING INDEX The only universal criterion of aegypti control is the "breeding index". Recogniz- ing that this ratio of premises found breeding to total premises inspected ob- scures local concentrations of breeding and ignores the number of containers found breeding and the number of larvae per con- Destroying Abandoned Cistern 34 COMPOSITE AEDES AEGYPTI BREEDING INDEX IN RELATION TO TEMPERATURE AND RAINFALL DATA FOR INDIVIDUAL PROJECTS WEIGHTED ACCORDING TO NUMBER OF INSPECTIONS tainer, it remains our best general meas- ure of aegypti occurrence in a city. In temperate regions, this index follows the temperature curve with a lag of a month or two. Incidental dips and peaks follow fluctuations in rainfall. When results of all projects in the continental United States are combined and plotted with tem- perature and rainfall data, it becomes ev- ident that the breeding index continues to rise cumulatively until cool weather slows down the breeding, and until frosts kill all adults outside. During the first full year of operations the average index for all projects reached 6.5%. Before control programs were completely established, ini- tial indexes for Key West were 30%, for Galveston 35%, for Houston 20%, for Browns- ville 38%, and for Savannah 34%. During the winter in Savannah and Charleston and more northern cities, breeding continues in protected places such as ivy bowls in- side houses, and fire buckets and barrels inside warehouses, but the index is low. Fggs remaining outside in bottles, cans, and other trash, are a source of breeding for the next season. Henry Rose Carter suggested an aegypti breeding index of 5% as the threshold of sanitary importance. This is admittedly an abstract figure because a 5% index in a particular zone in a city would make di- sease transmission possible. In fact, a single infected mosquito can cause a great deal of trouble, regardless of the index. Furthermore, the index is a nebulous fig- ure, dependent upon the efficiency of the inspectors, and the threshold of sanitary importance varies according to the number of immune people, the number of persons sick with dengue or yellow fever and ex- posed to mosquitoes during the three-day infective period, and the number of adult mosquitoes in the immediate vicinity of these cases. Under the circumstances, it is useless to set a definite index as an objective in our anti-aegypti campaign. Nevertheless, it is clear that reduction in mosquito breeding results in fewer adult mosquitoes and therefore less chance for disease transmission. Finally, we reach a level at which mosquitoes are so few that they do not encounter a sick person during the three-day infective period. At this point the disease dies out. 35 EVALUATION OF RESULTS Results of individual aegypti projects defy comparative analysis. Differences in breeding indexes are often less than the error that would normally be expected under such conditions. However, relative size of the pro j ects in-relation to the total popu- lation gives some indication of the scope of the work. Key West, with a population of 13,000 people, is out of line because it was onerated with a different objective than the other projects. In general it is felt that one inspector per 1,000 population is necessary for complete 10-day cycle cover- age although Honolulu is being covered with one inspector per 4,000 population. Such coverage was not even approximated in our program outside of Key West and Honolulu, the over-all average being one inspector to 13,500 population. The average number of inspections per man-day is an indication of the type of ae£ypti program. However, progress will be slower in the early stages of clean-up, and the number of inspections per man- day is really only significant during the summer season, other activities dominating the picture in some projects during the winter months. Individual prodects varied in average number of in- Spraying Elevator Shaft spections per man-day from 28 in Savannah to 123 in Corpus Christi. Differences in stage of the control work are not sufficient to explain this disproportionate rate of routine inspec- tion. The real explanation lies in the philosophy of operations and in the rela- tive importance attached to inspectional, supervisory, service, and educational ac- tivities. A breakdown of these data shows New Orleans with the highest and Key West with the lowest proportion of man-hours dpvoted to routine premise inspections, and Savannah with {he most, and Key West with no time at all devoted to special educational activities. The principles and practice of aegypti control were worked out under tropical conditions in close proximity to monkey reservoirs of jungle yellow fever in Africa and South America. Under such con- ditions eradication proved to be cheaper than control. In the temperate zone cities of the United States it has been found that spectacular control is possible with a minimum expenditure of men and ma- terials. This has been accomplished by three methods in addition to routine in- spection of premises. First, project cities are searched for hidden breeding places, the so-called "mother foci" or Distribution of Man-Hours 36 permanent protected breeding places from which infestation spreads when conditions are favorable outside. Second, the cold weather of the winter which kills all adult mosquitoes outside is Used as an al- ly. During the winter months emphasis is placed on interior inspections and elimi- nation of mother foci as well as on city clean-up to eliminate cans and bottles containing over-wintering eggs. Third, education is stressed as an integral part of the control program. Quite apart from the long term effect, the value of educa- tion can be measured today in man-hours saved. Our limited preventive campaign can accomplish reduction of aegypti densi- ties to a safe level only by the fullest cooperation of an informed public. SPECIAL EDUCATIONAL ACTIVITIES It is felt that aegypti education can 'best be put over by the inspector during his routine examination of premises. The personal approach and actual demonstration of control methods is ideal. On the other hand, Hidalgo County, Texas with a popula- tion of over 100,000, reported that two men reduced the breeding index by 85% from June 1943 to June 1944, by stressing educa- tional measures rather than routine in- spection. An all-out educational campaign was conducted in San Antonio in 1944 under the leadership of the Director of the Health Department assisted by several outstanding Demonstratiny aegypti Control to Housewife authorities on aegypti control. This intense campaign reduced the aegypti breed- ing by 78% at a time when it would nor- mally have been expected to increase stead- ily. Success was attributed in large mea- sure to the complete cooperation of civic school, and medical authorities. Outside of project cities, educational measures are our only method of attack. For this purpose a mobile unit was outfit- ted with window displays, leaflets, spe- cialized training films, and other educa- tional material. Working through the Of- fice of Civilian Defense, leaflets were distributed and personal contacts were made with more than 600,000 homes repre- senting close to 2,000,000 persons. The work was started at \liami, Florida and moved along the Gulf and Atlantic Coasts as the breeding season developed. The program in Brunswick, Georgia from May 5 to 12, 1944 may be taken as an exam- ple of the OCT campaign. The breeding in- dex was determined as 10% by a crew of 8 inspectors borrowed from the nearby Savan- nah project. The. mayor issued a proclama- tion which summed up the dengue - yellow fever problem and called on the citizens San Antonia Conference on aegypti Control 37 to Cooperate through individual conti work. Health department personnel were instructed in aegvpti control. Air raid wardens received special training after which they distributed 10,000 leaflets to homes within their precincts and zones. Sight thousand school children were con- tacted with films, talks, and demonstra- tions. Addresses were made before civic clubs and to two shifts of shipyard work- ers. In addition, the general public was reached by means of three billboard dis- plays, movie trailers, daily radio forums, newscasts and spot announcements, and by newspaper articles. Under epidemic conditions this all-out approach in cooperation with the Office of Civilian Defense could be greatly expanded and the individuals already contacted could serve in a voluntary capacity with a real knowledge and background o-f anti- aegypti methods. EPIDEMIC CONTROL The United States Public Health Service is prepared to assist State and local health departments in the event of a den- gue or yellow fever out-break. Facilities are available for an intensive campaign to sterilize the area around a primary case of yellow fever or for a long term siege against a well-established dengue epidemic. Trained men have been assigned to particu- lar jobs, equipment has been set aside for the emergency, and sufficient yellow fever vaccine is available through the National Institute of Health and the Rockefeller Foundation to immunize the entire popula- tion of a city. Any or all of these facil- ities could converge on a given spot in the Southeastern States within a few hours. The organization has been set up in great detail to cover all possible contin- gencies, because we cannot anticipate which services will be required in any one instance. In general, it is recognized that two phases or types of operations will be necessary. In the case of yellow fever, an exhaustive local campaign must be started within a very few hours after diagnosis of the first case. Adult spray- ing around the scene of the case and vac- cination of people in the neighborhood OCD Warden Distributing Anti-aegypti Notes will dominate the first day’s work. If successful, there should not be any sec- ondary cases. Dengue is a different problem. Diffi- cult to diagnose and without a vaccine, the chances are very great that a city- wide epidemic would be under way before effective control measures could be start- ed. Under these conditions, or in case yellow fever gets out of hand, a general aegypti control program will be necessary. Routine inspection and correction of breeding places would have to De esta- blished on a 10-day cvcle. It may be argued that dengue is not a fatal disease and that it does not justify such drastic measures. This might be true in peacetime, but it is far from true in our critically important southern cities during wartime. Individually, dengue is not serious; but collectively it can pros- trate a city. literally everyone gets dengue if it is allowed to run its course. Shipyards would be closed, and troops would be restricted or immobilized. 38 DENGUE CONTROL IN THE HAWAIIAN ISLANDS Two cases of dengue fever were reported from Honolulu during the week ending July 6, 1943. Presumably the disease was in- troduced through air travel from the South Pacific. Previous epidemics occurred in 1903 and in 1912 and resulted in wide- spread suffering and general involvement of the entire population. It was impera- tive that an explosive epidemic be avoided at this time because of crucial mili- tary operations based upon the Hawaiian Islands. The Territorial Board of Health and the Army Medical Department took immediate action to control the mosquito vectors Aedes aegypti (Linn.) and i ts oriental rela- tive, the equally domesticated Aedes albo- pictus (Skuse). In spite of the efforts of 24 inspectors employed through Chamber of Commerce funds and five soldiers working as a crew to inspect the city section by section and in spite of an educational program through the press, radio, and Of- fice of Civilian Defense, dengue increased. Cases became so numerous that Waikiki was declared off-limits for military personnel on August 8. This directive attracted in- ternational attention. Strenuous measures were necessary to clean up this important commercial and recreational area so an all-out program was inaugurated to destroy infected adult mosquitoes. All premises in the Waikiki area were sprayed inside and out, utiliz- ing undiluted commercial insecticide ap- plied by high pressure Chemical Warfare decontamination truck sprayers. DENGUE CONTROL BY THE PUBLIC HEALTH SERVICE Late in August assistance was requested of the United States Public Health Service. The officer in charge of the Aedes aegypti Section of MCWA and the supervisor of the Savannah Aedes aegypti control unit were immediately sent to Honolulu to organize a control program. Interview Prior to Premise Inspection Becauseof wartime restrictions on trans- portation of personnel and equipment it was necessary to build up an entire program from the nucleus of inspectors already on the job. The greatest problemwas to quick- ly assemble, outfit and train enough in- spectors to cover the City of Honolulu on a 10-day cycle. However, a combination of good luck and hard work made i t possible to put 96 men, completely equipped, in the field on September 15. This would have been difficult in most mainland areas, but standard equipment or suitable substitutes were found by diligent search in supply houses in Honolulu. Inspectors were assem- bled by a hiring campaign which netted only 13 men, plus 33 men already working on the program, plus 50 detached service soldiers supplied through the Office of the Surgeon, 39 Crew of Dengue Mosquito Control Inspectors Central Pacific Area. The original intention was to release military personnel as the emergency sub- sided and as civilian labor was hired. However, the manpower shortage was so acute that additional soldiers had to be added as the disease spread to rural Oahu and the outside islands, and as dengue cases were imported in increasing numbers from the South Pacific. By the end of the fiscal year the entire organization num- bered 150 men in Honolulu, 75 men else- where on Oahu, 74 men on the island of Hawaii, 43 men on Maui, and 42 men on Kauai. Personnel on the outside islands consisted of 2 colored sanitary companies, each with 114 enlisted men and 3 officers. Control followed the standard inspec- tion-correction technique, but special problems were encountered here as in every city. Water standing at the bases of leaves of ape plants and in the leaf cups of pineapple lilies was particularly troublesome because these are the common- est ornamental plants in the gardens of Honolulu. Aedes albopictus was especially prone to breed in such places and in tree holes and was found breeding from the cen- ter of the city up to an .elevation of 2000 feet in the forest. Mosquito control was closely correlated with epidemiological findings. Confirmed cases of dengue were reported daily and a crew of "trouble shooters" was sent out to spray and inspect the disease premises and the area immediately surrounding these spots. A Public Health Nurse visited each dengue patient and set up a bed net to prevent the patient from infecting addi- tional mosquitoes. A case history was ob- tained to assist in tracing the source of infection. As was expected, a time lag occurred between the start of expanded control ac- tivities and the first noticeable decrease in dengue cases. During this interim, a second maior focus of infection developed in the congested Kakaako section adjacent to the business district near the center of the city. A prominent laundry in this district failed to cooperate in killing adult mosquitoes after breeding had been stopped. Many cases were traced to this source and the situation reached a climax 40 when 70 employees of the laundry were down with dengue at one time. This and subsequent disease foci were treated like Waikiki except that a more efficient and less caustic pyrethrum-base water-diluted spray was used in the 400 gallon decontamination spray rigs. Other special activities included clean-up of thousands of loads of tin cans, bottles, and other breeding containers, spraying of catch basins, clearing of roof gutters, stocking of ponds with mosquito fish and filling of rock and tree holes. Educational activities were vital to the program because reduction in mosquito breeding depended upon elimination of breeding places in and around the home and eradication of the disease depended upon prompt reporting of cases. Every avail- able means of contacting the public was utilized and the publicity was multiplied many times by inclusion in commercial ad- vertisements. Since three-fourths of the population is of foreign ancestry, publi- city was issued in the Japanese, Chinese, and Korean languages. The city-wide breeding index continues to prove useful for over-all supervision of the work but has the same disadvantages in Honolulu as elsewhere. Rainfall, in particular, confuses the picture because such dry sections of the city as Waikiki have as little as 20 inches of rain per year; whereas the residential sections near Army Decontamination Sprayers in Use Cleaning Clogged Roof Gutter Treating Water in Spider Lilies Killing Larvae in Tree Hole with Kerosene 41 the heads of Nuuanu and Manoa Valleys have over 100 inches of rainfall. As might be expected, mosquito breeding was closely correlated with rainfall but surprisingly the highest concentrations of dengue cases did not coincide with the zones where mos- quitoes were most abundant. Dengue flour- ished under congested conditions in the dry Kakaako District where houses are un- screened whereas it was self-limited in cases appearing each week began to levei off below 20 and by June, 1944, the aver- age had dropped to less than one new case per week. Prospects for the future are difficult to analyze. The commonest vector, Aedes aIbopictus, breeds throughout the dense forests up to 2000 feet, as well as in the cities, so elimination of this vector from the entire territory is impossible. On Trend of Dengue Caees Compared with Rainfall and Aedes Breeding Index the presence of screened homes with large gardens and extensive grounds in the wet, mosquito-ridden heads of the valleys. RESULTS OF DENGUE CONTROL The proof of any control program is measured by the results obtained. The Ha- waiian dengue epidemic started in July from two cases and built up to a maximum of 159 cases during the third week in October. Immediately after the peak, a marked reduction took place, with the de- crease occurring as rapidly as the earlier rise. In January 1944, the number of new the other hand, it has already been shown that breeding can be reduced to a satis- factory level wherever sufficient effort is devoted to the job. Dengue has not only been held within bounds, it has ac- tually been reduced to a small number of cases per week. Final elimination of the disease depends upon continued effort and prompt reporting and follow up of cases. Reintroduction is very possible because of dengue cases returning from the South Pa- cific, so constant vigilance and a thorough ujutine mosquito control program will be necessary for the duration of the war. 42 OTHER MOSQUITO-BORNE DISEASES AND INSECT PESTS OBNOXIOUS MOSQUITOES Health officials for years have been preoccupied with the anopheline vectors of malaria and the aedine vectors of dengue and yellow fever. All other mosquitoes were classified disparagingly as "pest mosquitoes. " The original MCWA budget specifically limited MCWA expenditures to the vectors of malaria, and later included a small fund for the control of dengue and yellow fever vectors. This was a sound policy considering the funds and manpower available for mosquito control. How- ever the public tends to judge the effectiveness of the program not in terms of malaria control, but in terms of mos- quito bites so area supervisors have been hard put to explain to irate citizens the mass emergences of gallinippers or flights ot sait-marsh mosquitoes. Mosquitoes can and do become extremely annoying, even to the point where vital war work or troop maneuvers are affected. MCWA is now authorized to survey and even to control pest mosquitoes upon specific request of the Army, but this work is con- tingent upon reimbursement by the request- ing agency and is limited to a few cases of major military importance. Surveys have been made in Dennsylvania, New Jersey and Mississippi, and control has been started in a New Jersey area. DOG FLY CONTROL The dog fly, Stomoxys calcitrans (Linn.\ is a serious hindrance to military person- nel along the Gulf coast of northwestern Florida. MSWA is continuing to support dog fly control work of the Bureau of Entomo- logy and Plant Quarantine. Breeding occurs in beach deposits of marine grasses, so the windrows are snrayed with creosote. MOSQUITOES THAT TRANSMIT DISEASES Studies on the role ot mosquitoes in the transmission of diseases otner thar malaria, dengue, and yellow fever, and war- time experiences in the South Pacific sug- Spraying Dog Ply Breading Places gest that the time has come to reexamine the concept of "pest mosquitoes." It now appears that many of our commonest mos- quitoes are capable of carrying diseases. Accepting this conclusion we are at once confronted with a general anti-mosquito campaign. Several projects of this kind have been highly effective in the United States, and th** increased interest and importance of mo sou i to-bo me diseases dur- ing the present war should stimulate many communities to establish all-out mosquito control programs ENCEPHALITIS The Western Equine and St. Louis types of encephalitis have caused several epide- mics: in this country. They have been transmitted experimentally by the following mosquitoes: Culex tarsal is, Culex corona- tor, Culex pipiens, Aedes lateralis, Aedes taeniorhynchus , Aedes vexans Culiseta inornata, Culiseta incidens and Anopheles freeborni. Fortunately, encephalitis has not broken out in epidemic form thus far during the war. FI LARI AS!S Filariasis has recently skyrocketed to prominence and may be of great post-war concern. It is a disease caused by the nematode worms, Viuchereria bancrofti and Wuchereria malayi. The adult worms occur in the lymph glands and tissues. They re- 43 lease small worms known as microfilariae which circulate in the outer blood where they are readily accessible to biting mos- quitoes. Some microfilariae circulate in the outer blood periodically either during the daytime or at night while others show no such regularity. A definite relation- ship exists between the biting habits of the mosquito vectors and the time when the microfilariae circulate in the blood. Unlike the malaria parasites, filaria worms do not multiply in the mosquito. They undergo larval development in the thoracic muscles and infective forms mi- grate to the proboscis sheath rather than to the salivary glands. From the probos- cis sheath they emerge and burrow through the skin of the mosquito’s victim. During the incubation period of 12 to 18 months, the worms migrate all over the body but especially to the region of the groin. They cause transient inflammation and swelling of the lymph glands. Ele- phantiasis of the scrotum and extremities only occurs after repeated infections and long exposure. .No specific treatment is known for filariasis and no satisfactory method of freeing the blood stream of microfilariae has been discovered. In the South Pacific, filariasis is second in importance only to malaria. On- ly a few cases showing microfilariae in the peripheral blood stream have been re- ported. So far the most serious effects of filariasis have been psychological. Victims of this disease fear the possibil- ities of advanced elephantiasis of the ex- tremities and scrotum. However, there seems to be no danger of this if patients are moved out of endemic areas soon after the disease is diagnosed. Filariasis is endemic in the Caribbean region. It has been introduced into this country by Puerto Ricans and by Negro im- migrants from the Virgin Islands. Thirty years ago an endemic focus of filariasis., presumably established following the in- troduction of the disease in Negro slaves from Africa, existed around Charleston, South Carolina. Since that time this fo- cus has apparently died out. An important question at the moment is which of our United States mosquitoes are capable of carrying this disease. It is known that the common Culex quinquefascia- tus is a potent vector. Other so-called pest mosquitoes are known to develop in- fective larvae The National Institute of Health is now conducting transmission stu- dies and research on diagnostic tests and chemotherapy of filariasis. Filariasis stands today as the greatest public health enigma of World War II. A certain number of filariasis carriers will no doubt be distributed over the country following the war. If a sufficient number of these should be concentrated in areas where effective mosquito vectors are pre- valent, it is conceivable that endemic foci of filariasis might become re-esta- blished in the United States. MCWA has designated a medical officer to keep abreast of the latest developments in this field and to provide popular and technical information on the subject. A summary of the distribution and density of all mos- quitoes in the United States is maintained and is available to military authorities and others on request. This information is a by-product of routine entomological inspection and surveillance for malaria, so no extra field work is involved. The potentialities of the filariasis situation warrant alertness: and the present policy of keeping informed, supporting research, and watchful waiting appears to be a sound procedure. Oiagraitmat ic Filariasis Cycis 44 IN-SERVICE TRAINING Entomological Inspection at Field Training Area The most critical shortage during war- time is not materials but manpower. MCW/, as an emergency program, started with only a nucelus of trained men. As the activi- ties and responsibilities of the organiza- tion increased, it was necessary to enlist the services of additional doctors, ento- mologists, and engineers, despite the di- minishing number of men available in these professions. This growth was facilitated by an orientation and training program de- signed to teach fundamentals of malariolo- gy to men trained in related fields, such as civil engineering, general entomology, biology, and general medicine. Well-trained professional personnel are vital to the program becatise they, in turn, trainsub-professional employees - inspect- ors and foremen - on individual projects. Herein lies the success or failure of the entire program. If inspectors and foremen are properly instructed, satisfactory re- suits will be obtained; if their training has been neglected, the effectiveness of the program will be diminished. The in-service training classes are conducted by experienced entomological, medical, and engineering officers. Every phase of the program is discussed, and lectures are supplemented by educational film strips, laboratory work, and directed reading. The program includes a period of field training which is most valuable to the trainees. Practice work is carried on at a specially selected training area near Atlanta. Here the trainee himself carries out the steps necessary in establishing and conducting an inspection and control program. Through the courtesy and cooper- ation of the Georgia Department of Public Health, the trainees visit Valdosta, Ga., where they study a malaria control area in actual operation. Aegypti control is studied at the Savannah, Ga. project. 45 A summary of administrative procedures, along with information on the organization, customs, and history of the Public Health Service are given each class of trainees. Newly commissioned officers are instructed in military courtesies, and the relation- ship of the Public Health Service to other uniformed services. Since December, 1943, 49 trainees have completed the course. Sixteen of these were entomologists, 25 engineers, 3 sur- geons, and 5 biologists in other special- ized fields. Twenty-eight of the 49 trainees had had no previous experience with the Public Health Service. In addi- tion to these, 12 Public Health Service officers attended selected portions of the course. Four of these attended the course as partial preoaration for duties with the United Nations Relief and Rehabilitation Administration. The Division of Health and Sanitation of the Coordinator of Inter- American Affairs sent a Fellow from Panama to the In-Service Training course in con- nection with his field study of various MCWA p rojects. Several visitors from other services have attended portions of the course. Results of the In-Service Training pro- gram have more than repaid the efforts that have gone into its organization. Field work has been more intelligently planned and executed, officers have had a better understanding of their duties and their relationship to the headquarters office, and reports have been more complete. Area Supervisor Explaining Dynamited Ditch Anoohslins Identification Study of Malaria Parasites Adjusting Nozzle on Knapsack Sprayer 46 EDUCATION Unscreened Houses Invite Mosquitoes Screens Protect Families from Malaria The effect of education on the incidence of mosquito-borne diseases is indirect but positive. General malaria awareness has been an important factor in the recession of this disease in the United States. The perpetuation of preventable di- seases depends largely on the habits of people. For example, the transmission of hookworm depends on the habit of deposit- ing human feces on the ground in easy ac- cess to people in the habit of walking with bare feet. If either of these habits is altered the disease ceases to be transmitted. This is exactly what has happened over a large part of the country during the last few decades. The transmission of mosquito-borne di- seases is more conplicated. Here the ha- bits of both mosquito and man must be con- sidered if the disease is to be prevented. There are no known methods for changing the habits of the mosquito. The habits of man can be changed through education. Malaria would disappear from the South- eastern United States within a few years if man would alter his behavior only slightly. It is stated by eminent malari- ologists that most malaria is man-made; all malaria is man-tolerated. It is large- ly a by-product of construction without regard to disease prevention. The habit of building artificial im- poundments without taking proper precau- tions to prevent anopheline breeding; the habit of building roads which impound wa- ter because culverts are not properly placed; the habit of making improperly drained borrow pits for road construction or other use; the habit of sleeping in un- screened houses or sitting around in the evening without protection from mosquitoes; these and other habits are responsible for man’s malaria. It is generally conceded that malaria could be eliminated from the United States if everyone protected him- self from mosquito bites. The danger of dengue and yellow fever in this country exists solely because of man’s habit of providing artificial breed- ing containers for the Aedes aegypti mos- quito. Being a purely domestic mosquito it could be eradicated in a very short time if everyone kept his home and prem- ises free of mosquito breeding 47 INFORMATION AND ACTIVATION tagonistic. It is the large segment of indifferent individuals that must be in- formed and activated if mosquito-borne di- seases are to be controlled or prevented. The objectives of our educational work are: 1. To present clearly the facts about mosquito-borne diseases. 2. To state specifically what the in- dividual and community can do to control or prevent mosquito-borne diseases. 3. To stimulate individuals and com- munities to assume responsibility and to take the necessary action to prevent these diseases. The most obvious place to carry on a program of health education is in the schools. This long term approach is sound because it gives correct information to the pupil at a receptive period of life. The facts about prevention of mosqui to-bo me diseases should be interwoven throughout the school curriculum. The prevention and control of mosquito- borne diseases through education resolves itself into two components: information and activation. Both are necessary. Peo- ple can become activated and yet waste time and energy in an unsuccessful attempt to control a disease because they are lacking in correct information. During the yellow fever epidemics in this country people were activated by the horrible dev- astation of this disease but, lacking cor- rect information on its prevention, they not only failed to control the disease but in many instances created greater disease hazards. Moss which was thought to harbor the disease was pulled from trees; chest pads advertised as "positive preventives for yellow fever" were worn; clothes were burned, and cups containing water were placed under tables as ant guards, ironically providing a breeding place for the vector of yellow fever within the home of people stricken with the di sease. Activation without information is trag- ic but can be corrected rather easily, whereas information without activation is more difficult to overcome. The task of activating people is greater than the task of informing them. This is particularly true in the case of malaria because it is a disease which transforms the inherent inertia of mankind into apathy. Fortu- nately this is not the impasse that it ap- pears to be--we work on a percentage ba- sis in dealing with human beings. Given the facts about malaria a small percentage of people will not only apply preventive practices themselves but will actively campaign for community control measures. Others will apply individual control measures and will give community enterprises their active support. Many will be indifferent, and a few may be an- Scouts Aid Clean-up Drive Teaching units on mosquito-borne diseases were prepared and used in many schools. In Charleston, South Carolina, and Savannah, Georgia, special student surveys were conducted. Each student inspected his own home and eliminated mos- quito breeding places. Results were re- ported on forms showing name, address, and number of containers eliminated. Special problems were also reported. 48 Mosquito Control Education in an Elamantary School School children were further activated by an Aedes aegypti clean-up program. Two teachers, devoting full time during the summer vacation*period, organized school children into "Skeeter Sentinels." These patrols met once a week at their schools and went out as clean-up gangs to elimi- nate mosquito breeding places in their neighborhood. School children played an important Part in the control of the dengue epidemic in Honolulu. The principals, teachers, and school nurses were instructed in den- gue mosquito control by movies and demon- -s trations at a mass meeting. They, in turn, conducted the special student survey during which school children made over 25 000 seoarate inspections and eliminated over 30,000 water holding containers, of which 17% contained mosquito wrigglers. Two members of the MCWA staff devoted full time to malaria education during the winter season. Extensive use was made of motion pictures and film strips, and prac- tically every school child in Mississippi County and Jefferson County, Arkansas was reached. A number of malaria units have been established in schools during the past year as a result of previous communi- ty education programs. PROFESSIONAL GROUPS The need for education of professional groups on methods of preventing mosquito- bome diseases becomes increasingly appar- ent when we observe their role in creating and tolerating these diseases in their professional activities. Malaria control is essentially an en- gineering job, yet most engineers are taught little about how to build malaria out of construction jobs. The result is an anomalous situation wherein one group of engineers, through ignorance or indif- ference, is busily engaged in creating ma- laria hazards while another group of en- gineers is engaged in eliminating the haz- ards so created. The answer to this glar- ing defect is the incorporation of malaria control principles and other phases of sanitary engineering into the general cur- riculum of engineering schools. The MCWA program has assisted in this field by fur- nishing motion pictures and informational materials to engineering professional groups and engineering schools. Members of the operational staff of the headquart- ers office also assisted with professional education by a series of lectures at Van- derbilt University and at the DeLamar In- stitute at Columbia University. Lectures 49 have been given by various members of the MCWA staff to other engineering groups. Lack of interest, and in some cases a lack of technical information on the pre- ventive aspects of mosquito-borne di- seases, is noted in the medical profession. In the most malarious areas of the United States physicians are encountered who take little interest in careful malaria diagno- sis and malaria reporting. There is also a lack of interest and support for mosqui- to abatement as a disease preventive meas- ure. To increase the interest in and knowledge of mosquito-borne diseases among the medical profession it will be necessa- ry to incorporate more tacts about these diseases in the medical school curriculum and to assist in disseminating the facts more widely among medical practitioners. Various members of the medical and entomo- logical staff gave approximately 50 lec- tures to medical students, medical societies, and other medical group meet- ings. To assist further in the training of professional groups, a Kodachrome film is now being prepared on the diagnosis, treatment, and prevention of malaria for the medical profession. Another training film is being prepared on the microscopic- al diagnosis of malaria for technicians and physicians. A display on malaria pre- vention was prepared for the convention of Military Surgeons held in Philadelphia, Penn sylvania. ADULT EDUCATION The greatest challenge to education as a positive approach to prevention of mos- quito-borne diseases is in informing and activating the general adult public. Formal adult education is not extensive enough to serve our purpose so other ap- proaches must be used. To carry on the adult educational program several methods have been employed. The aegypti educational work has been conducted primarily as a part of the op- erational program. Most of the education- al work has been planned at the area lev- el. Area supervisors delivered 1673 il- lustrated lectures to various adult groups. The Aedes aegypti inspector has made a special effort to inform and to activate the householder during his routine inspec- tions. For the malaria educational activities a summer community program was conducted as a line of secondary defense beyond the one-mile MCWA operation zones. Under the Chief of Field Activities in Health Educa- tion, 91 persons, most of them local teachers, were appointed to serve as mala- ria educators in 91 counties of thirteen States. These teachers were given prepa- ration for the community educational pro- gram prior to their summers work. Each educator made a preliminary survey of the county in which he would work and attended a two week intensive training course in Memphis, Tennessee. During this period of Display on Malaria Prevention Prepared for Meeting of Military Surgeone 50 Orientation Course for Field Workers in Malaria Education orientation the educators were instructed in malaria and in methods of community health education. After the two week training period these educators returned to their respective health departments and, in most instances, worked under the direction of the county health officer. Their purpose was to inform and to acti- vate individuals and communities on mala- ria and its prevention. The malaria educators worked both with groups and individuals. They worked pri- marily with existing group organizations. It was generally found that the most ef- fective work could be done by cooperating with the Office of Civilian Defense, home demonstration agent, county farm agent, civic groups, churches, Boy Scouts, and school groups. In certain instances, a great number of people were reached at incidental gatherings in farm yards, at picnics, church suppers, and health de- partment clinics. About 3000 meetings were held or attended by malaria educators. More than 19,000 personal interviews were reported. In many instances anopheline NFORMATION ACTIVATION MEETINGS 2,699 ATTENDANCE - 142,068 HOUSES SCREENED AND SCREENS REPAIRED 0,470 PERSONAL CONTACTS 19,609 DITCHES CLEANED OR DUG (MILES) 14 NEWS ARTICLES (COLUMN INCHES) 4,951 BREEDING PLACES CONTROLLED RADIO PROGRAMS 384 BROADCAST II ME-30 HOURS COMMUNITY CONTROL PROJECTS STARTED 72 Rasul t b of Conxnunity Malaria Education for tha Sumner of 1943 51 mosquito breeding places were inspected and householders instructed specifically on what to do to protect themselves and their families from malaria. By malaria education the incidence of malaria and the dangers of transmission can be reduced in the broad area beyond the one-mile MCWA operation zone. The cost in manpower, materials and equipment for extension of MCWA control activities into this area would be prohibitive. INFORMATIONAL CHANNELS Since newspapers reach a large propor- tion of the public, MCWA has used this medium extensively, 5000 column inches ap- pearing on the subject of dengue-yellow fever control. In some instances local firms donated space for messages on both yellow fever and malaria. Through the assistance of the Division of Public Health Methods, nine cartoons have been prepared as newspaper mats for use in Aedes aegypti control work. Ideas for these cartoons were suggested by area supervisors and were stimulated by the needs which field men noticed from day to day. Cartoons such as these attract more attention than long articles. On the radio, short quiz programs and spot announcements have been employed both in dengue-yellow fever and malaria control work. More than 50 hours of broadcast time have been consumed by these programs. The 16mm motion picture and 35mm film strip are visual aids which are effective means of reaching small groups such as service clubs, schools, and church groups. They serve best when used in conjunction with brief discussions. MCWA has prepared a short Kodachrome motion picture for use on the Aedes aegypti control program. This film tells the story of individual and community action against the dengue-yellow fever mosquito. A series of colored film strips on malaria are also being prepared. Extensive use has been made of the malaria film strip prepared by the Division of Public Health Methods and the motion pic- ture *The Winged Scourge" prepared for the Office of the Coordinator of Inter-American Affairs. The Division of Public Health Methods assisted in preparing posters, window displays, billboards, premise bul- letins, and handbills for use in educa- tional campaigns against Aedes aegypti. Many aegypti and malaria educators design- ed and prepared their own window displays and stimulated individuals in the commu- nities where they were working to prepare posters for local use. The most effective, though time-consum- ing, educational procedure is to inform people through personal interviews, by de- monstrating specifically the problem and its solution. Aedes aegypti inspectors personally interviewed 968,337 persons during the year and indirectly contacted other members of households, reaching a grand total of over two million people. Courteous, informative interviews were conducted by the inspectors in order to help the householder clean up his premises. An attempt was made to impress the house- holder with the necessity of being his own inspector. He was shown exactly what to do to prevent mosquito breeding; and where conditions were most serious, the premises were rechecked to make sure that the nec- essary corrections had been made. Seven hundred and twenty nine of these check- backs in Savannah, Georgia revealed that the householders’ work was 94% effective. Although education is generally consid- ered to be a long term approach, it is clear that it has an immediate effect in dengue-yellow fever control. Education Movies are Effective in Malaria Education 52 makes the entire aegypti campaign possible in the face of our acute manpower shortage. It would be impossible to do for the householder what he can be stimulated to do for himself through education. With our present funds aegypti projects can on- ly be operated in 12 key cities. Educa- tional methods are our only hope at pres- ent for covering the many other critical cities in the Southeastern United States. The Aedes aegypti Division has carried on an extensive educational campaign in these non-project cities. FUTURE PROSPECTS Never before have so many people been mindful of insect-borne diseases, nor have so many doctors, engineers, and entomolo- gists been trained in malaria control. The war has raised serious problems in the control of malaria and other mosquito- borne diseases but these problems are being met, and the war is setting the stage for the greatest mosquito control effort in history. If the proper sort of educational work is done, individuals and Billboard Publicity for aegypti Control communities will incorporate mosquito abatement in their post-war planning and will carry on with local funds the work which was inaugurated as a wartime emer- gency with federal funds. It seems apparent that malaria educa- tion has served us well. The remarkably low incidence of malaria in the United States today has been attributed to many influences, not the least of which is education. Malaria education has been cu- mulative- - the long term approach of former years becoming the solution of today. In a paper delivered at the Fourth An- nual Conference of Malaria Field Workers at Chattanooga, Tennessee in November, 1922, Assistant Sanitary Engineer Leslie C. Frank said, "Malaria control education . ....must be begun and never ended. It must become a permanent part of the school program. It must be ceaselessly pressed through the channels that reach adults.... it is the most important part of our prob- lem. Malaria control education will be the ultimate secret of malaria eradication; and a given amount of money, if spent upon education, will yield very much more than if spent upon any other phase of malaria control. " His statement is as true today as it was a quarter of a century ago. Conmunlty-sponsored Mosquito Control 53 ADMINISTRATION EXPENDITURES FOR MEN AND MATERIALS 1943-44 The Administrative Division acts as a service unit for the operating divisions. Coordination of administrative functions with these divisions is maintained through established liaison under the ex- ecutive office. Functioning under the Administra- tive Division with respect to general policies are the State and Territorial business offices of the MCWA program. Decentralization of this work through State offices has proved its value in integrating the activities of operations and administration. Much credit is due the field offices for the satis- factory performance of their duties. Primarily the Administrative Division is re- sponsible for furnishing men, materials, and equip- ment when and where needed in conformity with gov- ernmental rules and regulations. MCWA operates in areas where nearly all avail- able manpower has been drained by industry or by the armed forces. In spite of this situation, an ade- quate number of employees, approximately 3300, was maintained. Manpower is by far the most important single item on the MCWA budget. Approximately 80% of the total funds were expended in payment for personal services as against 20% for equipment and other ac- tivities. For this reason it was imperative that labor saving equipment be used in order to insure the most efficient use of manpower. Under the cir- cumstances, the man-hour has replaced the dollar sign in calculating the efficiency of operations. Second only to the manpower shortage is the dearth of supplies and materials needed for carrying on the MCWA program. Supplying such an organization would have been difficult in normal times and has been doubly so under present conditions. The Region- al Office of the War Production Board has provided necessary priorities, and a great deal of equipment has been available through Treasury Procurement. 54 PERSONNEL Each symbol represents 100 people COMMISSIONED TECHNICAL ' SUB-TECHNICAL TOTAL SALARIES $5,222,847.81 CLERICAL LABOR EQUIPMENT Each symbol represents 50 units POWER DUSTERS POWER SPRAYERS BICYCLES AUTOMOTIVE HAND DUSTERS HAND SPRAYERS Some vitally needed pre-war equipment was obtained by transfer from other government agencies, particularly from WPA and NYA. Most of this type of property has now been allocated so it may become impossible to fill needs from this source in the future. Automotive equipment has been particu- larly scarce. Since the Appropriation Act prohibits the purchase of new or used pas- senger carrying vehicles, more efficient utilization of the equipment already on hand was the only answer. The States showed a fine spirit of cooperation in this effort. In Virginia and in Puerto Rico, for example, repair shops were set up which made these projects practically independent of the overcrowded private shops and garages. Major repairs can now be handled through a central garage and repair shop in Atlanta. During the year arrangements were made permitting the auditing and payment of miscellaneous public vouchers in Atlanta. This arrangement naturally reduces the time of payment and has improved operating conditions of the entire MCWA program. 55 MALARIA CONTROL IN THE STATES MCWA administrative offices have been established in 19 States, the District of Columbia, Puerto Rico, and the Territory of Hawaii. In 22 additional States programs were operated in the vicinity of prisoner>of*war camps and Army and Navy general hos- pitals. In these areas, the problem is handled by mobile units. 56 ALABAMA problem in this region. Nineteen of 36 military establishments and 49 war essential industries are located in or near areas where malaria is of suf- ficient importance to warrant control measures. Practically all of these essen- tial industries are located in the Mobile Area. With the exception of a narrow strip bordering the Gulf of Mexico, topographic features of the State are favorable for drainage. Consequently, the policy of eliminating mosquito breeding areas, wher- ever feasible from an economic and engi- neering standpoint, has been adopted. A program of major drainage around war areas was instituted early in 1941 with the as-, sistance of the WPA and continued under the MCWA program. As a result, the signi- ficant and permanent anophe- line breeding areas effect- ing military and essential war establishments in most instances have been com- pletely eliminated. This accomplishment has not only greatly improved mosquito control but also has made possible a considerable re- duction in labor forces. IXiring the year 18 areas, embracing 36 zones, were under active control, vary- ing in scope from major drainage projects to larvi- cidal operations and inspec- tional service. Routine larvicidal operations were necessary in the Mobile Area where insuffi- cient fall renders drainage impossible. Larvicidal treatment of temporary bodies of water, construction of minor drainage systems and maintenance of major drainage projects were in force in ten areas and constituted the major function of the pro- gram. Routine entomological inspections were the only measures necessary in seven areas. A unique filling material was used in STATE HEALTH OFFICER BURTON F. AUSTIN M.D. During the past six years the trend of malaria in Ala- bama, as in other southeast- ern States, has been decided- ly favorable. However, it would be presumptuous to as- sume an attitude of compla- cency because malaria is still taking its toll. In the southern and south cen- tral portions of the State, relatively flat topography and the broad flood plains of the major streams provide suitable breeding places for Anophelet quadrimaculatus. The northern portion is characterized by "lime sinks" resulting from the disintegration of limestone stra- ta closely underlying the surface of the ground. In the north central and north- eastern sections the topography is hilly or mountainous. The rapid rate of run-off in these areas is not conducive to the formation of mosquito breeding areas. Therefore, malaria has never been a serious BUREAU OF SANITATION STATE OFFICE M.C.W.A. 21 WAR AREAS III WAR ESTABLISHMENTS PROTECTED 57 the Mobile Area. Several small bodies of water having a total area of approximately three acres were filled with sawdust. The availability of material, its ease of hand- ling, and a flat topography with a rather slow rate of run-off are factors contribut- ing to the success of this operation. When using this type of material for fill- ing, approximately 25% should be allowed for settlement. Prisoner-of-war camps were the only military establishments activated in the State during the year. Two of these, which are central camps, were located within the reservations of military in- stallations already under control. Six prisoner-of-war branch camps were also lo- cated within the State. Fortunately, five of these are in areas considered relative- ly free of Anopheles quadrimaculatus and consequently have been operated as inspec- tional services. The sixth, located at Chatom, is almost surrounded by areas po- tentially capable of producing the malaria mosquito. Through arrangement with the Army, prisoners of war are being utilized on larvicidal treatment of these areas un- der the general supervision and direction of personnel attached to the MCWA program. The agreement between military authori- ties and other agencies interested in the location of temporary prisoner-of-war camps, whereby the State Health Departments will be requested to inspect and report on the sanitary conditions existing at proposed sites, should prevent the selection of areas in which malaria is considered a serious problem. Inspections have been made and eports prepared for four propos- ed sites of prisoner-of-war camps at the request of the War Manpower Cormussion. In constructing the two major drainage projects, methods commonly practiced in ditching with dynamite were successfully employed. It is interesting to note that one of the projects resulted in the elimi- nation of approximatelv 400 acres of water surface by the construction of 37,000 lin- ear feet of ditch involving excavation of 36,250 cubic yards of material. Hie rela- tively excessive length of ditch was nec- essary in order to secure a suitable out- Loading Sawdust into Truck Spreading Sawdust Sawdust Fill Completed 58 during the year. Comparing the periods July through September 1943, and May through June 1944, inclusive, the average density per nA" station for Aliceville was 4.77 while that for Mobile was 1.78. The situation in Aliceville is believed to have been considerably improved by the construction of a major drainage project during the winter of 1943-1944. The in- tensified larvicidal program should result in a reduced anopheline population in the Mobile Area. The number of cases of mala- ria occurring within military reservations is not available. However, the matter has been discussed with responsible officers, and it appears that local transmission has been almost negligible, the majority of cases being of overseas origin. In addition to the malaria program, an Aedes aegypti control unit was established in Mobile during March 1944. This unit is composed of a supervisor, an assistant supervisor, and eight inspectors. The program is progressing favorably and has been well received by citizens of Mobile. The local newspaper and civic organiza- tions have cooperated to the fullest ex- tent with the control unit and the Board of Health. Treating Firs Barrel witn Phenothiazine let. In connection with this project, a concrete pipe having a diameter of 54 inches was installed under a main highway. Thirty-two feet of this pipe were jacked through the highway fill 14 feet below the road surface, using hydraulic jacks. Con- siderable difficulty was experienced dur- ing this operation because of the slough- ing of material and the necessity of con- tinuously pumping large quantities of wa- ter from the working pit. Although this undertaking was successful, it is the opinion of those in charge of the work that in the future all other methods should be considered before hydraulic jacking is chosen for such projects, par- ticularly if the ground water table is near the surface and if the soil is of a plastic nature. Hie success of the year’s work can best be measured by the densities of malaria vectors in the index zones of control, and by the incidence of malaria among persons whom control efforts are designed to pro- tect. Of 18 areas now under some form of control, two, Aliceville and Mobile, show- ed density indexes of 10 or more Anopheles quadrimacuiatus in "A* zones at some time Boy Scout Clean-up Craw in Mobile 59 ARK AN S AS largest rice growing area in the State. Within one mile of the cantonment area of the School there are approximately 28 acres of rice. It was not consider- ed justifiable to treat this small area with paris green by means of an airplane, so a spray program was set up to kill all adult "quads" before they could become infective. In this same area experiments were carried on in cooperation with the Rice Branch Experiment Station of the University of Arkansas to determine the effect of paris green dusting on rice plants. Tests showed no apparent etfect on the yield of rice or rice straw. Tests were carried on in cooperation with the-Memphis Laboratory of the National Institute of Health to determine the lar- vicidal effect of DDT when added to irrigation water. Results are not yet avail- able on these tests. The Walnut Ridge and New- port Armv Air Fields are located near extensive rice fields. The rice fields re- main flooded practically continuously from the end of May to the middle of Septem- ber, providing a source for extremely neavy Anopheles quadrimaculatus breeding. Airplane dusting with paris green gave satis- factory control at the Newport Air Field, but there was not sufficient reduction in anopheline breeding in the rice field which lies within the city limits of Walnut Ridge. Airplane dusting with DDT was tried in coopera- tion with the United States Department of Agriculture but the tests were in- conclusive. In seven areas there were located large bodies of water which were too small to justify the use of an air- Approximately 80% of the war areas in Arkansas are located in the malarious section of the State. This area is in the flood plains of the Mississippi, Arkansas and Red Rivers. During the year 17 war areas, consisting of 62 zones, were protected by the MCWA program. The principal work in each-area was larviciding and minor drainage accomp- lished by hand labor. It was impossible to effect satis- factory control with manual- ly operated equipment in certain areas, so it was nec- essary to dust by airplane and with power dust- ers and to oil with power sprayers. A summary of the cost of the MCWA program in Arkansas was prepared on the basis of square miles of area actually controlled. In flat, poorly drained areas where extensive larviciding, clearing, or major drainage op; erations were necessary, the cost was $1531.00 per square mile. By contrast, in hilly areas, where drainage was much better and where control was obtained primarily by larvicidal measures, the cost was only $633.00 per square mile. In the Stuttgart Area an advanced Pilot Training School is located in the midst of the STATE HEALTH OFFICER T. T. ROSS, M.D. BUREAU OF SANITARY ENGINEERING STATE OFFICE M.C.W.A. 88 WAR ESTABLISHMENTS PROTECTED 18 WAR AREAS 60 pi arte and too large to be controlled ade- quately by hand operated equipment. The most practical method of controlling these areas was with a power dust unit or power spray unit mounted on a boat. Seven boats 5 feet wide, 14 feet long, and 18 inches deep were built for this purpose. Each boat was driven by an outboard motor. One man operated the motor and one man operat- ed the power unit. The water-oil unit consisted of a centrifugal pump which sucked lake water and oil into the pump, mixing the two together. The pressure which was built up by this pump would throw the water 50 to 60 feet. The weight of the water was sufficient to carry the oil down through shoreline vegetation such as cattails, water grasses, water lilies, and other types of aquatic growth, enabl- ing the oil to reach the surface of the water. The spray reached back into the willows, which had grown up along the shoreline for 25 to 30 feet. The amount of oil used in the pimp unit averaged ap- proximately ten gallons per acre of water surface treated. This was found to be one of the most economical methods of control- ling large bodies of water. Airplane Dusting Rica Field Rica Plante Checking for Larvae in Rica Irrigation Water 61 Large swamps and bodies of water which were inpossible to control adequately with larvicides were drained. A dragline was used instead of dynamite when a large quantity of sand was found in the soil, or when the soil was excessively dry. At Helena, 14,300 linear feet of ditch vary- ing from 3 feet to 10 feet in depth were constructed by dragline. At Jerome it was necessary to clean out 17,000 linear feet of existing drainage ditch in order to accomplish drainage of a swamp of approximately 250 acres. An average of three cubic yards of dirt per run- ning foot was moved at a cost of 18£ per cubic yard. A State total of 31,800 linear feet, or 6 miles of ditch, was completed. Dynamite was used throughout the State in draining swamps and sloughs in which the soil was so wet it was inpossible to move a dragline into the area. In such places dynamiting is considered to be the most ef- fective and quickest method of securing adequate drainage. Certain dynamiting jobs were completed before it would have been possible to move a dragline from one loca- tion and walk it into the area. Ditches Constructing Ditch with a Dragline varying in size from 18 in- ches in depth with a 5- foot top to ditches 5 feet in depth with a 15-foot top were constructed in the State by this method. Where dynamite was found to be more economical it was used in preference to any other me thod. A blood survey was con- ducted in 34 counties during the sunnier and fall of 1943. A total of 32,341 slides were made. Most of these slides were obtained in schools, but 1,243 were se- cured in a house-to-house survey. By the end of the fiscal year, 17,637 of the slides had been examined. Only .09% of the total num- ber examined were positive for malaria. Dynamite Ditch Blast 62 CALIFORNIA DIRECTOR OF PUBLIC HEALTH WILTON L.HALVERSON M.D. History records the presence of malaria in California at the time of the Gold Rush in 1848 and 49. From that time until ap- proximately 1900 records and reports were very meager, but those available indicate that malaria of epidemic propor- tions was scattered in the low foothills and across the floor of the area known as the Great Central Valley. Since early days, malaria has been closely associated with agriculture through the use of wa- ter for irrigation purposes. In Southern California where water is comparatively limited, only a few cases of malaria have been record- ed. The Central Valley is 30 to 50 miles inland from the coast, which it parallels, and is approximately 500 miles long by 40 to 70 miles wide. Numerous streams and rivers origi- nating in the mountains flow onto and tra- verse the floor of the Valley, providing extensive breeding areas for A. freeborni which is the western malaria vector. In addition, man-made canals, ditches and im- poundments used for irrigation provide suitable breeding pi aces. Irrigated rice fields in the north central portion of the Valley wnere the soil is permeable, are often responsible for heavy breeding of A. freeborni. Anti-anopheline measures for malaria control have been practiced in California since 1910, although pest mosquito cam- paigns were inaugurated as early as 1907. The malaria rate began to decline about 1920 and has reached such a low point in the last few years that only a few cases have been reported yearly. Nevertheless, in the Central Valley A. freeborni is very abundant, sometimes exceeding 5000 over- wintering individuals per resting place. California is experiencing an enormous amount of military activity. There are many Army, Naval and Marine camps handling BUREAU OF SANITARY ENGINEERING STATE OFFICE M.CW.A. 6 WAR AREAS 30 WAR ESTABLISHMENTS PROTECTED not only military personnel leaving this country for war theatres, but also many that are returning from highly malarious battle zones for temporary assignment and regrouping into new combat units. Many of these establishments are located within the region where, in former years, malaria was endemic. In some of these, men are being hospitalized and treated for malaria. Two mobile units were allotted to the California program in March 1943. One unit was established in northern and the other in southern California to carry on approxi- mately semi-monthly inspection and anophe- line control near general hospitals and 63 prisoner-of-war camps. These units are also considered as emergency units and are available at a moment’s notice should a ma- laria outbreak occur anywhere in the State. During the fiscal year 1943-44, MCWA established anopheline control projects on a 12-months basis around two general hos- pitals, two cities, and two Army air bases located within the Central Valley, using standard diesel oil as a larvicide. Dur- ing the summer and fall of 1943 all larvi- ciding oil was applied with hand sprayers. To facilitate the application of oil and because of an acute manpower shortage, two power sprayers were put into service at the beginning of the spring breeding sea- son in March of 1944. In each control area hand ditching, brushing, and clearing supplemented the larviciding work. Another and equally important phase of the MCWA program was the inspection work around many military establishments throughout the State. These inspections, made from time to time, determine the presence and density of the malaria vec- tor. Anopheline species common to the Paci- fic coast have not previously been report- ed breeding in anything but fresh water, however, Anopheles freeborni larvae were collected in water reached by high tides along the beach at Santa Barbara in August 1943, and again in the Sorrento Wash Area near Camp Callan about 15 miles north of San Diego in the spring of 1944. This wash for a distance of 1 lA to 2 miles in- land from the ocean is heavily overgrown with Salicornia and an analysis of the water showed a saline concentration equiv- alent to 17% sea water. Along the cool coastal belt of the State there is no history or record of malaria transmission, even though A. freeborni is present at scattered spots. It may be that the mean average temperature of this area is not sufficiently high for favora- ble development and transmission of the plasmodia in the mosquito. Due to the lack of evidence of transmission, the po- tential malaria problem in this section does not seem to be very great. However, because of the heavy concentration of mili- tary personnel where a known capable vec- tor is present, inspection and some con- trol is being carried on primarily by mo- bile uni ts. Very close inspectional service is be- ing maintained at Hamilton Army Air Field because it is one of the main ports of en- try for planes from the Pacific. Breeding Place of Anopheles freeborni Dragline Ditching Eliminates Breeding Area 64 FLORIDA V IX-iring the past fiscal year malaria transmission throughout Florida contin- ued its steady decline of the past eight years. Extensive spleen and blood smear surveys were performed, particularly in populations adjacent to war establishments, and rates were found to be relatively low except in Citrus County where no war establish- ment has been located. Since informa- tion provided by present blood and spleen surveys is limited, more and more reliance has been placed on ento- mological inspections in the orienta- tion of control work. Special entomological studies were made in 31 areas not under control, to determine whether regular working crews would be required to keep mos- quito breeding within safe limits. As a result of this work seven new projects were established. The location of eight prisoner-of-war camps in Florida prior to July 1 required prompt field studies to evaluate the local malaria hazard. In only one case was it found that control could not be achieved with the resources avail- able. The installation of various conval- escent hospitals for overseas veterans had led to special entomological surveys which necessitated the inauguration of regular area operations at Daytona Beach. Twenty areas were selected for minor drainage and larvicidal operations. This represented control around approximately one hundred different war establishments. In addition, major drainage involving dy- namite blasting of large canals was done in nine of these areas. This work has given excellent results and has proven to be an economical solution to many serious drainage problems. Dragline ditching was utilized in Tallahassee, Leesburg Service Center, and Sarasoia - in some cases with the assistance of local civil or military STATE HEALTH OFFICER HENRY HANSON M.D. BUREAU OF MALARIA CONTROL STATE OFFICE M.C.W.A. 37 WAR AREAS 115 WAR ESTABLISHMENTS PROTECTED • authorities. Oiling and dusting opera- tions for the present season have been re- duced over last year as a result of engi- neering work during the winter. In fact, dusting is being used in only three areas at the present time. A problem which still remains unsolved is the destruction of water hyacinths by some economical method. Many herbicides and aquatic weed killers have been assem- bled for experimentation. The standard treatment with sodium arsenite cannot be generally employed because of the danger of poisoning livestock. Leesburg is situated on a neck of land between two broad lakes, and several large sawgrass marshes extend inwards toward the city. These areas could be controlled by airplane dusting, but a locally-made hy- draulic dredge has been supplied by the city and is steadily reducing the sawgrass marsh area which is responsible for con- tinued anopheline production. MOWA coop- erates with the city authorities by fur- nishing an operator and an assistant oper- ator for the dredge. The dredge cuts a 65 Control of Anopheles quadrimaculatus by Dredging at Leesburg, Florida channel around the marsh, throwing the spoil into a dike-line. The sod, muck, and sand are then pumped from the center behind the dike, and the marsh becomes a lake with clean margins. In this way the breeding areas are permanently cor- rected. A gratifying result of the statewide emergency malaria control work performed by MCWA has been the numerous cities and towns that have formally requested assis- tance in converting the work to a permanent basis, using local funds. Among these are Tallahassee, Marianna, Gainesville, and Leesburg. Detailed engineering reports for these communi ties will be prepared with recommendations for future work. Un- der the supervision of the Bureau of Mala- ria Control in the Florida State Board of Health, these towns can assure themselves of freedom from malaria-carrying mosquitoes after the termination of the present emer- gency. In addition to the malaria control pro- gram, Aedes aegypti control projects were in operation in three cities. These are Key West, Miami, and Jacksonville. Physi- cal survey work for Jacksonville was com- pleted around July 1 and plans were under way to create a surveillance unit in Tampa also. Educational campaigns were conduct- ed in Miami and Jacksonville, and local governmental and civilian organizations were encouraged to assist in the campaigns. Public response has been excellent, but manpower shortages have made it most dif- ficult to secure saus factory inspectors. Public services related to the program - such as trash removal - have fallen behind the needs of Florida communities. Throughout the year the MCWA pro- gram in Florida has had the assistance of experienced malariologists and engineers contributed by the State Board of Health and the Rockefeller Foundation as a sup- plement to the technical supervision of the Atlanta office. The various organiza- tions have cooperated effectively from the start, special skills and experience being utilized to the utmost in assuring that the malaria hazard to military and vital industrial installations is reduced to a minimum. Killing Adult Mosquitoes in a Cistern 66 GEORGIA tions during a brief period of the year where there was any likelihood of malaria transmission. The control problem was not limited to any particular type of watered area. Con- trolled malaria mosquito breeding areas included natural and artificial pools, lime sinks, ponds, abandoned rice fields, abandoned and active brick yard excava- tions, power development reservoirs, swamps, ditches (both paved and unpaved), canals, and other water holding areas. Since the inception of the State pro- gram in March 1942, plans and operations have been directed toward securing control of the malaria vector, A. quadr imaculatus, at minimum cost, in accordance with the original USPHS directive. Accordingly, larvicidal control measures have been con- fined to those locations in which "quad" breeding was demonstrated by lafval collections. Paris green was selected as the main larvicide to be employ- ed due to its proved effec- tiveness and lower cost as compared to other present known and available larvi- cides. No major drainage project has been, or will be undertaken unless it can be shown that its cost can be amortized by the consequent saving of larvicidal costs during a reasonable period. Minor drainage has been con- fined mainly to maintenance or reconstruction of existing waterways and clearing and cleaning of areas to be lar- vicided, all of which are performed by crews ranging in number from 2 to 20 men per area whose principal duties are appli- cation of larvicides. From April to October, the breeding season in most areas, every station show- ing the presence of "quad” larvae was placed on. a weekly schedule of larviciding. In Georgia, during 1943, reported malaria morbidity and mortality were very low as compared to previous peak years. The mortality rate per 100,000 population was 1.1, as compared with 19.8 in 1936 and 23.3 in 1929. The morbidity rate per 100,000 population was 15.0, as compared with 390.7 in 1936 and 235.8 in 1929. ftCWA activities contributed to the statewide reduction of malaria, but there was also a startling reduction in mala- ria in areas unprotected by larvicidal programs. War establishments were located through- out the State, but with the exception of Battey General Hospital at Rome, control activities were confined to those located in the lower half of the State where mala- ria is of sanitary significance. Judging by adult anopheline indexes in protected areas, there were only one or two loca- STATE HEALTH OFFICER TFABERCROMBIE M.D. DIVISION OF PUBLIC HEALTH ENGINEERING STATE OFFICE M.C.W.A. 19 WAR AREAS 114 WAR ESTABLISHMENTS PROTECTED Principal breeding in the Macon area is found in brick yard excavations and perma- nent ponds. During 1943 ex- tensive breeding developed in the Fuse Plant Zone swamp. This breeding was brought under control by large scale hand dusting operations and cleaning of the main out- fall, utilizing manual and dynamite methods. A com- plete topographic survey was made of swamps, and plans were made for reconstruction of the outfall by means of a 4" hydraulic dredge. One pond was controlled by week- ly fluctuations. At Augusta, interesting features of control were the filling of shallow areas by the diversion of inflow to two ponds. Waste brick plant materials were hauled by plant trucks and, under 1CWA supervision, used as minimum depth fill to eliminate shallow areas difficult to control. Some breeding areas were con- trolled by connecting them to varying stage industrial and sewage canals which fluctuated the water level. Although Hinesville is in a very mala- rious section of the State, control by hand dusting has been satisfactory. Prin- cipal breeding is in a ditch fed by artesian wells, one of which is controlled by flush- ing methods effected by automatic siphon. The malaria problem in Savannah is characterized by extensive breeding areas, including abandoned rice fields, in the vicinity of fresh water tidal canals and tributaries. Control by hand dusting was considered satisfactory except in the Port Wentworth and Qjartermaster Zones. Remed- ial measures, including county installa- tion of major tide gates, has been planned for winter months. In Albany extensive breeding areas in the power development reservoir were sat- isfactorily controlled by Georgia Power Company personnel. MZWA hand dusting op- erations secured satisfactory control in other breeding areas- Hydraulic Dredge in Operation at Macon, Georgia A majority of the ornamental pools in the city of Moultrie were found to breed "quads" but very satisfactory control was obtained in this area by hand dusting methods. In Bainbridge plans were made for prosecution of dragline work to provide drainage outlet for several lime sinks. In Americus limited breeding was con- trolled with hand dusting performed by County personnel using MCWA dusters and larvicide. Hand dusting and minor drainage main- tained satisfactory control in Statesboro. Ditch paving will be installed during winter months with the county and city furnishing all materials. The success of the 1943 program might be confirmed by the fact that in no in- stance has any complaint or criticism of the work been received from responsible service officers of the military areas protected. Likewise, there has been no report of malaria infection caused by mosquito breeding in the control zones. Collection data obtained in the cantonment and extra cantonment areas are exchanged between the service officers and the re- spective area supervisors, providing full coordination. 68 ILLINOIS Due to its geographical position, Illi- nois has often been referred to as a bor- derline State. The problem in malaria control has been mainly to determine just where the borderline is and to prevent the establishment of new foci of malaria. Un- til agricultural drainage was established on a large scale through the vast plain area of Illinois, malaria was widespread and endemic throughout the State. The en- demic malarious area of the State now lies south of a line from St. Louis, Mis- souri to Terre Haute, Indi- ana. At times mild epidemic outbreaks may occur north of this line, usually along the Mississippi Piver or the Illinois River. However, the distribution of Anopheles quadrimaculatus is quite general throughout the State and se'ems to be limited only by the absence of favorable breeding areas. In the most southern por- tion of the State, however, the period of weather warm enough for anopheline breed- ing is commonly from 30 to 50 days longer than in the northernmost part, where the season of fa- vorable conditions is comparatively short. In war areas where malaria vectors are numerous, surveillance is maintained even though evidence of malaria transmission is lacking. Surveillance as conducted in these areas consists of the following ac- tivities: (1) entomological inspection of all areas in question to determine the ac- tual "quad" breeding areas, the adult den- sities, and the potential danger to the area under protection; (2) close coopera- tion with military or other officials con- cerned, so that they are aware of condi- tions in the extra-cantonment area; (3) constant reporting and summarizing of all DIRECTOR OF HEALTH ROLAND R. CROSS, M.D, DIVISION OF SANITARY ENGINEERING STATE OFFICE M.C.W.A. 23 WAR AREAS 73 WAR ESTABLISHMENTS PROTECTED malaria cases in these areas through the Division of Com- municable Diseases; and (4) tentative control plans for each of these areas which may be set up promptly, should they be needed. Control measures were carried out in six zones in two areas in the southern part of the State during the past year. In the East St. Louis area the record- breaking Mississippi River flood of 1943 and the resultant backwater and seepage into the Parks Air College zone greatly increased the control problem there. Em- ergency measures were inadequate in re- pairing the Drainage District pumps, and the breeding season was almost terminated before the drainage system was able to draw the water to normal levels. Most of 69 the breeding areas caused by this condi- tion were long, narrow sloughs which were satisfactorily controlled from the shore- line with a large, power-driven duster mounted on a small, 4-wheel-drive truck, using a larvicide of one part paris green to ten parts of lime. In the Granite City zone of the East St. Louis area counts as high as 5,000 Anopheles quadr iwacul atus were recorded from points two miles from protected zones near a large lake breeding area, but at no time during the season did there appear to be any migration of this large population into the protected area. It is believed this may have been due to the large amount of smoke and fumes from factories located between the protected area and breeding si tes. The largest and most difficult control problem was Area #2, Illinois Ordnance Plant, where a large artificial lake with extensive breeding areas was producing great numbers of Anopheles quadrimacula- tvs. Power dusters mounted on boats, sup- plemented by a small power duster operat- ing from a pick-up truck, affected fair control except in very thickly overgrown, portions of the lake. In order to reach these areas and to insure adequate weekly treatment of them, control by airplane dusting is being undertaken during the 1.944 season. A local epidemic outbreak of malaria occurred in a small city near the Illinois Ordnance Plant area, where many workers from the war plant were housed. Initial surveys showed a high densi- ty of Anopheles quadrimacu- latus present, ranging from 10 to 200 per collecting place, and approximately 75 potential Anopheles quadri- maculatus breeding areas, including unmaintained ditches and streams, mine ponds, stock ponds, artifi- cial ponds, and natural swamp areas. Many of the swamps are caused by subsidence of the ground due to mining operations. A sudden drop in counts occurred soon aTter control measures were begun and were only partial- ly attributable to our control operations. However, a large number of what appeared to be very suitable breeding ponds and streams had dried up about two weeks be- fore MCWA operations began, and it seems possible that a natural drop in densities may have resulted. Investigations in the northern areas along the Mississippi Piver indicated an abnormal drop in Anopheles quadrimaculatus populations from the 1942 season. A re- view of conditions existing throughout the two seasons indicated that frequent floods and water recessions on the Mississippi River and its tributaries during 1943 had produced effective natural control of breeding during 1943. This was most strik- ing in the Savanna area where counts had been excessive during 1942, reaching 6,000 in one station, whereas in 1943 all sta- tions remained less than 10 throughout the season. In order to facilitate proper sur- veillance and to add to our control effi- ciency, complete maps of 22 areas were prepared during the winter months. These maps show accurately all potential breed- ing areas and their relation to the pro- tected areas. Dusting Shoreline of a Small Lake 70 INDIANA where the Army has reported the presence of malaria patients. Certain areas in the southern portion of the State were consid- ered to be of negligible importance either because of the absence of "quads" or of the absence of malaria, or both. The Terre Haute Area, with its past history of malaria epidemics and the high "quad" counts recorded since the opening of MOVA activities, was considered highly important. The city of Terre Haute has had its own malaria mosquito control pro- gram since the 1938 epidemic. MONA opera- tions supplement this program by control- ling a zone one mile wide around the city. Each spring the many lakes and depressions in this zone are flooded with sufficient water to remain for the entire summer. A major drainage project was instituted by which it was hoped to elimi- nate some of the extensive breeding areas. Unfortunate- ly, early spring floods from the Wabash River prevented completion of this project. Larviciding with paris green and oil, and pumping some of the ponded water from behind the levees was attempted. However, it was found impos- sible to control this area without power equipment dur- ing 1943. If power spraying proves unsuccessful this year, dusting by airplane will be the only way to re- duce "quad" counts. Through an agreement with the City of Evansville, the city will fur- nish labor and automotive equipment for larviciding this highly industrial area. Evansville and Vanderburgh county have consistently reported a fairly high number of malaria cases, and "quads" are known to breed prolifically in the region. Evans- ville, located in the southwestern section of Indiana along the Ohio River and The State of Indiana is divided into two areas inso- far as malaria control is concerned. In the area north of the 40th parallel of latitude, the degree of endemicity is believed to be low, although high "quad" breeding may be encountered for relatively short periods. The remainder of the State includes two well establish- ed areas of relatively high endemicity. Here the breed- ing season is of longer duration. With the above division in mind the program for the fiscal year ending June 30, 1944 was planned. Inspections were made in the northern areas and epidemiological reports were studied. It was decided that the only area to be kept active, and this only on an inspectional basis, would be the Fort Wayne Area where "quads" have reached as high as 10 per station and STATE HEALTH COMMISSIONER THURMAN B. RICE, M.D. BUREAU OF SANITARY ENGINEERING STATE OFFICE M.C.W.A. 10 WAR AREAS 41 WAR ESTABLISHMENTS PROTECTED 71 Flood Conditions Near Terrs Haute Hand Spraying across from Kentucky, might well become a danger point if preventive measures were not taken. The Army has considered the areas in the vicinity of Fort Benjamin Harrison, near Indianapolis, to be of sufficient im- portance to certify it for control meas- ures. Plans have been made to begin oper- ations if and when station counts become high enough to justify larviciding. Al- though no unusual problems have been en- countered, areas along the Ohio, Wabash, and White river basins warrant surveil- lance, but it is hoped that control will not become necessary. Because of a rela- tively mild winter, early floods, and an early rise in temperature, the nquadn breeding season started five weeks earlier in 1944 than in 1943. The ,S!CWA program in the State of Indi- ana takes into consideration and affords protection to approximately 25 Army and Navy establishments and another 16, or more, war industries and recreational areas where soldiers, sailors, marines, and war workers congregate. Ousting Near Terrs Haute 72 KENTUCKY The State of Kentucky, although not a borderline State, is located toward the outer edge of the malarious belt, and only portions of the State extending westward from Louisville present ma- laria problems of serious proportions at the present time. The eastern portion of the State ranges from roll- ing hills in the vicinity of Louisville to mountains along the Virginia boundary; while the western portion, although generally rolling, presents some flat areas ir the valleys of the Tennessee, Cumberland, and Ohio rivers. The average summer temperatures in the western end of the State are approximately two to three degrees higher than in the eastern end, and the rainfall in the west- ern end is heavier than in the central and eastern portions. Surveys have been conducted to deter- mine the densities of Anopheles quadri- maculatus throughout the State. These in- dicate that the heaviest breeding occurs at the western tip of the State near Paducah, falling off to light breeding east of Lexington. There are large num- bers of lime sinks and artificial ponds for watering livestock throughout the ag- ricultural districts, and these furnish COMMISSIONER OF HEALTH R E. BLACKERBY, M.D. potential breeding places despite the rolling nature of the terrain. Impoundment of the Dix River in the central part of the State has not increased "quad” breeding seriously, since the river has a clean- cut shoreline and the banks rise sharply, particularly in that part of the impound- ment in which is included the Darnall General Hospital zone. A TVA impoundment on the Tennessee River has not yet been filled. This is created by the Gilbertsville Dam in the western end of the State, which will create a lake 184 miles long. TVA has laid care- ful plans and is building in many control measures throughout the reservoir. The locations of most of the nine mili- tary establishments under surveillance or control have been wel1-selected from the viewpoint of malaria control, and for this reason no control has yet been required ir areas surrounding three of these estab- lishments in the east central part of the State. Since many of the war industries in the State are centered in Louisville, malaria control measures are of grave im- portance in that vicinity. There are, however, other large plants located in the western part of the State at Henderson, Paducah, and Mayfield. BUREAU OF SANITARY ENGINEERING STATE OFFICE M.C.W.A. 6 WAR AREAS 51 WAR ESTABLISHMENTS PROTECTED 73 Probably the most effective single con- trol project in the State was completed at West Louisville, where a 75-acre slough was practically eliminated by drainage. The slough was located in a critical posi- tion between several large war plants and the neighboring residential areas. In one week last year collections of acquit mos- quitoes from four stations surrounding the slough showed a total of 164 "quads." This was in July 1943 after control measures had been conducted for only one week. Drainage work was carried on during the winter months and to date, June 30, 1944, only two adult "quads" have been taken from resting places in the drainage area. The upper portion of the slough is com- pletely dry and in the lower portion water is confined to a freely flowing channel. Data on "quad” breeding in the war areas indicate a somewhat earlier appear- ance of larvae in 1944 than occurred in the preceding year, particularly in the Paducah zone. "Quad" larvae were found in abundance early in May in backwaters caused by the flood conditions of the Ohio River. Intensifying inspection and sup- plementing the labor crew with workers from the nearby Mayfield zone prevented the development of these larvae into adult mosquitoes. The backwaters were thorough- ly inspected and immediately larvicided, and the adult "quads” never appeared in the natural resting places in large numbers. The employment of new laborers pro- ved quite difficult in the early part of 1944. Young men are not available for the work, and many of the older men refuse em- ployment because the work is too strenuous. The inspection force, however, has been filled with men of very high caliber--gra- duate college students and high school teachers. The generally high quality of these men has been of great value in ac- curately determining the sources of "quad" breeding. In the city of Elizabethtown the local government contributed approximately $700 in the form of power equipment, materials, and laborers, while the MCWA program fur- nished technical supervision and a part of the labor crew. In this case a 1500 foot winding ditch was relocated; 600 feet of it was lined with concrete; approximately 100 feet were piped; and the balance was of open earth construction with sloping banks. New zones have been added recently at three of the army canps to afford protec- tion for soldiers remaining overnieht on Anopheles quadrimaculatus Breeding Area Near a War £etablishment 74 extended period of flood conditions pre- vailing in the early spring; and the shortage of manpower, coupled with the early abundance of "quad” breeding, prevent- ed completion of the project after the flood waters receded. The State Department of Health rendered technical assistance to a special course in malaria control which was conducted at the Murray State Teachers College. Hie purpose of the course was to acquaint tea- chers and county sanitarians with the gen- eral procedures of such a control program. The course was inaugurated for the par- ticular benefit of the teachers and sani- tarians in the counties bordering the new Gilbertsville Dam. The class was attended by approximately 60 men and women, and field trips and laboratory work comprised a vital part of the studies. Another educational project of the State Department of Health was conducted at Louisville where approximately 140 me- dical and dental students from the Univer- sity of Louisville were shown the field methods of inspection and control in the Louisville area. This field trip is part of an annual program in which the medical and dental students of the University of Louisville are shown the operations and procedures of the entire State Department of Health. "Quads" Breed in Emergent Vegetation firing ranges. These new zones have in- creased the areas under surveillance and control by approximately 45 square miles. In all of the war areas the control of breeding places has been performed entire- ly with hand operated oiling and dusting equipment. Scattered small-size breeding places make the use of power equipment im- practical. The high quality of the in- spection force permits larviciding to be 1 imited to those locations where "quad" lar- vae are actually found. This practice enables the program to operate with fewer larviciding crews, thus effecting a saving in both materials and manpower. In the war areas most of the drainage work was completed during the winter of 1942-43. However, major drainage projects were in operation in three of the areas during the winter of 1943-44. In the Paducah area one of the major drainage projects could not be completed due to the A quadrimaculatus Breading Area 75 LOUISIANA salt water. However, the malaria vector breeds in surface waters in sufficient numbers to require close watch and control at all times to guard against increased malaria in- cidence. The area occupied by camps and airfields near Baton Rouge is high and easily drained. Most of the control work during the breeding season was carried on by the use of larvicides, with No. 2 fuel oil as the principal larvi- cide. Approximate! y 700,000 gal- lons of this oil were spread during the season. It was found that breeding in an 800-acre swamp near Jackson Barracks could not be controlled by hand oiling or hand dusting. When the zone was dusted once a week by airplane, 90% control was ob- tained; but the remaining numbers of "quads" were suf- ficient to present a serious problem to the Barracks. It was decided, therefore, to drain the swamp, which was kept flooded by wind tides. A levee two miles long and six feet high was constructed along the south bank of Bayou Bienvenue. A culvert was built through the protection levee railroad embankment on the south side of the swamp, thus connect- ing the swamp with a low-level canal. A tide gate was installed on the swamp side of this culvert as a precaution in case the levee should break at any time and overload the city pumps. The city of New Orleans is handling the water at its No. 5 punping station free of charge. To facilitate quick surface run-off, a series of drainage ditches was con- structed by dynamiting. This project has just been finished and put into operation. The entire State of Loui- siana is within the area of endemic malaria along the Gulf Coast. Where the salt water reaches inland, how- ever, large areas have never been seriously afflicted with malaria. During the fiscal year 1943-44, malaria incidence was the lowest on record. Most of the cases occurred in the northern half of the State where sluggish streams in the delta areas and seep- age flats along the banks of the streams in the rolling uplands constitute topo- graphical features which contribute to anopheline breeding. The Valleys of the Red and Ouachita rivers, and their tributary bayous running north and south, continue to furnish A. quadrimacvlatus breeding areas and have the highest rate of malaria cases in the State. All but one of the Army training camps in the State are located within this critical area. The camps and airfields located in the vicinity of New Orleans, Lafayette, and Lake Charles are relatively near the Gulf, where vector breeding is lessened by the occasional presence of PRESIDENT, BOARD OF HEALTH DAVID E. BROWN, M.D. PUBLIC HEALTH ENGINEERING DIVISION OF STATE OFFICE M.C.W.A. 8 WAR AREAS 90 WAR ESTABLISHMENTS PROTECTED 76 by well considered and executed drainage programs. This office is inclined to agree with the arbitrary limit of ten adult female "quads" in "A" stations as a measure of effective anopheline control. However, during May and June flood conditions back up the waters of the Red, Ouachita, and Mississippi rivers and their tributaries. At this time large areas of the flat coun- tryside are inundated. Tremendous numbers of "quads" are produced and what is or- dinarily considered as adequate "quad" control is not economically feasible. But the number of human carriers during the winter is so low under present conditions that the disease does not build up to serious proportions before adequate anoph- eline control is effected. Therefore, the scope of normal operations has not been increased in an attempt to meet this sea- sonal problem in the absence of any indi- cation of local malaria transmission. In this State, the large areas of flat marshy ground with shallow water and ex- truding grasses are difficult to larvi- cide.• Such areas may be doubled and quad- rupled in extent by only a small vertical rise in the water level and by only one rain. The areas are usually wooded to such an extent that it is impossible to use mechanical control meuiods. Further- Jacking a Culvert at Jackson Barracks Early results indicate that it will be completely successful where all other measures failed. At Lake Charles 1000 acres of rice and at Alexandria 300 acres of rice were dust- ed by airplanes during the breeding sea- son. About one pound of paris green per acre per dusting was used each week. Con- trol was accomplished in the "A stations of the Alexandria zone, but numbers of quads" were found in the "A" stations at Lake Charles even though it was estimated that the dusting was 90% effective. Small quantities of some other larvi- cides were used, such as 12 coefficient phenol in a 1 to 24 solution in water. Very small quantities of proprietary sprays were used on a few ornamental pools. Normally the larviciding season closes in Louisiana on November 1 of each year except in the areas of New Orleans, Lafay- ette, and Lake Charles, where some larvi- ciding and inspection are required all winter. During the winter period, from November 1st to Nfay 1st, the minor drainage program was continued from the previous season and resulted in the elimination of large areas which formerly required larviciding. Minor drainage installed during the winter effected a saving of 89 men in the State when the larviciding season began. In Louisiana, it seems that emphasis should be placed on drainage, both minor and major, as a prime control measure, be- cause of the results achieved in all areas Mississippi River Flood Waters 77 Constructing Levee with a Dragline Breeding Conditions in Swamp more, the overhead verdure is usually too thick to let in dust spread from airplanes. Therefore, it is necessary to oil these areas by hand. It has been found by ex- perience that this type of place is a con- tinuous breeder and must be oiled once each week during the entire breeding season. Ten to twenty men with pump sprayers line up about five yards apart and move forward in a line until the zone boundary is reached, then the line moves over and comes back, covering another strip. This maneuver is repeated until the entire area is covered. A glance at the acreage controlled and the amount of larvicide used will give some idea of the magnitude of the physical job necessary to obtain any control in Dipping for Larvae in Flood W'atars many of the zones in Louisiana. During the last season of twenty weeks when nor- mal larviciding operations were carried on, a total of 42,400 acres were treated with oil, using 706,500 gallons of oil. During the maximum month of this period 6,832 acres were oiled using 117,500 gal- lons of oil, or a coverage of 1,7Q8 acres each week, using 29,325 gallons of oil in each coverage. There has been little malaria reported in the State during the year. Cases re- ported from military establishments usual- ly have been due to infection at points outside our protected areas, according to the reports of Army surgeons. Ditch Cut Through Mat ted Vegetation 78 MARYLAND Maryland is on the north- ern border of the malaria belt, and the disease has not been an important public health problem for almost 20 years. However, the pres- ence of large Anopheles quadrimaculatus breeding areas in close proximity to some of the important war establishments where numer- ous malaria carriers are concentrated has required that control work be carried on in spite of the absence of active malaria transmis- sion. Growth of water chestnut in the Potomac River provid- ed thousands of acres of 'quad" breeding surface within mosquito flight range of Army and Navy establish- ments. During the latter part of the fis- cal year, the water chestnut was eliminated DIRECTOR OF HEALTH R. H. RILEY, M. D. DIVISION OF SANITARY ENGINEERING STATE OFFICE M.C.W.A. by cutting and by manual re- moval work done principally by the U. S. Engineers and the Navy Department, with some assistance from MCWA and private property owners. Careful coordination of the entomologi- cal inspection service with control opera- tions has made possible considerable econ- omy in manpower and materials. Larvicid- ing is strictly limited to * quad" breeding places and is not started until adult counts of significant magnitude have been found in "A" stations, or until adjacent areas show high larval populations. In addition to four zones where control work is done, inspections are carried on around some 25 other establishments. Ten of these were inspected or surveyed during the 1943 breeding season. Four prisoner- of-war camps, one general hospital, and several other stations with considerable numbers of troops recently returned from malarious areas overseas, are among the 25 establishments. Fortunately, most ot them are located in areas where nquad" breeding is relatively light. However, some con- trol work may be necessary at four or five of these places. A school for training inspectors was held during May. Several Army and Navy personnel engaged in mosquito control work on their respective stations attended this 3 WAR AREAS 32 WAR ESTABLISHMENTS PROTECTED Cutting Water Chestnut Plants 79 MISSISSIPPI During 1943, fourteen active areas afforded malaria protection to fifty-four war establish- ments in Mississippi. The current 1944 season has necessitated a considerable increase in acti- vities, and probably still greater efforts will be required to provide control for numerous pris- oner-of-war branch camps being established in areas of extreme labor shortage. Present knowledge of the malaria problem has made it appear necessary to carry out active control measures in all areas established under the MCWA program, although some are considered of much greater importance than others, and a few zones are requiring only inspection and a watch- ful eye. In the State generally, malaria is known to be on the decline, although some sections remain where the incidence is relatively high The most clearly defined geographi- cal section in the State, and one which has long comprised an endemic focus for mala- ria, is the Mississippi Delta. This elliptically- shaped plain extends from Vicksburg, Mississippi, to Memphis, Tennessee, a dis- tance of approximately 200 miles. Its greatest width is 85 miles. Army air bases in the region of Greenville, Greenwood, and Clarksdale have been the scenes of the program’s most difficult problems and tnost intense endeavors to date. Airplane dusting of Archer Island at Green- ville was again necessary this season. The Mis- sissippi River reached its peak of nearly 42 feet more than three weeks earlier than in 1943, and as a result flood water covered this heavily wooded island. Abundant logs, flotage, and emer- gent vegetation provided ideal "quad" breeding over more than 600 acres. Control by airplane dusting had proved only partially effective in 1943 be- cause of the thick undergrowth and tall trees. In 1944 increased amounts of paris green were EXECUTIVE OFFICER STATE BOARD OF HEALTH FELIX J. UNDERWOOD, M.D. DIVISION OF PREVENTABLE DISEASES DIVISION OF SANITARY ENGINEERING used per acre to compensate for the heavy foliage. Two applications of 20% paris green dust were made by airplane dusting at a rate of two pounds per acre. The f irst applications, sup- plemented by hand and power dusting from boats, proved very effective. The following week saw the water receding, and an attempt was made to limit the second appli- cation to the remaining lakes and sloughs. These results were spot- ted and unsatisfactory. It was concluded that (1) airplane dusting can be very effective even in over- grown wooded areas, provided the rate of application is increased to compensate for heavy foliage, and (2) precision dusting of relatively small individual bodies of water from altitudes necessary to clear tall trees may not be feasible due to lack of control of the dust STATE OFFICE M.CW.A. 20 WAR AREAS 57 WAR ESTABLISHMENTS PROTECTED 80 cloud or excessive spread of the dust path. During the last few years an exodus of agricultural workers from the Delta has resulted in planters’ contracting for a large number of prisoners of war. P.O.W. canps are being constructed in eight dif- ferent localities. Malaria control opera- tions in this connection bid fair to rele- gate previous MCWA Delta activities to a minor role. Practically all of these branch camps are located on or within easy flight range of bayous, which require drainage as a control measure. Great importance is attached to the need for malaria control in the Delta, but the fact remains that climatic conditions throughout the entire State are favorable to the development of the Anopheles mos- quito, and ecological factors favor the principal vector, Anopheles quadrimacula- tus, in all but the Gulf coast region. The largest MCWA area in the State is Grenada No. 11. In addition to control around the Air Base and in the City of Grenada, 28 square miles are under control adjacent to Camp McCain. Here an unusual situation was observed in 1943 and during the present season. Large numbers of adult "quads" occur under highway bridges located on the camp boundary, which serve as adult index stations for both Army and MCWA programs. Other natural resting Curing Period for a Lined Ditch places seem to indicate reduced numbers of "quads1' away from the highway, both on the reservation and in the extra-cantonment area. High percentages of adult males seem to indicate nearby breeding. However, intensive searches by Army and MCWA per- sonnel have failed to locate any breeding areas capable of producing such numbers within a mile. It has been observed that in this and other areas some natural rest- ing places have particular attraction for "quads. " The problem of providing trained in- spectors was attacked by establishing a training organization. Inspectors have been appointed in Jackson, trained by State Office personnel, and given field experience with crews working around vari- ous military installations. As the train- ees became adept, they were assigned to full responsibility as inspectors when the need for such employees occurred. A re- organization, involving the forming of two sectional offices, has served to simplify and to decentralize some of the numerous administrative details formerly confined to the one State Office in Jackson. Con- crete benefits have been observed as a re- sult of work by malaria educators. Results include a greater understanding of malaria control by the general public and better cooperation by private land owners. Airplane Ousting of Archer Island 81 MISSOURI larvae and pupae into the control zone. This situation was controlled by erecting an intercepting fence at the upper limits of the mile-zone and cleaning the fence at regular intervals. In the St. Louis area 16 cases of ma- laria were reported in 1943 from both city and county, which is not surprising in view of the dense population. The Jefferson Barracks Zone is unique in the large num- ber of lime sinks present within the con- trol limits. Ninety-two of these sinks hold water at least during part of the year, and some hold water all summer. The largest of these, known as the "lemay Sink, " is located north of the Barracks and was controlled by vertical drainage early in the year. Control work was also carried on around Kratz Field and Lambert Field, in the northern part of the county. Malaria is not considered a problem by health officers in the Fort Leavenworth area However, there are large populations of Anopheles quadrimaculatus in the extra- cantonment zone and it is necessary to operate a pre- ventive program there. Dur- ing 1943 a number of East Indian troops were encamped on the post, many of whom were from endemic malarious areas. A major drainage project which would drain almost all of the area now being larvi- cided on the Missouri side of the river is partially completed. This flood plain produces tremendous numbers of Aedes and Psorophora in the early part of each year, but the silty character of the soil prohibits any method of larvicid- ing except by plane. Anopheline control is also difficult because of the mud and silt but, since control for anophelines is not inaugurated until sometime in May, the footing becomes sufficiently firm to per- mit entrance to the zone. During the year 1943, control operations were car- ried on in the following areas in Missouri: St. Louis County, Fort Leaven- worth, Louisiana, McBride, and Springfield. Projects involving inspection only were instituted at the Fort Leonard Wood Area and at Camp Crowder. Malaria has been endemic in the Sikeston area in southeast Missouri where two airfields are being protect- ed--one at Sikeston, the other at Malden--but the disease has followed the general downward trend ap- parent throughout the county. This section of the State, formerly known as "Swamp-east Missouri," has been drained for agricultural purposes and the breeding area for Anopheles quad- rimaculatvs is confined, for the most part, to sluggish ditches which become heavily vegetated during the summer. One of the problems which arose in this area, parti- cularly during times of high water, was caused by patches of Ceratophyllum break- ing away from ditch banks and floating downstream, carrying quad r i tnacul a tus STATE HEALTH COMMISSIONER JAMES S. STEWART, M.D. DIVISION OF ENGINEERING STATE OFFICE M.C.W.A. 10 WAR AREAS 33 WAR ESTABLISHMENTS PROTECTED 82 Lemay Sink befors Drainage in our laboratory. The Camp Crowder area, including the town of Neosho, is rolling and well drain- ed, and malaria is not a problem in this section. A small larvicidal project has been instituted in Neosho, which has mili- tary importance because of its proximity to Camp Crowder. The Springfield area is also rolling and well drained with the exception of one large sink near the Frisco Shops, which has a water surface of approximately 30 acres. A poor economic section exists in the immediate vicinity, and local health officers state that practically all the malaria in the vicinity of Springfield has been reported from this section. Regular inspection projects at Rose- crans Field, St. Joseph, and Fort Leonard Wood did not indicate the necessity for beginning control operations. Some fairly high adult counts were recorded at Rose- crans Field, but they were taken in what would be the "D" or "En sections of our control zones. At Fort Leonard Wood, in the Ozarks, very large numbers of anophe- line larvae may be taken in the cool moun- tain springs and streams, but upon exami- nation the large majority of these are found to be Anopheles punctipennis. Ano- pheles barberi has also been taken in this zone. Clearing Hocks from Vertical Drain Construction of Drain The water in the Louisiana area has been impounded by the Clarksville Dam, and local physicians state that the incidence of malaria has increased since 1938, the year the dam was built. Quoting from the Interstate Malaria Survey Reports for the years 1940 and 1941: Questioning local physicians in Louis- iana revealed that there was a total of approximately 150 malaria cases. These cases were confirmed, for the most part, by laboratory findings. A house to house survey of an area at the edge of Louisiana and along the river was made. A total of 26 houses, in which 132 persons lived, were visited. The financial, social and hygienic conditions of the families were poor. A total of 21 persons reported that they had malaria this year. Nine of these cases were confirmed by blood examinations 83 NORTH CAROLINA North Carolina has con- ducted a malaria parasite survey since 1937. Over 75,000 slides have been tak- en, giving the State an ex- cellent record of the loca- tion of most malaria foci. Continuous use has been made of these data to evaluate the malaria hazard in vicinities of war establishments oper- ating in North Carolina. The information gained from the slide survey was used, when- ever possible, to influence the location of such war establishments. During the past year, the War Manpower Commission and the War Department have * agreed tnat each proposed prisoner-of-war camp site must be approved by the State Board of Health. As a result of this ar- rangement the camps have been placed in areas where there is no serious malaria STATE HEALTH OFFICER CARL V. REYNOLDS, M.D. threat; thus, malaria con- trol work around P.O.W. camp sites has been very limited in extent. The most difficult con- trol problem in the State at the present time is in the vicinity of Williamston P.O.W. Camp which was esta- blished in a malarious area before the system requiring State approval was inaugurat- ed. It is extremely doubt- ful if adequate control can be obtained for this area ■ without the expenditure of an unreasonable sum of money for drainage, larviciding, and additional construction work. When the malaria control program was initiated, the policy was to do control work in all areas where there was a proba- ble malaria hazard. By utilizing inspec- tion service to full advantage, it has been possible to discontinue control work in three whole areas of North Carolina, as well as in several zones in other areas. Of course, all of these areas are main- tained under surveillance in order that no sudden outburst of "quad" production will slip by unnoticed. An unusual malaria control problem has developed in the vicinity of Asheville, in the most mountainous section of the State, where malaria would not ordinarily be ex- pected. Because it is so far from other control activities in the State, special arrangements have been made with the Army authorities to do the small amount of con- DIVISION OF EPIDEMIOLOGY AND VENEREAL DISEASE CONTROL STATE OFFICE M.C.W.A. 15 WAR AREAS 89 WAR ESTABLISHMENTS PROTECTED Constructing Ditch with Hand Labor 84 trol work necessary outside of the canton- ment area. The City of Asheville has agreed to control breeding in a nearby recreational impoundment lake. Thus, the need of setting up an expensive control area has been eliminated. In the New Bern area a difficult con- trol problem was encountered in the low marshy area subject to tidal fluctuations. It is impossible to drain this area, but by digging broad, flat ditches in these marshes it was possible to permit the free ingress and egress of tidal water, giving very good control of "quad" breeding. The Elizabeth City area, With well over 125 miles of flat ditches, presents another difficult control problem. Although sat- isfactory control was obtained over a ma- jor portion of this area, adult densities in one section remained high throughout a considerable part of the breeding season. No single heavy production area was found, but there were numerous small breeding areas in ditches adjacent to the station. Satisfactory control has been obtained by placing special emphasis on keeping all ditches clean and free of standing water. Removing Stump from Ditch Bank Dragline in Operation Dragline Ditch Completed 85 OKLAHOMA COMMISSIONER OF HEALTH GRADY F MATTHEWS, M.D. BUREAU OF PUBLIC HEALTH ENGINEERING STATE OFFICE M.C.W.A. ed numerous impoundments. These range in size from pasture ponds to huge lakes, one with a shore-line in excess of 1200 miles. The numerous brushy shallows and inlets thus formed have added considerably to anophelihe production. Many of the Oklahoma war areas fall within this generally malarious area, but the local situation is often much less a- larming than the total picture. The poli- cy has been to effect an economical pro- gram of control by concentrating on exact foci of production which have been dis- covered through preliminary surveys and inspections. The Malaria Control Program in the State of Oklahoma has been increasing in size due to the establishment of prisoner- of-war ‘camps and hospitals. A survey has been completed around each war establish- ment, and those which show Anopheles quad- rimaculatus in sufficient numbers have been placed under control. Others are under regular inspection in a survey pro- gram that has been extended as new prison- er-of-war camps have been established in various parts of the State. Two very economical drainage projects have been conpleted during the past year. 14 WAR AREAS 72 WAR ESTABLISHMENTS PROTECTED In Oklahoma, the incidence of malaria decreases from the fringes of the Ozark Plateau and Gulf Coastal Plains on the north and southeast to the Gypsum Hills and High Plains of the extreme west as the annual precipitation lowers from 40-50 to 20-30 inches and as the general elevation increases from 500-1000 to 2000-4000 feet. High tenperatures and hard winds are char- acteristic of the State but are most sig- nificant in effect on the arid western plains, which are largely unsheltered by forests or hills. Suitable breeding places for malaria mosquitoes are thus most evident in the crescentic area broadly covering the southeastern corner and extending in one direction to the extreme northeast corner and in the other direction half across the southern border along the Red River. To the swamps, marshes, ponds, pooled streams and bayous of this large area must be add- 86 A 40-acre lake at Hugo was eliminated by cutting through a dam, and a 15-acre lake at Durant was removed by opening a tile drain. Last winter the program consisted of revising maps in some of the areas which were operated during the previous year and preparing maps and estimates in new areas. Surveys were completed in thirteen towns, cities, and war establishments where it was probable that control work would be needed this year. Information for each zone was collected in order that project proposals could be made. Labor, equipment, and materials needed were computed for each project, and a summary of the problem with recommendations for control were submitted in narrative form. In addition, forms were devised which contained ques- tions for local doctors and druggists in order that information might be obtained on the number of malaria cases treated and the amount of anti-malaria drugs sold. A "sectional method" of reporting lar- val collections is now on field trial in Oklahoma as an innovation in area inspec- tion which offers advantages in simplicity, usability of data, and exact correlation of inspection and control routines. .In brief, this method requires an accurate field map showing land sections and all water bodies. Collections are made in routine circuit to cover each section com- pletely through no more than one month, and at least one quarter of each section through each week. The actual land sec- tion number, used by the foreman in direc- ting the crew, is used as the station num- ber, followed by ME, NW, SE, or SW to in- dicate the quarter-section, and by the standard letter indication of actual dis- tance at which the collection is made. Under "Locations or Remarks" on the Stan- dard Report Form, the nature of the breed- ing place is given. This method binds the area inspector to routine responsibilities, yet invites extensive exploratory trials. At the end of the season results of in- spection pan be correlated exactly with the materials and labor of control. Breeding Places before Drainage Breeding Places Eliminated by Drainage 87 OREGON These are prolific sources of freeborni breeding. Densely shaded sloughs of the river furnish admi rable punctipermis breed- ing places but, fortunately, little free- borni breeding has been discovered in these areas. The malaria that has occurred in recent years has been largely of an epidemic type and has been localized in small areas where human carriers have found employment in temporary agricultural labor camps. Surveys of civilian communities near Camp Adair at Corvallis last winter disclosed the pres- ence of occasional histories of attack. Camp Adair was the only war establishment in the State where extra-cantonment control work was undertaken last year. Surveys at Camp White, near Ashland, toward the end of the fiscal year disclosed concentrations of both free- borni and occidental is. The latter penetrates farther inland in Oregon than it does in Califor- nia, aided, no doubt, by the topography and the cooler, relatively moister interi- or climate. Steps are being taken to in- stitute control of freeborni at Camp White. Oregon has a long and very interesting history of malaria. The disease was so prevalent prior to 1845 that the original settlement of Portland was abandoned. The state is traversed from north to south by the Cascade Range, which extends from Mt.Hood near the Wash- ington line to Klamath Falls in the south. A little less than one-third of the State lies west of the range. This is a well watered expanse of rolling hills with extensive forested areas interspersed with cleared areas devoted to agriculture and industry. Midway between the Cascades and the ocean is the Willamette River. It is formed by a number of tributaries near the city of Eugene and flows north to join the Columbia at Portland. Its valley, which is devoted to intensive agriculture, is the sole remaining focus of malaria in the State. Anopheles freeborn!, the western mala- ria vector, is sporadically distributed over the entire State but builds up to heavy densities in the Willamette Valley in the late summer. The control problem here is not difficult but requires pains- taking, detailed work. The Valley floor is relatively narrow, with many seepage areas resulting from the nearby hills. HEALTH OFFICER FREDERICK D. STRICKLER,M.D. BUREAU OF SANITARY ENGINEERING STATE OFFICE M.C.W.A. I WAR AREA 7 WAR ESTABLISHMENTS PROTECTED Breeding Place of Anopheles treeoomi 88 SOUTH CAROLINA STATE HEALTH OFFICER BEN WYMAN, M. D. DIVISION OF PREVENTABLE DISEASES STATE OFFICE M.C.W.A. 24 WAR AREAS 122 WAR ESTABLISHMENTS PROTECTED Malaria is endemic, widely distributed, and probably the leading cause of morbidi- ty in most of the southeastern half of South Carolina although it occurs in all parts of the State. Anopheline mosquito breeding places in the southeastern part of the State are found in swamps, abandon- ed or overgrown farm drainage canals and ditches, abandoned and overgrown phosphate mining strip pits, many natural depres- sions, limestone sinks, un'drained highway borrow pits, and roadside ditches. The sandhill section, about 15 miles in width, extends across the center of the State from the Savannah River on the south- west to the North Carolina line on the northeast. There are many natural high- land ponds throughout this section but the chief breeding places for anopheline mos- quitoes are the many small artificial ponds, narrow swamps along the streams, and abandoned brickyard clay pits in Aiken and Sumter counties. Malaria is of low endemic incidence in this section. The remaining topography of the State varies from gently rolling hills adjacent to the sandhill section to mountains in the northeast. Malaria in this area oc- curs as small explosive epidemics geogra- phically limited almost entirely to the vicinities of artificial ponds and lakes. Extensive thick blood film malaria sur- veys throughout the State during the past seven years have enabled the State Board of Health to locate known foci of malaria. This information was not utilized in the establishment of many new Army and Navy bases, but it was of great value in deter- mining the kind and amount of control to be done by. the State Board of Health and the U. S. Public Health Service. Although fuel oil was th£ chief larvi- cide used, paris green was utilized in 12 of the 24 areas and kerosene was employed on the Orangeburg Fish Hatchery as well as on many small artificial pools. The chief means of applying the oil and paris green was by hand. However, a power spray boat was used on two large lakes near Fort Jackson and on a large mill pond in Camden. The power spray boat was transferred from one area to the other by truck. In Sumter a power sprayer mounted on a truck was used. 89 Drainage and Filling. Since the spring of 1942, all but two of the large and dif- ficult "quad” breeding places in the 24 control areas in the State have been elim- inated. The Jeffries Creek swanp near the Florence Army Air Base, with approximately 910 acres of breeding area, gave very lit- tle trouble until the spring of 1944. Due to excessive spring rains or other factors, it has been necessary to dust the greater portion of this swamp regularly since ear- ly May. The other large undrained breed- ing place is in the Charleston area where old abandoned phosphate strip mines, cover- ing approximately 500 acres, have long been a source of heavy "quad" breeding. Drainage has not been practicable since many of the mines are below sea level. Control in these pits has been very diffi- cult and not as satisfactory as desired. During the fiscal year 1944 82.0 miles of maior and minor ditches were dug, elimi- nating 369.43 acres of mosquito breeding surface. Of the above amount, 64.2 miles were constructed by hand labor, 14.1 miles by dynamite, and 3.7 miles by machine. Four acres of mosquito breeding surface were eliminated by filling. Most of the filling was done with a small bulldozer. It is planned to extend this type of control to the Charleston and Beaufort Dynamite Ditch after Blast areas where there are a number of small Sink holes and bays suitable for filling with a bulldozer. Larvicidal work. Drainage work has eliminated many of the known breeding areas, thus reducing the amount of larvi- cidal work necessary for control in the 290.34 square miles under supervision. Eight hundred thirty-nine miles of ditches were cleared and 1040.1 acres of re-clear- ing was completed during the year on the larvicidal program to facilitate the lar- vicidal work and further reduce the amount of larvicide used and to improve the qual- ity of control. When the malaria control program was first initiated, control work was carried on in the vicinity of all war establish- ments. Following the collection of exten- sive entomological data, it was possible to eliminate three areas from active con- trol and place them on an "inspection" ba- sis after the first year, thus saving the cost of control. Djring the past year one other area was placed on an "inspection" basis after the known breeding areas were eliminated by drainage. In the control areas entomological data were used to limit active control to those places in the area where "quads" were breeding. This not only reduced the amount of larvi- cide used but also the number of men need- ed for control in the respective areas. Dynamits Blast 90 TENNESSEE The malaria problem in Tennessee is primarily in the western section, between the Tennessee River on the east and the Mississippi River on the west. The most serious problem in this region is encountered in and adjacent to the areas, sub- ject to the overflow of the Mississippi River. This territory includes the val- leys of tributary streams, as well as several smaller creeks, and regions around Reel foot Lake. The valleys of these tributary streams range from one fourth of a mile to four miles in width. Their lower courses have a fall of only about one foot to the mile. There is also a potential problem in the middle portion of the State where malaria is present in endemic form. Anopheles quadrimaculatus is found throughout both the middle and western portions of the State; however, it is much more abundant in the western portion. Malaria has not been a problem in the east- ern portion of the State. There are nine areas in the State consisting of 24 zones in which malaria con- trol programs are being op- erated. Of these, four areas including 17 zones are located in the western part of the State. There are four zones in addition to the above under surveillance. Since the MCWA program has been in op- eration in Tennessee, a considerable amount of drainage work has been done in those areas where it was practical, in COMMISSIONER OF PUBLIC HEALTH R.H. HUTCHESON, M. D. DIVISION OF PREVENTABLE DISEASES STATE OFFICE M.C.W.A. 9 WAR AREAS 159 WAR ESTABLISHMENTS PROTECTED Power Dusting on River Quadrimaculatus Breading Place 91 Installing Precast Lining order to facilitate larvicidal control. In all cases where it was possible, permanent or semi-permanent types of drainage methods have been utilized. In the Camp Tyson Area, 2.6 miles of under- ground pole drainage have been installed, practically eliminating several extensive swamps caused by seepage springs outcrop- ping around the base of the hills. As a result of this work, the amount of larvi- cide used has decreased; thus manpower and material have been saved. Permanent ditch lining construction has been made possible in three areas during the winter months by local sponsors furnishing all materials and the Public Health Service furnishing labor and supervision. One and six-tenths miles of ditches have been lined with monolithic concrete in these three areas. Considerable difficulty has been expe- rienced in hiring labor in most of our areas. The labor turnover has been so great that some of the areas began the larvicidal season with insufficient per- sonnel to secure efficient control. □itch witn Precast Lining 92 TEXAS STATE HEALTH OFFICER GEORGE W. COX, M.D. The greater part of the State of Texas is well within the malaria belt of the Uni tec States, malaria being recognized and reported throughout the year, with the greatest number of cases occurring from June until October. The disease is most prevalent in the region lying between the Gulf Coast and a line parallel to it, roughly 150-200 miles inland, exceot that in East Texas as far as the Red River it approx- imately parallels the Louisiana border at a dis- tance of 10h-150 miles. The more arid portions of the State have seen relatively free of the disease Jntil recent years when flood con- trol projects, localized erosion control projects, stock tanks, and nirrerous construction impoundments vere developed which afforded ex- cellent breeding places for Anophe- les qvadrimaculatus, the principal /ector. The problem in all war areas is accurately charted, and rigid control neasures are main- tained. Control neasures that are effective in one area are sometimes impractical in an- other; therefore, the importance of consistent and well-planned procedures is em- phasized. Texas has a large concentration of military encampments, shipyards, and essential war esta- blishments. One hundred fifty-four are located in the malarious section. War establishments located outside of the malaria belt are under surveillance and can be placed under immediate control if the need arises. Surveys are now be- ing made at the request of the Army for several additional prisoner-of-war camps. The Counties of Gregg, Smith, Harrison, Bowie, and Morris lie in one of the heaviest malaria areas. Numerous small running streams, lakes, seepage areas, and bottom land swamps caused by averflowing rivers create an acute breeding haz- ard. Control is obtained by vegetation clear- BUREAU OF SANITARY ENGINEERING STATE OFFICE M.C.W.A 14 WAR AREAS 213 WAR ESTABLISHMENTS PROTECTED ing, small ditch construction, and constant oiling of stagnant areas until water has drained off. Five large drainage ditches were con- structed this winter and they should aid greatly in water run-off. The City of Tyler has contributed labor and equipment. The officials of Camp Fannin, near Tyler, have been very cooperative with respect 93 to the use of prisoner-of-war labor. eral drainage ditcnes were laid out by our staff, and good work done by the prisoners contributed a great deal to future control. In the Rio Grande Valley, particularly in Cameron County, Anopheles albimanus is a prolific breeder. This is the only area in the State in which this vector appears. Breeding of both albimanus and quarlrimacu- Isius is enhanced by the numerous resacas, seepage areas, and many irrigation canals. Good control has been attained by constant cleaning of vegetation, removal of silt from small drainage ditches to prevent clogging, and dusting with paris green. Effective dusting was accomplished with hand-operated equipment. In the Corpus Christi Area there are quite a number of small marshes and ponds resulting from inadequate drainage. The area is practically at sea level and the soil, which is light sand, is subject to silting and washing. Very good control is being maintained by ditch cleaning and oiling of stagnant ponds until they have been drained off by seepage or new laterals. The Houston, Galveston, and Beaumont regions have the largest concentrations of essential war establishments in the State. In these areas swamps, marshes, abandoned slusn pits, bayous, and numerous drainage ditches occur. A very high annual rain- fall, along with poor drainage, adds great- ly to the control problem. Constant removal of water hyacinths from drainage canals and cattails from marshes is necessary. These operations are supplemented by oiling and dusting. Power equipment has been used to great ad- vantage . The completion of six drainage ditches has permanently eliminated many acres of swamps and marshes. The terrain is a sil- ty loam. There is practically no silting from run-off as the fall is very low; some damage, however, is caused from torrential rains. The cities and counties of this area nave supported the program well. In the construction of a concrete in- vert the City of Port Arthur contributed all materials, MCWA supplying the techni- cal supervision and labor. The ditch Pusning Vegetation to Shore flemoving Vegetation from Shore Control of Anopheles in Aquatic Vegetation 94 forms an outlet for 16 acres of water and will eliminate all maintenance work. The total cost of materials contributed was approximately $3,200.00 In Brazoria County the Drainage Commis- sion has loaned a bulldozer and two drag- lines, together with the operators, for the construction of ditches. Technical supervision and other necessary labor have been furnished by this office. This work is a fine example of public-spirited coop- eration and will greatly benefit the county. Bexar County has one of the largest military concentrations in the United States. This area is dotted with numerous intermittent streams, seepage areas, small lakes, and ponds, along with Sal ado Creek and the San Antonio River. Practically all of the water surface is subject to heavy vegetative growth, and constant cleaning is a necessary control factor, supplemented by larviciding where neces- sary. In and around the City of El Paso an intricate system of ditches for sub-irri- gation requires considerable maintenance. A large overflow region near the city has been artificially created as a result of straightening tne Rio Grande River. The City of El Paso assists in the control work by furnishing small tools and a truck which it maintains and operates throughout the year. Control of aegypti Breeding in Used Tires Numerous stock ponds, lakes, and tanks art scattered over the Area comprised of Coryell, Limestone, McLennan, and Bell counties. Abandoned gravel pits, and low- lands covered by overflow of the Brazos River, create additional hazards. Drain- age is fairly good, but the run-off is very slow because of the flatness of the terrain, making thorough oiling and clean- ing operations a necessary practice. Quite a number of borrow pits and abandoned ponds were filled with the excavation from a large drainage ditch near the McClosky Hospital Annex, which was constructed in cooperation with McLennan County. A pris- oner-of-war camp near Mexia, in Limestone County, is being controlled by prison la- bor with MCWA supervision. Control projects in Corpus Christi, San Antonio, Houston', Galveston, Brownsville, and Hidalgo counties have been most suc- cessful in reducing Aedes aegypti densities. The general program has made progress in spite of handicaps, the greatest diffi- culty being in recruiting labor. Every area in the State has a manpower snortage. However, a fairly adequate force of labor- ers and inspectors has been maintained. All new inspectors were trained in a five- day course at the State Office Laboratory, which resulted in a definite monetary sav- ing to the Government, since it eliminated the possibility of placing untrained em- ployees on the payroll and having to dis- miss them almost immediately. Sealing Cistern 95 VIRGINIA A1 though the State of Vir- ginia is on the northern edge of the present malari- ous area of the United States, it has a history of numerous severe epidemics of malaria and a few cases are present most of the time. Most of the war esta- blishments are located in the Hampton Roads area and along the upper Potomac Riv- er near Washington, D. C. There were 106 war establish- ments under control in Vir- ginia during the 1943-44 season, 81 of which received regular inspection and lar- viciding. The remaining 25 received occasional inspec- tion only. They are concen- trated primarily In the Nor- folk -Portsmouth Area and the lower Peninsula Area sur- rounding Newport News. Be- cause of the heavy- concen- tration of war establish- ments, the labor shortage has been one of the main problems of the control program. Although oil has been the chief larvi- cide used on the program, extensive use has been made of paris green when it was impractical to use oil. New Jersey larvi- cide has been used in several water im- poundments. Almost all of the New Jersey larvicide has been applied with a small power sprayer mounted in a boat. Airplane dusting and cutting operations were used in the control of the water chestnut prob- lem in the Potomac River adjacent to Fort Belvoir and Quantico. During the winter months considerable drainage work has been completed, totaling 305 miles of ditches cleared, regraded, or installed. This drainage work has had an COMMISSIONER OF HEALTH I. C. RIGGIN , M. D. appreciable effect on the amount of larvicidal control work necessary during the present breeding season. Dynamite drainage has been used extensively since it is very well suited to the mucky soil present in Tidewater Virginia. In a number of highly de- veloped areas where perma- nent structures have been built, some ditch lining has been installed in order to eliminate expensive ditch cleaning and larviciding. In the least permanent areas where lining is not economi- cal or feasible, extensive use has been made of ditch cleaning. Clearing work has been carried on quite extensively to make the application of larvicide most effective. A special control program is in progress in the water chestnut area of the Potomac River. Excellent control was obtained by airplane dusting last year. The United States Engineers have for some years been carrying on a cutting program to eliminate this plant from the Potomac. With the ad- ditional under-water cutters furnished by the U. S. Public Health Service, it is hoped that all except a very limited amount of the water chestnut area will be removed from the river this year. Cutting is restricted to the period between emer- gence of the plants from the water surface BUREAU OF SANITARY ENGINEERING STATE OFFICE M.C.W.A. 6 WAR AREAS 106 WAR ESTABLISHMENTS PROTECTED 96 in May and maturity of the seeds in July. Among the most serious Anopheles quad- rimaculatus breeding areas in the Norfolk- Portsmouth Area have been six lakes owned by the City of Norfolk. Larvicide has been applied by power sprayers, dusters mounted in boats, and by hand operated dusters from the shores. In general, sat- isfactory control has been obtained except in the more heavily vegetated coves. Clearing work is in operation on these areas to make larviciding more effective. In order to relieve the manpower short- age, the malaria control program has made arrangements with the War Department to use prisoner-of-war labor for control around prisoner-of-war camps. If the la- bor situation does not improve, or if the control problem becomes more difficult, plans are under way to employ prisoner-of- war labor for work in areas other than those immediately adjacent to prisoner-of- war camps. Excellent relationships have been main- tained with both the Army and Navy canps and on a number of occasions it has been possible for the State Director to give considerable aid to the Army and Navy per- sonnel in planning their control programs. Boat for Dusting Water Chestnuts Casting Ditch Lining Installing Ditch Lining 97 DISTRICT OF COLUMBIA The fiscal year just ended has witnessed the elimination of most of the important breeding places of Anopheles quadrimaculatus in the District of Columbia. The water chestnut in Oxon Run, which supported abundant "quad" production, has been eliminated by cutting and by manual removal of the plants. The Chesapeake and Ohio Canal, which became a "quad" breeding place when it fell into disuse of a result of destruction of inlet works by a Potomac River flood, was restored for pleasure boating and no longer presents a control problem. Numerous smaller breeding places have been eliminated by drainage and fill- ing. The principal remaining breeding places are ornamental pools and ponds which vary in size from less than 50 square feet to as much as an acre. There are over 1000 of these in the District and a small per- centage of them breed Anopheles quadrima- culatus. Although malaria has not been an impor- tant disease in the District of Columbia HEALTH OFFICER GEORGE C. RUHLAND BUREAU OF SANITATION DISTRICT OF COLUMBIA M.C.W.A. OFFICE 21 WAR ESTABLISHMENTS PROTECTED I WAR AREA since the early part of this century, the world importance of the area at this time and the presence of large numbers of mala- ria carriers among the population requires that greater care than usual be taken to prevent malaria transmission. A thorough entomological inspection program covering the entire 69 square miles of the District of Columbia has been maintained, and the density of Anopheles quadrimaculatus has been held to a very low level. In January 1944 the MCWA program was transferred from the Bureau of Communica- ble Diseases to the Bureau of Sanitation of the District of Columbia Health Depart- ment. Coordination of MCWA work with the normal functions of the latter Bureau has led to the elimination or control of some of the mosquito breeding places by private property owners through use of the police power of the Health Department over public nuisances. More extensive use of these powers will probably be made in the future and closer coordination of MCWA work with other environmental sanitation activities of the Health Department effected. Plans are being made to train inspec- tors of the Bureau of Sanitation in the technique of mosquito control in order that they may report more intelligently on mosquito nuisances discovered incidental to other work. This will enable Health Department personnel to continue anti-ma- laria and anti-mosquito work after the war. ’Quad’ Breeding Place in a Lily Pond 98 PUERTO RICO JAMAICA 16 WAR AREAS 29 WAR ESTABLISHMENTS PROTECTED he is assisted by the other MCWA officers, who oarti cipate in detailed malaria investiga- tions for the Board. Control work is directed against the larvae of Anopheles aIbimanus and is concentrated largely in extra-reservation breeding places within mosquito flight range of military populations. MCWA activities in Puerto Rico and Jamaica are character- ized by the following features which distinguish them from op- erations at other locations. (1) The ob- jective has been the reduction of existing malaria among military forces rather than the suppression of a malaria hazard. Ma- laria incidence provides a sensitive yard- stick in planning and prosecuting malaria control operations. Work undertaken has been rigidly selected and systematically operated, and its effectiveness in terms of malaria reduction has been adequately demonstrated. (2) Lines of administration have been simplified because of the mili- tary urgency of the problem. (3) The ma- laria mosquito vector involved, Anopheles albimanus, breeds in a great, variety of aquatic situations and has a long flight Animal Bait Trap for SampIing Mosquitoes MCWA performs two functions in the Car- ibbean Theater of Operations. Its major activity is the prosecution of malaria control operations at Army and Navy bases In Puerto Rico and Jamaica. It is also concerned with a larger area comprising all Army posts in the West Indies and British, French, and Dutch Guiana on the northern coast of South America. The officer in charge of MCWA opera- tions in Puerto Rico and Jamaica is a member of an Army Malaria Board which ex- ercises general technical supervision over Army malaria control planning, practices, and financial allotments in the general area described above. In this assignment 99 downs have occurred. At the beginning of the fiscal yeai 1944, albimanus mosquitoes in 4 main war areas were being controlled satisfactorily by concentrated larvicidal and minor drainage activities. It was anticipated that this level of albimanus production could not be maintained by larviciding alone during and following the heavier rains in the fall. Consequently, effort was directed towards the completion of ma- jor drainage projects in these areas. The work was not sufficiently complete at the onset of the rainy season in the fall of 1943 to prevent some increase in albimanus Dipping for albimanus Larvae range. These factors have necessitated intensification of control effort and ex- tension of the control area to four times the size customary in continental United States. (4) Supply and procurement have been particularly important elements of program operation. The slow arrival of shipments from the United States and the difficulty of securing services, supplies, materials, and equipment locally to meet unexpected exigencies, have necessitated planning activities and requirements far in advance and have resulted in lengthy delays and stoppages when equipment break- Portable Pump production, but mosquito collections rose above arbitrarily safe limits in only two oosts, and malaria increased at only one oost. During the year, larvicidal and minor drainage projects have been operated in five principal war areas, and major drain- age projects in four areas; inspection programs have been carried on in two Army areas and in one Navy installation. MCWA has also operated a concrete products Larviciding Crawr at Work 100 drainage personnel from a maximum of 478 in November, 1943 to 329 in May, 1944. A further reduction is expected in two or three of the main control areas. A portable pump was used to dry up shallow ponds which formed in "chaca" sinks after heavy rains. This method was used because the ponds are surrounded by higher ground and cannot be drained by or- dinary ditching. In general, minor drainage has been carried on with personnel assigned to the larvicidal projects. Cleaning and clear- ing, an important activity on the island, has been performed with larviciding crews after dusting operations have been com- pleted. The most important problem asso- ciated with larviciding in Puerto Rico, as Concrete Products Plant plant and storage warehouse project, and a Service officer has supervised the opera- tion of an Army concrete products plant. LARVICIDING AND MINOR DRAINAGE The larvicidal program, which has been the major activity, has functioned almost continuously in five areas. Activities have consisted mainly of applying paris green with hand and power equipment at weekly intervals. Emphasis has been placed on providing closer supervision to field operations and applying control measures in accordance with entomological interpretationofbreed- ing conditions. This policy, together with effects of relatively dry weather from January to May 1944, has made possi- ble a reduction in larviciding and minor Lossy Field Pumping Station compared to general war areas in the States, is extensive cultivated or aban- doned sugar-cane lands, pasture lands with seepage areas fed by sugar-cane irrigation systems, and brackish mangrove and cattail swamps. MAJOR DRAINAGE Major drainage of a permanent nature has been prosecuted in the intra-reserva- tion areas of all military posts of mala- ria importance by the U. S. Engineers and by MCWA in adjoining extra-reservation areas where experience and entomological data indicated that satisfactory control could not be achieved with larvicidal measures alone. The most important proj- Constructing Large Drainage Ditch 101 ect involved ditches at or below sea level, making pumping necessary. A pumping station was constructed under the direct supervision of MCWA and financed jointly by the Public Health Service, Insular Health Dept., and FWA. This dewaters an area of approximately 500 acres. Another MCtyA sponsored and operated project con- sists of two drainage systems. One was designed primarily to lower the elevation of Lake Tortuguero by a canal into the sea, and the other is a canal system designed to drain a marsh of approximately 1,000 acres. Both systems, which were completed about the end of 1943, have been beneficial to successful larvicidal operations during the present calendar year and should en- sure the maintenance of low mosquito popu- lations during the approaching wet season. One major drainage project operated Dy MCWA and the U. S. Engineers in the vicin- ity of Ft. Buchanan has been completed re- cently. This work was necessary largely as a result of a hydraulic fill made by the U. S. Engineers in a drainage basin. The completed work consists of a pumping station equipped with two 30,000 gal lor per minute low lift pumps. The main canal is approximately 12,500 feet long and 5( feet wide and has a system of open, lined tributary ditches. An initial phase of this project consisted of moving Santa Ana --a small village of 66 houses. This vil- lage was located in a direct line between a large swamp and the western inhabited area of Ft. Buchanan. A blood film survey made by the Antilles Dept. Laboratory and the Insular Health Dept, showed that a large percentage of inhabitants had mala- ria at the time. The Army purchased land and moved the village to a location more remote from the base. In Puerto Rico the MCWA program was op- erated more as an auxiliary service of the Army and Navy than as a civilian service. All Army malaria control projects were ap- proved by a Malaria Board composed of an officer of the U. S.-Army Medical Corps, a U. S. Engineer Officer, and the Officer in Charge of MCWA operations; and MCWA projects were initiated or terminated with the full knowledge of the Malaria Board. Consequently, malaria control activities of the Army and Public Health Service were very closely integrated. Installing Highway Cross Drain Canal Draining into the Sea Puerto Rican Village that was Moved 102 HAWAIIAN ISLANDS PRESIDENT, BOARD OF HEALTH C. L. WILBAR, JR., M.D. BUREAU OF SANITATION DENGUE MOSQUITO CONTROL OFFICE 62 TOWNS PROTECTED Dengue Warning to Inter-island Travellers The Hawaiian Islands are isolated oy two thousand miles of ocean from the near- est malaria mosquitoes. Although well within the tropics, Hawaii was entirely free of mosquitoes until about one hundred years ago. Since that time three species have successfully invaded the Territory. Culex quinquefasciatus Say was the first to arrive and is looked upon with suspi- cion because of its ability to transmit filariasis. It is the domestic, foul wa- ter, night-biting and singing mosquito and is being partially controlled incidental to the dengue control program. Aedes aegypti (Linn.) and Aedes albo- pictus (Skuse), the dengue vectors, were introduced at a later date. These are the day-biting mosquitoes, aegypti being large- ly confined to cities while albopictvs is actually the predominant urban species and extends over the lowland forests of all the islands. Mosquito control was carried on in Honolulu in 1903 and 1912 and has been in operation continuously in recent years. The Rat and Mosquito Control Squad of the Chamber of Commerce was on the job at the time of the present outbreak of dengue and provided a nucleus of trained men for the emergency program. The Public Health Com- mittee of the Chamber of Commerce was able to assist the Board of Health in this work 103 because of funds accumulated through a voluntary tonnage levy on all shipments passing through the port of Honolulu. Dengue has been reduced almost to the vanishing point during the past year. Future efforts will be directed at complete elimination of den- gue transmission and at con- trol of mosquito breeding, to decrease the hazards of a new epidemic in case new carriers arrive in the Territory. Quarantine measures will con- tinue to be the first line of defense against introduction of malaria vectors. Treating House Plant to Kill Larvae Draining Water from Pineapp1 a Lilies Dusting Junk Pile 104 HIGHLY ENDEMIC AREAS MODERATELY ENDEMIC AREAS LOW ENDEMIC AREAS IMPORTED MALARIA MALAR IA CONTROL IN WAR AREAS J.S.PUBLIC HEALTHSERVICE MALARIA CONTROL IN WAR AREAS 1944 - 45 The Malaria Control in War Areas pro- gram, established in March 1942, is a joint undertaking by the U. S. Public Health Service and State Health Departments. The original objective was to reduce the hazard of mala- ria transmission in extra-cantonment mi 1itary and essential war industry areas by supple- menting the control measures of military authorities within the reservation. Concen- tration of malaria carriers in military hos- pital and prisoner-of-war camps created the necessity for protecting the civilian popu- lation from infections which could originate in these military areas. Return of malaria carriers from overseas caused further ex- pansion of control measures to non-military zones. Critical appraisal of areas in which malaria transmission may occur is based on medical, engineering, and entomological in- vestigations. In malarious areas operations are directed against the insect vectors of the disease. In this way coordinated forces offset the danger of an increase in malaria — the disease which has earned the reputation of being the worst of human scourges. FEDERAL SECURITY AGENCY - U. S. PUBLIC HEALTH SERVICE CONTENTS RETURNING MALARIA CARRIERS 1 ORGANIZATION FOR MALARIA CONTROL 4 WAR AREA PROGRAM 8 EXTENDED PROGRAM 14 TRAINING PROGRAM 26 AEDES AEGYPTI PROGRAM 3 0 INVESTIGATIONAL PROGRAM 35 Imported Malaria Studies, Columbia Lab.,NIH . . 36 Emory University Field Station 38 Carter Memorial Laboratory, Savannah, Ga. . . 40 DDT Investigations, Memphis Laboratory, NIH . . 5 1 Malaria Field Studies — South Caro 1ina . . . 52 MALARIA CONTROL IN THE STATES 5 6 Returning The Office of Malaria Control in War Areas (MCWA) was established in March 1942. IXiring the first season the program was confined to extra-cantonment zones of military areas and to essential war industries. The work complemented malaria control activ- ities of military authorities within reservation limits. During 1943 training and war pro- duction were still the main themes of the war effort. The tremendous expansion along these lines involved mass migration of millions of draftees and war workers into the South where the climate was not only favorable for year around training but also for malaria transmission. In spite of acute shortages of men and ma- terials, MCWA expanded during this period to keep pace with the war area problem. 1944 saw the first change in pro- gram objectives and emphasis. As the casualty figures mounted, Army gen- eral hospitals and Navy hospitals were filled. Prisoners were held not only in main camps but in temporary branch camps in areas where tempo- rary labor was needed. These were new war areas and were more hazardous than regular military reservations since they pro- vided greater concentrations of malaria carriers than were present elsewhere 1 Malaria Admissions per Thousand Men per tear for the Army in the Continen- tal United States. Wo rid War I — World War II. (U.S. Army) in the United States. Here for the first time there arose the necessity for pro- tecting the civilian against military malaria in addition to the earlier ne- cessity for protecting troops from the civilian reservoir of the disease. Within the southeastern United States where malaria is endemic, this problem was met by existing MCWA facilities. In the marginal or nonendemic states mosquito vectors occurred in sufficient numbers in close proximity to hospitalized malaria carriers and infected prisoners-of-war to present a serious hazard. Mobile units were commissioned to cope with this situ- ation. These units were equipped for rou- tine survey and for emergency control work. Under the direction of an experienced malaria control officer, they covered cir- cuits of military installations in the northern and western states and performed the tasks deemed necessary for the pro- tection of the public. By 1945 the shift in emphasis was complete. The downward trend of malaria cases had been uninterrupted and malaria admissions among troops in continental United States had reached an all-time low. Meanwhile, service men were returning in increasing numbers, many of them from hyperendemic areas and some of them active malaria carriers. Although the greatest danger will come still later when large-scale demobilization takes place, civilian cases of malaria have already been traced to these returning carriers. In anticipation of this, plans were made early in 1945 for the so-called “Extended Program” which was inaugurated at the beginning of the 1945 mosquito breeding season. The Extended Program is designed to meet the impact of returning malaria carriers. It shifts the scene from po- tentially hazardous war areas to actually malarious endemic foci. This shift is based upon the principle that imported malaria is most likely to manifest and perpetuate itself in places where the presence of the disease proves that con- ditions are ideal for its transmission. In these important malarious areas, cities are being protected by the usual methods — drainage and larviciding — and houses in small towns and rural areas are being treated with residual spray applications of the remarkable new in- secticide, DDT. The residual spray pro- gram is based upon the premise that the mosquitoes most likely to become infec- tive are those found resting on the walls and ceilings of homes occupied by man. Killing these particular mosquitoes be- fore the parasites have completed their 2 cycle interrupts the chain of trans- mission at its most vulnerable point. Other disease and pest control pro- grams have long been associated with MCWA, though on a relatively small scale in comparison with the whole effort. Keefes aegypti control was in- stituted in June 1942 as a precaution against the reestablishment of dengue or yellow fever in this country. Over 4 million premise inspections have been made and epidemics of these diseases have not occurred within the continental United States during the present war. Dengue broke out in Honolulu in 1943 and was brought under control early in 1944 by a cooperative effort of the Terri- torial Board of Health, MCWA, and mili- tary personnel.. Currently this program is maintained in order to incorporate anti-aegypti measures into the sanita- tion programs of vulnerable cities to hold.trained personnel for possible epidemics. Dog fly control, started during the first months of MCWA, was necessary in a few areas because of the serious effect of these pests on certain Army bases. Dog fly control is carried on in cooperation with the Bureau of En- tomology and Plant Quarantine for the purpose of protecting Army Air Force training bases along the seriously infested northwest coast of Florida. Beach deposits of marine grasses in which the flies breed are treated with dilute creosote sprays or, more re- cently, with DDT sprays. Reports for the 1944 season were most favorable, no annoyance from the vicious biting flies having been reported on the mil- itary reservations within the control areas. Early in the MCWA program it became evident that the public is often more interested in avoiding mosquito bites than in preventing disease. The concept of species sanitation — e.g. control of disease vectors only — is logical and economical but less comfortable in prac- tice than general control of all mos- quitoes. In spite of the very human desire to be comfortable, MCWA funds were limited strictly to use against dis- ease vectors. Work undertaken against the so-called “pest mosquitoes” was re- stricted to places where military training or essential war work was seriously hin- dered. By cooperative agreement with the various Army Service Commands, work of this type was authorized in 1944 on a re- imbursement basis. The returning carrier problem of 1944 and 1945 was not limited to malaria. Theoretically every disease that plagues mankind may be introduced by our troops which are returning this time from the most disease-ridden countries of the world. Actually our men are being pro- tected by phenomenal wartime methods and are receiving the very best of medical care. However, tropical diseases have already been introduced and the problem may become even more acute with the postwar expansion of air commerce. The first step in meeting this emer- gency is to train practicing physicians and medical technicians in the diagnosis of tropical and parasitic diseases. In 1945 such a training program was estab- lished under MCWA. In this connection training materials have been prepared for use in schools for technicians and for distribution to state diagnostic laboratories and to medical schools. Looking to the future we visualize a broad program of prevention of insect- borne diseases. Malaria and mosquitoes, endemic typhus and fleas — to mention only two of the already existing situ- ations, will demand aggressive control measures. Federal activities will be limited to the following services which are beyond the facilities of individual states: 1) Vocationa1-internship type of training and production of visual and other training aids; 2) Specialized epidemiological service including sur- veys and laboratory and field studies; 3) Development of equipment, materials and operating techniques for improving field control measures; 4) Cooperative tropical and related disease control demonstrations with state health depart- ments, and operational assistance in emergencies. 3 NATIONALINSTITUTEof HEALTH MALARIA INVESTIGATIONS SANITARY ENGINEERING DIVISION DIVISION of PUBLIC HEALTH METHODS COMMISSIONED OFFICERS’ DIVISION FOREIGN QUARANTINE DIVISION STATES RELATIONS DIVISION STATE MCWA MILITARY MALARIA CONTROL IN NAR AREAS LINES OF AUTHORITY AND INTERRELATIONS 4 ORGANIZATION FOR MALARIA CONTROL Malaria Control in War Areas is an Office of the States Relations Divi- sion. Its lines of authority stem from the Surgeon General through the Bureau of State Services and the States Rela- tions Division. Interrelations exist with other Public Health Service Di- visions such as Foreign Quarantine, Public Health Methods, Sanitary Eng- ineering, Commissioned Officers, and the National Institute of Health. MCWA maintains liaison with mili- tary authorities in the various service commands through Public Health Ser- vice liaison officers and operates through State health departments. Each State directs its own program through existing administrative chan- nels. Assistance from the Atlanta head- quarters consists of 1) trained per- sonnel, 2) specialized equipment, 3) materials under wartime priority, 4) technical consultation, and 5) assistance with administrative and fiscal ma tters. Within the States a director of malaria control activities is respon- sible for over-all supervision of the work. In most cases a state engineer and a state entomologist supervise the field work. An MCWA engineer and an entomologist are assigned to Public Health Service district offices and are available for technical consultation and guidance when needed. A total of 250 “war areas” were in operation dur- ing the year. In addition to this there were 150 Extended Program areas and 15 Aedes aegypti control areas- Personnel on duty for all or part of the year included 300 commissioned officers, and the following Civil Ser- vice personnel: 75 professional and scientific employees, 600 subprofes- sional, 200 clerical, and 3000 custo- dial employees. Additional help is rendered by numerous employees pro- vided by state and local agencies and by a number of men assigned to dengue control in Hawaii by the Army. Within the headquarters office, or- ganization is atong the lines of pro- fessional services. Five divisions are set up for administration of Medical, Entomological, Engineering, Training, and Administrative (fiscal) matters, respectively. These divisions are fur- ther divided into units charged with responsibility for specific types of work as indicated by their titles on the accompanying chart. Three inde- pendent units are directly responsible to the Executive Office as indicated. The Administrative Division handles all fiscal matters. This includes per- sonnel recruitment, classification and placement; preparation of budgets and processing of pay roll and travel vouchers; and procurement, distribu- tion and repair of equipment. As in past years, personal services accounted for a large proportion of the MCWA budget. The relative expendi- tures for personal services as com- pared with supplies, equipment, con- tractual services, and transportation are shown in the accompanying table. Major items of equipment are like- wise shown. This gives a very incom- plete picture of the total of 1,046 se- parate items on property records ranging from $12,000.00 draglines to rat traps. Field and laboratory investigations play a vital role in translating the results of pure research into practi- cal field operations. This work is guided by headquarters personnel and is carried out by designated officers who are in charge of particular pro- jects. Among the projects carried on during the past year may be mentioned the Carter Laboratory at Savannah, Georgia, the DDT Residual Spray Study in South Carolina, Imported Malaria Studies in cooperation with the National Institute of Health at Columbia, S. C., the Emory University Field Station at Newton, Georgia, investigations in co- operation with the Tennessee Valley Au- thority, and other special investigations. 5 MCWA H EADOUARTOR»SW®BM8gyi ADMINISTRATIVE DIVISION IMiHIMIMMP mmwismis iHM M 11 ENTOMOLOGY DIVISION TECHNICAL DEVELOPMENT CARTER MEMORIAL LABORATORY Savannah, Ga. MALARIA FIELD RESEARCH, South Carolina OFFICER IN CHARGE EXECUTIVE OFFICER (OHMimONED OFFICERS'UNIT | EQUIPMENT UNIT RECORDS UNIT ! ENGINEERING DIVISION , DENGUE mum CONTROL IMPOUNDED WATERS I MEDICAL DIVISION TRAINING DIVISION w-m/am/mo fD/ron/M I *mmmmmmmmmmmmm mi me a ms ll■^l,l4<|■l^, ■ 'iVirii ■> iiiTiiriiii(iiii>iwiiiiiiiiiiiiiiiiiiiiilil pmsmAmimk 6 PERSONNEL Each symbol represents 100 people COMMISSIONED TECHNICAL SUB-TECHNICAL CLERICAL LABOR EXPENDITURES Each symbol represents $200,000 EQUIPMENT CONTRACT SERVICES SUPPLIES AND MATERIALS TRANSPORTATION PERSONAL SERVICES EQUIPMENT Each symbol represents 100 units POWER SPRAYERS AND DUSTERS AUTOMOTIVE HAND DUSTERS HAND SPRAYERS 7 ARMY-NAVY-WAR INDUSTRIES PUBLIC HEALTH SERVICE COOPERATION INTRA-RESERVATION MILITARY OPERATIONS EXTRA-RESERVATION USPHS OPERATIONS WAR AREA PROGRAM As in past years, the war area pro- gram employed conventional control measures directed against the larval forms of the prin- cipal malaria vec- tors, Anopheles quad- r imaculatus Say, Ano- pheles freeborni Ait- ken and Anopheles al- bimanus Wied. Opera- ting around critical war establishments, this program has con- tributed to the pro- tection of military and other war-essen- tial personnel. This work complements that which the Army and Navy carry on in can- tonment areas. It is purely preventive and is based upon the thesis that the presence of malaria vectors is a potential hazard, even though actual malaria cases may not be demonstrable in an area at any par- ticular time. Since the control program is based upon the mosquito vector ra- ther than on mala- ria, its success should be judged in terms of mosquito reduction. However, the decrease of the disease within the Army in continental United States is so clear and specta- cular that it should not be overlooked in this c onnec- t ion. Densities of Anopheles quadrimacula- tus, freeborni, and albimanus in controlled versus uncontrolled areas. 8 ENTOMOLOGICAL EVALUATION Mosquito densities are a reliable guide for control operations. They point the way to places in need of control and provide a means of eva- luating the effectiveness of the fin- ished job. An average of the highest single station counts inside of pro- tected areas for the 1944 season shows peaks of 9 in June and 8 in September as compared with outside counts ave- raging 23 and 24 respectively. Since an arbitrary figure of 10 has been set as a maximum number of mosquitoes consider-ed to be safe in any adult catching station in a zone, the sea- son’s work may be considered as satis- factory. When over 10 female mosquitoes persist in any resting place in a zone for a period of three or more weeks, the zone is classed as unsatisfactory. Zones in this category included many which were newly activated during the season and those presenting such over* whelming control problems that satis- factory low densities could not be maintained at all times. Collecting Mosquitoes in Chloroform Tube Entomological survey and surveil- lance activities serve to restrict control operations to those areas where significant vector densities exist. The chart below shows that the number of zones, in which unnecessary control was avoided by these activities, is approximately equal to the number of zones in which anopheline control was prosecuted. This represents a hypothet- ical saving equivalent in extent to the project operations actually performed. CONTROL NOT INDICATED control! INDICATED ■ , Total War Areas under Entomological Surveillance — 1944 9 LARVICIDAL OPERATIONS SUMMARY COMPARATIVE METHODS As in previous years the principal control operation of MCWA was app 1 ica- tion of larvicides. Next in terms of man-hours was drainage maintenance. Ma- jor and even minor drainage projects were few in number and limited in extent. LARVICIDES. Paris green and oil were the two principal larvicides used on the MCWA program. A review of the year’s activities reveals that in terms of acre-treatments, paris green was the more extensively used larvicide. However, in terms of man-hours expended in distribution, it was greatly sur- passed by oil. Paris green was used extensively in Puerto Rico and Jamaica because, under the variety of albimanus breeding conditions, it has proved to be the most economical and effective larvicide. It is more suitable than oil for distribution where anopheline breeding is associated with dense vege- tation and heavy flotage. During 1945 132,726 acres were larvicided with paris green at an average cost of $2.01 per acre-treatment. Oil larviciding was performed in 174 areas of 27 states. Diesel or fuel oil No. 2 was used in most instances. The principal advantage to be gained by the use of oil is that control of general mosquitoes is accomplished in the areas treated — in short, pest mosquito control as well as malaria vector control. During 1945 about 100,000 acres were larvicided with oil at an average cost of $5.90 per acre-treatment. APPLICATION OF LARVICIDES. Hand larviciding was used less extensively this year than in any previous year. This was due to better selection of methods as a result of several sea- sons’ experience and to an increased need for labor conservation in most areas. Of 214,666 acres treated with paris green and oil, 34.2% of the applications were made with power equipment including airplane dusting. Last year about 20% of the acre-treat- ments were by power equipment. Sav- ing in man-hours by use of power equipment is graphically illustrated on the basis of MCWA operations for 1944-45. TIME-COST DATA ON LARVICIDING. Over 80% of MCWA funds are expended for personal services. It has been shown that the basic field operation is larviciding. Hence it is here that the greatest saving may be accom- plished by increasing the efficiency and thus decreasing the man-hours ex- pended on the job. From a field study it was determined that the foreman is the key man in maintaining a high level of efficiency. Training and care- ful planning at this level can perhaps do more than anything else to improve the control program. 10 TOTAL WATERED ACREAGE (120,646 ACRES) TOTAL LINEAR WATERED AREA (54,921,072 LINEAR FEET) PERMANENTLY WATERED SEMI-PERMANENTLY WATERED TEMPORARILY WATERED BREEDING MALARIA MOSQUITOES BREEDING OTHER MOSQUITOES NON-BREEDING CONTINUOUSLY FREQUENTLY OCCASIONALLY DRAINAGE Drainage activities for the year included machine and dynamite excava- tion, filling, installation of perma- nent lining, ditch stabilization, con- struction of cross-drains and outlet structures. At the close of the fiscal year 1945, little major drainage re- mained to be done on the war areas program in the continental United States. Completion of drainage in most esta- blished areas, inactivation of some military bases, and the end of expansion in most states were responsible for this. To determine the extent of the pro- blem and the percent eliminated by the drainage, a census of watered areas was conducted during the winter of 1944 throughout the war areas. A total of 120,646 acres of watered area were re- ported. Fifty-two percent of this area was classified as permanent, 28% semi- permanent, and 20% temporary. In addi- tion to the above, 55 million linear feet of water-holding ditches, canals and other watered courses under 10 feet in width were reported. Somewhat over one-third of each class of watered area was found to be breeding malaria mosquitoes. This acreage (42,177 acres plus 25 million linear feet of ditches) probably represents the significant acreage of watered area from the stand- point of MCWA. It was further report- ed that 15,000 acres and 680 thousand linear feet of watered area have been eliminated by drainage during the course o f MCWA operations. A summary of various types of drain- age activities is given for the past year. Hand excavation cost an over-all average of $1.57 per cubic yard; dynamite ditch- ing $0.58 and machine drainage $0.42. FUTURE DEVELOPMENTS For the future we may expect sig- nificant developments along two lines. First, the development of the new larvicide, DDT, may profoundly alter the picture. DDT is effective in such small quantities that real savings in the critical matter of man-hours re- quired for application may be attained. Secondly, power equipment designed for application of DDT as a smoke or ther- mal aerosol may completely revolution- ize control operations. Work is prog- ressing on tfiese and other points and results should become incorporated into field practice as soon as materials and equipment can be released in suf- ficient quantity. 13 Returning carrier upsets the balance More control tc compensate EXTENDED PROGRAM The Extended Program is a compre- hensive plan designed to meet the hazard of large numbers of malaria carriers returning from military service. Other things being equal, the addition of these active malaria carriers upsets the present favorable balance and cre- ates a serious menace to public health in the United States. Estimates vary as to the number of active carriers to be expected but whether it be one thousand or one million, local out- breaks may be expected because it has been proven that our mosquitoes can carry exotic strains of malaria and the first locally acquired cases stem- ming from a World War II veteran were reported a few months ago. Malaria carriers will return to every state and to most towns and crossroads throughout the country. Complete pro- tection over such a vast territory would be infeasible. Therefore, attention has been concentrated in those areas where, by the continued presence of malaria, it is known that optimum conditions exist for transmission. In these endemic areas an intensive attack on malaria vectors is being waged. Drainage and larviciding are the methods of choice in towns of 2,500 or more people. But malaria is a rural disease. Heretofore there has been no economically feasible method of carry- ing malaria control to the individual tenant farmer or share cropper. Now, 14 DDT HOUSE SPRAYING. The is toxic to mosquitoes i ODT spray emulsion evaporates leaving a layer of crystals which upon contact for several months. for the first time, a method is avail- able —- the application of DDT residual spray to walls and ceilings of homes. DDT residual spray evaporates leaving a layer of crystals on the treated sur- face. For several months these crystals are toxic to mosquitoes upon contact. Anopheles quadrimaculatus commonly rests upon walls and ceilings after taking a blood meal. By killing these particular mosquitoes which have entered houses and fed on human beings and thus are most likely to have become infected, the malaria chain is broken. It is only necessary for a mosquito to rest on a treated surface for a few minutes to be killed but DDT is slow to take effect so death may not occur for several hours. Dichloro-diphenyl-t r i chloroethane, or DDT, was first synthesized over 70 years ago but its insecticidal properties were not realized until 1939, and it did not reach this country until 1942. Because of military urgency years of research were crowded into the brief span of the war months. Under the general super- vision of the Office of Scientific Re- search and Development tests were run by many agencies in laboratories and in the field, at home and on the battlefronts. MCWA investigations were concentrated on the technic of application of the ma- terial as a residual spray in practical field operations. The methods developed at the Carter Laboratory, Savannah, Georgia, and in field tests in Arkansas and Puerto Rico are now being used on the Extended Program. 15 for practical control purposes. Hence, within States, areas selected for con- trol operations vary somewhat from those dictated solely by county dis- tribution of mortality. Such devia- tions are made largely in consultation with State and local health officers and are based upon their intimate know- ledge of local conditions. The extent of the problem of en- demic foci of malaria is shown in the accompanying table. A mortality rate of 10 per 100,000 population has been set as a threshold of malaria significance. It is believed not only that the bulk of the mala- ria problem is repre- sented by the counties reporting rates of 10 or over but that operations involving a population of that magnitude are prac- t i c ab 1 e . Counties with rates of 10 or more per 100,000 population number 188 in 13 Sta- tes. According to Bu- reau of Census figures 957,425 homes are in- cluded in the rural portions of these coun- ties. The remainder of the endemic malaria problem is scattered over 649 counties with mortality rates from 0.1 to 9 per 100,000 population. It is proposed to attack this problem by residual spraying of individual homes where the presence of malaria has been confirmed by a positive blood slide or by a positive history of malaria on the part of returned service men. On the arbitrary assumption that there are about 400 cases for each malaria death the number of homes to be treat- EPIDEMIOLOGY The problem of precisely delimit- ing the endemic foci of malaria was most difficult. Whether malaria spreads outward from endemic foci in times of resurgence or gradually comes out of hiding throughout its range is a moot question. In either case, practical control measures depend upon deline- ating endemic foci a ° a*./*,, «•«.«■ ~ possible. It was founc that malaria mortality as reported by coun- ties left much to be desired but was the most reliable meth- od available short of expensive and time- consuming technics which are still in ar experimental stage. Mortality data also are useful in follow- ing trends and are supported by morbid- ity data as shown ir the accompanying graph. In addition to the general downward trend, three peaks are clear- ly evident. Because the three cycles evi- dent since 1920 are not equally spaced they cannot be used accurately to predict the next cyclic in- crease of malaria. How- ever, inspection of the chart would indi- cate that this increase is overdue. The reasons for its fail- ure to materialize between 1939 and 1944 are not clear. Mortality data also provide an objective criterion of the relative “weight” of the malaria problem in the'various States. However, within the States the county distribution of malaria mortality may not deline- ate the problem sufficiently closely Malaria Morbidity and Mortality Rates per 100,009 Population in all States reporting - 1920-19U?. 16 ed in these marginal counties has been estimated by multiplying the average number of deaths by 400. The resulting figure, 264,800, added to the number of homes in regular Extended Program counties, gives a total of 1,222,225 homes as the goal for fairly complete coverage. This figure may be low if an attempt is also made to spray homes of returned military carriers. TABLE I Number of counties and homes per state with malaria rates of 0.1 to 9 and 10 or over per 100,000 population respectively. STATE COUNTIES WITH RATES OF 10 OR MORE PER 100,000 POPULATION COUNTIES WITH RATES OF 0.1 — 9 PER 100,000 POPULATION TOTAL HOMES % OF TOTAL NO. COUNTIES NO. HOMES * * NO . COUNTIES NO. HOMES* A1abama 19 118,833 42 29,280 148,133 12.06 Arkansas 32 198,298 37 21,200 219,498 17.88 Florida 25 70,627 36 16,000 86,627 7.06 Georgi a 33 93,732 80 22,560 116,292 9.47 Kentucky 2 5, 711 36 7,040 12,751 1.04 Lou i s i ana 9 48,309 50 28,800 77,109 6. 28 Mississi pp i 20 114,308 59 30, 160 174,468 14. 21 Mi ssouri 5 37,182 44 8,080 45.262 3. 69 N. C. 4 18,779 49 15,360 34,139 2. 78 Ok 1ahoma 2 13,758 43 15,040 28,798 2. 34 S. C. 15 85,810 26 18,080 103,890 8.46 Tennessee 4 20,451 51 21,920 42,371 3. 45 Texas 18 101,627 96 36,880 138,507 11. 28 TOTAL 188 957,425 649 270,400 1,227,825 100.00 * Number of Homes ; 400 x average number of deaths reported annually ** From Bureau of Census volume on Housing, 1940. Total includes homes in towns of less than 2500 population 17 OPERATIONS Actually only a fraction of the total number of homes was sprayed before the end of the fiscal year. Spraying began in most States during March and all but one State had started by the middle of April. Because of the delay in supplying equip- ment and materials to meet the essential requirements of all States, only 300,000 houses had been sprayed through the end of the fiscal year. It is estimated that this represented approximately 27 square miles of potentially lethal resting sur- face (walls and ceilings) offered to ma- laria vectors in the worst malarious regions of the country. The average spraying time per house was 1.35 man-hours. It is expected that this figure will be reduced significantly as operational experience increases. The direct cost per house application includ- ing labor and materials averaged $1.58. The average area sprayed per house was approximately 2,200 square feet. At the recommended application rate of 100 mgs. of DDT per square foot,this represents approximately 8 ounces of DDT per house app1i cat ion. EQUIPMENT AND SUPPLY — A major prob- lem prior to Extended Program operations was obtaining proper equipment in time and in sufficient quantity to meet project requirements. Procurement, specifics- tions, testing, and modification of equipment were joint responsibilities of the Engineering Division, the Equip- ment Unit, and the Carter Laboratory at Savannah, Georgia. Numerous types of sprayers, spray nozzles, gaskets, hose, solvents, emulsifiers and other items incidental to DDT residual spray- ing were tested. Procurement of xylene resistant gasket and hose material was perhaps the most serious difficulty. Of the variety of gasket materials test- ed, only two were found satisfactory for field use. Three kinds of synthetic rubber hose proved usable. After test- ing and selecting suitable materials, further delay was experienced in furn- ishing such large supplies of special- ized equipment, due to the failure of various manufacturers to meet delivery schedules. Most of the difficulties were finally overcome so that field crews even- tually received all essential equipment. PERSONNEL — Although Extended Pro- gram work was conducted during a period of critical manpower shortage, no great difficulties were encountered in hiring personnel. Twelve hundred laborers were employed for the work. Supervision was by area supervisors specially trained or borrowed from the war area program. In- spection of premises was handled by the State Entomologists. DDT SPRAY CREW. The average spray time was 1.3 man-hours and the cost was $1.58. 18 DDT RESIDUAL SPRAY FORMULAS AND APPLICATION SUMMER FORMULA 35% DDT* WINTER FORMULA 20% DDT* POWER MIXER HAND MIXER POWER MIXER HAND MIXER DDT 125 LBS. 84 LBS. 70 LBS 44 LBS. XYLENE 31.5 GALS. 21 GALS. 35 GALS. 22 GALS EMULSIFIER 2 GALS. 5M QTS. 7 QTS 4V4 QTS- EMULSION CONCENTRATE 1 PART SUMMER CONCENTRATE + 13 PARTS OF WATER 1 PART WINTER CONCENTRATE + 7 PARTS OF WATER ~ 2H% DDT SPRAY * ~ CONTAINING 25 MG DDT PER CC. SPRAY SOLUTION SPRAY MIXTURE 100 MG. DDT PER SQUARE FOOT OR 4 CC. 2Vi% DDT SPRAY PER SQUARE FOOT THIS DOSAGE. APPLIED TO WALLS AND CEILINGS, EFFECTIVE 3-5 MONTHS DOSAGE NOZZLE NO. V4T 8002 80° FAN-SHAPED SPRAY DISCHARGED AT 0.2 GALLONS OR 757 CC. PER-MINUTE AT 40 LBS.PRESSURE. TO APPLY 4 CC. OF SPRAY AT 100 MG- OF DDT PER SQUARE FOOT, SPRAY AT THE RATE OF 190 SQUARE FEET PER MINUTE, RATE OF APPLICATION ONE HOUSE — 1700 SQUARE FEET OF SPRAYED SURFACE — WILL REQUIRE AT 100 MG. /SQ- FT. 170,000 MG. OR 170 GRAMS OR 6 OUNCES OF DDT 1 PINT OF SUMMER CONCENTRATE AT 4 CC /SQ- FT. 6800 CC OR 1.79 GALLONS 2Vx% DDT SPRAY QUANTITIES PER HOUSE 1.3 MAN-HOURS PER AVERAGE HOUSE WITH HOUSE PREPARED FOR SPRAYING LABOR * Exp ress eel in percent for simplicity 19 TRAINING. Residual spraying with DDT was an entirely new method of ma- laria control. Field experience was limited to test projects in Arkansas, Tennessee, Georgia, and Puerto Rico. With only a handful of trained men and the most critical transportation situ- ation in the history of our country, a decentralized training program was set up. The Carter Laboratory at Savannah, Georgia was the scene of the basic course. Designed for District and State supervisory personnel, this course was conducted as a series of discussions and field demonstrations. The follow- ing main subjects were treated in de- tail during the three-day sessions: operational set-up, decentralized train- ing, lay education, entomological ser- vices, principles of residual spraying with DDT, field practice in spraying, hand and power spraying equipment, hand and power mixing of DDT and occu- pational hazards. As a result of this course the nu- cleus of trained men was increased from a dozen to over 75 and each Extended Program State had at least two men with first hand knowledge of the subject. Decentralized training was then inaugurated. Each State set a date and completed arrangements for a train- ing course for area supervisors and others charged with immediate respon- sibility for doing the work. Two mobile training units were equipped with literal ture, training aids and equipment and were made available to the States. An officer with first hand experience in DDT residual spraying was available to all States that requested assistance in con- ducting their in-service training program. Two sorts of training aids were pro- duced for immediate and widespread use. Film strips on “Hand Spraying of DDT”, “Power Spraying with DDT,” “Mixing of DDT Emulsions,” and “Safe Practices in Handling DDT” were prepared in time for the Savannah course and were made available for use throughout the decen- tralized training program. A “Hand- book of DDT Residual Spray Operations” was prepared to give detailed instruc- tions and formulas. Demand for the Handbook has already necessitated a third printing. Results of the DDT training program can only be measured in terms of smooth working operations. The fact that 1,200 men were put in the field within two months without any evidence of occu- pational hazards, major public com- plaints, or operational failure is mute testimony as to the effectiveness of the job. TRAINING FOR THE DOT RESIDUAL SPRAY PROGRAM. With the aid of decentralized training, 1,200 men were put in the- field within 2 months without any evidence of occupational hazards, major public complaints, or significant operational difficulties. ABOVE: Malaria control assistants contact- ing householder prior to spray crew's arrival. RIGHT: House being prepared for spraying. Participation by householders enabled crews to spray over twice as many homes as would otherwise have been possible. PUBLIC RELATIONS. Wholesale spraying of the interiors of half a million homes in a free country poses certain prob- lems in public relations. Respect for personal property rights was a basic principle of operations. But the house- holder's respect or acquiescence was not enough. No less than full, active cooperation was needed to cover the ground in the few months of mosquito breeding. It is estimated that partic- ipation by householders in the prepar- ation of homes for spraying made pos- sible the spraying of over twice as many homes as would otherwise have been possible. The job of selling the Extended Program was made easy because of the phenomenal reputation of DDT. In spite of wartime secrecy and rigid control by the War Production Board, the let- ters DDT sky-rocketea to national prom- inence. The demand for DDT and for free household spraying far exceeded the supply of materials and equipment. In some States malaria education was handled as a part of the general program of health education. In oth- ers, public relations problems were handled by malaria control assistants. Many of these “malaria educators” were selected on the basis of their training and experience as teachers. Local residents were chosen upon rec- ommendation of health officers when- ever such qualified persons were avail- able. The malaria control assistants were offered two weeks of intensive in-service training and orientation by personnel from Washington and At- lanta and further training and assis- tance in the field. 21 PUBLIC LECTURE ON MALARIA PREVENTION AND CONTROL. State reports indicate that approxi mately 75,000 persons per month received basic information on malaria prevention. Educational materials were avail- able from various sources. Among such materials were: a film strip, “ Spray- time,” showing what the householder can do to prepare his premises for spraying; a folder, “How DDT Spray Keeps Mala- ria Away”; a leaflet, “Spraytime Top- ics”; a DDT window sticker; a post card to inform persons of the time of visit of the spray crew; suggested copy for radio spot announcements, interviews, and plays; and sample newspaper releases. State reports indicate that: 1) ap- proximately 75,000 persons per month have received basic information on the prevention of malaria; 2) approximately 250,000 pieces of printed materials have been distributed per month since March 1945; 3) approximately 500,000 persons have been contacted through some medium each month in the 13 States in which residual spray programs are being operated; 4) of the 300,000 houses contacted up to June 30, 1945, less than 2% were not sprayed because of lack of cooperation of householders. But statistics are not the whole story. The number of persons contact- ed and the number of pieces of print- ed material distributed are no more reliable as criteria of the effective- ness of malaria education than is the number of pounds of DDT as an indi- cation of the efficacy of malaria control. As a matter of fact the re- sidual effect of the educational pro- gram will outlast that of the DDT. LAY EDUCATION. Each individual has a responsibility in malaria preven- tion. If this responsibility is ignored, either through ignorance or indiffer- ence, malaria is likely to persist and even increase as a public health problem, in spite of the efforts of organized agencies. It is fundamental- ly unsound to continue to do for indi- viduals what they should be able to learn to do for themselves. Although the immediate objective of the educational work on the MCWA pro- gram is to obtain the full cooperation and assistance of the householder in order to facilitate operations, the larger objective of stimulating the public to assume responsibility for malaria prevention must be kept in mind. The range of individual activi- ties may extend from repairing screens to cheerfully contributing money for the development of permanent malaria control or mosquito abatement projects in communities throughout the country. Furthermore this work should be seen in its true light, as part of a general health program including improved nu- trition, general sanitation and medical care. This, in turn, influences and is influenced by general economic and sociologic conditions at home and throughout the world. 23 in areas having various densities. From these places, engorged females are collected and forwarded to the Savannah laboratory where precipitin tests are made to determine the per- centage of specimens which have had human blood meals. If the residual spray is effective, the percentage of mosquitoes positive for human blood should be less than the 4 % normally found. By the end of the fiscal year, in- spections had been reported from 45 areas in 9 States. In these areas a total of 2,469 sprayed houses had been inspected, in only 60 of which anoph- elines were found late in the day, although 160 had them present at the morning inspections. On 40 percent of these premises over 10 anophelines were counted in outside resting places and on an additional 21 percent out- side resting place counts of from 1 to 10 were found. From 27 areas in 6 States a total of 4,082 specimens hadbeen sent in for precipitin tests. 2 ,955 speciraens from unsprayed areas gave a human blood feeding rate of 4.8 percent , while 1,090 specimens from sprayed areas gave a human blood rate of 1.3 percent. Of even greater significance 425 mos- quitoes collected inside unsprayed houses showed 30.6 percent positive for human blood whereas all 22 mos- quitoes caught inside sprayed houses were negative for human blood. Sample inspections are made after spraying to determine the presence of live anophe- lines. Unsprayed favorable adjacent rest- ing places are also inspected to judge the effectiveness of the spray. ENTOMOLOGICAL EVALUATION Because of the low malaria rates prevailing in this country at present and the errors of the known methods of measurement during this low ebb of the disease, the effectiveness of the re- sidual spray program is determined by entomological data. Random inspections of a number of premises on each con- trol project are made at monthly in- tervals after the start of spraying to determine if any live anophelines are present. Also, the number of anophe- lines found in an unsprayed favorable adjacent resting place such as a barn or stable is determined so that the effectiveness of the spray can be judged Precipitin tests of engorged female anophelines are made at the Savannah laboratory. 2955 specimens from unsprayed areas gave a human blood feeding rate of 4.8 percent, while 1090 specimens from sprayed areas gave a human blood rate of 1.3 percent. MOBILE UNIT. Each unit is directed by an engineer or entomologist with a labor crew of 2 or 4 seasonal employees. Last year, 12 units were in operation in 15 States. MARGINAL STATES The problem of returning malaria carriers in the so-called marginal States is a difficult one. Efficient vectors occur in enormous numbers in some sections of the northern tier of States, far from the endemic centers of* the disease. The co-existence of malaria vectors and malaria carriers presents a very real hazard, wherever found. Furthermore, sporadic epidemics have occurred under such conditions after previous Avars in this country and elsewhere. From the standpoint of operations the problem resolves itself into a question of degree of hazard. The exis- tence of a hazard in endemic areas in the Southeastern States is proved by the persistence of the disease. Con- versely, the disappearance of the dis- ease in recent years in the marginal States and its total absence from the northern limits of distribution of the vectors, prove that the hazard is less. Consequently, routine operations have been concentrated in the endemic mala- rious areas and mobile units have been outfitted to cover marginal States. Each mobile unit is directed by an engineer or entomologist with a labor crew of two to four seasonal employees. Equipment includes a station wagon and a truck outfitted with standard appa- ratus and materials for inspection, larviciding, spraying for adults, minor drainage and drainage maintenance. Mobile units are assigned to Public Health Service District Offices and operate in cooperation with health de- partments of the various States. Opera- tions include (1) surveillance and inspection services where needed, (2) training of local crews in control measures, and (3) actual control around military installations where resident MCWA projects do not exist and malaria mosquito breeding is sig- ni ficant. In the event of a malaria outbreak mobile units can be dispatched to the area immediately to start control opera- tions. Later, if needed, a resident project may be set up or personnel and equipment may be transferred from the nearest regular project. Mobile residual spraying units are coming into use for spot malaria con- trol of premises where presence of the disease has been verified by a posi- tive blood smear. This promises to be the answer to the returning carrier problem outside of the endemic Ex- tended Program areas. In some States the premises are sprayed wherever a case of malaria is proved by blood examination or, in the case of an ex- service man, by positive evidence of recent history of the disease. During the fiscal year 12 mobile units were in operation to serve 15 States. Control was carried out in 10 areas. Surveillance or inspectional services were rendered in 63 zones. 25 TRAINING PROGRAM Training activities form an integral part of the malaria control program. As the control program expanded to take on new responsibilities, the scope of the training activities increased. During the past year the work included the formal pre-service orientation course and the in-service training course for operations personnel, the preparation and distribution of month- ly field bulletins, entomological and engineering field handbooks, bulletins, pictorial keys, posters, displays, newspaper and radio releases, training and educational film strips and motion pictures, photographs, and lantern slides. IN-SERVICE TRAINING PROGRAM The need for orientation and train- ing became evident early in the malaria control program. With the great demand for specialized personnel it became increasingly difficult to find indi- viduals with training and experience in malaria control. Therefore it was necessary to introduce specific training for the professional personnel recruit- ed to carry on the engineering and entomological phases of the program. The In-Service Training and Orienta- tion Course as conducted during the past year includes a brief account ofU. S. Public Health Service and MCWA activi- ties, with instruction in military regu- lations for commissioned officers. Technical training involves entomolog- ical, engineering, medical and adminis- trative aspects of malaria control and limited study of Aedes aegypti control. 26 Training in entomology covers mos- quito identification, anopheline ecology and habits, station establishments and inspection and the interpretation of entomological data. The engineering aspects of the course include survey- ing, mapping, larviciding, drainage, DDT residual spraying and control mea- sures. Medical subjects are discussed as follows: epidemiology, life cycle of malaria parasites, microscopical and clinical diagnosis as well as treat- ment of malaria. Training in adminis- tration includes consideration of pay rolls, personnel, procurement and sup- plies, property records and travel vouchers. Mosquito and parasite identifica- tion make up the major portion of the laboratory work, and practical ex- perience is gained in a field demon- stration and training area near Atlanta. In the field the students have an op- portunity to obtain first-hand experience in collecting and identifying mosqui- toes, setting up adult and larval sta- tions, surveying and mapping a control project. In this area they also have an opportunity to apply and check the effectiveness of larvicides. Following this fie1d%experience the students visit an area of actual opera- tion near Valdosta, Georgia. Under supervision, the students participate in various control activities. These may range from administrative proce- dures to the application of larvicides or digging a ditch. At the Carter Memo- rial Laboratory in Savannah, Georgia, trainees are given experience on the Keefes aegypti control project and in the use of DDT as an insecticide. Recently the course has been broad- ened to include other arthropod-borne diseases. Since some members of the MCWA staff have had months or years of experience in various theatres of mili- tary operations, trainees are given the benefit of discussions on the con- trol of malaria and other tropical diseases in the China-Burma-India, Pacific, Middle East, European, and American theatres. The complete course requires from two to three weeks, depending upon the experience of the trainee enrolled. Du ring the past fiscal year officers and civil service employees totaling 81 have completed the course. Of these, 48 were engineers, 7 entomologists, 2 were medical doctors, and 24 were specialists in various other profes- sions. Special short courses of a week’s duration were given to 10 State Health Department employees and to 72 MCWA clerical employees. Visitors to the course numbered 138 including repre- sentatives from state health depart- ments, UNRRA, the Army and Navy, various universities and foreign countries. FIELD TRAINING. Students have an opportunity to obtain first-hand experience in collect- ing and identifying mosquitoes, setting up adult and larval stations, surveying and mapping a control project. aiding, permanent ditch lining, the use of dynamite in anti-malaria drain- age, and the mixing and application of DDT emulsions. Technical and pop- ular units in English and Spanish have been produced on Aedes aegypti cont rol. During the fiscal year three motion pictures were released, 14 were start- ed, and 5 were brought practically to completion. Documentary film covering all phases of MCWA reached the impos- ing total of 10,000 feet in unedited form. In addition to a general docu- mentary film sufficient footage is now available for the production of 15 short units on special phases of the program. These will include four or five beautiful units covering each step from inauguration to dedication in the preparation of a reservoir based upon sound malaria control principles. Substantial progress was also made in the development of a film strip series. Most of the film strips released during the year were emergency orders to meet the needs of immediate opera- tions. But several of the 80-odd sep- arate subjects in the proposed malaria film strip series were also completed. In addition to its main projects the Training Aids Section received numer- ous special requests for services frg>m Headquarters personnel and from field personnel. Photographers took 3,944 photographs and the photographic lab- oratory made 12,524 prints, 1,223 — 3 Va" x 4" slides and 1,335 — 2" x 2" slides. The art unit, in three months of its activity, completed 28 original layouts, 52 titles, 24 sketches, and 133 retouched photographs. Special mention is made of these training materials in order to stimu- late wider interest in their development and utilization. These and other mater- ials are available upon request for use by state and local health departments and by universities and medical schools. Production memoranda on each of these have been sent to Public Health Service District Offices and to state health of ficer s. MOTION PICTURE CREW. 22 motion pictures were started or released last year. VISUAL AIDS With only a few exceptions, the audio-visual materials available on malaria at the beginning of our pro-* gram were found to be inadequate and out of date. Such materials were need- ed urgently in order to conserve the time of teaching personnel and to in- crease the effectiveness and intensity of the training program. It was there- fore necessary to develop facilities for the production of motion pictures, film strips, and other visual materials for use in headquarters training and in the States. Units have now been prepared covering the following sub- jects: entomological field surveys, mosquito identification, mosquito proofing, oil and paris green larvi- ART UNIT. The work of this unit includes: original layouts, titles, sketches and re- touching of photographs. 28 LECTURE IN TROPICAL DISEASE LABORATORY (Below). A compre- hensive training course is offered to health department personnel in the laboratory diagnosis of parasitic diseases. SCRIPT PLANNING. A conference is held to work out details of production. cans returning and upsetting the exist- ing balance in this country. Malaria is of greatest concern but other trop- ical diseases are involved. Prac- ticioners throughout the land will be confronted with cases of filariasis, schistosomiasis, leishmaniasis and other exotic diseases during the im- mediate postwar period. Furthermore, tropical diseases will continue to crop up as implications and responsi- bilities of the new Air Age become apparent. Since ignorance and neglect are the basic causes of the present situation', enlightenment and aggressive action may be prescribed as a cure. Accord- ingly a comprehensive program is plan- ned for the production of training aids and for the distribution of these and other materials and specimens to schools of medicine, engineering and parasitol- ogy. Technical materials are available for medical societies and general in- formation is available to interested parties upon request. PROFESSIONAL RELATIONS It has been stated that all mala- ria is man-tolerated and most malaria is man-made. This reflects a general neglect of the subject, not only by the general public but by those con- cerned with the construction of high- ways and various types of impound- ments. No less important in this respect is the neglect on the part of the medical profession of adequate technics of malaria diagnosis and reliable case reporting. Most medical schools pass over the subject of malaria rather lightly and hospital staffs devote little or no time to discussions on malaria and other parasitic diseases. Ignorance and neglect of these mat- ters is all the more important under war conditions with millions of Ameri- 29 Gi^G^pSl(K^njn The key-note of the Aedes aegypti control program for the fiscal year was integration of inspection and con- trol activities with city sanitation programs. The transition from a strict- ly war emergency program to an integral part of local sanitation activities has been gradual but inevitable. In their house-to-house search for aegypti breeding places, inspectors encoun- tered many insanitary conditions which they had no authority to remedy. Some of these, such as leaking sewers, accu- mulations of garbage and rat harbour- ages, were of greater immediate concern than the mosquito breeding places. Such conditions were commonly referred to general sanitary inspectors but the du- plication of effort was wasteful and unnecessary. Hence the emergence of the concept of house-to-house sanitary in- spection which, in effect, means carry- ing public health down tothe indi- vidual. In actual operation, the integra- tion program is a joint effort of MCWA and various city health departments. carried on in cooperation with State health departments. At least half of the crew is onthe city pay roll. A month’s course in general sanitation was arranged within participating lo- cal health departments. A sanitary survey was undertaken in each participating city, in order to determine the nature and extent of the existing problems. Records were kept as to: 1) premises inspected, 2) premises breeding mosquitoes, 3) containers, 4) sewage disposal, 5) general sanitation, 6) garbage dis- posal , and 7) rats. During the fiscal year integration programs were started in the follow- ing cities: Charleston, S.C.; Savannah, Ga.; New Orleans, La.; Houston and San Antonio, Texas. The program was such a success that one city surpassed its original commitment of matching Federal employees, man for man, and took over the most experienced and reliable men on a permanent basis. In this way the city built up a very effi- cient group of sanitary inspectors. 30 SUMMARY OF ACTIVITIES A summary of activities is given for 1944 with data for the previous two years included as a comparison. The total number of inspections in the continental United States for 1944 was 1,231,146, with Aedes aegypti breed- ing appearing in 53,156 of these. The breeding index, or percentage of total premises inspected where breeding was found, decreased from 8.7 in 1942 to 5.3 in 1943 and 4.3 in 1944. Key West, Florida started with a high index of 13.2 in 1942. This was reduced by an all out campaign to 3.3 for the year 1943. At one point during the year the index reached a fraction of 1 percent but complete eradication was never achieved. In 1944 the attempt at eradication was abandoned because of the greater need for protection in other critical areas in the Southern States. With a decrease in person- nel in 1944 the index climbed back to 10.1. Miami is the largest airport of entry and consequently a large pro- portion of the total Aedes aegypti ef- fort was concentrated there. The city of Miami maintained an anti-mosquito project for a number of years before the war and many of the techniques now used throughout the program were patterned after Miami procedures. The Miami procedures in turn were based on experiences of the Rockefeller Foun- dation in Brazil. The 1942 index of 5.85 was low because of a backlog of seven years’ previous work. This work was intensified under our wartime pro- gram and the 1944 index shows a satis- factory decrease to 3.7. TABLE II Aedes aegypti Summary PROJECT PREMISES INSPECTED INDEX 1 942 1 943 1944 1942 1 943 1944 Key West, Fla. 43,411 68,871 29,218 13.2 3. 3 10. 1 Miami, Fla. 216,373 523,173 383,344 5. 8 7.8 3. 7 Savannah, Ga. 55,150 76,201 21.8 3. 1 New Orleans, La. 118,971 92,409 7.7 6. 0 Charleston, S. C. 60.608 194,456 66,834 3.3 1.8 2. 5 Brownsville, Tex. 96,500 224,022 75,809 10.9 5. 5 1.4 Corpus Christi, Tex. 58,903 169,945 86,936 9.2 0.9 0.9 Houston, Tex. 152,924 447,421 147,136 9.7 4. 6 2.8 Galveston, Tex. 59,247 144,364 48,880 1.5 1.4 1.3 Hidalgo Co., Tex. 3,100 33,166 54,937 8.1 4. 6 2.0 San Antonio, Tex. 14,436 55,837 10.4 5.4 La redo, Tex. 3,971 . 2 Mo bile, Ala. 69,946 10.3 Tampa, Fla. 22,606 2. 2 Jacksonville, Fla. 17,682 2.0 TOTALS 691,066 2,023,893 1,231,246 8.7 5. 3 4. 3 31 SANITARY INSPECTION. (Left) A sanitary survey was undertaken in each participating city, in order to determine the nature and extent of the existing problems. GARBAGE AND SANITARY COLLECTION. (Right) Inspectors reported accumulations of trash including mosquito breeding places to the Department of Public Works. The Charleston project also had a backlog of a number of years of in- tensified work by the city. Conse- quently the first wartime year show- ed a greatly reduced index of 3.3. This index was reduced slightly in the following years and actual mos- quito breeding has probably been re- duced even more because of the in- creased efficiency in inspection with the added experience of the crew. The Savannah and New Orleans proj- ects were started as mobile units in 1943. In the case of Savannah an at- tempt was made to cover the city as thoroughly as possible and satisfac- tory reduction was achieved in one year. New Orleans on the other hand, because of its large size, was not covered exhaustively. Hence, the in- dex of 7.7 might be deceptively low. The Texas projects followed a uni- form pattern of high initial index and progressively lower indices in succeed- ing years. Success was achieved in these instances by concentration on “mother foci” early in the program, by an all- out educational campaign and by a grad- ual intensification of routine in- spect ions. No generalizations are warranted in the case of Mobile, Tampa, and Jack- sonville because of the short period of operation of these proje'cts. 32 DENGUE CONTROL IN THE TERRITORY OF HAWA I I Last year it was reported that den- gue had been all but eliminated from the Territory of Hawaii. Starting in July 1943 the epidemic built up to a total of 159 cases during the third week in October. By the end of the fiscal year the incidence had subsided to an average of less than one case per week. The total number of cases reported during the epidemic was 1,506. No cases were reported during November and De- cember of 1944 and during the first four months of 1945. Dengue flared up anew during May and June of this year with 10 cases reported. It is assumed that these resulted from a new introduction, since the disease is widespread in the Southwest Pacific. In the follow- up of these new cases, complete pre- mise spraying was done in an effort to avoid another widespread epidemic. Routine operations during the fis- cal year included 922,788 premise in- spections of which 11,238 were found to be breeding Aedes aegypti or the more abundant Hawaiian species, Aedes alhopictus. Clean-up activities in- cluded removal of 661 truckloads of debris and breeding containers. In the campaign to eliminate tree and rock hole breeding places 17,325 tree holes and 5,343 rock holes were filled. Control of Aedes Breeding Places in Hawaii with DOT and by general clean-up activities. INVESTIGATIONAL PROGRAM DOT WILDLIFE INVESTIGATION DDT LARVICIOES DDT RESIDUALSPRAYS DDT PREMISE SANITATION BLOOD SLIDE EXAMINATIONS ENTOMOLOGY IMPORTED AHOPHEUNE HOST PREFERENCE STUDY HYDROLOGY MAIARIASTUDIES EPIDEMIOLOGY MALARIA FIELD RESEARCH DDT INVESTIGATIONS DDT AIRPLANE APPLICATION MCWA Laboratory Savannah Georgia SOUTH CAROLINA BOARD of HEALTH NATIONAL INSTITUTE of HEALTH Malaria Investigations fMORy , UNIVmiTY field Station TENNESSEE VALLEY AUTHORITY 34 9)\a£a/uixi <^ri/^e6tUfnc^ The scientific discoveries stimulated by World War II probably surpass those of any equivalent period in the history of mankind. Advancements in the field of malariology have been especially note- worthy. But a tremendous gap exists be- tween pure scientific knowledge and prac- tical control. To bridge this gap for MCWA operations, a program of technical development was inaugurated. Investigations were centered around the problem of the returning malaria carrier and the possibility of using DDT to meet the threat of local epidem- ics or a general resurgence of the dis- ease. Invaluable assistance was rendered in the investigational program by the National Institute of Health, the Health and Safety Division of the Tennessee Val- ley Authority, the Bureau of Entomology and Plant Quarantine, Emory University, the various State Health Departments, and others. MCWA acted as a participating agency in the over-all wartime program of the Office of Scientific Research and Development. 35 IMPORTED MALARIA STUDIES COLUMBIA, S. C, LABORATORY, N I H At the start, it was necessary to test the basic assumption that intro- duction of foreign malarias would con- stitute a hazard to residents of the continental United States. To determine the public health significance of the returning malaria carrier, an investi- falciparum and the rest were Plasmodium vivax. These infections originated in Guadalcanal (94), New Guinea (61), other South Pacific islands (24), Mediterranean (41), Caribbean (6), Burma (1), and Liberia (1). To carry out the infectivity experi- TABLE III Imported Malaria Studies Total Number of Mosquitoes Reared, Fed, Dissected and Infected SPECIES OF ANOPHELES REARED PUPAE APPLIED FED DISSECTED % INFECTED 1. quadrimacu1 atus . . 982,613 36,422 30,650 10,109 41. 1 2. f reeborni 164,835 16,169 12,787 4, 088 46. 1 3. a lb imanus 13,014 1,065 645 425 1.4 4. punctipennis 5, 294 40 6 171 139 50.4 5. pseudopunctipennis 1,075 160 81 61 24. 6 6. franciscanus 530 88 37 23 52. 2 7. occidental is 2, 200 285 138 59 61.0 8. waIker i 3,731 120 25 16 0.0 TOTAL 1,173,292 54,715 44,534 14,920 41. 4 gational program was set up in cooper- ation with the National Institute of Health and the U. S. Army. Four laboratories were operated during the program as follows: Headquarters — the National Institute of Health Malaria Investigations laboratory at the South Carolina State Hospital, Columbia, S.C. ; Letterman General Hospital, San Fran- cisco, Calif.; Harmon General Hospital, Longview, Texas; and Moore General Hos- pital, Swannanoa, N.C. These labora- tories had access to troops in about twelve Army and Navy hospitals and secured the cooperation of six mental hospitals for further study of malaria infections. Relapsing malaria infections of for- eign origin were studied in 228 soldiers. Three of these infections were Plasmodium merits, colonies of varidus species of United States anophelines were estab- lished and maintained in insectaries. More than one million mosquitoes were handled of which over 44 thousand were fed on malarious patients. A total of 41.4 percent of these mosquitoes became infected. The total numbers of mosquitoes reared, fed, dissected, and infected is shown in the table above. The species are listed in the order of their importance as vectors of malaria in this country, based upon epidemiological evidence. To test the infectivity of these mosquitoes, 246 attempts were made to induce 55 different infections in neuro- syphilitic patients. 67.1 percent of these attempts were successful. 36 In the course of the investigations it was found that: 1) Foreign malarias adapt- ed themselves readily to our insect vec- tors; 2) Successive transfers through our vectors did not result in a decrease in virulence; 3)Little immunity against these foreign infections resulted from previous infections with native malarias; 4) The foreign malarias were infective to mosquitoes as long as relapses occurred — hence some troops may be sources of infection for several years; 5) Some of the foreign infections seemed to be strains distinct from native malarias. In conclusion it may be said that: 1) Foreign malarias relapsing in returning troops can be spread by our native vec- tors; 2) The public health hazard of the foreign malarias seems to be as great, if not greater, than with a similar num- ber of cases of native malarias; 3) Con- trol measures are necessary against these foreign malarias in returning carriers. FOREIGN MALARIA INVESTIGATIONS. (Right) Mosquitoes are dissected to determine sporozoite and oocyst infection. (Below) Mosquitoes are fed on volunteer's arm. EMORY UNIVERSITY FIELD STATION Closely connected with the problem of the returning malaria carrier is the present status of malaria in the United States. The most fundamental questions in malariology in the continental United States remain unanswered to this day. Is malaria a disease of cycles? If so, what became of the last scheduled resurgence of the disease? Where does malaria go in periods of remission? In an effort to answer these and other basic questions, a field station was es- tablished by Emory University in an en- demic malarious area in Southwest Georgia in 1939. The approach was unique —— in- volving an intensive study of practically every phase of naturally occurring mala- ria over a long period of time. The pro- gram was outlined to measure systemat- ically the occurrence of malaria and as many attendant biological and physical factors as possible in the same area. MCWA has cooperated in this enterprise together with the Georgia Department of Public Health and the U. S. Geological Survey, bee ause of the importance of the work and because of the need for accumu- lated data of a number of years upon which to base current investigations. For ex- ample, it is hoped to test the effect of DDT residual sprays on a known popula- tion of mosqui toes as soon as vector counts become high enough to insure that the results will be statistically significant. Basic observations at the Field Station are of three general types: 1. Those pertaining to the measurement of malaria in man. (Epidemiology) 2. Those concerned with determina- tion of mosquito densities, both larval and adult, (Entomology) 3. The measurement of hydrological and meterological factors related to the occurrence of malaria. (Hydrology) INVESTIGATIONS OF MALARIA IN MAN. An intensive study has been conducted since 1939 of a group of about 1,000 persons. Weekly or biweekly visits are made by nurses and a careful clinical history is kept of each individual. Thick and thin blood films are collected if any symp- toms of malaria are noted. Persons are encouraged not to take anti-malarial drugs because of the danger of obscuring laboratory diagnoses. A complete course of treatment is given if the blood smear is positive. Under these favorable circumstances and in the absence of any control meas- ures, it is interesting to note that ma- laria declined in the Experimental Area just as it did in other parts of the count r y. COLLECTING METEOROLOGICAL DATA. (Left) Hydrological and meteorological factors related to the occurrence of malaria are measured at the Field Station. MORBIDITY SURVEY. (Right) Weekly and bi-weekly visits are made by nurses and clinical histories kept of all cases. BIOLOGICAL INVESTIGATIONS. Anopheles density depends upon a number of complex factors, both biotic and physical. Two strictly biological problems were studied during the past season.in addition to routine larval and adult counts. The little known habits of Anophelines during the winter months were studied with a view toward the possibility of control during this critical period. Populations are extremely low at this time of year and consist of females in semi-hibemat ion in such places as hollow trees. The problem of dispersal of Anopheles mosquitoes is closely related to their efficiency as disease vectors. Signifi- cant progress was made in methods of marking mosquitoes for dispersal studies. Fluorescent dusts were mixed with gum ar- abic and dusted on large numbers of mos- quitoes. Mosquitoes were collected later at various distances from the point of release. Marked specimens were detected readily by passing them under an ultra- violet light. HYDROLOGICAL INVESTIGATIONS. Hydro- logical conditions were determined for the Field Station area as follows: stream flow by seven gaging stations; ground wa- ter level by 90 observation wells; rainfall at 8 stations; and atmospheric tempera- ture and humidity at 3 stations. Fifteen ponds were equipped with continuous water level recorders, water temperature record- ers, recording rain gauges and, on the banks away from the influence of the pond water, temperature and humidity re- corders. ENTOMOLOGICAL EVALUATION OF THE EF- FECTIVENESS OF DDT RESIDUAL SPRAYS. The data accumulated in the Experimental Area since 1939 provide a sound basis for evaluating the entomological phases of the residual spray program. In the Exper- imental Area there is a backlog of in- formation on mosquito densities which may serve as a basis for comparison of mosquito densities after treatment of rural houses with DDT. The project will be undertaken as soon as mosquito counts indicate that statistically significant results can be obtained. ABOVE: Winter collecting of "Quads" by fumigation of a hollow tree. ABOVE: Collecting mosquitoes in red box. BELOW: Limnological investigations. 39 CARTER MEMORIAL LABORATORY SAVANNAH, GEORGIA Having determined that a hazard exists in connection with the return of ma- laria carriers from military service, it was necessary to develop methods of meeting the problem. This is being done at the Carter Memorial Laboratory at Savannah, Georgia. Activities are of two kinds: 1) fundamental investiga- tions on materials, methods, and pro- cedures, and 2) technical development of equipment and technics for practical application in the field. It was determined very early in the program that DDT was the most promis- ing material known for meeting the im- pact of returning malaria carriers. Accordingly, activities of the laboratory were centered around the development of methods of application and evaluation of the effectiveness of this remark-able insecticide for malaria control. Work projects cover each of the broad subjects under investigation as follows: DDT Residual Sprays, DDT Lar- vicides, Insect Premise Sanitation, and Effects of DDT on Fish and Asso- ciated Organisms. Additional facilities set up to support all phases of the program include: 1) Equipment Develop- ment, 2) Chemical Investigations, 3) Anopheline Host Preference Studies, and 4) the Insectary. CARTER MEMORIAL LABORATORY, SAVANNAH, GEORGIA. Fundamental investigations on materials, methods, and procedures are carried on here as well as technical development of equipment and technics for oractical application in the field. DDT RESIDUAL SPRAYS The concept of residual sprays for the control of individual malaria vectors is new. Potentially, DDT residual spraying is the greatest development in ma- laria control in many years because, for the first time, it becomes economically feasible to carry malaria control to individual homes, regardless of the financial status of the occupants. Since such an approach is vital to the successful prosecution of the cam- paign against imported ma- laria, this work carried highest priority. FORMULAS. The first job was to de- vise, mix, and test various formulas. Several were subjected to critical field tests to determine the most sat- isfactory one for use under opera- ting conditions. The following for- mula was finally recommended because of simplicity of mixing and ease of dilution in the field. The formula is expressed in weights and volume of ingredients and also in percentages by weight: DDT 35 percent 3 pounds Emulsifier 4 percent or 6 ounces Xylene 61 percent 3 quarts For regular field use the spray concentrate is diluted with water in the ratio of one gallon of spray con- centrate to six gallons of water. When this emulsion is applied at the rate of 4 cc. per square foot, the recom- mended dosage of 200 m.g. of DDT per square foot is obtained. Because of the limited supplies of DDT at first available, a 254 percent DDT spray was used in extended program operations. This permitted an application of 100 m.g. of DDT per square foot at the nor- mal spraying rate. With thisapplica- Mixing DDT Emulsion Concentrate with power equipment consisting of a centrifugal pump, a gasoline engine and a 55-gallon drum with appropriate fittings. tion retreatment must be done earlier. MIXERS. Various types of equipment were developed to meet the needs of a flexible operations program. Mix- ing equipment included a simple hand mixer and a power mixer. The latter was designed for large scale mixing at central plants. It consists of a centrifugal pump, a gasoline engine and a 55-gallon drum with appropriate fittings to permit thorough, safe and rapid mixing without the necessity of handling the solvent. SPRAYERS. Two types of sprayers were recommended, one an open-head pressure sprayer suitable for hand use, and the other a small power spray- er. Sprayers were equipped with xylene resistant gaskets and hose. A nozzle giving a fan-shaped spray of about 80° and delivery of approximately 0.2 gallon per minute was found to be most sat i s f actory. The spraying technic was worked out in great detail. At a pressure of 40 lbs. per square inch, properly diluted spray with the recommended nozzle, was applied at the rate of 100 m.g. DDT per square foot by covering approxi- mately 190 sq. ft. per minute. After 41 EXPOSURE CHAMBER. This consists of four removable panels, totaling one square foot of surface, to which the mosquitoes were exposed. a little practice it was possible for workmen to approximate this rate of application very closely. The nozzle was held about 18 inches from the sur- face being treated. It was found that great differences existed between va- rious types of surfaces, particularly as regards run-off and residual effect of the spray deposit. Freshly enameled surfaces lost their toxicity much soon- er than rough unpainted surfaces. PRECAUTIONS. Safe practices were employed in the use of DDT upon the recommendation of the Industrial Hy- giene Research Laboratory of the Na- tional Institute of Health. Precau- tionary measures included use of res- pirators, gloves, and goggles, and removal of DDT-oil solutions from skin and clothes with soap and water. EFFECTIVENESS AND DURABILITY OF DDT. The effectiveness of DDT residual sprays was tested in the laboratory and in the field. Since the subject was en- tirely new, special equipment and tech- nics were devised for this work. In the laboratory, tests were made in an exposure chamber constructed in such a way that four removable panels totaling one square foot of surface were available to mosquitoes during tests. Percent mortalities of Anopheles quad- rimacu1 at us adults at 48 hours after exposure periods of 35, 60, 90, and 120 minutes to DDT residues of known age are shown in the accompanying table. TABLE IV Percent mortality at 48 hours of A . quadrimaculatus adults after 35, 60, 90 and 120 minute exposure periods to DDT residues of known age. * TIME AFTER TREATMENT (weeks ) PERCENT MORTALITIES AFTER EXPOSURE PERIODS, (minutes) 35 60 90 120 1/3 92. 6 98.8 100 100 1/2 84.2 96.0 100 100 1 88.6 93.9 100 100 2 75.8 91.2 100 100 3 80.2 91.1 95.2 100 4 83.4 87.5 92.5 100 6 83. 7 80.4 83.5 98.9 8 68.0 92.0 94.0 96.0 10 66.7 80.4 78.1 88.6 12 41.5 51.8 58.8 81.5 18 28.0 54.0 72.0 90.0 20 25.4 41.5 66.0 82.0 ♦ These data are derived from average kills of 50, 100, 200 and 300 mgs. per sq. ft. DDT. 42 Wall cages were used in exposing mosquitoes to treated surfaces for test- ing the residual toxicity of DDT de- posits in houses and other buildings. The exposure cages were 3 inches in diameter and Vt inch high, soldered to a metal base witha 3-inch central opening. Wall cages were designed to slide in and out of wall brackets and a sliding panel was used to retain the mosquitoes while handling the cage. A cylindrical cage of the same dia- meter as the wall cage fitted with a plunger, was devised for placing the mosquitoes in the small test cage. A large cage was used as an observation and holding cage. The duration and effectiveness of DDT on various types of surfaces for periods up to 21 weeks, based upon wall cage tests, are shown in the ac- companying table: WALL CAGE AND CYLINDRICAL PLUNGER. These cages are devised to hold mosquitoes for tests of the duration and effectiveness of DDT on various types o* surfaces. TABLE V Duration and effectiveness of DDT when used as a residual house spray, as indicated by wall cage tests in occupied houses. DDT DOSAGE (Mgs. per sq . ft.) TYPE OF SURFACE TIME AFTER TREATMENT (Weeks ) MORTALITY AFTER 48 HOURS (Percent ) 100 Newspape r 19 58 100 Smooth unpainted wood 19 55 200 Rough wood 21 75 288 Smooth unpainted wood 19 53 288 Newspape r 19 71 385 Rough wood 19 70 385 Newspape r 21 93 43 when all mosquitoes have been knocked down. Live mosquitoes in the window trap are removed to a holding cage and mortality checked after 24 hours. Results of typical tests are shown in the accompanying table. TABLE VI Summary of effective morbidity and mor- tality of Anopheles quadrimaculatus re- leased in rooms at known periods after treatment with specific dosages of DDT. DOSAGE OF DDT (Mgs. per sq . ft.) AGE OF TREATMENT (Weeks ) EFFECTIVE MORTALITY 24 HOURS AFTER RELEASE (Percent) 100 1 day 100 ft 1 100 ft 2 100 « 4 94 ft 6 99 ft 10 100 200 1 100 If 2 97 ft 4 100 ft 6 100 ft 8 98 ft 12 100 ft 18 99.8 t! 20 100 ft 22 99.7 ft 22 100 ft 24 100 400 1 day 100 ft 1 100 ft 2 100 ff 4 100 ft 6 99 800 1 day 99.5 ff 1 100 ft 2 100 ff 4 99 ft 6 100 ft 8 100 ft 10 100 WINDOW TRAP. These were fitted to catch mosquitoes attempting to escape from treat- ed rooms after exposure to DOT. Window traps and floor recovery studies gave information on the ef- fectiveness of DDT under normal con- ditions. Unfortunately, most of this work had to be done in unoccupied houses but the results are nevertheless sig- nificant. Window traps were fitted to catch any mosquitoes which attempted to escape from the treated room after ex- posure to DDT. Mosquitoes entered through tapered inlets, or, in some instances, through doors or windows left open for the purpose. In still other cases mosquitoes were released in closed rooms fitted with window traps. The floors of such rooms in unoccupied houses were covered with paper to facil- itate recovery of dead mosquitoes. In typical tests several hundred specimens of Anopheles quadrimaculatus are released in a test room. They soon come to rest on the walls and ceiling where they come into contact with the deposit of DDT crystals. The first signs of DDT poisoning occur after about 10 minutes. A final accounting istaken 44 DDT AS AN ANOPHELINE LARVICIOE DDT is toxic to mosquito larvae in such minute quantities as 0.05 lb. per acre of water surface or one part DDT emulsion per ten million parts of water by volume. Despite high toxicity there are certain inherent disadvantages in its use as a larvicide. For spraying, it is insoluble in water and hence must be dissolved in oil or some other solvent. As a dust, it is slightly sticky and hence must be mixed with an inert carrier under special conditions. Amounts that can be applied with safety to wildlife are readily inactivated by mud, so there is little or no resid- ual effect. Tests have been performed with a view toward devising means of overcoming these difficulties. Various dust formulas were tested including a dust containing one percent DDT in pyrophyllite. This mixture in dosages from 1.0 to 0.025 pounds of DDT per acre gave strikingly uni- form kills (95% larval reduction or better). Sprays have been tested utilizing atomizing nozzles. Results with this equipment are shown in the accompany- ing table. The spray formula consis- ted of 1.25 percent DDT in No.2 fuel oil with 0.5 percent emulsifier. It will be noted that Station 12 with 97% mortality after 48 hours at 0.05 lbs. DDT per acre was the most promising of the tests. Even smaller amounts of DDT can be spread evenly over water surface in the form of “thermal aerosols.” DDT TABLE VII Mortality obtained with indicated DDT dosages applied as 1.25 percent DDT in No.2 fuel oil (containing 0.5 percent emulsi fier) . STATIONS DDT DOSAGE LBS./ACRE ANOPHELINE LARVAE MORTALITY (percent) 24 hrs. 48 hrs. 1 0.1 97 99 2 0.1 89 91 3 0. 1 88 93 4 0.1 93 89 5 0.1 94 -- 6 0.1 -- 88 7 0.1 72 65 8 0.1 -- 98 9 0.1 95 80 10 0.1 94 98 11 0.1 95 95 12 0.05 -- 97 13 0.05 * * 90 is dissolved in a solvent which is vaporized easily. Small amounts of the resulting solution are then pumped into the exhaust stream of an airplane or a jeep. The result is a cloud of smoke particles intermixed with a fog of extremely small droplets of DDT in solution. Much of this work was carried on in cooperation with the "thermal aerosol” project of the Ten- nessee Valley Authority at Wilson Dam. THERMAL AEROSOL. (Left) Small amounts of DDT can be spread evenly over water surface by airplane. (Below) Close-up of venturi tube used by TVA to dis- tribute thermal aerosol. In order to compare the effectiveness of DDT with paris green in routine MCWA operations, the regular MCWA project at Savannah was converted to DDT. Twenty- three areas treated in the usual manner with paris green showed an average reduc- tion of 70 percent after 24 hours. Re- duction in third and fourth stage larvae was satisfactory but the material was much less effective against the first t wo i n s t a r s. Results with DDT in dusts and in fuel oil showed the material to be equally effective against all instars. Sixteen breeding places treated with one percent DDT in pyrophyllite showed an average total reduction of 98 percent and ten areas treated with DDT in fuel oil showed an average reduction of 96 percent. The practical application of these studies is obvious. Use of DDT as an anopheline larvicide shows promise of increasing the mortality of all stages of larvae and decreasing the amount of ma- terial applied. This last factor is es- pecially important. About eighty percent of the cost of larviciding with oil or paris green is expended in labor. There is a possibility of reducing this factor by lightening the load of individual laborers and eliminating the costly re- turn trips to a central point for refilling spray tanks. This could conceivably double the efficiency of larvicidal operations and thus cut the cost in half. EFFECTS OF DDT ON FISH AND ASSOCIATED ORGANISMS The widespread use of DDT as an in- secticide in mosquito control is con- tingent upon its over-all effect on fish and other wildlife. A delicate balance exists in the biota of any environment and it is essential to determine the extent to which DDT upsets this bal- ance. For example, does DDT eliminate all fish food when applied as a larvi- cide? At what concentration does it kill the fish outright? What is its effect on wild bees which are so vitally con- cerned in the pollination of so many commercial crops? These and other ques- tions are being answered in cooperation with the Savannah National Wildlife Refuge, which is operated by the Fish and Wildlife Service, U.S. Department of the Interior, and with the Plant In- troduction Laboratory of the Bureau of Plant Industry, U.S. Department of Agri- culture. Results are not yet available but in a general way it appears that a mar- gin of safety exists between the con- centration of DDT satisfactory for mos- quito control and the concentration in- jurious to wildlife. Of great impor- tance in this connection is the form in which the DDT is applied. Stable emul- sions appear to be injurious to fish whereas dusts seem to be relatively in- nocuous . PLANKTON COLLECTOR. (Left) This device is used in tests of the effect of DDT on aquatic organisms. COUNTING PLANKTON SAMPLES. (Right) Specimens are examined under the micro- scope and recorded with automatic tabulator. DOT SPRAYING OF BARN. One badly infested dairy was treated with a 2i percent DDT-Xy- lene emulsion and is still* showing satis- factory control 10 mont hs later. An at- tempt is being made to establish a prac- tical and efficient procedure for the use of DDT by owners of dairies, restaurants, abattoirs and markets. INSECT PREMISE SANITATION The primary aim of this project is housefly control from the public health standpoint. An attempt is being made to establish a practical and efficient procedure for the use of DDT by owners of dairies, restaurants, abattoirs and markets. Residual sprays similar to those used in mosquito control have result- ed in satisfactory and, in some in- stances, spectacular control of house- flies in dairies. One badly infested dairy wastreated with a percent DDT-Xylene emulsion and is still show- ing satisfactory control 10 months later. Complete treatment of all pre- mises of two dairies showed an im- mediate reduction of 92.4 percent and 96.9 percent respectively. Coverage of walls and ceilings and other fly resting places has proved to be sufficient for adequate control in most cases. However, some dairies are so insanitary that some control of breeding is necessary. In these cases, a spray may be applied to the surface of manure piles. The object is to kill adult flies as they emerge rather than attempt the more difficult job of kill- ing the larvae. This is a temporary measure and should not be used in lieu of clean-up of the premises. RESTAURANTS. Average counts of houseflies in eating establishments, utilizing a small counting grill 18” square, gave 12.75 flies during the pretreatment period and 1.17 flies dur- ing the post-treatment period. The greatest limiting factor in restau- rant fly control is the difficulty of making a treated surface available to flies which enter during the day. At night the flies rest on the walls and ceiling and on such favored places as edges of doors and light cords. Here they come into contact with suf- ficient DDT so that a treated restau- rant is completely free of flies at the beginning of each day. To prevent excessive invasion of flies from outside, some work has been done on fly control around garbage cans in alleys. This approach or even complete coverage (environmental fly control) of entire city blocks may alter the picture of general sanita- tion in the future. 47 ANOPHELI ME HOST PREFERENCE STUDIES During 1944 tests were run on the blood meals of 38,932 engorged female anophelines from 28 States, the Dis- trict of Columb ia, and Puerto Rico. The specimens were collected by MCWA personnel while performing routine inspections of adult stations on con- trol projects. The data supplied with each collection included locality, place collected, species of mosquito, distance from nearest available con- tinual source of human blood, whether this source was screened or unscreened, the name of the collector and date collected. The Rice and Barber technic of mass precipitin testing is used. This tech- nic involves soaking the blood from the filter paper on which it was orig- inally collected and bringing the re- sulting mixture (antigen) into contact with prepared human, equine, bovine, porcine, and avian antisera in five capillary tubes attached to glass slides. A precipitate appears in the tube which contains antisera against the blood of the host that the mosquito fed upon, thus indicating the source of the orig- inal blood meal. Results of the year’s tests show that 3.27 percent of the blood meals of Anopheles quadr imaculatus were from human hosts. All Anopheles species other than crucians fed upon human hosts to a greater extent than did quadrimacuIatus. However, comparative- ly few collections were made inside houses. A distinct seasonal variation in human blood meals was indicated, speci- mens collected during the early months of the year showing a low percentage of human blood meals. A sudden rise to 15.5 percent occurred during April A drop in early summer was followed by an increase in the fall with a more gradual drop toward the winter months. After an early summer drop, puncti- pennis and pseudopunctipennis showed the highest human blood meals, puncti- pennis having taken nearly three times as many human blood meals as did quad- rim acuI at us . A considerable difference was noted in the percent of human blood meals of specimens from various States. For example, the percent of Anopheles quad- rimaculatus feeding on human hosts in Arkansas was over twice as high as that in Louisiana. This striking difference will probably be explained when the data are analyzed as to source of col- lection. As in previous tests, by far the greatest percentage of blood meals was bovine in origin. TABLE VIII Percent of anophelines found positive for human, equine, bovine, porcine, and avian blood. 1944. SPECIES OF ANOPHELES NO. OF SPECIES TESTED H E B P A NO REACTION 1. quadr imacula t us 29,511 3 23 48 11 4 11 2. punct ipenni s 2,939 3 13 56 12 4 11 3. crucIans 3,077 3 12 58 12 4 11 4. pseudopunct ipennis 1,208 6 5 67 9 3 10 5. f reeborni 593 5 9 57 7 5 15 6. a 1bi manus 1.548 7 4 73 5 2 8 48 EQUIPMENT DEVELOPMENT Throughout the year special types of equipment have been needed in con- nection with the investigational and operational programs. A power mixer for the preparation of DDT emulsions, a portable power sprayer, a thermal aerosol generator and numerous other items were developed. Also, commer- cially available sprayers and other equipment had to be modified for pur- poses of malaria control. Xylene re- sistant gaskets and hose were select- ed after extensive tests. Spray nozzles for use on the Extended Program were tested for rate of discharge and even- ness of spray swath. In general it may be said that equipment develop- ment was an integral part of practi- cally every phase of the invest iga- t i on a I program. CHEMICAL INVESTIGATIONS Laboratory studies on the chemis- try of DDT played an important part in the over-all program. The solubil- ity of DDT in various solvents was tested, the chemical properties of a DDT isomer were investigated and stud- ies were made of the explosiveness of vapors of several organic solvents used in connection with DDT interior residual spraying. In no case did explosive concen- trations occur during the investiga- tion, as measured by a combustible gas indicator. I An insectary was maintained to sup- ply mosquito larvae and adults for testing purposes. The insectary has a capacity for producing 10,000 “ quads” per day. Five hundred white enamel pans are used for rearing larvae and six colony oviposit ion cages house the stock colonies. The air tempera- ture of the room is held at 80° - 82° F. and the relative humidity at 80 percent. The temperature of the lar- val cultures is 78°-79°F. A rearing cycle is started each day with eggs laid during the preceding night. Approximately 1,000 eggs are placed in each pan and are held within a waxed paper ring to prevent stranding on the edges of the pan. Water from a nearby artificial pond is used. Larval food consists of brewers yeast and fine- ly ground dog biscuit. Special studies have been conduct- ed on the technic of larval rearing and oviposition habits — both stud- ies having a direct bearing on the maintenance of the colony at maximum product ion. This Insectary at Savannah, Ga., has a capacity forproducing 10,000 "quads" per day. White enamel pans are used for rearing larvae and colony oviposition cages house stock colonies. DDT INVESTIGATIONS PUERTO RICO Having determined that DDT as a re- sidual spray is toxic to mosquitoes, it might be assumed, a priori, that DDT will control malaria, but malaria is a complicated disease and many fac- tors are involved in its transmission. So a field test was undertaken in Puerto Rico where records of malaria inci- dence indicated that significant re- sults might be obtained. The work was conducted by personnel of the Carter Memorial Laboratory in cooperation with the Insular Health Department, the School of Tropical Medicine, and the Public Health Service District Office. Playa de Humacao was selected as the village to be sprayed and Loisa Aldea was used as a check. Playa de Humacao is a small town (2,500 popu- lation) located near the southeast corner of the island of Puerto Rico. The temperature varies from 65° to 85°F. (minimum daily average). During the course of the experiment some 20 inches of rain fell (Dece mb er 19 44 through June 1945). Most of the people in the village work as stevedores or laborers in the sugar cane plantations. The average family income is probably less than $500.00 per year, earned for the most part during the months of February through May, when the sugar is loaded on ocean-going freighters. The village is neat in appearance with well-kept houses and relatively clean streets and yards. None of the houses are screened and even if they were, considerable transmission of malaria could possibly occur because the peo- ple sit outdoors in the evenings either on their porches or at “ cafetines” (local coffee shops). The malaria incidence had been high in Playa de Humacao. An Insular Health Department Survey indicated a rate of approximately 20% before the experi- ment. However, this was a selective survey. Blood slides were taken only from persons who reported symptoms that might be indicative of malaria. A complete blood slide survey at the beginning of the experiment showed only 5.9% positive slides for Playa de Humacao and 4.7% for Loisa Aldea. The first spraying was done in Playa de Humacao from November 1 to 18, 1944 using a 5% solution of DDT in kerosene. This operation met with enthusiastic cooperation on the part of the vil- lagers because of the immediate ef- fect of the spray on bedbugs, cock- roaches and other insect pests. The second spraying began on June 30, 1945. The DDT-Xylene emulsion was used for the second spraying and 513 houses were covered in 13 working days. The second parasitemia survey showed a decrease in positive slides in both areas but the difference between the two is not statistically significant. There were 2.8% positive slides found in Playa de Humacao and 1.5% positive slides in Loisa Aldea. Final results will not be available until a complete season has passed. However, it may be said from evidence so far available, that the residual toxicity of DDT to the Caribbean ma- laria vector, Anopheles albimanus, is about the same as for Anopheles quad- rimaculatus in the continental United States. 0DT TEST HOUSE IM PLAYA DE HUMACAO. Mos- quitoes were released at regular intervals to test DOT residual toxicity. 50 DDT INVESTIGATIONS MEMPHIS LABORATORY, NIH The Division of Infectious Diseases of the NIH has a long term program of malaria investigations. MCWA benefited greatly from the cooperation of the Malaria Investigations Laboratory in Memphis, and, in turn, supported certain phases of the Memphis work by alloca- tion of funds and personnel. Four projects were undertaken as a part of the DDT studies. First, house spraying studies were conducted in a 36 square mile rural area near Helena, Ar- kansas. A total of 513 houses were treated with DDT residual spray to demonstrate the effectiveness, inexpensiveness, and practical application of DDT residual house spray as a method of malaria con- trol in rural areas. This work was done early in the program and pointed the way toward the eventual adoption of this method in the Extended Program. Second, laboratory studies were con- ducted on DDT solvents, emulsifiers, and crystal formations. This general subject was investigated independently by the Memphis laboratory, the Savannah laboratory, and the Tennessee Valley Authority, as well as by other agencies, because of the vast amount of work to be done and because it was considered desirable to obtain corroborative evi- dence on the subject. Third, the Memphis laboratory under- took studies which showed that DDT was completely effective as a surface lar- vicide using a 1 to 3 percent solution in oil sprayed at the rate of 4 to 10 gallons per acre. Kills of 95 to 100 percent were obtained with a reduc- tion of approximately 60 percent in labor cost and 70 percent in larvi- c i de cost. Fourth, a study was conducted dur- ing one season, in collaboration with the Arkansas Stuttgart Rice Experiment Station, to determine the effective- ness of DDT in control ling mosquito breeding in rice fields. Water emu 1- sion of DDT was applied at the pump to the flooding waters of a 100-acre rice Application of DOT to irrigation water. field. Complete mosquito control was obtained near the pump and in the canal. In areas surrounding the water entrance there was a gradual loss in toxicity as the water flowed to the far side of the field. In comparison with an un- treated field, 50 percent fewer A. quadrimaculatus larvae and 72 percent fewer culicine larvae were found in the treated field. A significant reduction, 50 percent, was observed in the rice water-weevil population, and no injury to rice was noted. In fact, harvested rice yields were highest ever report- ed from this Experiment Station. In addition to the investigational projects, over 45,000 blood films taken for survey purposes were examined at the Memphis Laboratory as a cooperative project with MCWA. Sampling Populations of Larvae In Treated Rice Field. 51 MALARIA FIELD STUDIES SOUTH CAROLINA In most areas throughout the South, including South Carolina as a whole, malaria has been decreasing and is now at an all-time low. However, the Santee- Cooper reservoir area is one of the few remaining endemic areas in the country. In studying records collected from this area over the last ten years, it is evi- dent that a clear-cut focus of malaria has existed and continues to exist in the vicinity of the Santee River in Claren- don, Berkeley and Orangeburg counties. Furthermore, these studies indicate that in some sections malaria has increased since the 1941 impoundage of water in the Pinopolis and Santee Basins, and that minor epidemics occurred during the sea- sons of 1942 and 1943 in Clarendon County near the Santee Reservoir. SANTEE — COOPER SURVEY Early in 1944, at the request of the South Carolina State Board of Health and the South Carolina Public Service Auth- ority, an intensive survey of the Santee- Cooper area was made. The survey included epidemiological, entomological and engi- neering studies and was designed to fur- nish complete data upon which to base a control program. CONDITION OF THE RESERVOIRS AT THE TIME OF THE SURVEY. Of the two reser- voirs, the Santee Reservoir is the largest — 30 miles long and miles wide on the average — with a maximum water surface of 97,000 acres and a shoreline of over 497 miles at the 75-foot contour. The smaller Pinopolis Reservoir, connected to the Santee by a diversion canal, is about 12 miles long and 10 miles wide and has a maximum water surface of about 65,000 acres and a shoreline of 151 miles at the same elevation. At the time of the survey the lower impoundment, the Pinopolis Reservoir, had been entirely cleared of standing timber and floating logs. Aquatic plants had not invaded this impoundment to any ex- tent except where they had been implanted in the Pinopolis Pool Wildlife Refuge on the south side of the lake. This refuge covers 2,000 acres, is well located, and was not considered important from the malaria standpoint because few people lived within flight range. The larger Santee Reservoir, on the other hand, contained 47,112 acres of standing timber, most of it dead, with considerable floatage and piles of fal- len branches. In the lower half of this reservoir, a mile-wide cleared strip of open water separated the flooded timber from the shoreline; but in the upper half, this strip was only one-half mile in width. In some places, these cleared strips of open water were quite deep; in others, the summer recession of the water level gradually exposed acres of stump- age. In a few places, the development of secondary growth and herbaceous vegeta- tion had created serious mosquito breed- ing situations. Alligator grass, in par- ticular, threatened to become a serious problem over much of the area. In addi- tion, several wildlife refuges with sus- tained water levels had been established on the reservoir. Where aquatic and semi- aquatic vegetation developed, these ref- uges presented a considerable anopheline hazard. The larger Santee Reservoir contained 47,112 acres of standing timber, most of it dead, with considerable floatage and piles of fallen branches. 52 MALARIA PREVALENCE. A widespread epi- demiological survey was undertaken in 1944 to secure information regarding the prevalence and distribution of malaria. Blood smears were obtained throughout the entire area lying within 1V4 miles of the 75-foot contour. Smears were also taken from more distant areas — 3 to 10 miles from the reservoirs — as a check on the normal incidence of the disease in the region. Some 15,000 individuals were ex- amined in houses or at work in the fields. Complete family rosters, data regarding the condition of the house, and a history of malaria were obtained. About 6,000 houses were surveyed. The area of highest malaria prevalence was located on the north shore of the Santee Reservoir in Clarendon County around Potato Creek, between Tawcaw and Wyboo Creeks. Here 38. 7% of the 470 blood films examined proved positive for para- sites. The area immediately adjacent to this section in Clarendon County and the area in Berkeley County just below the Santee Dam showed the next highest prev- alence — 11.3 to 15.7 percent positive blood smears. Relatively moderate prev- alence, ranging from 6.7 to 8.9 percent occurred in areas adjacent to the above mentioned high sections. The remaining area% showed a relatively low degree of prevalence. Detailed entomological surveys were made to locate the most favorable mosquito breeding places and to determine whether the principal breeding of quadrimaculatus was occurring in the reservoirs proper or in the adjoining territory. The upper two-thirds of the flooded woods in the Santee Reservoir were found to be the greatest single source of quadrimaculatus in the entire region. The extremely high breeding intensity and the thousands of acres available for breeding marked this area as a serious problem. Other problems studied included dispersal of mosquitoes over wide expanses of open water and mosquito breeding amidst flooded timber a mile and a half from shore. Detailed plans were submitted for the control of malaria in the Santee-Cooper Entomological surveys revealed heavy breeding In the flooded woods of the Santee Reservoir. area. The following temporary measures were recommended pending inauguration of the permanent program: 1) Larviciding to kill the aquatic stages of mosquitoes; 2) Spraying to kill adult mosquitoes in houses; 3) Removal of secondary growth from the reservoir areas; 4) Control of aquatic plants that form favorable breed- ing places for quadr imaculatus', 5) Use of drugs to reduce infection in the human population. The more permanent type meas- ures included: 1) Clearing of the partially submerged timber in which heavy breeding of quadr imaculatus occurred in 1944; 2) Drainage of ponds in the zone of fluctu- ation; 3) Mosquito-proofing of houses in certain areas where control would be most difficult; 4) Shoreline improvement; 5) Diking and dewatering of several areas where malaria rates were high and a large number of people were affected; 6) Filling of small areas to reduce larvicidal work. 53 MALARIA FIELD RESEARCH and mapping the houses and by record- ing the condition of the houses and screens. A population census is kept including the name, sex, race, age and length of residence of each person in the area. A record is kept of changes of persons from one house to another, names of new people moving into the area and names of deceased persons and those leav- ing the area. A complete census is kept of stables and other outbuildings and an animal census was made, noting the number of mules, cows, pigs, and fowls in each house group. These data serve as a basis for correlating information on host preference and sporozoite rates with malaria prevalence. A field study was undertaken in coop- eration with the South Carolina Board of Health to test the basic assumption that DDT controls malaria as a result of the residual house spray killing mosquitoes which transmit the disease. Two rural areas were selected which had been shown by previous parasitemia surveys to have sufficient malaria to enable statis- tically significant conparison of results to be made. Each study area was divided into a “test” and a "control” area based upon topography, size of area and charac- teristics of the population. TABLE IX Characteristics of Study Areas CONTROL TEST CONTROL TEST IA IB II A II B Length 6 miles 8 miles 5 miles 5 miles Breadth 5 miles 6 miles 4 miles 2 miles Area 25 sq. mi. 40 sq. mi. 15 sq. mi. 7 s q. mi. No. occupied houses .... 256 334 94 103 No. inhabitants 1,390 1, 824 417 483 • Parasitemia prevalence . . (Oct. 1944) 16.4% 20.9% 8.4% 11.0% ORGANIZATION OF THE STUDY. The effi- cacy of DDT as a residual house spray in preventing new cases of rural malaria is being gauged by carefully collected morbidity information. Entomological, climatological, and other pertinent data are being obtained to evaluate conditions related to malaria transmission. In short, every effort is being made to obtain a coirplete picture of malaria in the test •areas before, during, and after treat- ment with DDT. Housing is studied by means of a complete housing census, by numbering CLINICAL CASE STUDY. Each household in Study Area 1 is visited semi-monthly and notations are made regarding the health status of each person and his use of anti- malarial drugs. The symptoms manifested by those individuals who are ill or who have been ill during the two weeks prior to the visit are recorded. Entomological inspectors, while making their rounds of stations, note persons ill in bed and re- port to the medical officer. The purpose of this case screening is to pick out in- dividuals on whom more detailed study by a medical officer is warranted. 54 Cases warranting further study to es- tablish a diagnosis are visited by a medical officer. He obtairts a complete case history and performs a comprehensive physical examination. All clinical cases of malaria receive adequate anti- malarial treatment. Cases are followed carefully throughout the course of the di sease. PARASITEMIA SURVEY. A thick film blood smear survey is carried out in Area I during the first two weeks of each month (approximately 3,000 slides) and in Area II during the first two weeks of every second month (approximately 1,000 slides). The slides are being exam- ined in the Division of Preventable Diseases Laboratory of the South Carolina State Board of Health. MOSQUITO POPULATION STUDIES. Ento- mological observations provide infor- mation on the relative densities of Anopheles quadrimaculatus in the test areas for comparison with the malaria rates in these areas. Data are also obtained for compar ison of the resi- dual effect of DtiT (inside house counts in test vs. control areas). In Area I weekly anopheline mosquito counts are made at 20 percent of the farmsteads, using as “index stations” farms selected because of the presence of a stable regarded as a desirable rest- ing place. Counts are made of the mos- quito population inside of houses, in all outbuildings and, occasionally, beneath houses, in hollow trees, and on farmsteads where no stable is pre- sent. Daily anopheline counts are made in stables at six selected stations. These supplement the regular weekly station counts and are compared with a continuous hygrothermograph record of temperature and humidity in the area. Only occasional larval surveys are made since breeding places have already been appraised during previous surveys. In Area II entomological surveys are limited to weekly mosquito counts at 20 percent of the farmsteads. Counts are made inside houses and in all out- buildings in both control and test areas. The sporozoite rate is determined in the test area vs. the control area by dissection of mosquito salivary glands. A 10 percent sample of mosquitoes is taken from the out-buiIdings, but not over 100 mosquitoes are taken from a single farmstead. Precipitin tests are run on blood samples from the above mosquitoes after dissection of the salivary glands. DDT RESIDUAL HOUSE SPRAYING. All houses in Areas I and II were sprayed during the last two weeks of April at which time mosquito counts had begun to reach significant figures. The spray- ing will be repeated three months later. Spraying operations were carefully sup- ervised for thoroughness. Walls and ceil- ings were sprayed and also backs of furniture and pictures and both sides of mattresses and springs. The exact date of spraying of each house was recorded. RESULTS. No general conclusions are warranted on the basis of present data, but the schedule of the blood smear survey is being met with smears ob- tained in Area I during the first two weeks of every other month. The samp- ling of the population is being main- tained at over 90 percent. Two surveys have been carried out in Areas I and II in April and June. When complete data are available it is expected that any differences in parasite prevalence between the test and control areas will be evident. If a significantly higher rate is demon- strated in the control areas, it can be assumed that a reduction in the amount of malaria transmission in the sprayed area has been affected. Data being accumulated on clinical malaria, mosquito densities, sporozoite rates and percentage of human blood meals in both test and control areas, should aid in evaluating the efficacy of DDT residual house-spraying in preventing new cases of malaria. 55 OPERATIONS OF MALARIA CONTROL IN WAR AREAS STATES WHICH HAVE NO M.C.WA. ACTIVITIES STATES WHICH HAVE CONTROL ACTIVITIES IN OPERATION STATES WHICH HAVE SEASONAL CONTROL OR SURVEILLANCE ACTIVITIES 56 ALABAMA BURTON F. AUSTIN, M. D. State Health Officer PROJECTS 1. Huntsville 2-. Montgomery 3. Tuskegee 4. Decatur 5. Mobile 6. A1 icevi11e 7. Foley 8. Selma 9. Gadsden 11. Tuscaloosa 12. Cour11 and 13. Dothan 14. Ozark 15. Opelika 16. Ann iston 17. Chantom 18. Loxley 19. Ever green 20. Greenville 21. Clanton 22. Point Clear 23. Greene 24. Jackson Mont gome ry LEGEND State Hdqrs. 1War Areas iExtended Areas :Residual Spray !Extended Larviciding The accomplishments of MCWA for the past fiscal year are presented under three headings: (1) Regular MCWA, (2) Ex- tended program, (3) Aedes aegypti Unit. REGULAR MCWA Two additional war areas were es- tablished within the State during the fiscal year while 3 were abandoned or dropped giving a total of 21 areas in- volving malaria protection of 110 war e s tablishment s. An average of 39 employees includ- ing State Office personnel and those attached to four area headquarters offices were detailed to regular MCWA operations during the year. Control activities consisted princi- pally of ditch and pond cleaning and en- tomological surveillance. Larvicidal op- erations, except for occasional treatment of sporadic breeding areas, were limit- ed to the Mobile and Chantom areas. WATERED AREA CENSUS. In the watered area census of zones under MCWA control, approximately 2,500 acres of ponded water and 207 miles of ditches were recorded. Of these, 512 acres and 106 miles re- spectively were permanently watered. 57 Of permanently watered areas, 120 acres of ponds and 7 miles of ditches produced anopheline mosquitoes either continuous1y or frequently, while ano- pheline breeding was found in58 acres of ponds and 6.8 miles of ditches which contain water infrequently or occasion- ally during the mosquito breeding season. DRAINAGE. Some idea of the extent of drainage operations since 1941 may be obtained by comparing these figures of total watered area with the total of 920 acres of watered surface elimi- nated by drainage operations. Minor drainage was performed in 7 of the 21 war areas. Approximately 34 acres of watered surface were elimi- nated through the construction of 37,700 linear feet of lateral ditches requiring the excavation of 6,400 cubic yards of earth and 9,335 man-hours of 1abor. LARVICIDlNG/ In the seven areas where drainage was done, larviciding was also practiced. The efficiency of the latter operations was improved by removal of vegetation from 54 acres of ponded water involving 7,565 man-hours. Also, 162 acres of ditch area were cleaned using 33,046 man-hours. There were 644 acre treatments with 1,013 pounds of paris green, requiring 1,659 man-hours. Approximately 280 acre treatments were made with 5,550 gallons of oil at an expenditure of 3,033 man-hours. ENTOMOLOGICAL SURVEILLANCE. The re- maining 13 of the 21 war areas were under entomological surveillance. The State Entomologist andarea personnel routinely inspected 283 mosquito col- lecting stations during the year. Of this number, two “ A” stations or 0.7% showed counts often or more Anopheles quadrimacu1 atus for three consecutive weeks while from five to ten A. quad- rimacuI at us we recollected from eight “A” stat ions or 2.8% for similar periods of time. ROW CAMP SITES. At the request of the War Manpower Commission, investi- gations were made of 11 proposed sites for prisoner-of-war camps, and repre- sentatives of the State Office accom- panied the Army Site Boards on final inspections. This arrangement has proven its worth in that control other than entomological surveillance has not been necessary around sites selected under these conditions. LOADING SAWDUST. Small bodies of water were filled with sawdust which was an available material and was easy to handle. 58 EXTENDED PROGRAM In January 1945, the State Health Officer received authority to proceed with the organization of the Extended Program in Alabama. Six counties having the highest malaria mortality rate were selected for participation. These were: Autauga, Montgomery (Area 2), Dallas, Lowndes (Area 8), Marengo and Greene (Area 23). Upon the basis of the mala- rious portions of each county, 62 pre- cincts or beats were approved for DDT t reatment. TRAINING. During February and March, 61 new employees were processed and trained in residual spraying while 4 regular MCWA employees were assigned to part time duty on the Extended Pro gr am. MAPS. Maps suitable for Extended Program use were not available. There- fore tracings from aerial photographs were made of the 62 precincts and check- ed in the field as a part of the operation. The accuracy of these maps has resulted in a saving in time and in complete cov- erage of areas designated for treatment. SPRAYING. From April 1 to June 30, 1945, an average of 97,500 persons ben- efited by the spraying of 17,400 houses with DDT. This required a total of 2,500 gallons of 35% DDT concentrate and 29,500 man-hours, or 0.144 gallons of concentrate and 1.70 man-hours per house. LARVICIDAL PROJECTS. Extended Pro- gram larvicidal projects have been sub- mitted and approved for seven towns and cities in Extended Program counties. So far, it has been necessary to resort to larvicidal operations in only one city having a population of 2,800 while the remaining six towns and cities with a total population of 108,350 are under entomological surveillance. MALARIA PROTECTION. Approximately 208,650 residents of the State of Ala- bama are receiving malaria protection in one form or another through Extended Program operations. The results are not yet available but DDT spraying has been well received and reports of its effectiveness are quite optimistic. AEDES AEGYPTI ORGANIZATION. An Aedes aegypti unit was in continuous operation in the city of Mobile during the year. An average of 11 persons was employed including a supervisor, assistant supervisor, in- spectors, and a clerk-stenographer. EDUCATION. Inspections were made of 81,427 residential premises while the Program was publicized through 137 news articles, 52 talks and 161 radio an- nouncements. Industrial and non-resi- dential premises also received attention, and assistance was given in making a sanitary survey of the city of Mobile in conjunction with aegypti control. RESULTS. Rubbish collection and dis- posal was considerably improved as a consequence of control activities. Al- though there was no basis for compar- ison, it was felt that the aegypti breed- ing index for the summer of 1944 was substantially lower than that of pre- vious years. MOBILE, ALABAMA. Inspector recording re- sults of findings. Inspections were made of 81,427 residential premises. 59 PROJECTS 1. Little Rock 2. Benton-Bauxi te 3. Pine Bluff 4. Ma1vern 5. Hope 6. Texarkana 7 . Ft. Smith 8. El Dorado 9. He 1ena 10. Bly thev i11e 11. Walnut Ridge 12. Newport 13. Stuttgart 14. Camden 15. Lonoke 16. Jerome 17. Rohwer 18. Hot Springs 19. Russellville 20. Mari on 21. Wynne 22. Forrest City 'fC Li 111 e Rock LEGEND State Hdqrs. >War Areas \Extended Areas ‘jResidual Spray Extended Larviciding ARKANSAS T. T. ROSS, M.D. State Health Officer The Arkansas MCWA program operates under the authority of the State Health Officer as a division of the Bureau of Sanitary Engineering. Its work through- out the State is organized under six divisions: Engineering, Operations, Equipment and Supply, Administration, Entomology, and Education. MCWA operations were organized in 43 areas adjacent to military estab- lishments and in 15 areas around de- fense plants. Operations were also set up in recreation and housing areas. The Extended Program was put into operation in civilian areas of 18 Ar- kansas counties where malaria rates were highest. ENTOMOLOGICAL INSPECTION Eight hundred adult mosquito catch stations were examined weekly by en- tomological inspectors. When an “A” or “B” station showed a higher count than 10, the zone was considered out of con- trol and an immediate search was made for the breeding source. Such counts 60 ANOPHELINE BREEDING PLACE. Much time was spent in locating and larviciding sloughs, sink holes, and lakes caused by receding flood waters. indicated that a new breeding place had come into production, or that 1ar- viciding was incomplete or ineffective. Eleven light traps were in opera- tion in addition to several loaned to the Army. For the most part, traps were located in areas where records had not been available previously. LARVICIDING Larviciding was done in a majority of war area zones and in the larger towns in counties included in the Ex- tended Program. Excessive rainfall and four successive floods created many new breeding areas which had not been estimated as such when operational plans were set-up. Receding flood waters left many acres of water caught in sloughs, sink holes, and lakes. Much time was spent, first, in locating and, then, in larviciding such breeding areas. In hilly sections where drainage was good, larvicidal costs were $600 per square mile. Increased water surface and extensive clearing and major drain- age necessary in flat, poorly drained sections made costs average $947 per square mile in such areas. Shifting of military personnel from the State allowed discontinuance of several war area control zones during the s e as on. AIRPLANE DUSTING Airplane dusting with a mixture of paris green and soapstone was used to control anopheline breeding in rice fields in the Walnut Ridge and Newport areas and in a 45-acre rice field in the vicinity of a POW camp at Harris- burg. This dusting was done at five-day intervals although original plans called for dusting every seven days. Approxi- mately one pound of paris green was applied per acre. Although it was felt that effective dusting was being achieved in the vi- cinity of the POW camp at Harrisburg, 61 work was discontinued in August when a change was made to DDT residual in- terior spraying of the camp. It is believed that complete con- trol of anopheline breeding in rice fields cannot be obtained by airplane dusting with paris green, and DDT is being used experimentally. EXTENDED DDT PROGRAM The DDT house spraying in civilian areas of the 18 Extended Program coun- ties had a dual purpose: eradication of existent malaria and maintenance of a low malaria rate against the threat of increased spread from service men returning from malarious war areas. A total of 87,211 houses were spray- ed by 58 three-men crews working in the 18 counties. These crews were composed of two sprayers and a lead man. The lead man preceded the crews to see that houses were ready for spraying, and talked to the occupants about the purpose of the house spraying program and its func- tion in malaria control. When the program was inaugurated, people were not well informed of its purpose and in some instances, the crews had to assist in moving furniture before houses could be sprayed. The number of people re- fusing to have their houses sprayed was negligible. Most of those who refused at first, later asked the supervisors to spray their houses. Larviciding was used as a control measure in thickly populated areas and towns in the Extended Program. EQUIPMENT. When spraying operations started in March, spray and automotive equipment were not available from head- quarters’ office. Spray cans had to be bought locally, and transportation short- ages met by use of private trucks, wag- ons, and bicycles. Several spray crews began operations on foot, carrying spray equipment from house to house. When adequate transportation was available, weapon carriers and recon- naissance cars were assigned to the AIRPLANE DUSTING of rice field at Walnut Ridge, Arkansas. Ousting was done at 5-day intervals with approximately 1 pound of paris green being applied per acre. 62 spray crews. Each vehicle was fitted with cover cloths and an Army foot lock- er for tools. Many cars' had racks for carrying spray cans and hose, and most had 55-gallon drums to carry water need- ed in mixing DDT concentrate. Respirators and rubber gloves were supplied to all crews, but were dis- carded by most of them as summer tem- perature increased. TRAINING, PUBLICITY AND EDUCATIONAL ACTIVITIES. Area supervisors and dis- trict men were trained at Little Rock in spraying procedures as well as lar- viciding and all phases of malaria con- trol operations. These people in turn trained crews. Film strips, movies, lectures and demonstrations were used. Publicity for promotion of the Ex- tended Program was carried out by means of radio broadcasts, periodic news re- leases, distribution of literature, and group meetings in communities where spraying was to be done. Two hours’ radio time and 1,200 column inches of newspaper publicity were utilized. Pre- paratory to spraying 37,000 copies of “ Spray Time” (a modification of ” Spray Time Topics” ) were distributed. Lead men of spray crews gave a copy of ** How DDT Spray Keeps Malaria Away” to each person whose house was sprayed. Va- rious farm organizations assisted in the publicity by mailing 33,000 cir- cular letters regarding the spray pro- gram as envelope stuffers with their ma t e r ia1. Two men, employed in other capaci- ties by MCWA, were selected to act as Malaria Control Assistants on the basis of their apparent aptitude for the work. They were given a ten-day training course and were assigned to carry out general long range malaria control education and promotion of the program in the Extend- ed Program counties. Work was done in schools, with county health units and farm organization personnel and with various other community organizations. Three workshops in malaria control education were conducted during the year: one at the Agricultural and Me- chanical College at Monticello, one at the State Teachers Col lege at Conway and one at the Agricu1tura I-MechanicaI and Normal College at Pine Bluff. These workshops were designed to give teach- ers the basic facts about malaria and its control and to present methods for malaria control education suitable for use in the classroom. PROMOTION OF MALARIA CASE REPORTING. In attempting to intensify malaria control around actual malaria cases and to encourage better reporting of mala- ria, all houses where diagnosed and reported cases of malaria occurred, were sprayed with DDT. In addition to house spraying, the patients were vi- sited by the Malaria Control Assistants who inspected the premises and made recommendations for mosquito-proofing and destruction of breeding places. In the spring of 1945 until June 30, 72 cases were visited twice. The sec- ond visit was made 30 days after the original inspection to determine to what degree recommendations had been f ollowed. County health authorities were con- tacted regarding physicians’ reporting malaria. A letter was sent to physi- cians explaining the program and the part that routine blood smears could play in furthering the work. To facil- itate the physicians’ sending blood films to the State laboratory for exam- ination, slides and special mailing containers were given to the doctors. The objectives of this Program were: (1) to induce people to call doctors, (2) to arouse the doctors’ interest and encourage the taking of blood films and (3) to obtain more complete case report ing. PRESENT PROPOSALS. Present proposals include the spraying of 102,000 homes in 22 counties. Twelve of these coun- ties will be sprayed county-wide while the other ten will be less than county- wide. The limits of operation were de- termined by the extent of delta flood plains of the White River and Red Ri- ver Valley. 63 CALIFORNIA WILTON L. HALVE RSON, M. D. State Health Officer MCWA activities in the State of Cali- fornia during the fiscal year 1945 were a continuation of larviciding, minor drain- age and entomological surveys around Army and Navy posts. As in other western states, these efforts were directed against An- opheles freeborni, the western vector. Four permanent MCWA projects have been established in the Great Central Valley. In this area, anopheline breeding occurs from early March through October in irri- gation canals, irrigation spillage and seepage water, and also in large acreages of rice field water adjacent to control zones. During the year 2,949 acres were treated in the 6 war areas protect- ing 57 war establishments. DRAINAGE A contract was let at Marysville for a major drainage project which made possible the control of an LEGEND State Hdqrs. War Areas PROJECTS 2. Merced 3. Modesto 4. Marysville 5. Auburn 6. Northern Calif, 7. Southern Calif, 'fa Berkeley 64 area which formerly offered extensive breeding. A dragline was used in exca- vating to grade 10.5 miles of existing irrigation drainage ditches. Fifteen pri- soners-of-war were employed under con- tract with the War Department for cutting and burning trees and accumulated de- bris as well as for rebuilding fences and bridges. The completed project drain- ed many acres of standing water and confined the irrigation drainage within a definite canal. PUMP, The Merced area has utilized to considerable advantage a 20,000 GPH contractor’s type motor-driven cen- trifugal pump, mounted on a two-wheel- ed trailer and towed by a one-half ton truck. The fact that this pump is mo- bile has made it effective in drainage of many low areas within the control zone below the high water level in near- by irrigation canals. Since these areas are gradually replenished by excess irrigation water overflowing from ad- jacent crops and by seepage from irri- gation canals, pumping has been done periodically throughout the breeding season. FLUSH DAM An exception to tbe normal control methods was the construction and opera- tion of a flush dam on a creek located within the control zone near a a v a 1 establishment. Construction Battalion personnel from the Camp and MCWA labor performed the construction work. CB*s constructing flush dam in control zone around Naval establishment in Area 6. UNDERGROUND DRAINAGE In the Auburn area, the winter work of constructing numerous underground drains and open ditches materially reduced the amount of anopheline breed- ing found last season as compared with the previous season. A filler material of local broken rock was used success- fully for the underground drains. Sev- eral small hand-operated flush dams installed on the creeks have also help- ed to reduce the breeding. In the Modesto area the Irrigation District cooperated in replacing ap- proximately two miles of open drainage ditches with underground pipe, thereby eliminating considerable breeding area. A 20,000 GPH centrifugal pump dewatering an area in Merced. Water is being pumped into nearby irrigation canal. 65 SIMMERLY SLOUGH NEAR MARYS- VILLE. (Above) A dragline was used in excavating to grade 10£ miles of existing irrigation drainage ditches. (Left) Sim- merly Slough before drainage. This area offered extensive mosquito b reed i n g. HERBICIDES Weed control by application of pen- tachlor phenol as a herbicide was suc- cessfully accomplished along the banks or irrigation canals. A 0.5 percent so- lution of pentachlor phenol in Diesel fuel No. 2 was sprayed on the vegeta- tion of the canal banks so that 18 grams of pentachlor phenol were applied per square foot. Three applications were made at about six-week intervals and each time, prior to the application, the water level in the canals was tempo- rarily lowered approximately two feet. This work was done in collaboration with the Irrigation District and is particularly significant as the irriga- tion canals in this area constitute the main breeding problem. AIRPLANE DUSTING An unusual condition of Anopheles freeborni breeding in a 60-acre sec- tion of the Los Angles River, adjacent to Birmingham General Hospital, was satisfactorily controlled by airplane dusting at 0.1 pound of DDT to the acre, ENTOMOLOGICAL OPERATIONS MOSQUITO MIGRATION. In most areas adjacent to rice culture in the Cen- tral Valley, control measures of lar- viciding and minor drainage do an ef- fective job in reducing adult mosquito populations during the summer months. However, during the fall and winter months, beginning in September and last- ing until February, counts of adult females seldom remain below- 10 per sta- tion in control zone resting places. This is due to the incredible number of mosquitoes produced in nearby rice fields. These mosquitoes migrate or move aw’ay from the fields due perhaps to overcrowding or a desire to seek shelters suitable for winter. This mi- gration occurs each year, but the na- ture and cause are imperfectly known. It is not uncommon for good resting stations to have counts of 200 to 5,000 adult mosquitoes. Early in the fall there is a high proportion of males, about one-half, but by December they have diminished to only an occasional male. This migration has a direct bear- ing on the control problem because the greatest number of reported malaria cases occurs during fall. INVESTIGATION. Beginning in Septem- ber of 1944 in the Marysvi11e-Winters areas some investigational work was done to obtain additional information on the flight range of Anopheles free- born! in areas where there is exten- sive rice growing. Adult collecting stations extending from these rice field breeding areas were set up for a distance of about five miles. From con- secutive adult counts at these stations, it soon became apparent that the fall migration had been in progress for sev- eral weeks prior to the start,of the investigation. Evidence collected indi- cated that at this time of the year, some of the adults fly at least five miles. A further study of this problem will be con- tinued in the fall of 1945 beginning early enough to complete the investigation. Artificial pond producing anophelines at Auburn (Area 5). Careful records were kept of adults found in resting places near rice fields in the Merced area" for the entire year. These indicated a heavy population in shelters from mid-July until February when they dispersed in search of blood meals to be followed by egg laying. NATURAL RESTING PLACES, Routine in- spection records on A. freeborni in areas where breeding is occurring, show an absence of adults in nearby natural resting places during the summer. To account for this, a study of the rest- ing habits of this species is being made in the Auburn area. Artificial resting places (apple boxes painted black) are being used in conjunction with established natural resting places so that the two types may be compared. These artificial resting places were located at intervals along lines radi- ating away from the breeding areas. This work is continuing and it is hoped that conclusions may be made by the winter of 1945 in regard to some of the habits of the adults during the s umme r. SOUTHERN CALIFORNIA, In COmparison it has been noted generally that the population density of adults is con- siderably lower in Southern California than in Northern California. The fall migration of the adults into all types of man-made shelters in the Northern California zones has not been observ- ed in the Southern California zones. In some zones of this area, breeding is apparently continuous throughout the year, as evidenced by the finding of larvae and male, as well as fe- male adult forms during the winter mo n t h s. MOBILE UNIT OPERATIONS. A total of 20 military zones were included in the MCWA operations of the Northern and Southern California Mobile Malaria Con- trol Units during the 1945 fiscal year. Operations in these zones were on both a surveillance and control basis and included Navy and Army hospitals and training bases, Army airfields and ROW camps. Species control was carried out in the extra-cantonment area of 11 zones by the mobile unit personnel. Hand dusting with paris green was the usual larviciding method employed. DDT SPRAYING In December of 1944, selected build- ings except dwellings in the one-mile control zone around the Army airfield at Merced, were sprayed with DDT i n order to study its effects on the hi- bernating A. freeborni adults. Before spraying, the buildings were surveyed for adults, mapped, and their surface areas computed. In addition to a solution of DDT in Diesel fuel No. 2, two commercial DDT products were used with 1% refined summer oil. Straight Diesel fuel No. 2, and 1% summer oil were also applied as cont rols. On the basis of surface areas sprayed and amounts of each material used, the concentration of DDT in milligrams per" sq. ft. was: DDT and Diesel fuel No. 2, 160; commercial DDT product No. 1, 1.3; commercial DDT product No. 2, 1.4. All materials were applied at the rate of approximately 5 cc. per square foot of surface using a 50-gallon or- chard type power sprayer. Periodic adult population checking in both the treated and untreated build- ings was continued through the end of February 1945. These data showed that for this entire period, all three DDT mixtures, as well as the Diesel fuel, reduced the adult population nearly to zero. This was in contrast to popula- tions averaging 40 adults per station in the untreated area and that spray- ed with 1% summer oil. In view of the migration habits of A. freeborni and the results of the DDT work at Merced, DDT residual spray- ing projects in the Marysville and Merced areas wi11 be undertaken during the fall of 1945 in an attempt to cope with the fall migrations of adults into the control zones from the rice field breed- ing areas outside. 68 DISTRICT OF COLUMBIA GEORGE C. RUHLAND, M. D. District Health Officer LEGEND LWar Area* *The 69 miles of the District of Columbia compose one V/ar Area. During the past fiscal year the Dis- trict of Columbia MCWA program stressed entomological surveillance rather than control. The shift in emphasis was made possible by the removal, during the previous year, of the water chestnut from Oxon Run. INTEGRATION WITH HEALTH DEPARTMENT Mosquito control by agencies of the District of Columbia was expanded with the discontinuance of MCWA control ac- tivities. The MCWA work was transferred to the Bureau of Sanitation of the D. C. Health Department in January of 1944. This coordination led to the elimination or control of some of the mosquito breeding places by private property owners through the use of po- lice power of the Health Department over public nuisances. In a number of cases, orders from the Health Depart- ment were necessary to persuade prop- erty owners to eliminate breeding places located by the D. C. Health Department inspectors under MCWA supervision. Inspectors of the Bureau of Sanita- tion have been trained in the technique of mosquito control so that they are able to report intelligently on mos- quito nuisances discovered incidental to other work. In this way, anti-malaria and anti-mosquito work may be contin- ued after the War through the Health Department Personnel. 69 FLORIDA HENRY HANSON, M. D. State Health Officer PROJECTS 1 . Tal1 ahassee 2. Pensacola 3. Valpariso 4. Panama City 5. Jacksonville 6. Green Cove 7. Marinna 8. Apalachicola 9. Arcadia 10. Ocala 11. Tampa 12. San ford-De Land 15. Clewis ton 16. Gainsvi1le 17. Leesburg 18. Avon Park 19. Cross City 20. Lake City 21. Sehring 22. Lakeland 23. Perry 24. Car rate 11e 25. Wi11i s ton 26. Bushnelle 27. Buckingham 28. Sarasota 29. W. Palm Beadh 30. Boca Raton 31. Fort Myers 32. Zephyrhills 33. Bartow 34. Daytona Beach 35. Kissimmee 36. Dunnellon 37. Orlando 38. Venice 39. Punta Gorda 40. Brooksville 45. Citrus 46. Suwannee 47. Jef fer son 48. Madison LEGEND 'Jacksonville State Hdqrs. War Areas Extended Areas Residual Spray There was no visual or reported evi- dence of malaria transmission in the civilian population or in military areas under control in Florida during the past fiscal year. Minor drainage and larvi- ciding were performed around 27 of the 38 war areas in the State. A major drain- age project involving the use of dynamite was in progress in Lake City. However, there has been relatively little ditching during the past year whereas ditch main- tenance has assumed greater importance. LARVICIDING Airplane dusting was utilized on large lakes in the Leesburg area. In West Palm Beach and Boca Raton, large canals were dusted with a power duster mounted on a jeep. This method has been found to be expedient as well as prac- tical. Power dusting from a boat was 70 used in the Leesburg, Tallahassee, and Lake City areas, and likewise proved effective. HERBICIDES Some experiments were made with herb- icides, using a chemical compound of 2,4 dichlorophenoxy-acetic acid. This proved effective in combating the growth of water hyacinths, which has become a serious problem for malaria control, as well as to navigation and fishing. A complete kill was obtained by ap- plication with a hand sprayer of a solu- tion containing one quart of 2,4-D. to fifty gallons of water. These herbicidal investigations will be continued in the coming fiscal year. HYDRAULIC DREDGING Hydraulic dredging was continued in the large marsh area adjacent to the city of Leesburg. When this project is completed, possibly by the end of 1946, one of the most serious Anopheles quad- r imacuIatus breeding areas around the city will have been permanently elim- inated. RIGHT. Water hyacinths, before and after spraying with 2,4 d i c h 1 o rophe n oxy-acet I c acid. BELOW. Application of the spray. DITCH LINING June 30, although full operation was de- layed in some areas due to lack of equipment. During three monthsofspraying, houses which had been visited were averaging 3,200 square feet of interior wall space and each required the use of approxi- mately 0.7 pounds of DDT. Altogether 7,720 houses were sprayed, giving pro- tection to an average of 135,402 persons. Installation of permanent ditch lining is still in progress in the Leesburg and Gainesville areas. Both the city of Leesburg and the Univer- sity of Florida are supplying materials, while MCWA is furnishing the super- vision and labor required. The work at Gainesville is being performed onthe University campus where a malaria hazard exists. It is expected that the work will accomplish a two-fold purpose by eliminating the malaria hazard and by serving as a demonstration for the University in familiarizing the engineering students with the technical phases of permanent ditch lining for malaria control. EDUCATIONAL PROGRAM In conjunction with residual house spraying, an educational program was carried on to facilitate operations. In many civic clubs and possibly 30 schools, over 7,000 persons witnessed the animated short films: “Winged Scourge” and “Spray Time” and heard lectures on DDT house spraying. Several thousands of pamphlets on the subject were distributed. DDT RESIDUAL SPRAYING Ten counties were selected to re- ceive residual house spraying with DDT during 1945. A house-to-house sur- vey and mapping of these areas was com- pleted throughout the winter months. In Citrus County area, operations began March 1, 1945. In 9 other coun- ties: Sumter (Area 26), Levy (Area 25), Dixie (Area 19), Suwannee (Area 46), Jefferson (Area 47), Leon (Area 1) and Jackson (Area 7), work was under way by AEDES AEGYPTI CONTROL In addition to the malaria control program, Aedes aegypti projects were in operation at Miami, Key West, Jackson- ville, and Tampa. On these projects considerable stress was placed on edu- cational work. It is felt that much prog- ress was made in these cities. AEDES AEGYPTI CONTROL. (Left) Aegypti breeding places were cleared up in the course of general sanitary inspections. (Right) Window displays being prepared for exhibit. GEORGIA T. F. ABERCROMBIE, M.D. State Health Officer PROJECTS 1. Macon 2. Augusta 3. Hinesvi11e 4. Savannah 5. Brunswick 6. Columbus 7. Albany 8 . Va1dosta 9. Moultrie 10. Douglas 11. Atlanta 12. Bainbridge 13. Waycross 14. Americus 15. Thomasville 16. Statesboro 17. Tifton 18. Rome 19. Dub Iin 20. Dawson 21. Dona 1sonvi11e 22. Waynesboro 23. Cordele 24. Emory Field Station Atlanta LEGEND Hdqrs. War Areas Extended Areas fill;Residual Spray Reported malaria morbidity and mor- tality continued low in Georgia during the fiscal year 1945 as compared with previous years. Total cases of malaria reported as occurring in the civilian population during the calendar year 1944, were 288 while 11,931 cases were reported in 1936. However, malaria morbidity reported during the first four months of 1945 was approximately twice that reported in the same period for 1944. This increase in reported malaria may be due partly to natural causes but there is reasonable assurance that re- porting of malaria has been stimulated by the inauguration of the Extended Progr am. All MCWA activities were directed toward the control of the malaria vec- tor. Larvicidal and minor drainage pro- grams were conducted in 17 of the 19 war areas during the fiscal year. In four of these, operations have now been discontinued due to the cessation of war establishment activities. 74 LARVICIDAL ACTIVITIES PARIS GREEN. Paris green continued to be the main larvicide employed. Some 15,274 acres were treated during the year. With the exception of the Albany area, application was made by hand dusters. Power dusters operated from outboard motor-driven boats were used in cooperation with the Georgia Power Company’s reservoir. This reservoir is adjacent to Turner Field Army Air Base and the USO recreation area. OIL. Small amounts of Diesel oil were used in the vicinity of Army Gen- eral Hospitals at Rome and Thomas- v i 1 1 e . DDT. Some large scale experimental larviciding operations using DDT dust and DDT emulsions were conducted at Savannah in cooperation with the Carter Memorial Laboratory. OTHER CONTROL OPERATIONS In the Albany area, controlled weekly fluctuation of the reservoir level was of considerable assistance in reducing breeding. During the winter, a topo- graphic and hydrographic survey was made of the more critical areas of the reservoir and its shores. Landlocked pockets revealed by this survey will be drained. FILLING AND DRAINING. Near Augusta, minimum level filling continued using waste brick plant products and minor natural hydraulic fill. Lake Aumond, within flight range of Oliver General Hospital, developed heavy breeding which proved difficult to con- trol. The lake owner was persuaded to drain the lake and to perform major shoreline and vegetation improvements around the lake. This eventually will eliminate or materially reduce the ne- cessity for control measures. DYNAMITE. Three tons of dynamite furnished by the Richmond County Com- missioners, were used in the recon- struction of Phinizy Canal. Muck and debris, which dynamite did not remove from one of the Canal laterals, were removed by use of a slip pan powered by a Command car winch. DREDGING. In the Macon area, hydrau- lic dredging operations were completed in the Fuse Plant zone and were begun in the Camp Wheeler zone in cooperation with the Army. The four-inch dredge was further modified. Its cost of op- eration compared favorably with dyna- mite, dragline or other mechanical methods of excavation. DRAINAGE. Victory Lake on the Berry Schools property, at a distance of about 1.1 miles f romBattey General Hospital (Rome area), developed into a heavy breeder. The lake is being drained, shallow areas will be eliminated, and a new drainage outlet constructed in cooperation with the Berry Schools. T I DEGATES. Control operations have been materially improved in the Quar- termaster zone near Savannah through Chatham County’s reconstruction of the Pipemakers Canal Tidegates. These gates are counterweighed so that less than 0.1 foot head is required to close them. Most of the abandoned rice fields, adjacent to the canal, remain dry under normal conditions. A topographic sur- vey, using the transit plane table method, was of considerable assistance in lay- ing out the drainage system so as to effectively utilize the tidegates in maintenance of low stages in the Canal. DITCH PAVING. At Statesboro, approx- imately one-third mile of invert paving was installed, using circular side joint slabs, 10 inches wide and 36 inches long. Butt-joint tile and single flat slabs were used in tributary laterals. Bulloch County and the city of States- boro provided all materials for the ditching, paving and butt-joint tile installat ions. TOPOGRAPHIC SURVEY. A topographic survey of an area in the Moody Field- Valdosta zone, located the probable source of heavy breeding. Considerable dewatering was effected in this area by minor drainage. 75 EXTENDED PROGRAM AREAS. Extended Program operations were initiated in Seminole County on March 14, 1945. Four areas, totaling all or portions of 11 counties, are now in operation and plans have been made for coverage of portions of two ad- ditional counties, which will be in- corporated in existing areas. PERSONNEL. All area operations were conducted under the general supervision of the area supervisor. In multiple county areas, each county’s operations were closely supervised by a county supervisor. Other county personnel in- cluded an assistant, one or more spray- ers and one or more laborers. EQUIPMENT. Spray crew vehicles were equipped for all weather operations. Practically all equipment maintenance was performed within the county or area. HOUSEHOLD PREPARATION. The county assistants were responsible for dis- semination of program information to the public and for securing the coop- eration of individual householders. The assistants contacted householders, advising as to house preparation and approximate time of arrival of the spray crew. If the householder did not agree to the spraying of the house or if house preparations were not sub- stantially complete when the spray crew arrived, the house was not sprayed. It was estimated that 12,501 houses were sprayed, protecting approximately 91,863 persons. SUCCESS OF PROGRAM. To date, there have been extremely few complaints, none of which were serious, from resi- dents of houses sprayed. In fact, residents and governmental officials of nearby areas which are not in the Extended Program, were extremely anxious to have their dwellings sprayed. Several counties agreed to furnish personnel and equipment in order to secure participation in the program. From the general public’s viewpoint, this program is one of the most bene- ficial proposed or conducted by public health organizations. It is believed that with this stimulation of interest organized health departments in every county of the State may begin operation at an earlier date than has been here- tofore expected. PIPEMAKERS CANAL, CHATHAM COUNTY. Control operations have been greatly improved by modi- fication of existing control tidegates which are counterweighed so that less than 0.1 foot head is required to close them. 76 ILLINOIS ROLAND R. CROSS, M. 0. State Health Officer LEGEND State Hdqrs. Viar Areas A Extended Areas £$ Residual Spray PROJECTS 1. East St. Louis 2. 111. Ordnance Plant 3. Savanna 4. Rock Island 9. Seneca 11. Cairo 12. Mt. Veron 13. Lawrencevi11e 15. Table Grove 16. Rockford 17. Galesbur g 19. North Chicago 20. Danv ilie 21. Dwight 22. Rantoul 23. Schick Spr ing f ieId-Decatur The Illinois MCWA program followed the same pattern during the past fis- cal year as during the previous year. The problem was primarily one of sur- veillance except in the southern part of the State where control projects were in operation. Surveillance was maintained in 13 zones of primary in- stallations throughout the State. Entomological data at certain times during the season indicated that a few zones were on the border of requiring control. Close cooperation with mili- tary officials with respect to entomo- logical findings made it possible to evaluate needs for control measures with full knowledge of local situa- t ions. 77 ENTOMOLOGICAL PROGRAM The entomological program was de- signed to collect data on the inci1- dence of Anopheles quadrimacv1 atus in as many locations as possible. These data were of particular importance be- cause of the redistribution of malaria carriers throughout the State as a re- sult of war activities. The malaria vector is distributed generally through- out the State but the malaria rate was very low during the pre-war period. With personnel of the State MCWA program and mobile units available from the District and Headquarters office, prompt action could be taken in the event of an outbreak of malaria. The value of the program can be weighed by the fact that there were no cases of reported malaria caused by local transmission from military in- stallations and prisoner-of-war camps to local populations during the year. Malaria control surveys were made in 13 zones at POW side camps, minor military installations, Army general hospitals and Veterans Administration hospi ta1s. The selection of POW side camp sites was made in locations practically free of potential " quad” production, with the exception of one at Hoopeston (Area 20) where two ponds on the boundary line of the reservation were handled by military officials. Surveys were made at sites of Vet- erans Administration hospitals because of reported malaria cases during the previous season and the expected in- crease of malaria among patients. Twelve zones previously set up as part of the Illinois MCWA program were dropped during the past fiscal year, as a result of changed conditions. LARV IC I DAL CONTROL Larviciding was performed in five zones in two areas in the southern part of the State during the 1944 season. This con- trol was reduced to three zones with the opening of the I94S season because of reduced war activities. During the year 7,690 acres were treated around 80 war establishments in the 16 war areas throughout the State. Plane spreading a mixture of paris green and lime. In the Illinois Ordnance Plant area this method was employed and proved more satisfactory than surface power spraying. Silver Creek bottoms during seasonal floods. This Creek has long been a problem and It is believed that extensive drainage would prove to be the most effective means of control. AIRPLANE DUSTING In the Illinois Ordnance Plant area, the method of control was changed from the use of surface power equipment to airplane dusting. The latter method proved more satisfactory than treatment with surface equipment. In the late summer an extreme drought in this zone changed conditions of the breeding areas, so that it would have been almost im- possible to maintain control with sur- face equipment because of shallow water. At all times during the control sea- son “ quad” counts were maintained at safe levels and it is therefore plan- ned to continue this method of control during the 1945 season. DRAINAGE The main problem in the Scott Field zone (Area 1) was the Silver Creek bot- tom lands. It is believed from the ex- perience of the past two seasons that more economical and efficient control will be possible if extensive drainage is performed. Several times during the season, the creek rises because of sum- mer rains, and re-establishes exten- sive breeding areas in these bottom 1ands. Plans have been made and work is now under way to install large ditches which will give direct fluctuation of breeding areas with the water levels in the creek. Previously, it has been impossible to undertake drainage because of con- servation interests. However, when the extreme drought in September of 1944 destroyed all fish in the sloughs, ditch- es could be installed to keep these sloughs dry. DDT SPRAYING A residual spray project using DDT was put in operation in Alexander Coun- ty. Although comparatively small, this project gives public health officials an opportunity to study the use of DDT in rural malaria control. Experience gained from this project will be very valuable to public health officials when this chemical becomes available for more general use. 79 INDIANA THURMAN B. RICE, M. D. State Health Officer LEGEND State Hdqrs. A. War Areas PROJECTS 1. Indianapolis 2. Jeffersonville 3. Terre Haute 4. Columbus 5. Evansville 6. Fort V/ayne 10, Vincennes Indianapolis In the State of Indiana, the areas emphasized in malaria control have been Terre Haute on the Wabash River, Evans- ville on the Ohio River, and Indiana- polis on the White River. Surveillance has been maintained in five other areas around military estab- lishments in various parts of the State where Anopheles quadrimacu1 atus den- sities were found to be too low dur- ing the 1944 breeding season to war- rant con t ro1. TERRE HAUTE ENDEMIC MALARIA. High densities of A. quadrimaculatus are associated with a relatively high degree of endemic ma- laria in the vicinity of Terre Haute. During the period 1938-40, malaria re- appeared in epidemic form after an ab- sence of half a century. The estimat- ed number of cases was 1,500. MOSQUITO BREEDING. The principal ** quad” breeding places are situated in the Wabash River bottom within easy 80 flight range of the centers of popu- lation. Although levees have been*con- structed to keep these bottom areas from being inundated by the frequent floods of the Wabash, the underlying porous sand and gravel strata permit easy see- page. Subsequent drainage is delayed by inadequate and faulty drainage struc- tures. During July of 1938, a river stage of 20.7 feet (6.7 feet above flood stage) occurred. An effort has been made to provide structures which will permit ready drainage of these bottom areas after the floods have subsided. LARVICIDING. Fair control was ob- tained during 1944 by hand larviciding supplemented by some power spraying and pumping of impounded water. How- ever, it appears that drainage of the bottom areas after floods will be the only effective control measure. FORT HARRISON LARVICIDING, The major breeding place in the Fort Harrison control zone which includes the Billings General Hospi- tal, is Indian Lake, an impoundment one-half mile north of the reservation. Extensive shallow areas support a dense growth of aquatic vegetation during fa- vorable years. The extent of the hori- zontal growth determines the method of larviciding. During the 1944 season, hand spraying sufficiently inhibited “ quad" breeding. However, the increas- ed growth of horizontal vegetation in the late spring of 1945 necessitated power application of the larvicide. EVANSVILLE LARVICIDING. Numerous ornamental ponds in the parks of this highly in- dustrialized city provide satisfactory environments for ** quad” breeding. A joint mosquito control program with the city organization functioned during 1944. Hand spraying achieved good control. POWER SPRAYING at Indian Lake near Fort Harrison. KENTUCKY PHILIP E. BLACKERBY, M. D. State Health Officer PROJECTS 1. Morganfie1d-Henderson 2. Hopkinsville 3. East Kentucky 4. Paducah-Mayfield 5. Fort Knox 6. Louisville 7. Fulton 8. Hickman 9. Ballard 10. Carlisle Louisville LEGEND State Hdqrs. War Areas Extended Areas Residual Spray Extended Larviciding Malaria control activities in the State of Kentucky were greatly expand- ed with the inauguration of the Ex- tended Program. WINTER ACTIVITIES Winter activities were confined to making the necessary preparations for Extended Program operations. On the ba- sis of malaria mortality, the State De- partment of Health selected six coun- ties in the western part of the State. It was recommended that DDT residual spray be applied to all homes in these counties as a malaria control mea- sure. Mapping was started in December. County maps were drawn showing the lo- 82 ENTOMOLOGICAL SURVEILLANCE. (Left) Di pping for larvae. (Right) Catching adult moaquitoes In chloroform tube. Two inspectors using spot spraying equipment successfully controlled anopheline production when indicated In the Hopkinsville and Morganfield-Henderson areas. cation of each house. These houses were assigned numbers on the maps and these numbers were later stenciled on the houses. SURVEILLANCE AND CONTROL Nine military establishments con- tinued under surveillance, while 48 war establishments were protected in 6 war areas. No control measures were requir- ed in the areas surrounding three of these establishments in the east cen- tral part of the State, and breeding was adequately controlled in the vicin- ity of the others. Control activities in the Hopkins- ville and Morganfield-Henderson areas were reduced. The areas did not' produce Anopheles quadrimacu1 atus in serious numbers during the past season. At pre- sent, there are only three inspectors covering these areas. Although the military BREEDING AREA. One of the many stock pond breeding places found in Kentucky. During the past fiscal year approximate!y 985 acres were larvicided. 83 personnel at Camps Breckinridge and Campbell have been greatly reduced, control activities may have to be in- creased during the next fiscal year because the two military camps are being react iva ted. Control work in the Fort Knox area has been expanded to provide protec- tion for military personnel remaining over night on the firing ranges. Recent flood conditions along the Ohio River have created many more " quad” breeding areas and have greatly enlarged the existing breeding areas in the vicin- ity of Paducah. ROW LABOR By an agreement with the Nichols General Hospital and the Louisville Medical Depot, four prisoners-of-war were furnished to help relieve the la- bor shortage which was felt during the breeding season in the Louisville area. This was a temporary measure since the prisoners could be used only within one mile of the military installations. DDT RESIDUAL SPRAY Approximately 12,000 homes in west- ern Kentucky were treated with DDT re- sidual spray. It is estimated that some 18,000 homes in McCracken, Graves, Ballard (Area 4), Hickman (Area 8), Fulton (Area 7), and Carlisle (Area 10) Counties will be sprayed. Some difficulty has been experienced in securing and training personnel for DDT work. All men assigned to DDT work are thoroughly trained before they are assigned to field operations. The labor turn-over has made it necessary to con- tinue training new men for the DDT crews. The county health departments have shown fine cooperation in supplying the field personnel with materials, office and garage space, and furnishing funds for incidental cash purchases. Most of the DDT is being applied with hand spraying equipment. A power spray- er was used by one crew for a limited period, but did not prove economical. During the year, approximately 77,506 persons were protected as a result of house spraying. LARVIC ID ING Hand operated oiling and dusting equipment was used to control the breed- ing on the regular MCWA program. The small size and widespread locations of the breeding places made the use of pow- er equipment impractical. Larviciding was limited to locations where “quad” larvae were found. This practice per- mitted the program to operate with fewer larviciding crews of high quality and effected a saving in both labor and ma- terials. Some 985 acres were treated during the year. TRAINING COURSES A special course in Malaria Control, attended by approximately 75 teachers, nurses and county sanitary inspectors, was conducted at the Murray State Teach- ers College in collaboration with the State Department of Health, the Head- quarters Office, TVA, and several local county health departments. Several field trips were conducted through the various counties in the wes- tern part of the State where the ex- tended and regular MCWA programs were in operation. Other subjects studied were tuber- culosis, general sanitation, and food and nutrition. Another educational project of the State Department of Health was conduct- ed at the Louisville MCWA headquarters where some 130 medical and dental stu- dents from the University of Louisville were shown the field methods of inspec- tion and control of malaria mosquitoes in the Louisville area. The course in- cluded lectures, demonstrations, mala- ria films and field trips. This activ- ity is a part of an annual program in which the medical and dental students of the University of Louisville are shown the operations and procedures of the entire State Department of Health. 84 LOUISIANA DAVID E. BROWN, M. D. State Health Officer PROJECTS 1. New Orleans 6. Baton Rouge 2. Alexandria 7. Monroe 3. Leesville 8. Lafayette 4. Shreveport 9. Natchitoches 5. Lake Charles New Orleans State Hdqrs. War Areas Extended Areas Residual Spray Extended Larviciding LEGEND Louisiana is one of the States en- tirely within the endemic malaria area along the Gulf Coast. It is therefore interesting to note that there has been little incidence of malaria reported in the State in the vicinity of any of the controlled areas. The cases re- ported from military establishments were usually due to infection either before the men were transferred from points outside the protected areas, or were recurrent cases from overseas. During the year 97 war establishments were protected in the 8 war areas of the State. DDT SPRAYING An Extended Program of malaria con- trol was begun in parts of 6 parishes in the northern section of the State in which malaria mortality rate was at an index of 19. The Program was bas- ed on the spraying of some 16,000 houses which were sprayed at 3-month inter- vals or approximately 2 sprayings per breeding season. 85 In six towns within the specified wards more DDT would have been requir- ed than was available. In these instances larvicidal projects were put into opera- t ion. Power equipment was used for the application of DDT emulsion whenever it seemed more advantageous than ap- plication by hand sprayers. The ad- vantages of power equipment were a constant pressure for application and a better application rate per house where houses were close together. The disadvantages of power equip- ment included: difficulty in checking the amount of application per room or house; rapid deterioration of the ap- plication hose due to the xylene; loss of time at the end of each day in wash- ing equipment; the weight of sprayers set high on trucks, making a top-heavy load to carry over rough ground. As a solution to these difficulties, it was proposed to replace the heavy liquid pumps with light air compres- sors and tap the 2/4-gallon Hudson Cli- max to compressor spray cans for con- nection of air hose. This will not only produce constant pressure of applica- tion but will also reduce the deterio- ration of the rubber hose. In this way, only a short section of the hose on the sprayer will be in contact with the xylene. Each member of the crew will carry a sprayer and all sprayers will be connected to the air compressor out- side. REFUGEE CAMPS SPRAYED During early April, the levees along the Red River and Ouachita River broke in several places flooding large areas within some of the wards in which DDT spraying had been started. Numbers of refugee camps were es- tablished and it was asked that these camps be sprayed with DDT. In compliance with this request, spray crews used 400 gallons of DDT concentrate in treat- ing 3,500 houses or tents, which were temporary living quarters for some 16,000 re fugees. BACKWATER The flood backwater was so exten- sive in Catahoula and Concordia parishes of area seven that a request was made to spray with DDT all the houses in the towns of Jonesville, Harrisonburg, Ferri- day and Vidalia. Here the floods had increased the breeding of “ quads” and thickly seeded the entire area with adult mosquitoes. One thousand pounds of DDT and the necessary xylene and triton were made available for this purpose and the spraying of the towns was completed early in July. JACKSON BARRACKS The 800-acre swamp lying just north of Jackson Barracks in New Orleans on which a major drainage project was com- pleted in July 1944, was entirely dried up in September by completion of the lateral ditch system. This area had remained dry through the spring wet season and no breeding had been found in the drainage ditches. However, immediately to the east of this swamp was a heavily wooded area, A Ditch m the New Orleans area cut with vertical banks due to a heavy root system which holds the soil and makes the banks more stable. 86 which was overflowed almost entirely during the breeding season. This area was about 550 acres in size and ex- tended south to the St. Claude highway almost to the Mississippi River. It was drained by St. Bernard parish ca- nals leading to a pumping station where the water was lifted over the levee into Bayou Bienvenue at a point some two miles east of Jackson Levee. The Parish pumping plant was found adequate to handle the water and main- tain a level in the canal system from 1.5 to 0.5 mean gulf level. Pumping would dry up completely the surfaces of the wooded areas provided the equip- ment was operated regularly, a suffi- cient number of hours per day. The Parish was unable to obtain and keep labor pumpers to assure regular pumping. Therefore, MCWA furnished la- bor for the pumping and the parish sup- plied operating costs, such as fuel, repairs, etc. With this arrangement, sufficient punping was done at all times to keep the water below the flood level. The area was dried up and no breeding was found last spring and summer. There were, however, a few places outside the control zones where the canals were checked with vegetation which is being eliminated by a dragline. The entire zone was larvicided week- ly last season by 30 men using three lV4-ton trucks. At present two men util- izing one jeep with a small power oil pump and drum of oil, can cover the entire zone in less than two days each week. This indicates a saving in labor of 2 foremen and 27 laborers and a sav- ing in equipment of 3 large trucks. During the last season of 30 weeks when normal larviciding was in opera- tion, a total of 26,657 acres was treat- ed with 541,036 gallons of oil. This can be compared with 42,400 acres treat- ed with 706,500 gallons of oil during the previous season of 24 weeks. There was a 47% reduction in the use of oil in acres treated with 3 additional zones of control over the previous sea- son. This reduction was due to drain- age which eliminated breeding areas and to inspection which disclosed those watered areas known to be intermittent breeders. Part of the drainage system of Jackson Barracks near New Orleans. (Left) Levaa construct- ed by dragline to prevent overflow of stream into adjacent swamp which will be drained into another outfall. (Right) Dragline in action. 87 MARYLAND ROBERT RILEY, M. D. State Health Officer LEGEND State Hdqrs. War Areas PROJECTS 3. Suburban Washington 4. Bal t imore (Maryland Statewide) 5. Southern Maryland Balt imore During the past fiscal year, most of the important malaria breeding pla- ces remaining around war establish- ments were eliminated. An expanded pro- gram of entomological surveillance de- termined the lack of need for control work around a number of war establish- ments which have never been adequately inspected. WINTER PLANNING Extensive preparations for the next season’s work were made during the win- ter. Maps, both original and revised, station descriptions and map keys, were made of 15 zones. The inspectional force spent most of its time on a watered area census of eight zones under sur- veillance and on the identification of culicine mosquitoes. There were three schools conducted on general malariology. The first two were for inspectors immediately concerned with the project. The third was pri- marily for State Health Department per- sonnel, and included representatives from most county health departments facing a potential malaria problem. MOSQUITO COUNTS Only eight zones produced significant counts of malaria mosquitoes. At Scot- land (Area 4) counts were as high as 10,000 per station. There was great variation in time of occurrence of peak populations, ranging from the earliest on June 22 (at Scotland) to September 16 (at Cedar Point, Area 4). DITCH CLEANING During the early part of 1944, a considerable amount of ditch cleaning and spring-fed marsh drainage was done at Camp Springs (Area 5). Most of the “ quad” breeding areas were thus elimi- nated before the beginning of the breed- ing season. 88 PONDS CLEANED OR DRAINED cutting of water chestnut by the Navy greatly reduced breeding of Anopheles quadrimaculatus. Only fringes of this aquatic plant were left after cutting. Breeding in this limited area was suc- cessfully controlled by paris green dusting from boats. By the end of July, most of the wa- ter chestnut plants at Fort Washington (Area 5) which had already been cut, had drifted from Piscataway Creek or had disintegrated and sunk. With their disappearance, adult counts of “quads” lapsed into insignificance. Small areas of scattered stranded beds of cut plants, which were associated with a limited amount of breeding were dusted with paris green. In 1945 arrangements were made to obtain 40 prisoners-of-war to assist in removal of water chestnut. These men eradicated the plant from all of the Maryland shores of the Potomac ex- cept for one small area. Because of this work, no larviciding will be nec- essary in Maryland during the 1945 season. Heavy mosquito breeding in the vi- cinity of Bradburn*s Pond (Area 4) was eliminated when the Pond was thoroughly cleaned and larvicided. A drought la- ter in the season made further work unnece s s a r y. Major reduction of breeding surface at Indian Head (Area 5) was accomplish- ed by drainage of a 27-acre marsh along the Potomac River and a large swamp in the triangle bounded by Highways 224 and 225. The ponds of the V & M Sand and gra- vel Company (Area 5) were cleaned after tHe water in the ponds had been low- ered. The work was done during the winter when ice coverage facilitated ope r a t i on s. Prolific aquatic growth on the ponds near Cedar Point (Area 4) caused mos- quito breeding which was eliminated by drainage of the ponds during the spring. WATER CHESTNUT At Stump Neck (Area 5), extensive Extensive cutting of water chestnut at Stump Neck and at Fort Washington greatly reduced anopheline breeding. 89 MISSISSIPPI FELIX J. UNDERWOOD, M. D. State Health Officer PROJECTS 1. Biloxi 2. Pascagoula 3. Hatties burg 4. Meridian 5. Jackson 6. Greenville 7 . Gulfport 8. Columbus 9. Cent r ev i11e 10. Clarksda1e 11. Grenada 12. Greenwood 14. Como 15. Picayune 16. Brookhaven 17. Richton 18. Lake Washington 19. Indianola 20. Drew 21. Lei and 22. Belzoni 23. Tunica 24. Quitman 25. Bolivar 26. Holmes 27. Yazoo Jackson LEGEND rState Hdqrs. - War Areas .Extended Areas 'Residual Spray Despite some curtailment of mili- tary training within the State of Miss- issippi, the advent of the Extended Malaria Control Program and the estab- lishment of numerous prisoner-of-war branch camps necessitated a consider- able expansion of MCWA activities for the fiscal year 1945. FIELD UNITS REORGANIZED. Because of changing control methods involving house spraying with DDT, field units under the State Division of Sanitary Engi- neering were reorganized to conform more closely in general responsibili- ties and relationships to other local public health programs. FIELD CREWS. Field crews were made an intergral part of the various county health departments, and a concise statement of policies was drawn up to guide direc- tors of county health work and MCWA per- sonnel attached to their organizations. 90 GENERAL POLICIES The statement of general policies pertaining to malaria control work in the counties purports to set up: (1) The general responsibilities of and the relationships ex- isting between the agencies involved in the operation of the program within the State. (2) The relation of the MCWA program with respect to the over-all public health program of the county health departments. (3) The responsibility of the county health department to the malaria control program. (4) The relationship of all malaria control personnel, on the county level, with respect to the health department with which they are employed and the director of the department. TRAINING CONFERENCE With the basic organization policy for the Extended Program established, the Mississippi office called a two- day training conference for supervi- sory personnel, conducted by represen- tatives of the State and MCWA head- quarters office. By utilizing a centrally located county organization for within service training of newly appointed supervisors and inspectors, the program was able to expand field operating personnel as quickly as the flow' of needed equip- ment and supplies warranted. Last year for the first time, edu- cational activities were carried out by full-time educators. The recruit- ment of educator personnel was aided considerably by the availability of several educators having former ex- perience in summer malaria educational programs• Although the primary purpose of the public relations program is to facil- itate field operations, it was soon learned that emphasis on DDT alone was not necessary and that householder co- operation could be secured without door- to-door contacts. The educational phases, therefore, were broadened and direction from the State level was placed under the Assis- tant Director of Health Education with close liaison maintained through the operations division and the local health officer. With organizational work completed and problems of recruitment and train- ing solved, the outlook is bright for the efficient operation of a well coor- dinated program of Malaria Control in Mi s si ssippi. There are in this State 21 MCWA areas; 65 war establishments have been pro- tected in the regular MCWA program and in the Extended Program 34,824 houses have been sprayed, and 5,735 acres have been treated. During the past year 316,384 persons have been protected through MCWA activities. Demonstration of Malaria Control equipment by full-time educators. MISSOURI JAMES STEWART, M.D. State Health Officer LEGEND State Hdqrs. War Areas Extended Areas Residual Spray Ex tended Larviciding PROJECTS 1. Ft. Leonard Wood 2. Sikes ton 3. St. Louis Co. 4. Ft. Leavenworth 5. Louisiana 6. McBride 7. Camp Crowder 8. Springfield 9. Nevada 10. St. Joseph 11. Pemiscot 12. New Madrid Jefferson City Entomological inspections during the years 1942-43-44 indicated that Anopheles quadrimaculatus occurs in varying numbers in all parts of Mis- souri from the sparse populations of the Ozark hills to the heavy densities in the river bottoms of the Missouri and Mississippi Rivers. During the past fiscal year, oper- ations were discontinued around the McBride Air Base at McBride; Cape Gir- ardeau School of Aeronautics in the Sikeston area; and the Katz Air College in the St. Louis area. These flying fields were closed because of general curtailment of primary contract school flying. The Sikeston School of Aero- nautics at Sikeston was closed October 15 and it is anticipated that it will not be reopened in 1945. Control areas which were added dur- ing 1944 were the Smart Field Naval Flying School in the St. Louis area; the city of Neosho near Camp Crowder; the Chesterfield POW camp in the St. Louis area and Rosecrans Ferrying Com- mand flying field at St. Joseph. The Veterans Administration Hos- 92 LARVICIDING Approximately 10,318 acres were lar- vicided during the year throughout the State. A feature of the Camp Crowder area was larviciding of the State Fish Hatch- ery of the city of Neosho where heavy “quad” breeding was occurring. A pro- nounced decline was noted in the town’s “A” stations when these ponds were lar- vicided weekly during the summer. Power dusting from outboard motor boats was done in the Louisiana area. The results indicated that more of this type of work should be inaugurated in other areas. Boats were equipped with a 100-pound hopper capacity power dust- er and a 5 h.p. outboard motor, which made a successful operating unit for navigating the river and spreading dust. A ratio of six parts of lime to one part of paris green was used for dusting. pital at Wadsworth (Ft. Leavenworth area), which will provide 2,800 beds for World War II patients, will be in- cluded in the coming year’s program. Last year through MCWA activities, 45 war establishments were protected in the 10 war areas of the State. DRAINAGE Vertical drainage of the “Frisco Ponds” eliminated the only serious “quad” breeding in the Springfield area. In the future, larviciding will be con- fined to spot work wherever “quads” are found. The LeMay Sink Hole (St. Louis area) was vertically drained in the winter of 1943 and is still functioning. The ter- rain around Jefferson Barracks is very rolling and underlaid with limestone. There are 92 limestone sinkholes which breed mosquitoes during the year. Many of these have been vertically drained. "Frisco" Ponds in Springfield Area. The drainage of this 30-acre sink eliminated the only serious breeding spot in this area. 93 DDT EXPERIMENT In the Extended Program 19,961 houses were sprayed with DDT during the year. A DDT experiment was conducted around Duck Lake (Ft. Leavenworth area) where heavy “quad” breeding occurred. A so- lution was prepared using 5 gallons of xylene, 13 pounds of triton, 210 ounces of DDT and sufficient water to make a 30-gallon solution. This 5% solution was used to spray all natural resting places on the Missouri side of the river, thus laying down an insect bar- rier between the breeding places and the Fort. The mixture was applied with an Indian Head trombone-type hand sprayer. Field reports showed that the exper- iment was successful because of almost total absence of mosquitoes from the resting places for several weeks after the conclusion of the experiment. It is intended to repeat this early next year so that results over a longer per- iod of time may be studied. ENTOMOLOGICAL SURVEY An entomological survey was made of Big Piney Bivouac area adjacent to Fort Leonard Wood, where a case of malaria is a rarity due to the rolling and well drained country. No control was considered necessary because the highest count of “quads” in an adult s tat ion was six. A POW side camp has been located at Rosati and will house about 120 prison- ers. This camp will be inspected during the coming year by personnel from the State Office at Jefferson City. Plans also include an occasional survey of the Weingarten POW camp lo- cated in a hilly, stony, well drained area with only a few stock ponds and barrow pits for mo&quito breeding. There are about 2,000 prisoners at the camp and 600 army soldiers and civilians stationed there. Among the Italian prisoners several cases of malaria are under treatment at all times. VERTICAL DRAINAGE. Ditch to a natural lime sink that has been opened up and is used for vertical drainage. 94 WATERED AREA CENSUS The watered census of the Sikeston area showed acres of ponds and streams over 10 feet in width and 105,960 lineal feet of ditch under 10 feet in width under control or surveillance in 1944. A total of 28/4 square miles of area were under control or surveillance in this area. In the St. Louis County area, the watered surface under surveillance or control isas follows: 2,021 acres of ponds and streams over 10 feet in width and 248,120 lineal feet of small streams and ditches. The area under surveillance or control totals 27 square miles. The protected section in the Fort Leavenworth area is 3 square miles and the total area controlled and protected is 18.5 square miles. The watered area is 319 acres of ponds and streams over 10 feet in width and 65,800 lineal feet of ditch under 10 feet in width. The watered territory of the Louisi- ana area includes 2,802 acres of ponds and streams over 10 feet in width and 33,600 linear feet of ditch under 10 feet in width. In this area, there is a small shanty settlement along the Mississippi River which seems to be a focus for endemic malaria according to blood smears taken during the Upper Mississippi River Surveys in 1941 and 1942. The employees of the Missouri Ordnance Plant, the military estab- lishment protected, number between 500 and 650. The Town of Louisiana has a population of 5,000. 120 German prison- ers are housed in the old NYA barracks and work in the Stark Nurseries. There are 700 acres in the McBride area and the watered area is 0.45 acres of ponds and50,160 linear feet of small streams. In the Camp Crowder area, there are 34 acres of ponds and streams over 10 feet in width and 32,600 feet of small ditches and streams. The total area under control and surveillance is 11.7 square miles. Neosho Fish .Hatchery, which is larvicided weekly. The protected zone in the Springfield area comprises much of the populated section of the city of Springfield, and includes 3% square miles. The watered area after major drainage is about 3 acres of ponds and 16,500 linear feet of small ditches. EXTENDED PROGRAM Dunklin County (Area 2), where the Malden Air Base is located, is one of the 68 counties selected by MCWA head- quarters for extended malaria control. The Malden Air Base has about 4,000 military personnel and 1,000 civilian employees. The terrain around the Base is very flat and drained by an exten- sive system of agricultural drainage ditches. Water vegetation abounds in these ditches and “quads” are found in large numbers, both in the larval and adult stages. The inclusion of New Madrid (Area 12), Dunklin (Area 2), and Pemiscot (Area 11) counties in the War Areas Extended Program will result in a substantial expansion of the pres- ent MCWA program. 95 NORTH CAROLINA PROJECTS 1. Ft. Bragg 2. Wilmington 3. Jacksonville 4. New Bern 5. Elizabeth City 6. Camp Butner 7. Monroe 8. Goldsboro 9. Maxton 10. Hof fman 11. Rockingham 12. Charlot te 13. Edenton 14. Asheville 15. Greenville 16. Ra1e i gh CARL V. REYNOLDS, M. D. State Health Officer LEGEND State Hdqrs. War Areas Residual Spray 'State-wide Extended Hq. The basic changes in malaria con- trol operations which have occurred in the State of North Carolina during the past fiscal year are: a drastic reduc- tion in major drainage; an increase in the amount of maintenance work per- formed; and the addition to the pro- gram of the DDT residual spray opera- t ions. During the past year, 88 war estab- lishments in 15 war areas were pro- tected. MAJOR DRAINAGE One major drainage project was under- taken in the Wilmington area in co- operation with the city and county au- thorities. MCWA assisted by furnishing the necessary hand labor. This project eliminated an outlet ditch at the city limits which for years had presented a control problem because of its in- accessibility to 1 a rv ic id ii\g. Another major drainage project was recently started in an area adjacent to Moore General Hospital near Ashe- ville to eliminate abandoned gravel pits. Although this area is in the moun- tains and not near what may be con- sidered a malarious section, it has special significance in that Moore Gen- eral Hospital is caring for thousands of malaria and other tropical disease cases, and that considerable “-quad” breeding has been found at the area to be drained. Although larviciding could be employed, it is felt that per- manent drainage is preferable in view of the permanence of the hospital in- stallations. A total of 279 acres of watered sur- face was eliminated by drainage dur- ing the past year. This involved the movement of 26,278 cu. yards of earth from 588,347 linear feet of new dit- ches. 96 LARVICIDING One hundred and thirty four acre applications of paris green were made during the year and 1,527 acre appli- cations of oil were made. Power equip- ment was used for application wherever field conditions permitted. This was particularly true in the Elizabeth City area. With few exceptions, it has been practical to discontinue larviciding by proper maintenance of drainage sys- tems in a number of small areas. Lar- viciding has also been discontinued in several areas where it was formerly necessary to do extensive control. By combining many areas which have been drastically reduced in size of opera- tion, it has been possible to reduce the overhead supervision as well as the number of persons employed to do t-he job. Greater use of inspection has made it feasible to discontinue areas or small portions of areas which do not produce significant numbers of ma- laria mosquitoes. MAINTENANCE OF DRAINAGE SYSTEMS Maintenance of existing drainage systems was used whenever possible to reduce the watered areas and hence the need for larviciding. A number of MCWA activities are lo- cated in regions where considerable construction is either under way or has been completed recently. An exten- sive erosion problem was created in these areas by the removal or dis- turbance of earth. As a result, many new drainage ditches and old canals, filled by debris from erosion, neces- sitated much work in maintenance. On numerous occasions dynamite was used advantageously to blow silt from the ditches, particularly in the lar- ger swamp ditches. There were 10,000 acres of ditches cleaned and 2,251 acres cleared during the year. Dynamite was used advantageously for ditching near Ft. Bragg. 97 DDT RESIDUAL SPRAY OPERATIONS The program of home spraying of ma- laria cases is planned as an effec- tive and important stride in the di- rection of preventing a recurrence of a large scale malaria epidemic in North Carolina. The original state-wide project has been revised to include DDT spraying of all homes of current malaria cases, irrespective of location. The malaria cases, however, must be substantiated by a positive blood slide by the State laboratory or other responsible source. The local health officers have con- tacted the medical practitioners and have requested that they report immed- iately all cases of malaria to the lo- cal health department. Army authorities have also been con- tacted in order to obtain information as to the home locations of discharged soldiers having a malaria history. When a case of malaria is reported, a thick film blood slide is obtained before treatment is started. This slide is sent to the Division of Epidemio- logy, State Board of Health, Paleigh, together with a report card sh ow i n g complete address of the patient. In cases of servicemen, a blood smear is requested when the disease is ac- tive. When inactive, a statement signed by the health officer that the patient has had a malaria history, suffices. If the smear is found to be posi- tive in the State malaria laboratory or if the service record is positive, arrangements are made to have the resi- dence of the patient sprayed with DDT. Since only a limited amount of DDT is available, spraying is confined to homes where malaria has been demon- strated by smear or where a service- man’s record shows a history of this disease. DRAGLINE CANAL. Two hundred and seventy-nine acres of watered surface were eliminated by drainage during the oast year. 98 OKLAHOMA GRADY F. MATHEWS, M. D. State Health Officer PROJECTS 2. Braggs 3. Pryor 4. Miami 5. McAlester 6. Ardmore 7. Hugo 8. Dawson-Okmu1 gee 9. Durant 10. Chi okas ha 11. Tonkawa 12. Alva 13. Camp Gruber 14. Lawton 16. Idabe1 Oklahoma City LEGEND State Hdqrs. War Areas Extended Areas Residual Spray Extended La rv ic id in g The MCWA program in Oklahoma during the past fiscal year was a continua- tion of control methods already in operation with emphasis on improve- ment of technics and development of an improved method of entomological i nspect ion. One of the most expediential pro- cedures employed was a “ sectional meth- od’*of sampling larval mosquito breed- ing places. This system uses land-sec- tions and quarter-sect ions, instead of arbitrarily selected stations, in list- ing, locating and reporting collection sites. Numbering of individual breeding places is unnecessary on the area map, and inspections can be accurately re- ported by any qualified inspector on first acquaintance with the area. The collection data are given permanent significance by direct relation to the land-section numbers, and are subject to interpretation by anyone who can read an ordinary county map. This meth- od was used experimentally during the previous year and proved successful. It is applicable, however, only when section lines are well defined. The first requisite is an accurate field map showing 1 and-sections and all watered areas. In zones under rou- tine inspection and control, the in- spector also carries a field list of all possible breeding places in each quarter-section. Control operations precede the inspection and are also 99 organized on the sectional system. The circuit of inspection covers every type of productive water body in at least one quarter of each section through each week, with complete coverage of every section thus accomplished monthly. Collection results are entered on the field record and transcribed on the summary sheet according to stand- ard procedure with two exceptions. The section number plus the quarter- section designation (NW, NE, SW, SE) becomes the station number, followed by the conventional indication of sta- tion distance (-A,-B,-C,-D). And, the specific type of water body is always stated for each collection site (i.e., 1IVW-B, Stock pond; 2SE-A, Intermittent stream, etc.). On the weekly entomo- logical report (Form M-7), the number of larval stations equals the number of land-sections wholly or partially included by the control limits. Cuar- ter-section collections thus have the general nature of substations. COST REPORTS. The usual procedure of submitting progress reports for each area is followed and broken down to zone reports. These reports are pre- pared in the fall and furnish infor- mation to the State Department of Health on amounts of oil, paris green, ditch- ing, clearing, cleaning, man-hours, etc., used. The reports will also be valuable in setting up malaria control projects for towns and cities in the future. CONTROL OPERATIONS WINTER ACTIVITIES. During the win- ter, a watered area census was made and zones were remapped. Inspections were made during the winter to deter- mine hibernating habits. Stations were selected at random. This was primarily to locate stations for the next season. STATE MEETINGS. The area sup e rvi- sors and inspectors met in Okmulgee, April 23-24, and in Hugo, April 26-27, to review the basic responsibilities of inspection procedure and to ini- tiate the seasonal program. The Hugo meeting was also attended by inspec- tors attached to the Lake Texoma mos- quito survey, inaugurated in May with headquarters in the Denison sub-office of the U. S. Engineer Department. On March 1-2 a meeting was held at Hugo OKLAHOMA CONTROL AREAS. (Left) Back water area on Neosho (Grand) River near Ft. Gibson. (Right) Swamp along Arkansas River at Gore. 100 and all DDT procedures were discussed with the personnel who were to work on the Extended Program. On April 12 an educational meeting was held in' Oklahoma City. INSPECTIONS, Routine inspections began in May in all regular MCWA zones. There was low production in these zones with evident seasonal delay, cool weath- er and heavy rains persisting through the spring. LIGHT TRAPS. Seven light traps were strategically placed to determine the types of mosquitoes and their abun- dance . LARVICIDING. With the peak of the season during July, considerable lar- viciding was done from July to Septem- ber of 1944. This work was terminated in October but resumed in April of 1945. DRAINAGE. Labor crews were kept in- tact for clearing, cleaning and drain- age work in McAlester, Pryor, Miami, Okmulgee and Dawson during January, February and March. EXTENDED PROGRAM The Extended Program started in April and consisted of interior spray- ing of rural houses with DDT. The south- ern halves of McCurtain (Area 16) and Choctaw (Area 7) Counties were spray- ed because previous blood surveys had indicated malaria prevalence. As of June 30, some 5,039 houses had been treated with 1,269 pounds of DDT. This work required 5,818 man-hours of labor or 1.15 man-hours per house. In the Extended Program counties, high mosquito production was already under way by the last two weeks of June. Single station collections of adult Anopheles quadrimaculatus were some- times in excess of 100. Monthly inspections provided infor- mation as to the local seasonal occur- rence of malaria mosquitoes and the numbers remaining in sprayed houses after various time intervals. From this information, the effectiveness of the spray and the adequacy of field tech- nique could be determined. The first inspection was completed during the latter part of June. This included random selections of about 2% of the houses sprayed in each county. Inspections were made of at least one unsprayed natural resting place in each house location to check the seasonal production of malaria mosquitoes. PUBLIC RELATIONS. A public rela- tions section was organized to inform householders of the objectives of the Program and the preparation of dwell- ings for application of DDT. This sec- tion also outlined an educational pro- gram on fundamental knowledge of mala- ria, its transmission and control. The public relations work and in- spection in connection with the Ex- tended Program were handled by one ma- laria control assistant, who alter- nated his duties in the two counties with assistance from the State MCWA office. At present an educator is preparing a malaria workbook for use in schools. EQUIPMENT, More equipment was need- ed for the Extended Program than was on hand, so 19 weapon carriers, 2 ambO- lances, 1 sedan and three 114-ton trucks were obtained. It was evident that automotive re- pair bills would be excessive during the coming year because of the age and condition of equipment. Consequently a building was rented at Hugo as a ga- rage and warehouse, and one mechanic, one mechanic’s helper and a clerk were hired. The program of special reconnais- sance surveys and occasional inspec- tion in areas of POW branch camps and Army and Navy hospitals was continued. An entomologist from the Oklahoma De- partment of Animal Biology, University of Oklahoma, was assigned to these sur- veys with direction and assistance by the State MCWA entomologist. This rep- resentative of the State Department of Health and member of the University staff, will thus become familiar with the work that MCWA is doing and will be able to contribute to malaria con- trol activities when these are dis- continued by MCWA. 101 OREGON LEGEND PROJECTS War Areas 1. Corvallis 2. Medford H. M. ERICKSON, M.D. State Health Officer 3. Klamath Falls fid. in Calif. Sporadic outbreaks of malaria have occurred in various sections of the Willamette River Valley during the past few years, but generally control work is confined to areas around Camp White near Medford and Camp Adair at Corvallis in the heart of the Willamette valley. LA R V IC ID ING AND MINOR DRAINAGE A larviciding and minor drainage project was initiated in the vicinity of Camp White, when periodic inspec- tion disclosed significant breeding of Anopheles freeborni within a mile of the prisoner-of-war stockade. Close cooperation was received from the Army authorities at Camp White who furnished a POW crew. Thus, the hazard of mala- ria transmission from infected prisoners was satisfactorily reduced, as evi- denced by the resultant absence of lo- cal transmission. Some 57 acres were treated in the 3 war areas protecting 11 war establishments. MOSQUITO SPECIES The anopheline fauna in the Camp White area differs from that found in 102 the Willamette Valley in two respects. Instead of A. punc t ip enn i s being the dominant species, A. freeborni greatly exceeds it, making up 95% of the adult anopheline population, while A. puncti- pennis constitutes 1.5% and A. pseudo- punct ipenni s franciscanus, 3.5%. Sec- ondly, the franciscanus adults taken here were the first confirmed speci- mens of this species in the State. Pre- viously A. franciscanus had not been confirmed north of northern California on the west coast. INSPECTIONS Control measures were discontinued at Camp Adair and surrounding towns when the Army disbanded the Camp. Sub- sequently, the Navy reopened the Camp Adair Hospital, and periodic inspec- tions were inaugurated in the vicinity thereof. Periodic inspections were also made at the U. S. Marine Barracks, Klamath Falls where 3,000 Marine Corps per- sonnel are convalescing from malaria and filariasis. No extra-cantonment control was found necessary. Reconnaissance surveys of various areas have shown the presence of some malaria vectors but no history of ma- laria. In Josephine County in the south- ern part of the State, there was a recent report of two proven cases of malaria contracted from a returned sol- dier having malaria. This incident proved that the entrance of a suitable human carrier into an area previously free of malaria, may supply the conditions nec- essary for transmission. anopheline breeding AREAS IN OREGON. (Above) Near Camp White. (Right) Near Sant i am -Wi 1 I amette River junction. 103 SOUTH CAROLINA LEGEND BEN F. WYMAN, M. D. State Health Officer State Hdqrs. Wa r Areas Extended Areas Residual Spray 1 Extended Larviciding PROJECTS 1. Beau for t 2. Bennettsvi11e 3. Camden 4. Charleston 5. Columbia 6. Florence 7. F t. Moultrie 9. Greenville 10. Lexington 11. Myrtle Beach 12. Aiken 13. Orangeburg 14. Spartanburg 15. Sumter 16. Hiltonhead 17. Wa1terboro 18. Georgetown 19. Pa gel and 20. Summerville 21. Congaree 22. Greenwood 23. Moncks Corner (Santee-Cooper) 24. Harleyville 25. Hampton 26. Barnwell 27. Clarendon 28. Kings tree 29. St. Mathew 30. Ridgeland Approximately 122 war establishments were protected in 24 war areas. As a result of MCWA activities 155,213 per- sons were protected. The air bases at Camden and Bennets- ville were terminated during the year. The Georgetown area, discontinued since 1943, was reopened when the Marine Air Corps established an air base there. Four new prisoner-of-war branch camps were established in Berkeley (Area 23), Greenwood (Area 22) and Newberry (Area 14) Counties where it was necessary to do some mosquito control. The county health officers and area supervisors had frequent conferences with the camp commanders and effected satisfactory solutions to mutual prob- 1 eras. Columbia In this State, all MCWA employees working in a county were assigned to the respective county health depart- ment and operated as a part of that health department. The increased exper- ience of the field personnel made the operation of the program more efficient than in preceding years. DRAINAGE The drainage accomplished in pre- vious years reduced the control work 104 during the past year since many breed- ing areas that were difficult to con- trol had been eliminated. Ten major drainage projects were completed in the State at a cost of $40,703 in seven areas. All major drain- age projects were constructed by hand except one large project in the Fort Jackson area which was done under contract. Some minor drainage was undertaken during the year in all areas. Special emphasis was placed on maintenance of previously constructed drainage proj- ects. This resulted in 22,670 square feet of ditch cleaning and the expend- ing of 123,396 man-hours. A small bulldozer was used in the Charleston area to eliminate a number of small ponded areas. All drainage and filling projects eliminated known “quad” breeding areas. Some 81,162 yards of filling were accomplished to elim- inate 170 acres of breeding water surface. LARVICIDING “Quad” control was simplified in the fall months by unusually dry weather throughout the State, riowever.it was necessary to keep all areas under sur- veillance and to larvicide most of the water that remained during the dry we a t he r. Due to warm weather during February and March, breeding occurred approxi- mately one month earlier than previously recorded. In several areas, “quad” adults reached a relatively high den- sity before they were brought under control. With few exceptions the stations in the “A” and “B” zones have shown very low “quad” densities. To achieve this control 74,874 gallons of oil larvi- cide were sprayed on 4,899 acres of “quad” breeding water surfaces. This work required 37,623 man-hours of labor. Paris green dust was used in limited areas not readily accessible to oilers; 1,922 pounds of dust were applied to 1,704 acres of breeding area. Larvicidal work around the larger towns in the Extended Program counties has not been inaugurated because of lack of equipment. It is planned to start this work as soon as equipment and labor are available. An intensive medical, entomological, and engineering study of the malaria problem was made during the year in the vicinity of Clarendon (Area 27), Ber- keley (Area 23), Orangeburg (Area 13), Calhoun (Area 29), and Sumter (Area 15) Counties. This work supplemented the data previously obtained by the State Board of Health. Likewise it corrob- orated previous findings of the State Board that malaria was quite prevalent in this area and that “quads” were breeding in large numbers. Much addi- tional detailed information regarding housing, drainage, and mosquito con- trol problems was collected by the stud£. DDT SPRAYING Residual house spraying was begun in 11 counties in April and early May. Previous malaria investigations in- cluding county-wide thick film blood surveys and subsequent mapping, enabled MCWA to select the known malarious areas in these counties for spraying. The program was organized into spray crews of 3 m?n each including the foreman. One entomologist was made respon- sible for the inspection wo r k to de- termine the effectiveness of the spray. Assisting him were 5 inspectors making the routine field inspections in the counties. A total of 19,412 houses were sprayed from April 15 through June 30, using 9,288 pounds of DDT and requiring 33,597 man-hours of labor. There were occa- sional refusals to having houses sprayed but as a whole the response to the program was enthusiastic and cooper- ation excellent. The houses sprayed were principally 5-room and 6-room homes of farm tenants and landlords. Greater efficiency in spraying has been noted with the increased experience of the 105 ABOVE. Batter boards set to finish grade to proper elevation. RIGHT. Parasitemia su rvey in the vicin- ity of the Santee- Cooper Rese rvo i r. labor. Probably this will be reflected further in the following months. A demonstration study of the effective- ness of DDT residual house spraying on malaria prevalence was begun in Claren- don and Berkeley Counties in areas where a significant malaria prevalence has been shown on previous surveys. Other cooper- ative research studies on the prevalence and epidemiology of malaria were begun during the year. AEDES AEGYPTI One Aedes aegypti control program was successfully operated in Charles- ton and vicinity. This program has been in operation in Charleston continuously since 1937. The aegypti premise index reached slightly higher levels this year than last year. The highest index of 8.83 for the year occurred during September 1-15, 1944. A few abandoned cisterns were found during the year. Breeding was also found in the City catch basins. Surveys were made at Beaufort where an index of 18 was found in March. At Florence an index of 3.5 was found in early July. Integration of the aegypti program in Charleston with the general sanitation program was effected during the year. 106 TENNESSEE R. H. HUTCHESON, M. D. State Health Officer PROJECTS 1. Camp Tyson 2. Camp Forrest 3. Alcoa 4. Volunteer Ordnance Plant 5. Wolf Creek Ordnance Plant 6. Camp Campbell 7 . She1 by 8. Halls Air Base 9. Smyrna i Nashvi11e-Smyrna LEGEND State Hdq rs . War Areas Extended Areas Residual Spray Extended Larvicidin£ The MCWA program in Tennessee has continued to function as a service in the Preventable Disease Division. Ma- jor drainage, minor drainage, and lar- viciding for control of malaria mos- quito breeding were employed in the vicinity of Army and Navy posts, es- sential War industries, and housing areas where there was a potential ma- laria p rob 1em. LARVICIDING As indicated by adult counts in “A” stations, Anopheles quadr imaculatus in general was satisfactorily control- led during 1944. However, during May and June heavy rainfall resulted in extensive flooded conditions in cer- tain zones in west Tennessee where 1ar- vicidal projects were in operation. The extensive flooded condition could not be controlled and vast broods of ** quads” emerged. ** Quad” counts in these zones were among the highest on record. Counts in “E” stations as well as “A” stations were much higher than they had been in those zones which have been in operation for several years. EXTENDED PROGRAM Congress appropriated funds in Jan- uary 1945 for an Extended Malaria Con- trol in War Areas Program. This was to be an emergency measure to prevent the spread of malaria as a result of returning malaria carriers being re- leased by the armed forces. This pro- gram was restricted to the most mala- rious areas in the State as determin- ed by mortality statistics. The program provided for the spraying of all rural homes in the selected areas with an emulsion containing DDT. 107 DDT SPRAYING Approximately 12,000 houses in the most malarious areas of Dy e r , Lake, Lauderdale, Obion, Tipton (All Area 8) and Shelby (Area 7) Counties were sprayed during April, May, and June of 1945. Plans are being made to extend this program into one or two other counties in west Tennessee which have problems almost as great as those in which the program has been operated. In the Fisher Aircraft zone which is located near the mouth of the Wolf River in Memphis, late spring floods each year result in the establishment of large inaccessible areas of “ quad” breeding. As a result **quad” counts are heavy for many weeks each summer. Accordingly, this zone was treated in 1945 with residual spray. CONTROL OF IMPOUNDED WATERS The first impounded water regula- tions were adopted by the State De- partment in 1935 under the basic public health laws and the 1945 General As- sembly enacted a law pertaining to the construction and impoundage of water. This legislation holds great promise in controlling malaria and other mos- quito-borne diseases which may result from artificial impoundages. Also, the enforcement of the law and the regu- lations promulgated under the Taw will benefit vacationers and sportsmen on State-owned and privately-owned lakes by reducing pest mosquitoes. EDUCATIONAL PROGRAM During the summer months, malaria health educators were employed to work in some of the west Tennessee counties ANOPHELINE BREEDING PLACES created In impounding water. In 1945 the General Assembly enacted a law pertaining to impoundage of water. This law holds great promise in control- ling malaria and other mosquito-borne diseases. where malaria is most prevalent or where it is a potential problem. These per- sons held group meetings where talks were made, demonstrations given, and sound pictures presented. In addition, the educators worked in schools as- sisting teachers in instructing child- ren concerning the cause and preven- tion of malaria. ENTOMOLOGICAL DATA Forty-three species of mosquitoes have been recorded for the State of Tennessee. The following species were found for the first time by MCWA dur- ing the past fiscal year: Aedes dupreei, fulvus pallens, grossbecki, mitchellae; Culex tarsalis; and •Culiseta inornata. STATISTICAL DATA During the year 3,493 acres were treated in 9 war areas protecting 68 war establishments. Some 12,408 houses were sprayed protecting 57,691 persons. Dusting of anopheline breeding places. (Above) by boat; (below) by airplane. TEXAS GEORGE W. COX, M. D. State Health Officer LEGEND State Hdqrs. ISar Areas Extended Areas Residual Spray Extended Larviciding PROTECTS 9 . Hi 11een 10 Fort Worth-Dal las 11. Bastrop 12. West Texas 13. Wichita 14. El Paso 15. Hi Ida I go 16. Lamar County 1. Valley 2. Caddo Lake 3. Texarkana 4. Corpus Christi 5. Gulf Health 6. Houston 7. Port Atthur 8. San Antonio Austin The State of Texas continues to have a large concentration of military es- tablishments, essential war industries, and prisoner-of-war camps. The fiscal year saw a big increase in the number of POW camps, with at least half of them being located in the malaria sector. RE-EVALUATION OF CONTROL MEASURES The problem in all 16 war areas of the State has been re-evaluation of the program and intensification of con- trol measures. Through MCWA activities, some 245,861 persons were protected. Considerable economy was effected in manpower and materials by coordination of the entomological inspection service with control operations. MINOR DITCH CONSTRUCTION. In order to reduce control work during the breed- ing season, much time was devoted to minor ditch construction, and to fill- ing of numerous sink holes, abandoned slush pits and tanks. 110 COUNTY COOPERATION. Through the loan of a small bulldozer and an operator from the Drainage Commission of Bra- zoria County, many lateral ditches were constructed leading to a large drainage ditch. This loan also facilitated the filling of numerous pot holes and low pi aces. WATER HYACINTHS. Constant removal of water hyacinths from drainage .ca- nals and swampy lakes is still nec- essary, and also re mo val of cattails f r om mar she s. POWER EQUIPMENT, Dusters, sprayers, and other power equipment were used to good advantage in the Houston, Lake Jackson, and Brownsville areas. OIL. Waste oil, contributed by serv- ice stations and war establishments, was used on small, sluggish running streams, stagnant ponds and abandoned slush pits. AIRPLANE DUSTING OF PARIS GREEN During the current year, airplane dusting of paris green was inaugurated in Orange and Jefferson Counties, W'hich are located on the coast. Two dusting operations were made approximately a month apart; 1200 acres of marsh area being covered in the first operation, and 1420 acres in the sec- ond. The rate of application was 1 Vi pounds of paris green per acre per dusting. Immediately following the first dust- ing, there was a continued drought and low tides. During this interval, adult counts were low and few larvae were found. Prior to the second dusting consid- erable rain fell which filled in the swamp areas with fresh water causing adult and larval counts to rise. Larval checks revealed approxi- mately 90% kill in the Jefferson Coun- ty marsh. Adult counts were used to show the effectiveness of the opera- tion in Orange County, as it was dif- ficult to obtain larvae in sufficient quant i t ies . LIGHT TRAPS Because of the importance of mos- quitoes in the epidemiology of mala- ria, a program for obtaining added re- liable information on the distribution and ab undance of individual mo squi- to species in the State was inaugu- rated. Light traps were strategically- plac- ed in several non-MCWA counties in the northwestern part of the State where satisfactory arrangements for trap operation were made with the respec- tive city and county health officers. In other places aid was solicited from city mayors, county judges, and super- intendents of parks. The program was further designed as an adjunct to all entomological work directly connected with the present program, and direct assistance was given by the State Health Depa r tment. DDT SPRAYING OF POW CAMP In the fall of 1944 there were 9 POW camps established in the coun- ties of Colorado, Fort Bend, Brazoria, Wharton, and Jackson (all Area 5). A mobile unit was set up to control these camps, with utilization of pri- soner labor. At the instigation of the Army, one camp was sprayed with DDT as an experiment. The Army sup- plied the material, while M C W A fur- nished the equipment and labor. A good job was done and favorable results were obtained. DDT HOUSE-TO-HOUSE SPRAYING An individual house-to-house spray program on a county-wide basis, was begun last spring. Project proposals and plans were made and approved for operation in 3 counties in the Rio Grande Valley area and 3 in the east- ern part of the State. Spraying operations were begun in three counties in March and in two counties during the first week in April. Work in the other county was not start- ed, due to the lack of equipment. SPRAY OPERATIONS. Approximately 30,653 houses were sprayed, and ento- mological inspections were made to test che thoroughness of spray operations and the effectiveness of control. RECRUITING OF LABOR. Practically all labor was obtained in a week through the cooperation of the Civil Service Commi s s i on. AUTOMOTIVE EQUIPMENT. Automotive equipment was obtained from the Army through the Procurement Division. Sup- plies and equipment were furnished by the Headquarters office and through direct local purchase. MIXING PLANT, A large warehouse and mixing plant was maintained at the State office where alterations and re- pair of equipment were made. From this central point, equipment and DDT con- centrate were funneled to the various projects. PUBLICITY. A public relations and educational office was set up to plan and coordinate all publicity attendant to the program. Use was made of film strips, newspaper articles, and short radio talks. All work has been direct- ed from the State level, and coordi- nated with the respective health unit. AEDES AEGYPTI Most of the Aedes aegypti projects throughout Texas have been integrated with the local health units and are now doing general sanitation work. The integration activities include: Aedes aegypti control, a rat poisoning program, pest control, and DDT spray- ing of homes to control the fly popu- 1 at ion. This program has been most success- ful in Houston, because of the complete cooperation of the city health depart- ment. In January 1945 when the inte- gration began, there were 10 U. S. Pub- lic Health Service men and municipal employees. To date there are still 10 USPHS men but 56 inspectors are hired by the city. LEFT. Covering barrel with screen to prevent Aedes aegypti breeding. RIGHT. School children learned to root house plants in earth to prevent Aedes aegypti breeding. ABOVE. Anopheline breeding area created by irrigation ditching. BELOW. Hand ditching. VIRGINIA I. C. RIGGIN, M. D. State Health Officer PROJECTS Fort smouth Virginia Beach P ensular Northern Virginia Central Virginia Eastern Shore Fort smouth LEGEND State Hdqrs. VJar Areas Extended Areas Residual Spray During the fiscal year 1945 control was done around 119 war establishments in the six war areas of Virginia. The northern Virginia area along the Potomac River was combined with Mary- land and District of Columbia MCWA work. This was practical from a geo- graphical standpoint and also because of reduced work resulting from exten- sive cutting of water chestnut in re- cent years by the U. S. Engineers. This arrangement likewise allowed the Vir- ginia organization to concentrate its efforts in Hampton Roads (Area 3) where the scope of work has increased. The Army moved fromCamp Pendleton, thereby eliminating several work sec- tions. At the same time, new terri- tory formerly within the Army’s juris- diction was added for the protection of Dam Neck Naval Training Reservation. The Norfolk Army Airport was demobil- ized but little reduction in work was possible because of the proximity of other war establishments. LARVICIDING Small ponds and swamps, not easily accessible t o conventiona1 two-wheeled 114 trucks, were larvicided by a power sprayer rigged to a jeep. This most efficient piece of equipment was accom- plished by mounting a motor and pump over a square tank placed on the floor of the jeep between the two rear wheels. A frame was built around the edge of the back which made the body larger and facilitated the carrying of hose, cans of oil and other equipment. SURVEILLANCE Surveys have been made at all pris- oner-of-war camps established in the State. Preliminary investigations gen- erally showed no imported malaria cas- es, but several areas were put under further surveillance. PEST MOSQUITO CONTROL By agreement with the FPHA, pest mosquito control was conducted in and around five large housing developments. Cost of the work was defrayed by a transfer of funds. A pest mosquito control project in the off-post area around the Conva- lescent Hospital at Fort Story has been started by MCWA on a reimbursement basis. It was considered necessary to do substantial salt marsh drainage as well asoil larviciding in a five-mile belt around the Hospital. Inspection will beextensive, especially in the State Park area where wildlife interests requested that no control be done. LABOR Throughout the entire war there has never been sufficient labor in the war areas of Virginia. In order to meet the labor shortage, German prisoners have been used whenever practical. It was found that on drainage projects, prisoners work very well, but it is not feasible to use them in spreading 1arvi c ide. UTILIZATION OF ABANDONED MATERIALS In the early stages of the war many small Army units were established in the Hampton Roads section as anti- aircraft and search-light stations. As the war progressed and need for this activity was eliminated, the Army abandoned many stations. The Virginia organization, through the Liaison Of- ficer of the Third Service Command, was successful in obtaining the wreck- age material from two of these camps. Twenty-two barracks were razed and over 75,000 feet of lumber were obtained at a cost of about $20 per thousand. This figure represents the labor cost in- volved in razing buildings and cleaning lumbe r. With this lumber, two buildings were built to house the MCWA activities in Virginia: one at Money Point, south of Hampton Roads, and the other at Hilton Village, north of Hampton Roads. The latter has a field office and storage space for seven trucks. The former is a larger building having storage space for 15 trucks, a ware- house, offices, auto repair shop and carpenter shpp. A grease rack, oil plat- form and plant for manufacturing con- crete ditch linings have been installed in the yards. Three boats especially designed for lake dusting have already been built at the carpenter shop and the mechanical equipment is kept in repair by the personnel at the auto repair shop at a substantial saving to the government. In each case the county purchased or owned the land on which the building was constructed and furnished a con- siderable portion of the material cost, such as roofing, siding, nails, and other hardware. DOT SPRAYING The Extended Program has not been operated in Virginia, although a small 115 supply of DDT with equipment has been received. About 100 houses were sprayed for the purpose of instructing personnel in the technique of application. Thus, trained men with equipment will be available in the event of a malaria outbreak in Virginia or neighboring states. PERMANENT MOSQUITO CONTROL In Virginia there is a law provid- ing for mosquito control districts sup- ported by local taxes. One such dis- trict has been in operation for the past five years and has proved its work- ability. With the present program serv- ing as a demonstration, it is planned to organize other districts, in areas where MCWA has operated. The work al- ready done with MCWA funds will be the start of mosquito control on a perma- nent basis in Virginia, not merely a current expenditure of funds. Several local subdivisions have shown sufficient interest in the plan to re- quest assistance in setting up such an organization. Under this plan, the mos- quito control district would contribute labor and equipment in sufficient quan- tity to permit a general mosquito con- trol program. Accordingly, malaria control would be able to survive the discontinuance of MCWA after the War. With a reservoir of trained personnel available, a rel- atively permanent malaria control pro- gram would be possible whenever fe.d- eral funds are discontinued. PHYSICAL ACCOMPLISHMENTS Paris green larviciding was done in city water supply lakes, and a few other places where oil was not per- mitted or was not feasible. A total of 4,499 acres was dusted with an average application rate of 4 pounds per acre, utilizing four man-hours per acre. Good results were obtained. Other places were larvicided with oil. Approximately 963 acres were treat- ed with oil with an average rate of 39 gallons per acre and 8 man-hours per acre. Maintenance of existing ditches is important in Virginia because.of the flat grades. Some 7,170 acres of ditch- es were cleaned and maintained and 342,670 linear feet of new ditches constructed. Since drainage in this area required extensive maintenance, the policy has been to install ditch lining wherever feasible and promote its use by other public and private agencies. An average of 1,672 linear feet of monolithic lining was poured. As a result of the success attained with small ditch lining projects, it was possible to encourage and assist several counties in planning a $500,000 drainage job which includes both storm drains and ditch lining. AEDES AEGYPTI A survey conducted in Norfolk during October of 1944, showed a high index of Aedes aegypti. As a consequence of this survey, the U. S. Public Health Service has initiated programs in Nor- folk and Portsmouth. The cities in- volved are matching federal personnel with employees on their pay rolls. Hand Dusting near Norfolk. 116 CONCRETE PRODUCTS PLANT. Ditch lining was manufactured at Money Point. LINED DITCH. In Virginia 7,170 acres of ditches were cleaned and maintained; 3^2.*70 linear feet of new ditches were constructed. 117 PUERTO RICO EDUARDO GARRIDO MORALES Terriforial Healfh Officer PROJECTS 1. Camp Tortuguero 2. Losey Field 3. Fort Buchanan 5. Insular Wide (Rio Piedras) 6. Ensenada Honda 7. Camp O’Reilly 10, Salinas 13. Boringuen Field 16. Carolina 17. Ponce 18. Playa de Humacao San Juan LEGEND Island Hdqrs. k War Areas Malaria has continued to decrease among military personnel during the three consecutive years that MCWA has been operating in Puerto Rico. Work has been accomplished in close coordination with the Army, Navy and Insular Health Departments. MCWA activities were restricted to areas immediately adjacent to military reservations until April 1945. At that time a cooperative Insular Health De- partment'MCWA comprehensive planning survey was begun in the vicinity of the city of Ponce, the second largest civil- ian population concentration on the Island. Of necessity, MCWA activities in Puerto Rico differ considerably from those in the continental United States. For example, through an agreement with the Insular Health Department, MCWA has been operating its projects indepen- dently in areas immediately adjacent to Army and Navy bases with a known mala- ria problem. The Bureau of Malaria Control of the Insular Health Department agreed to furnish certain key personnel and materials to MCWA on an exchange basis and to continue its extensive drug treatment program, particularly in 118 villages adjacent to military bases. In all cases, the object has been the reduction of existing malaria among military forces rather than protection against a potential malaria hazard. Initiation of control operations has been confined solely to camps with ac- tual malaria incidence and sufficient military strength to justify intensive control activities on a large scale. Initial reduction in malaria trans- mission among military personnel was accomplished in some camps as early as the fall of 1942 following intensive larviciding, mosquito proofing of mil- itary structures, and routine appli- cation of malaria discipline. The ob- jective has been to reduce further and to maintain the military malaria rate at a level commensurate with expendi- tures for malaria control. SPECIES OF MOSQUITOES The principal malaria vector in Puerto Rico is Anopheles albimanus, whose breeding and feeding habits dif- fer greatly from Anopheles quadrimacu- latus in the eastern United States, An- opheles freeborni in the southwest, or even Anopheles albimanus in the lower Rio Grande Valley of Texas. In the Greater Antilles, A. albimanus breeds in a variety of aquatic situ- ations including fresh and brackish water. It has at least a two-mile flight range, does not rest in large numbers in daytime resting places and is easily collected in light traps. ANIMAL BAIT TRAPS Animal bait traps, using either horses or calves as bait, are utilized as index stations in locating heavy breeding areas, or in judging efficiency of control activities. After three years’ control operations around military bases, it has been found that in a popu- lation living in screened buildings and exercising ordinary malaria disci- pline, relatively few new cases of ANIMAL BAIT TRAP at Camp Tortuguero. Bait traps are used as index stations in locating heavy breeding areas, or in judging efficiency of control operations. FORT BUCHANAN AVERAGE "A" BAIT TRAP COLLECTION ALBtMANUS MALARIA RATE LOSEY FIELD AVERAGE "A" BAIT TRAP COLLECTION ALBtMANUS MALARIA RATE CAMP O'REILLY - AVERAGE "A" BAIT TRAP COLLECTION ALBtMANUS - MALARIA RATE CAMP TORTUGUERO AVERAGE "A" BAIT TRAP COLLECTION ALBtMANUS MALARIA RATE 120 EXPLANATION OF CHART The chart indicates the reduction in malaria rate among military person- nel and the size of average, overnight, animal bait trap collections of A. albi- manus in the intra-cantonment zones at four major Army posts where MCWA proj- ects have been in operation from 1942 through the fiscal year 1945. The g r aph s show a great reduction in average albimanus collections during this period as a result of major drain- age activities by both the Army and Public Health Service. The military rate has been plotted as a trend. 1. Graph for Fort Buchanan shows a downward trend in military malaria. 2. The Losey Field graph indicates a seasonal rise in numbers of albimanus and a higher malaria rate than at the other three projects. During the rainy season from May through November, there are more breeding places and more albi- manus produced than during the dry season from mid-December to April. The graph for the years 1942 and 1943 is almost a clas- sical demonstration of the principle that the malaria rate rises and falls one to two months after similar rises and falls in albimanus populations. The peak in malaria rate in September 1944 before the season- al increase in albimanus population has occurred, is the result of the Army re- porting system. A large number of sol- diers had been on field maneuvers in a highly malarious part of the Island two to three weeks before they returned to Losey Field, where the clinical symptoms of malaria became evident. These cases are therefore reported from Losey Field, even though there is good epidemiological evidence that these soldiers were infec- ted while on maneuvers off the Post. 3. Graph for Camp O’Reilly, like the one for Fort Buchanan, shows a downward trend in military malaria. 4. Graph for Camp Tortuguero indi- cates a downward trend in malaria from '1942 through 1945, with the exception of one peak in October 1944. This rise in malaria rate was apparently caused by soldiers returning from maneuvers, rather than from infections contacted on the Base, as previously explained for Losey Field. MOSQUITO COLLECTIONS AND MALARIA MCWA has been operating for three years at Camps O’Reilly and Tortuguero. No animal bait trap in intra-cantonment zones had collections of 5 albimanus or more during any 3 consecutive weeks of the fiscal year 1945. At Fort Buchanan the average for 8 intra-cantonment bait traps was below 5 albimanus per trap per night through- out the year, except during August 1944, when the average was 6.4 albimanus. How- ever, one bait trap had counts of 5 to 56 albimanus per night most of the time from July through November 1944. Since December 1944, control has been at a satisfactory level throughout the Post. malaria are contracted when counts in “A” station bait traps canbekept at an average of two to five female al- bimanus per trap per night. In unscreen- ed civilian villages near these camps, the counts must be kept at an even lower level to provide adequate pro- tect ion. LIGHT TRAPS Light traps in general collect more albimanus than animal bait traps. How- ever, light trap collections show such a regular alternation of high and low counts correlated with the lunar cycle that great care must be taken in inter- preting light trap data. 121 red in September and October of 1944, but was brought under control by mid- November by intensive larvicidal and minor drainage activities and a DDT residual spray program of the Army and Public Health Service. No malaria has been reported from this Base since De- cember of 1944. At Fort Bundy where there are no major drainage operations in progress, more than a thousand female A. alhimanus were collected in single intra-canton- ment bait traps on individual nights during the months of June, July, Aug- ust, and September 1944. Despite an ex- tensive larvicidal and minor drainage program by both Army and Public Health Service, counts continued to rise from June through September. In October 1944, all control by standard methods was abandoned and arrangements were made with the Army for airplane dispersal of DDT in Diesel oil. A spectacular drop in anopheline mosquitoes occur- red in less than a month and became so marked in January 1945 that all con- trol except by drainage was stopped until June 1945 when airplane spray- ing with DDT in Diesel oil was resumed. The only malaria cases reported from Fort Bundy were a Signal Corps officer stationed on night duty off the Base and two auxiliary military police on night duty at the Main Gate, remote from military housing areas. POWER OUSTING from manually transported equipment. Both hand and power dusters are used in applying paris green to watered a reas. Control at Losey Field was satis- factory throughout the year except dur- ing the rainy season months of October and November, when collections in 2 intra-cantonment bait traps rose above the arbitrarily assumed safe level of 5 aIbimanus or more, for 3 successive weeks. During this time, the wind shift- ed from northeast to northwest. The prevailing wind in this particular area is from east to west, consequently, the control zone west of the Base is normally limited to about 1.5 miles. The MCWA project at the Salinas Train- ing area has operated intermittently. An explosive outbreak of malaria occur- power Dusting from a Jeep. 122 AIRPLANE DUSTING Through a cooperative agreement with the U.S. Navy, airplane dusting is done at the Fort Buchanan-San Patricio proj- ect. The Navy provides the plane and pilot while MCWA furnishes the larvi- cidal dust which is a mixture of paris green and hydrated lime. Airplane dispersal of DDT in Diesel oil was used successfully at Fort Bundy to control a serious outbreak of A. albimanus after larviciding supple- mented by minor drainage, had failed to provide control. MCWA supplied data regarding larval and adult mosquito collections and a considerable portion of labor; the Army provided the air- plane, pilot, DDT and Diesel oil. The p'ane is also available to treat simi- lar areas at other bases where usual control methods prove inadequate. ■* DECONTAMINATION UNITS Knapsack sprayers are used at the Camp O’Reilly project to oil the mu- nicipal reservoir of a nearby town ifi order to control breeding within a mile of the Base and still not contami- nate the drinking water of the munic- ipality. Army decontamination units have been used at three projects to carry oil into the field and mix it under pressure as an oil-water emulsion. This emulsion is sprayed on watered areas by hose- lines attached to the decontamination unit tank, or from ordinary sprayers filled from the truck in the field. Spraying with Army decontamination unit. Army decontamination units have been used at three projects to carry oil into the field and mix it under pressure as an oil-water emu 1s i on. 123 CABLE SAW At Camp Tortuguero, heavy growths of pondweed, pond lilies, and hornwort were formerly removed by men standing in ditches and cutting vegetation with machetes. Last year a cable saw was devised which has proven time-saving and labor-saving. It is operated by two men standing on either bank of a ditch and cutting aquatic growth by pulling the cable back and forth. STREAM MAINTENANCE Clearing and cleaning is an impor- tant phase of ditch and stream main- tenance because a 1 bimantis breeds pro- lifically in streams. In hilly sections, stream maintenance and stream channel- ing have saved much labor and larvi- ciding. After two or three years of cunet- ting however, some streams have had con- siderable vertical and lateral erosion. GRADE MONUMENTS In order to prevent further erosion and reduce the cost of stream main- tenance, grade monuments have been in- stalled in streams at 75-foot to 100- foot intervals at a cost of about $.28 a linear foot of stream bed as com- pared with $1.00 to $2.25 a linear foot for inverting these same streams. The grade monuments are of precast, re- inforced concrete, 6’xl5”with 3” thick- ness. Many of these have been complete- ly hidden by depositing silt. Conse- quently, building-up of stream beds is occurring rather than continued ver- tical and lateral erosion. TIDEGATES At Camp Tortuguero, March and most of April were devoted to maintenance work on a drainage system with approx- imately ten miles of major canals. Tide- gates were installed on the main east- ern outlet canal to prevent sea water or fresh flood water from the Pio Cibuco backing up in the canals and flooding the thousand-acre swamp east of Camp Tortuguero. These tidegates are of novel design. The pivot points of each gate ride in channels so that the four gates may be raised entirely from the water, thus allowing maximum discharge during the dry season. It was also nec- essary to provide arrangements for raising the gates during the periods of low outward flow because of the flat grades and low head. TIDEGATES. These were installed on the main eastern outlet canal to prevent sea water or fresh flood water from the Rio Cibuco backing up in the canals and flooding the 1000- acre swamp east of Camp Tortuguero. 124 ABOVE. Cable saw removing vegetation in drainage canal. This method has proved more eco- nomical in both labor and time. Men formerly removed vegetation with machetes. BELOW. (Left) Ditch in.mangrove swamp after initial dynamite blasting (Ft. Bundy). (Right) Grade monuments installed in upland streams to prevent vertical and lateral erosion (Camp O’Reilly). . MAJOR DRAINAGE During the past three years at all Army posts with signifleant malaria hazard, the U.S. Engineers and Post Engineers have carried out intra-reservation ma- jor drainage programs of permanent type, where experience and entomological data have indicated that satisfactory con- trol could not be obtained by larvi- ciding alone. The same is true of Naval instal- lations where similar, permanent drain- age has been prosecuted under the di- rection of the Officer in Charge of Construction. In one instance a large extra-reservation pumping station and drainage system were constructed by U. S. Engineer s. In the extra-cantonment zone, MCWA has carried on extensive drainage where satisfactory control could not be ob- tained by other measures. There has been constant cooperation among Army, DYNAMITE DITCHING at Ft. Buchanan. This method was used to provide adequate outlets into major drainage canal where streams had been blocked by hydraulic fill. PANAMA INVERTS installed outside Ft. Buchanan. MCWA installed precast Panama inverts and side-slabs in the extra-cantonment portion of two streams which had already been inverted inside the reservation by the Army. 126 Navy, and Public Health Service malaria control officers in order to coordinate intra-cantonment and extra-cantonment drainage programs. At Fort Bundy a net- work of old ditches in an extensive area of abandoned sugarcane fields and pas- tureland was renovated by MCWA. A tem- porary pump was installed by the Post Engineer to drain the large extra- cantonment breeding area west of this Base, and the western portion of the intra-cantonment zone. At Fort Buchanan, MCWA installed precast Panama inverts and side-slabs in the extra-cantonment portion of two streams which had already been inverted inside the reservation by the Army. The lower portion of both of these streams had been blocked by hydraulic fill, so dynamite ditching was employed to provide adequate outlets into a major drainage c ana 1. Dynamite ditching was also employed at Fort Bundy to provide an adequate outlet ditch through Mangrove swamp for the discharge from the temporary pump- house. OTHER ACTIVITIES At the request of the School of Tropical Medicine, 6 students of the Division of Health and Sanitation of the Coordinator of Inter-American Af- fairs, 3 Chinese physicians, and 18 sanitarians of the Puerto Rico Insular Health Department have been shown va- rious MCWA projects inPuerto Rico dur- ing the year. Students on scholarships oif the Coordinator of Inter-American Affairs have come from Peru, Panama, Costa Rica, Honduras, Santo Domingo, and Hai t i. Some have been interested in merely seeing the MCWA projects which are among the largest in the Caribbean area. Others have spent a month or more study- ing mosquito adults and larvae in de- tail, actually working on projects and learning malaria control from personal e xp erience. The 18 sanitarians of the Insular Health Department were given a 2-weeks’ course in malaria control in cooper- ation with officials of the School of Tropical Medicine. Lectures on malaria control have been given by the District MCWA entomologist to four groups of Army officers, and il- lustrated slide lectures have been de- livered toFarm Security Agency repre- sentatives at their quarterly meetings. DDT RESIDUAL SPRAYING In October 1944, the Atlanta Head- quarters of MCWA sent three commis- sioned officers to Puerto Rico to de- termine the value of DDT in killing A. aIbimanus and if possible, the value of this method of mosquito control in reducing malaria incidence. The U. S. Public Health Service and Insular Health Department selected Huma- cao Playa and Loiza Aldea as test and check areas because these two towns had the highest known malaria rates among the civilian population where no malaria control measures had been prac- ticed. They were also comparable in size, type of houses, racial composition, rainfall, geographical location, and general ecological habitat. Blood film surveys were made by per- sonnel of the Insular Health Depart- ment. The first survey was made in Oc- tober 1944; the second in March and April 1945; the third will be made in October 1945. The blood slides were sent to San Juan for staining by a MCWA technician and then sent to the Memphis Laboratory of the National Institute of Health for examination. The first spraying of houses in Humacao Playa was done during the first three weeks inN'ovember 1944, and the second spraying was during the last two weeks in June 1945. Available data indicate that the ac- tion of DDT on albimanus in Puerto Rico is about the same as on quadrimaculatus in the continental United States. There is no indication yet that DDT residual spraying controls actual transmission of malaria in Puerto Rico. 127 Member of a DDT spray crew visiting typical houses in Humacao Playa. The first spraying of houses was done In November 1944 and the second in June 1945. Available data indicate that the action of DDT on Anopheles albimanus In Puerto Rico is about the same as on quadrimaculatus in the continental U. S. DDT Truck and Crew in Native Village. In October 1944, commissioned officers of USPHS were sent to Puerto Rico to determine the value of DOT in killing A. albimanus. 128 JAMAICA PROJECT LEGEND 1. Fort Simonds A War Area Hdqrs. San Juan, P.R. The Fort Simonds, Jamaica project is the only MCWA project located in a foreign country. The Base is a lend- lease airfield entirely surrounded by Jamaican-owned or British-owned land. Considerable caution must therefore be exercised in work in the extra-canton- ment area in order to avoid complica- tions with the Jamaican government and local agencies. The Base is situated in the flat coastal plain of southwest Jamaica where many sink holes, cattle ponds, and gullies along streams provide ex- cellent breeding places for malaria mosquitoes. During the rainy season, water stands for weeks or even months on the gumbo-like soil and is ideal for the production of Anopheles albi- manus, the malaria mosquito of this i s1 and. ENTOMOLOGICAL STUDIES Four light traps and nine animal bait traps were operated on the Base or within a 1-mile zone around the Reser- vation where at least 44 species of mosquitoes have been reported. 129 A separate Army warehouse is used for storage of lime and paris green and mixing of dust with an eccentric barrel mixer. Two half-ton Ford pick- up trucks and four bicycles are available for transportation. The MCWA supervisor directs both the Post Engineer’s crew of 3 larvi- cidal men working with oil inside the Pase, and 17 USPPS employees composed of a general foreman, 2 crew foremen, 2 inspectors, 1 animal bait trap op- erator, and 11 larvicidal men using paris green outside the Rase. Turing the fiscal year 1945, extra- reservation malaria control operations at the Jamaica Base Command were per- formed by the U. S. Public Health Ser- vice at a cost of approximately $14,000. About $11,000 was expended through Army channels to meet pay rolls for native laborers and local material pur- chases . SUCCESS OF PROGRAM The success of the program is at- tested by the fact that only two cases of military malaria have occurred since control operations were started 16 months ago. Roth cases were men who were assigned to night duty. No seasonal rise in a 1bimanus popu- lation has occurred since the begin- ning of the project in May 1944, al- though pest mosquitoes, particularly Psorophora, have at times been numerous and troublesome to ground crews ser- vicing airplanes between sunset and s unr i s e. CONTROL Most control is by larviciding. Lit- tle drainage is done outside Fort Simonds because the country is very dry half the year, and local people need all the water for personal use or for live stock. However, a 2,200-foot ditch is being constructed just outside the re- servation limits. There is also con- siderable cleaning and clearing in the already constructed ditches. PROJECT OPERATIONS Excellent field headquarters for MCWA activities were made available by the Army. The MCWA office is the orig- inal Post infirmary, fully equipped with hot and cold water, electricity, typewriter, storage space, and other facilities. LEFT. Irrigated sugar cane field is source of breeding. RIGHT. Hand Dusting. Host control in Jamaica is by larviciding. Little drainage is done outside Ft. Simonds because the country is very dry half the year and the water is needed for personal use. 130 HAWAIIAN ISLANDS C. L. WILBAR, JR., M. D. President, Board of Health Kauai Mi ihau Oahu Mo I ok a i Lanai Maui Kahoolawe LEGEND Territory Hdqrs. Mono lulu Hawaii The mosquito-borne disease of great- est concern to the Territory of Hawaii is not malaria, but dengue. This disease was introduced from the South Pacific in July 1943, reached its peak in No- vember 1943 and was brought under control by June 1944. Sporadic cases were re- ported during the summer of 1944. Two cases in early March 1945 and nine cases in May and June 1945 indicated a pos- sible new introduction. The Hawaiian Islands, with their ex- cellent Pacific Ocean quarantine barrier, have only three species of mosquitoes: Aedes aegypti, Aedes albopictus, and Culex quinquefa sciatus. The control program is directed against the two dengue vectors, Aedes aegypti and Aedes albopictus. Approximately 350 sanitary and mil- itary personnel were engaged in the program by July 1944 and 156 men by June 1945. The territory-wide Aedes program continued until the fall of 1944 when Army personnel on Kauai, Maui, and Hawaii were withdrawn. Ac- tivities in Honolulu, rural Oahu, and Hilo, Hawaii were continued. Honolulu, 131 containing half the population of the Territory, is the main port of entry for all air travel and practically all sea travel. During the 1943 dengue epi- demic, all dengue cases occurred in Honolulu orwere directly traceable to a Honolulu contact. PUBLICITY Residents were urged to rid their premises of all mosquito breeding. Hand bills were distributed and radio talks and lectures were given. During the year 534 column inches of English and 300 column inches of foreign language articles appeared in various publications. MOSQUITO DAY In October of 1944, a school Mos- quito Day program was inaugurated in 49 schools on Hawaii and 21 schools on Maui in cooperation with the Department of Public Instruction. Talks were given at all schools, presenting basic facts concerning Aedes mosquitoes and dengue fever. Students made inspections of their homes once a month for Aedes breeding and eliminated the containers in which breeding was found. During the school year 89,322 students reported finding 178, 190 containers of which 56,089 were found to have wrigglers. PREMISE INSPECTION Originally, premise inspection ac- tivities were initiated in all areas by assigning individual inspectors to single zones to be inspected on a 10- day cycle. In Honolulu 77 inspectors were required to cover the 77 zones. Following reduction in manpower, several zones were assigned to each foreman and crew of four to six inspectors, with all inspectors working in one zone under the close supervision of the foreman until that zone was completed. Zones, in which the dengue fever hazard was considered greatest, were worked on a 10-day to 12-day inspection cycle, while all other zones were worked as often as manpower permitted. Routine inspections were made of 922,778 premises during the year. Of these 11,238 were found breeding Aedes mo squitoes. LARVtCIOING DIESEL OIL. Crews on motorcycles were organized to larvicide catch basins and other permanent breeding places re- ported by the premise inspectors. These include storm drains, manholes, ground pools, swamp areas, ditches, cesspools, and bomb shelters. A power sprayer was used to larvicide large swamp areas and streams. The breeding spots reported were larvicided on a regular 10-day cycle until corrected. PYRETHRUM. To minimize the danger of possible secondary cases of dengue, houses of patients were sprayed inside and outside with a pyrethrum spray mix- ture. Three hundred and thirty-eight premises were sprayed using 400 gallons of pyrethrum emulsion. Approximately 100 homes were sprayed with sure-shot sprayers using pyrethrum propelled by Freon gas. One school containing 92 rooms and 2 theaters containing 722 and 1,089 seats respectively were also sprayed using pyrethrum extract diluted with 3 parts of kerosene. FISH A widespread fish-stocking program was inaugurated. During the year 66 fish- ponds, 37 barrels, 7 ground pools, 4 swamps, 3 streams, 2 ditches, 2 catch basins, as well as numerous cisterns, were stocked with mosquito minnows to prevent mosquito breeding. PHEHOTHIAZI HE STRIPS Phenothiazine strips prepared by the entomological staff fulfilled a definite need in the control program. Water- proofed pint jars filled with pheno- thiazine strips were suspended from all 132 water spigots in Nuuanu Cemetery with instructions for their use. Inspections indicated that most visitors to the cemetery made use of these strips in flower vases and urns. Envelopes containing phenothiazine strips were distributed in hotels and office buildings with data for use. No breeding has been found where strips have been used. COOPERATION WITH SANITARY DIVISION Activities of dengue mosquito con- trol inspectors and sanitation inspec- tors of the Board of Health were co- ordinated. It was agreed that dengue mosquito control inspectors during their premise-to-premise inspections would inspect premises for the following: overflowing and improperly covered cesspools, leaking plumbing and broken sewers, heaps of garbage containers at food establishments. Whenever one or more of these con- ditions were observed, the inspector referred them to the Oahu inspection staff. This section provides for the handling of referrals, abatement by the sanitation inspectors and notifi- cation to the mosquito control section of the abatement of these nuisances. Difficult problems of mosquito control which require the issuing of abatement orders by the Board of Health are in- cluded. EXPERIMENTS An entomological laboratory was maintained for the critical review and improvement of control operations. Routine work included the examination of all larval specimens collected by the premise inspectors, the prepar- ation of phenothiazine strips and main- tenance of Aedes mosquito colonies for experimental purposes. The average dispersal range of Aedes atbopictus was experimentally deter- mined to be less than 200 yards. DOT One of the biggest control problems in the Hawaiian Islands involves Aedes breeding in axils of lily and ape plants. It is necessary to find a method of treating these plants which does not harm the plants but gives a lasting control. Paris green and kerosene in- jured the plants, and phenothiazine was difficult to use. The effect of DDT in combination with various sol- vents and emulsifiers on plants was investigated. While detrimental effects were obtained from the emulsifiers and several solvents, no damage to the plants resulted from DDT and ethyl alcohol. Field tests indicate that automatic applicators can be used to apply this form of DDT effectively for Aedes control. Aedes breeding in bucket containing rooted plant. 133 ABOVE. Motorcycle larviciding unit using Diesel oil No. 2 to larvicide catch basins. BELOW. This trash pile provided numerous breeding'pi aces for dengue mosquitoes. A total of 922,778 premises were inspected during the year. 134 MALARIA CONTROL IN WAR AREAS 1945-46 FEDERAL SECURITY AGENCY U. $. PUBLIC HEALTH SERVICE ATLANTA, GEORGIA Sept. 16, 1940 - “Selective Service” Act passed.... March 11, 1941 - “Lend-Lease” Bill passed by Congress.... (May 1941 - USPHS Mosquito Control in Defense Areas organized,) May 22, 1941 - German and Italian consulates closed.... Dec. 7, 1941 - Japan attacks U. S. at Pearl Harbor.... Dec. 11, 1941 - War declared against Germany and Italy.... Jan. 14, 1942 - “Battle of the Atlantic” begun..., (Feb. 9, 1942-Malaria Control in War Areas inaugurated.) Nov. 8, 1942 - Invasion of North Africa.... May 12, 1943 - North African campaign concluded.... July 10, 1943 - Invasion of Sicily.... Sept. 8, 1943 - Italy surrenders unconditionally.... June 6, 1944 - Invasion of Normandy.... Jan. 7, 1945 - Invasion of the Philippines.... (Feb, 1945 - Extended Malaria Control opera- tions begun.) May 6, 1945 - Germany surrenders unconditionally. ... (July 1, 1945 - Typhus Control dusting begun.) Aug. 6, 1945 - Atomic bomb dropped on Hiroshima.... Aug. 8, 1945 - Atomic boob dropped on Nagasaki.... Aug. 10, 1945 - Japan sues for peace.... (Aug. 28. 1945 - War Area Program ordered cur- tailed. ) Sept. 2, 1945 - Japan surrenders unconditionally.— (July 1, 1946 - MCfA terminated. Communicable Disease Center inaugurated.) CONTENTS ORGANIZATION: Malaria Control in War Areas. . . i INTRODUCTION: An End -And A Beginning v OPERATIONS War Malaria Control 2 Extended Malaria Control 11 Typhus Control 19 Aedes Aegypti Control 25 Impounded Water Surveys 29 Water-Hyacinth Surveys 30 TRAINING In-Service Training 33 Internship in Public Health 37 Diagnostic Laboratory Training 43 Training Aids 49 INVESTIGATIONS Technical Developments 57 Malaria Bionomics Observations 63 Malaria Field Studies 67 Imported Malaria Studies 71 DDT Investigations 74 Typhus Investigations 75 Encephalitis Studies 77 Dysentery Control Studies 78 STATE PROGRAMS 79 DISTRICT PROGRAMS 149 APPENDIX ix Material in this report is not for publication. MALARIA CONTROL IN WAR AREAS ORGAHIZATIOH Malaria Control in War Areas is an office of the States Relations Division, with lines of authority stemming from the Surgeon General through the Bureau of States Services. Functional interrelations exist with other USPHS divisions such as Foreign Quarantine, Public Health Methods, Sanitary Engineering, Commissioned Officers, and the National Institute of Health. Liaison is maintained with military authorities in the various service commands Of the Army and districts of the Navy through UKPH3 liaison officers, and with state and territorial health departments through USPHS district offices. U. S. PUBLIC HEALTH SERVICE SURGEON GENERAL BUREAU OF MEDICAL SERVICES NATIONAL INSTITUTE OF HEALTH BUREAU OF STATE SERVICES DIVISION OF PUBLIC HEALTH METHODS DIVISION OF COMMISSIONED OFFICERS DIVISION OF FOREIGN QUARANTINE DIVISION OF STATES RELATIONS MALARIA INVESTIGATIONS MALARIA CONTROL IN WAR , AREAS USPHS LIAISON OFFICES USPHS DISTRICT OFFICES STATE HEALTH DEPARTMENTS MALARIA CONTROL IN WAR AREAS ORGANIZATION EQUIPMENT AND CONSTRUCTION UNIT COMMISSIONED OFFICER UNIT EXECUTIVE OFFICE CARTER MEMORIAL LABORATORY OFFICER IN CHARGE RECORDS AND STATISTICS UNIT TRAINING AND . EDUCATION a DIVISION J ADMINISTRATIVE DIVISION A MEDICAL DIVISION ENGINEERING DIVISION A ENTOMOLOGY k DIVISION A PUBLIC HEALTH INTERNESHIP SECTION PERSONNEL SECTION MALARIA EPIDEMIOLOGY SECTION MALARIA VECTOR CONTROL OPERATIONS a IN-SERVICE TRAINING SECTION MALARIA VECTOR CONTROL EVALUATION u DRAFTING AND REPRODUCTION SECTION TYPHUS EPIDEMIOLOGY SECTION TYPHUS > VECTOR CONTROL OPERATIONS a TYPHUS VECTOR CONTROL EVALUATION^ WAREHOUSING AND DISTRIBUTION SECTION EDITORIAL SECTION FIELD INVESTIGATIONS IMPOUNDED WATER SURVEYS TRAINING AIDS SECTION FIELD > INVESTIGATIONS OF VECTORS^ BUDGET AND FISCAL SECTION AEDES AEGYPTI CONTROL OPERATIONS STATISTICAL SECTION TRAINING AND DIAGNOSTIC LABORATORY SECTION MCWA ORGANIZATION i i i Each state in which insect-borne disease is an endemic problem directs its own program through its existing administrative channels in cooperation with the re- spective USPHS district offices. In the marginal and northern states control ac- tivities are carried out by district personnel in cooperation with the respective state health departments. Assistance from MCWA headquarters in Atlanta consists of: (1) trained personnel, (2) specialized equipment and materials, (3) technical consultation, (4) administrative and fiscal assistance, (5) training and training aids, and (6) laboratory diagnostic services. Within the states a director of MCWA activities is responsible for over-all supervision of the work. In most cases a state engineer and entomologist supervise the field work; MCWA assigns engi- neers and entomologists to the state for supervision of state programs if the state so requests. MCWA engineers and entomologists are also assigned to USPHS district offices and are available for technical consultation and guidance as needed. Within the MCWA headquarters office, organization is along the lines of pro- fessional services. Five divisions administer medical, entomological, engineering, training, and administrative matters, respectively. These divisions are subdivided into sections charged with responsibility for specific types of work, as indicated on the accompanying chart. Functional units within each section further subdivide the various phases of the work. MCWA personnel on duty for all or part of this fiscal year included a monthly average of 211 commissioned officers, and the following civil service employees: 89 professional and scientific, 708 subprofessional, 339 clerical and administra- tive, and 1,976 custodial. Of these totals, 16 commissioned officers, 12 profes- sional and scientific, 142 subprofessional, 7 clerical, and 123 custodial enployees were allotted to typhus control activities. Additional employees were assigned to control operations by state and local agencies. A total of 4,131,511 man-hours was utilized this year on all MCWA activities; 55 percent was employed in war malaria and Aedes aegypti control, 27 percent in the extended program, and 18 percent in typhus control. As in past years, personal services accounted for a large propor- tion of the MCWA budget —69 percent. Supplies and materials required 18 percent of the budget; contract services — five percent; equipment — four percent; and travel — four percent. Field and laboratory investigations play a vital role in translating the results of pure research into practical field operations. This work is guided by head- quarters personnel and is carried out by designated officers who are in charge of particular projects. Investigational stations supported largely or wholly by MCWA include: Carter Memorial Laboratory at Savannah, Georgia; the Typhus Investiga- tion Project at Thomasville, Georgia; and the Malaria Field Research Station at Manning, South Carolina. The National Institute of Health and MCWA jointly support projects conducted at the NIH Malaria Investigations Laboratory at Columbia, South Carolina; the NIH Office of Malaria Investigations at Memphis, Tennessee; and the Dysentary Control Project at Pharr, Texas. MCWA shares the cost of operating Em- ory University Field Station at Newton, Georgia, with Emory University, and the encephalitis investigations at the Hooper Foundation in Berkeley with the Uni- versity of California. MALARIA CONTROL PERSONNEL Each symbol represents 100 people COMMISSIONED TECHNICAL CLERICAL SUB-TECHNICAL LABOR EQUIPMENT EXPENDITURES Each symbol represents $200,000 CONTRACT SERVICES SUPPLIES AND MATERIALS TRAVEL PERSONAL SERVICES TYPHUS CONTROL* PERSONNEL Each symbol represents 10 people COMMISSIONED TECHNICAL CLERICAL SUB-TECHNICAL LABOR EXPENDITURES Each symbol represents $10,000 EQUIPMENT CONTRACT SERVICES SUPPLIES AND MATERIALS TRAVEL PERSONAL SERVICES INCLUDES AEDES AEGYPTt CONTROL AND TRAINING -X- INCLUDES TRAINING an END and a BEGINNING During 1945 the war malaria and ex- tended malaria control programs operated concomitently for the protection of the military and civilian populations re- spectively. Although the war in Europe had ended approximately two months before the start of this fiscal year, World War II appeared to be far from over. The foe in the Pacific was firmly entrenched in far-flung positions and was prepared to wage what he termed a “Hundred Years War.M When this fiscal year began, of- ficial policy did not contemplate any significant changes in the Malaria Con- trol in War Areas program. Hospitals were receiving increasing numbers of casualties, including tropical disease cases; prisoner of war camps were filled, training camps and other military installations were still operating at maximum capacity, and thous- ands of troops from malarious areas were being shuttled through this country on their way to Pacific theaters. AN END. Suddenly the war was ended by the birth-pangs of the “ atomic age.” The Japanese sued for peace on August 10, 1945. On August 28, MCWA Headquarters issued Field Memorandum No. 59, entitled “ Curtailment of War Establishment Malaria Con- trol Operations.” This memorandum stated that the appropriation for war malaria control had been reduced approximately 50 percent for the remainder of fiscal year 1946 as a result of post “ V-J Day" review. During the calendar 1946 malaria sea- son, war establishment anti-malaria protection was to be confined to separation and debarkation centers, permanent posts and large camps containing substantial numbers of troops, military hospitals and associated rehabilitation and recu- peration centers, and active arsenals and service of supply depots containing large numbers of troops. Establishments dropped from the MCWA program included prisoner of war main and branch camps, civilian housing areas, war industries, recreational areas, access roads, ar- senals, ordnance works, navy yards, and service of supply depots not containing large numbers of troops, and most tern- INTRODUCTION porary camps, posts, and airfields. No reduction was made or anticipated in ex- tended malaria control. In fact, emphasis was placed on the necessity for prompt termination of as many war malaria zones as possible by the end of October, since the financing of residual spray operations through the end of the fiscal year was contingent upon major reduction in war malaria activities. Personnel employed in the war malaria program were to be released to the extended malaria and typhus con- trol programs. The extended malaria control program expanded greatly in 1946 as a result of the funds made available by the termination of anti-malarial protection around the majority of war establishments, and the increased amount of local participation. The results of residual spraying during the beginning of the 1945 mosquito-breeding season aroused great enthusiasm and the desire for cooperation on the part of the general public. Fortunately, this enthusiasm for residual spraying coincided with USPHS plans for taking advantage of the lowest level of malaria in history to erad- icate the last traces of the disease from this country. DDT residual spraying was the most effective means known to control the potential hazard introduced by the discharge of millions of servicemen, some of whom had subclinical cases of malaria, especially vivax malaria, with symptoms suppressed by atabrine treatment. Release from the strict regimen of military life coupled with a change of climate could combine to bring about a relapse or even a primary attack which had remained latent. Since the mosquitoes most likely to become infective were those found in human habitations, killing these mosquitoes would break the chain of transmission at its most vulnerable point. The organizational setup for extended malaria control was ideally suited for the control of endemic typhus fever, which was recognized as an increasing health problem in southern and southeastern United States. In the past, in those states in which typhus was a problem, ratproofing and rat poisoning programs were operated with state and local funds under state and local ordinances; USPHS participation was limited to the operation of a Typhus Control Unit, primarily for demonstrating ratproofing methods to local municipalities. On July 1, 1945 typhus control activi- ties of the USPHS were transferred to MCW4 and federal funds were made available to the states for a program of DDT dusting for the control of rat ectoparasites, which were implicated in the transfer of the typhus fever rickettsiae from rats to man. TTie various state activities were integrated into an over-ail MOVA Typhus Control Program, with operations conducted under state health department jurisdic- tion in close liaison with the USPHS. MOVA personnel were loaned to states, upon request, to supervise and train state and local personnel on the job. Supervision of residual house spraying and typhus dusting activities was effectively combined in several states. Ratproofing activities continued with state and local funds and labor in business establishments of cities and towns, and rat poisoning campaigns were conducted in conjunction with both dusting and proofing. Local participation in the typhus control program this fiscal year amounted to 62 percent of the total expenditure. It is anticipated that eventually typhus control dusting, ratproofing, and rat poisoning will be conducted entirely with state and local health department funds and personnel, with USPH3 participation limited to consultative services and operational aid in emergencies. Another program that was effectively integrated into the general sanitation activities of state and local health departments in several states this year was INTRODUCTION Aedes aegypti mosquito inspection and control. Ibis combining of inspection work resulted in a more complete public health program with a minimum number of field personnel and a large savings in cost. MCWA participation in aegypti control has been decreasing each year, aiming at the eventuality of complete state and local health department operation of the respective state programs. The returning overseas veterans were potential carriers not only of malaria but also of numerous other tropical infections, many of which were unknown in all or certain parts of this country. Since physicians and local health depart- ment technicians were the first line of defense against the introduction of these foreign diseases, and since millions of servicemen were being discharged and re- turned to their homes in every part of this country, the program of train- ing physicians and medical technicians in the diagnosis of tropical and para- sitic diseases and in public health methods was considerably expanded this fiscal year. Representatives of state and local health departments and other agencies were offered instruction in effective control practices against malaria, typhus, yellow fever, dengue, etc., including instruction in the laboratory diagnosis of parasitic in- fections. Special seminars and courses were offered to malaria control con- sultants, typh us control personnel, members of the War Department Corps of Engineers concerned with ma- laria control on impounded water, and to trainees from foreign coun- tries. The production and dis- tribution of audio-visual training aids were increased to keep pace with the expanding training pro- gram, Special investigations of operational significance were car- ried on in association with other governmental agencies, various universities, and state health departments. Research subjects included studies of foreign malarias , epidemiological and entomological evaluation of DDT residual sprays, the design and testing of spray equipment, the durability of DDT residuum under various conditions, evaluation of DDT as a larvicide, anopheline host-preference studies, DDT dusting in relation to human typhus prevalence, the significance of flies in the transmission of diarrheal diseases, and encephalitis investigations. v i i i INTRODUCTION A BEGINNING. By the very nature of its original purpose and plan of operation, MCWA was destined to pass into oblivion at the conclusion of the war. The extra- cantonment program of malaria control was rapidly liquidated with the inactivation of the great majority of military establishments in 1945 and 1946, and the rapid demobilization of the armed forces. However, during the more than four years of its existence, it became increasingly apparent that MCWA programs fulfilled a pub- lic health need that went far beyond the war emergency. Experience had shown the wisdom of coordinated attack upon such problems as insect-borne diseases with a single, coordinated unit specially trained and equipped to deal effectively with such public health problems. No such agency had existed before the institution of MCWA, and it appeared to be a progressive step to maintain the basic organization of physicians, engineers, and biologists, skilled and experienced in the control of insect- and rodent-borne disease, which could: (1) combat certain endemic dis- eases, notably murine typhus, sylvatic plague, and insect-borne virus infections which are progressively infiltrating and entrenching themselves in new sections of the United States; (2) prevent the establishment of exotic infections in this country by returning veterans and constantly increasing global air traffic; and (3) serve as a safeguard against the recurrence of that unfortunate state of af- fairs which prevailed in 1942 when this nation could not find enough competent malaria control teams to service the Army and Navy overseas and at the same time protect the health of its civilian and military personnel at home. It was there- fore logical that, with the termination of the Malaria Control in War Areas program, the highly developed basic organization and skills should be utilized for public benefit by some permanent unit of the U. S. Public Health Service. Such a step was to be taken on July 1, 1946 with the inauguration of the Communicable Disease Center. The Communicable Disease Center would continue certain training and research functions of the present MCWA and, in addition, deal with special phases of com- municable disease prevention not heretofore provided as a federal service. This would include field investigation and control of diseases of protozoan and hel- minthic origin, such as malaria, amoebiasis, schistosomiasis, ancylostomiasis, and filariasis, and also certain bacterial or virus infections transmitted by insects, such as yellow fever, dengue, certain neuro-virological disorders, the various forms of typhus and plague, sand-fly fever, and diarrhea-dysenteries. The functions undertaken by the Communicable Disease Center would exceed the resources and fa- cilities of individual states. They would be concerned to a large extent with inter- state and extra-continental health hazards. The scope and magnitude of this enter- prise remains to be defined by future events. WAR MALARIA CONTROL OPERATIONS Larviciding Surveillance Mobile Unit Operations LEGEND War Malaria Control With the cessation of hostilities in August 1945, the war malaria control pro- gram underwent a rapid reduction in a relatively short time. Operations from July through December 1945 were planned on the same scale as in the preceeding three years, with the exception that almost all permanent and semi-permanent drainage, most of which had already been accomplished in previous years, was discontinued. After " V-J Day” the malaria control program in the vicinity of war establishments was rapidly reduced and operations included only those military installations which remained active after the end of the war and had a significant malaria hazard. The liquidation of war malaria control projects closely paralleled the rapid military demobilization. During the year operations were suspended in 245 of the 307 war areas, and many of the areas still in operation in 1946 were reduced in scope from seven zones down to one or two. In the first half of the fiscal year war malaria control projects were protecting 819 zones, while on June 30, 1946 this had de- creased to 118 zones. During the course of the year war malaria control around critical war estab- lishments followed much the same pattern as in the previous years in regard to species sanitation in extra-cantonment areas. Control measures were, however, limit- ed to larviciding and minor drainage as the means of combating larval production of the three malaria vector species in this country — Anopheles quadrimaculatus in the east, A. free bo rni in the west, and A. albimanus in the lower Rio Grande Valley. The presence of malaria vectors and recent malaria history as prima facie evidence of a potential hazard, even though a large number of actual malaria cases were not reported, continued to be the basic premise for control and the suc- cess of the program was judged in terms of mosquito reduction rather than on the decrease of malaria mortality and morbidity. MALARIA TREND. In 1944 and 1945 ma- laria at first glance appeared to have reversed its previous downward course in the United States. From 1935 until 1944 there was a consistent, decreasing mortality and morbidity rate. In both 1944 and 1945 there were reported re- spectively more cases than the preced- ing year. However, when those cases which were known to have been acquired outside of the continental limits of the United States were subtracted from the total figures reported, there still was an actual decrease in the mortality and morbidity rates. To date no known outbreaks of any size can be attributed Malaria morbidity and mortality rates per 100,000 population in all states report- ing cases and deaths during 1920-1945 in- clusive. *Excluding extra - continentally acquired cases. 4 WAR MALARIA CONTROL to the return of servicemen from malaria-infested areas. Undoubtedly anti-malar- ial efforts have contributed toward the maintenance of this continued downward trend. ENTOMOLOGICAL FACTORS From January through December 1945 larvicidal operations for the control of malaria-carrying mosquitoes were carried on in 874 zones which were grouped into 192 areas. The over-all effectiveness of these operations during 1945 is shown graphically in Figure I. Here the densities of malaria vectors as measured by the numbers occurring in index stations inside the protected zones are compared to those encountered outside but adjacent to the protected zones. It will be noted that the average of the maximum densities in the protected zones was one-third or less of that occurring at outside locations throughout the season; also that the averages of the inside densities, with the exception of one week during July, were less than ten mosquitoes per resting place. In presenting these data it is neces- sary to point out that these averages are those of the highest single anopheline count each week in each control zone rather than the averages of all index stations. This procedure rates the zones on their worst conditions with respect to vector densities. It has been adopted for evaluations because anophelines frequently are a menace in only one section of a camp or community. Under such conditions if all index station counts for an area were averaged, any unsatisfactory condition would be effectively masked. On the MCWA program the occurrence of ten or more Anopheles mosquitoes in any FIG. I. RESULTS OF CONTROL WORK IN WAR AREAS Densities of malaria vectors* inside compared to outside war establishments. 31 7 14 21 28 5 12 19 26 2 9 16 23 30 7 14 21 28 4 II 18 25 I 8 15 2229 6 13 2027 3 NOV APRIL MAY JUNE JULY AUGUST SEPTEMBER OCTOBER NOV * ANOPHELES OUADR/MACULATUS (SOUTHEASTERN STATES) ANOPHELES FREEBORN/ (WEST COST) WAR MALARIA CONTROL 5 FIG.2. PERCENTAGE OF ZONES HAVING INSIDE ADULT DENSITIES ABOVE TEN resting place for three consecutive weeks was arbitrarily established as a cri- terion of unsatisfactory control operations. Based on this criterion a total of nearly 16 percent of 136 of the control zones were unsatisfactory with regard to adult densities at one time or another during the 1945 season. This compares with 14 percent in 1944 and ten percent in 1943. The apparent diminishing percentage of satisfactory work was caused by several factors, among which may be mentioned the more favorable mosquito breeding conditions during 1944 and 1945, and the ad- dition to the program during the active breeding season of zones in which mosquito densities already were high and in which a considerable amount of preliminary work was necessary to prepare the areas for efficient larvicidal work. Also, during the 1945 season, the inauguration of the extended program and the necessity for trans- ferring to that program some of the more capable, trained supervisors undoubtedly adversely affected larvicidal programs in some cases. Figute II shows for each week during the 1945 season the percent of control zones in which the densities of malaria vectors were considered to be high enough over a sufficient period of time to present a possible malaria transmission hazard. In this connection it should be pointed out that in many of these so-called ’‘un- satisfactory zones" the percentage of Anopheles quadrimaculatus reduction achieved was excellent and undoubtedly the malaria hazard was greatly reduced. In all lar- vicidal zones facilities for intensifying anopheline control were available if reports of malaria transmission were received. LARVICIDES Of the total of 130,000 acres of mos- quito-breeding surfaces larvicided dur- ing the course of the fiscal year, 81,000 acres were dusted with 132,300 pounds of paris green and 49,000 acres were oiled with 1,003,500 gallons of Diesel or No. 2 fuel oil. Paris green was used more extensively because it was more effec- tive and economical where anopheline breed- ing was associated with dense vegetation or heavy floatage. However, since paris green kills only the Anopheles larvae, oil was used when it was desirable to kill all aquatic stages of all mosquitoes. APPLICATION. In terms of acres treated as well as expenditure of man-hours of labor, hand dusting of paris green rather than power dusting was the more exten- sive method used this year , requiring some 166,000 man-hours. Power application ef- fected the dusting of 36,000 acres, but only 11,400 man-hours were required to complete this task. Airplane dusting this year was confined mostly to experimental projects. The application of oil was ac- complished almost entirely by hand-oper- ated sprayers; 44,500 acres were hand- oiled at an expenditure of 412,000 man- LAHVICIDING: (upper left) hand spraying oil; (middle left) power spraying oil; (lower left) hand dusting paris green; (below) power dusting. WAH MALARIA CONTROL 7 hours, while 4,500 acres were power-sprayed at the expense of 15,600 man-hours. The cost of larviciding was increased this year by a 20 percent rise in the price of labor, bringing the average operational cost per acre-treatment of paris green to approximately 12.33 and oil to $6.84. DDT OIL-MIST SPRAY. During the year a technic was developed for the hand-ap- plication of a DDF larvicide in a No. 2 Diesel oil-mist spray. While it is almost axiomatic that all new insecticides making their initial appearance are heralded by the statement that here at last is “an insecticide to end all insecticides, ” the results obtained with this spray seemed to surpass by far any previous lar- vicide. A detailed account of the method of application of this oil-mist spray and the comparative costs of larviciding with DDT-oil, paris green, and fuel oil may be found in the “Investigations" section, under “Technical Developments.” It was found in using the DDT oil-mist larvicide that 0.05 pound of DDT per acre was ade- quate to insure 90 percent control of all instars of anopheline larvae and most culicine larvae, and was reasonably safe from the standpoint of damage to fish and fish-food organisms. In Tennessee a solution of DDT in oil applied at the rate of 6.5 gallons per acre at ten-day intervals gave successful control of mosquito production and af- fected a reduction of 40 percent in over-all costs as compared to oil alone. Ken- tucky reported a one-third decrease in costs and Arkansas recorded a saving of from 63 to 90 percent in material and from 20 to 80 percent in labor. California used this new larvicide for the control of Culex tarsalus in connection with Japa- nese “B” encephalitis prevention and also reported very favorable results. The new larvicide was popular with the crews because of greater ease of application, in- creased spray swath, greater penetration of vegetation, and less frequent refilling of the spray cans. CLEARING. In order to render more easily accessible the places to be lar- vicided and to eliminate favorable anopheline breeding conditions, extensive clearing of brush and aquatic vegetation was carried on. In all a total of 2,000 acres of aquatic vegetation and 1,900 acres of terrestrial vegetation was cleared. Water chestnut and hyacinth did not present much of a problem this year since wide-spread cutting during the previous year had eradicated most of the trouble- some areas. Experimental airplane herbiciding proved very efficient in control- LEGEND | ACRES 1ST HALF FISCAL YEAR [ACRES 2ND HALF FISCAL YEAR [MAN HOURS 1ST HALF FISCAL YEAR [MAN HOURS 2ND HALF FISCAL YEAR LARVICIDING COMPARATIVE METHODS 8 WAR MALARIA CONTROL ling the growths of water-hyacinth in Florida. In those areas still infested with these prolific aquatic plants, paris green dusting was sufficient to control malaria mosquito breeding. DRAINAGE At the close of the 1945 fiscal year little major drainage remained to be done on the war area program in the continental United States. Most perma- nent or semi-permanent drainage projects were discontinued except where local or state funds were made available to continue projects beneficial to civilian populations. Prime emphasis was placed on the cleaning and maintenance of pre- viously constructed ditches and addi- tional temporary ditching was utilized wherever necessary as a supplement to larviciding operations. A total of 9.550.000 feet of previously constructed ditches was cleaned and otherwise main- tained during the year. Hand ditching amounted to 636,000 feet, as compared to 48,000 feet of machine ditching and 58,500 feet of dynamite ditching. Only nominal amounts of ditch linings - 31,000 feet - and underground drains — 2,700 feet - were installed and the fill totalled 77.000 cubic yards. In all some 1,000 acres of water surface were eliminated by combined drainage operations. DISTRICT-OPERATED PROGRAMS Since the endemic malarious areas are for the most part centered in the southeastern states, programs in each of these states were conducted under the jurisdiction of the respective state health departments in cooperation with the USPHS district offices. However, (upper left) DDT oil-mist spraying, (middle left) Clearing vegetation from a ditch, (lower left) Cleaning debris from a drain- age ditch. WAR MALARIA CONTROL 9 certain marginal and northern states are well within the distribution range of malaria vectors, and during the war years a potential malaria haz- ard was introduced into almost all parts of the United States by the es- tablishment of prisoner of war camps, military hospitals, and cantonment zones, in which were housed many cases of malaria contracted in endemic and epidemic regions throughout the world. MCWA programs were begun in these states to forestall the possibility of ma- laria gaining a foothold in presently non-malarious areas. Since the prob- lem was essentially one of preven- tion it was not considered necessary to carry on an extensive program in each of these marginal and northern states with actual operations around each war establishment. Instead ac- tivities were conducted under the gen- eral supervision of the various dis- trict offices in cooperation with the respective state health departments and military authorities. Major reliance was placed on the entomological phases of the work and the data so obtained were used as a guide to control operations. District entomologists conducted reconnaissance surveys and the necessary larviciding and drainage was carried on by district mobile units and “fixed” resident projects. MOBILE UNITS. Two types of mobile units were operated out of the district of- fices during this fiscal year. One type, initiated in the early summer of 1946, served to demonstrate insect control measures to*federal institutions and state health departments. Such units contained the different kinds of larviciding and residual spray equipment and chemicals, and the personnel were trained to carry on exhibitions of the various methods currently in practice. One demonstration unit was maintained in District 7; District 3 had completed plans for a unit; and District 8 had one which was loaned to District 9 for use in Indian Territory in New Mexico. Another such unit is being completed in District 8. These d emonstra tion units were available to the states f o r control of insects in case of an outbreak on insect-borne diseases. The other type of mobile unit DRAINAGE LEGEND 1st. HALF FISCAL YEAR 2nd. " CLEARING and CLEANING WAR MALARIA CONTROL was used to carry on mosquito control meas- ures in war areas around installations where resident control was not considered necessary. California had two such units operating under state supervision. Three units under District 1 supervision oper- ated throughout ten northeastern states, accomplishing 1,000 acres sprayed with 13,000 gallons of oil, 9,200 acres dusted with 18,500 pounds of paris green, 46,000. feet of hand-dug ditches, 8,200 feet of machine ditching, and 700 cubic yards of fill. The District 3 unit used 850 pounds of paris green to larvicide 270 mosquito- breeding acres and cleared four acres of aquatic vegetation to create unfavorable anopheline breeding conditions. The Dis- trict 8 operational unit sprayed 54 acres of water surface with 250 gallons of oil, dusted 570 acres with 200 pounds of paris green, and completed 700 feet of hand ditching. Since the basis of district- operated programs was essentially one of prevention, each mobile unit spent con- siderable time on entomological inspection in those zones requiring surveillance. MOBILE UNITS IN OPERATION: (upper left) entomological inspection; (center) oiling; (below) paris green dusting. Extended Malaria Control LEGEND i Residual Spraying - » 1st half fiscal year ] Residual Spraying - J 2nd half fiscal year Larviciding, Drainage The inauguration of the Extended Malaria Control Program was predicated on the assumption that there was a possibility of malaria spreading from malaria carriers returning from foreign countries to the civilian population of this coun- try unless adequate preventive measures were instituted. Investigation had shown that foreign malarias adapted themselves readily to our insect vectors, and that successive transfers through our vectors did not result in a decrease in viru- lence. Previous infections with native malarias conferred little immunity against these foreign malarias, some of which seemed to be separate strains. Also, since mosquitoes can be infected as long as relapses occur, some carriers might be sources of infection for several years. It was believed that malaria could be introduced most easily in the areas where the disease had last been prevalent. Efforts were therefore directed toward elim- inating the residuum of malaria in endemic foci and preventing its reintroduction in sections with a history of significant malaria morbidity. The principle in- volved in the DDT residual spray method was that those anophelines which enter houses to bite humans, and thus are most likely to become infected with malaria, will rest on the treated surface before or after feeding and be killed by the residual insecticidal action of the DDT-crystal coating. 12 EXTENDED MALARIA CONTROL The shift in emphasis to the extended program for the protection of the civ- ilian population against imported malaria was completed by 1945. When the war ended, military demobilization was rapid and millions of men from malarious areas overseas returned to their homes throughout this country. Among these men were former malaria patients who might later have relapses of the disease. Also, pos- sible subclinical cases whose symptoms had been suppressed by atabrine could suf- fer a primary attack when released from the strict regimen of chemical prophy- laxis. For these reasons, and because of the enthusiastic reception on the part of the general public accorded the highly effective results of DDT residual house spraying, the extended program was greatly expanded in scope during this fiscal year. ACCOMPLISHMENTS During the last half of 19 45 , 413,500 houses in 123 counties were sprayed with DDT. This program was expanded in 1946 to operate in 274 counties in 13 states, accomplishing 650,000 house spray applications. Funds for operations were al- located to the states in accordance with a formula determined by the headquarters Medical Division based on the relative importance of their respective malaria problems. SELECTION OF AREAS. States were encouraged to initiate operations in those areas which had been shown by a review of malaria mortality statistics to be the most important foci of malaria in the immediate past. All counties which had an average annual mortality rate of ten or more per 100,000 population during the five-year period 1938-1942 were considered as important malaria foci. There were 188 such counties in 13 southeastern states. Of these, 167 were under actual con- trol operations during the fiscal year. In addition there were 107 other counties in which residual spraying operations were undertaken. Thus a grand total of 274 counties benefited from operational control on the Extended Malaria Control Pro- gram. While it was practicable to use statistical data as a criterion in selecting the more important malarious counties in a state, it was difficult to select spe- cific malarious areas within a particular county. Several of the states on their own initiative undertook to determine on an entomological basis those por- tions of a county where control opera- tions should be conducted. This proved to be a means of expending materials and supplies where most needed and served the purpose of making a budget cover*" mo re territory than would have been possible if county-wide opera- tions had been the rule. Some states approached the problem from another viewpoint, giving top priority to homes of veterans with malaria histories, followed by homes in which positive blood smears occurred, and lastly, com- munities with a high incidence of ma- laria. DDT residual house spraying, (left) Contact man prepares householders for arrival of spray crew (right) Spray crew entering home to begin work. OPERATING PROCEDURE. The general operating procedure followed was to have a contact man for one or more spray crew units. Working from previously prepared operational maps, the contact man scheduled the day's activities, visited and enlisted the cooperation of the householders in preparing their homes for spray- ing before the crew arrived, and solved problems concerning public relations. Spray crew units varied from one to four men, depending upon density of houses and other local conditions, with most states favoring either two or three men — foreman and one or two laborers. PROCEDURE AND EQUIPMENT INNOVATIONS. The most generally adopted practice was that of utilizing central mixing plants to prepare the DDT concentrate. The con- centrate was then transported to various stations throughout the state where it was converted into an emulsion by dilution with water and distributed to the spraying crews in 55-gallon drums equipped with lock-type faucets. Various pro- visions were made for clarifying the mixture to prevent clogging of spray noz- zles. Continuous agitation of the emulsion in the drum was provided by the jost- ling of the truck over the road. These procedures eliminated handling of DDT, xylene, and other toxic chemicals and also did away with the necessity for care- ful measuring of concentrate and water each time a spray can required filling. A more versatile spray can was produced by installing a valve stem on the filler cap or cover plates of hand sprayers so that air pressure could be provided by a compressor unit mounted on the truck. This method proved more satisfactory than the old hand pumping method not onl y in saving time and energy but also in saving spray can maintenance. Some states used power sprayer units in the more populated areas and hand sprayers in sparsely settled districts. A note- (right) Power spraying unit on % ton truck. EXTENDED MALARIA CONTROL worthy modification of automotive equip- ment was the jeep-trailer combination. The jeep transported personnel and the trailer carried the equipment. In the spray area the crew used the trailer while the contact man used the jeep in his visits to prepare houses for spraying. PERFORMANCE. With the experience gained from one year’s operation and the increased development, of equipment and materials it proved possible to reduce the average man-hours required for residual spraying from 1.15 man-hours per house application at the beginning of the 1945 spr aying season to 0.96 man-hour at the end of the year. The rate of DDT application varied from state to state but the program average was 0.68 pound per house, or approxi- mately 135 mg. per square foot for the average size home. This rate of appli- cation has been found to be effective for three and a half to four months. DDT applied during the spring did not last the entire season; however, all homes sprayed after July 15 did not require respraying during the same mos- quito breeding season. The cost of residual spraying of homes was gradually reduced as the program developed. At the end of this fiscal year the average gross cost per house application was $3.75, which included all field supervision, state office overhead costs, and local contributions. Federal cost varied among the several states from $2.35 per house to as much as $5.50 per house, depending on the av- erage size of homes, the equipment used, crew organization, and the efficiency of the personnel assigned. The residual spraying program was primarily limited to spraying of rural homes and small communities. Towns within any given extended program area which required protection were usually provided for by larviciding projects. In communities where the population was more than 2,500, control of anopheline mosquitoes was provided by larviciding, unless the necessary materials and per- sonnel for spraying were furnished locally. (top) Spray can with valve stem on cover plate. Pressure is applied from a compressor on the truck, (lower) Filling spray can with emulsion from 55 gallon drum. Interior DDT spraying with pressure equipment. EXTENDED MALARIA CONTROL 15 Precipitin testing of blood-engorged mosquitoes to determine the percentage which have fed on humans. Marginal states having limited or scat- tered malaria problems were given assist- ance with mobile malaria control units attached to the district offices of the U. S. Public Health Service. These units were also available for control of any sudden outbreaks of malaria that might have occurred in these states. EVALUATIONS Entomological measurements of the effectiveness of this work in decreasing the likelihood of malaria transmission were made in two ways: (1) Inspections of a small percentage of treated houses selected at random were made at intervals after spraying to determine results of the spray in keeping houses free of A. quadrimaculatus. At the time each of these house inspections was made, an ad- jacent unsprayed resting place was inspected to determine the general abundance of quadr imaculatus in the vicinity so that efficiency of the spray in the pres- ence of various anopheline densities could be approximated. (2) Collections of engorged specimens of quadrimaculatus were made routinely from resting places on premises having sprayed hpuses and also on premises where houses were not sprayed. Precipitin tests were made of blood from the stomachs of these mosquitoes to determine the percentage on each type of premise that had fed on man, and com- parisons were made. This method of checking the effects of DDT residual deposits was used because, if quadrimaculatus feeds principally on humans while indoors, as is commonly supposed, and these human feeders are being killed by resting on the sprayed surfaces, the general quadrimaculatus population about the sprayed premises should then show a low human feeding rate in comparison to that of the population about unsprayed premises. The records of house inspections for the season are summarized in Table I. These data show that a total of 14,129 inspections was reported and that the inspections were made at intervals fol- lowing spraying varying from less than one month to a maximum of over four months. Three hundred and ninety sprayed houses, or an over-all percentage of only 2.8 percent of those houses inspected, con- tained quadrimaculatus during the after- noon. It will be noted that there was a gradual decrease in the effectiveness of the DDT deposits at successive monthly intervals after application. Inspections T able I HOUSE INSPECTIONS ON RESIDUAL SPRAY PROGRAM Total houses inspected and per cent in which A. quadr imaculat us was found during afternoon inspections. MONTHS FOLLOWING NUMBER OF HOUSES HOUSES WITH A. QUADR IMACUL ATUS SPRAYING INSPECTED NUMBER PER CENT Less than 1 3916 42 1.1 1 - 2 4558 79 1.7 2 - 3 3557 154 4.3 3 - 4 1375 73 5.3 4 - 5 723 42 5.8 Totals 14129 390 2.8 Per cent 16 EXTENDED MALARIA CONTROL made up to one month after spraying indicated that 1. 1 percent of the treated houses were positive for quadrimaculatus. This percentage increased to 1.7, 4.3, and 5.8 after intervals of two, three, and four months, respectively. The smaller number of house inspections made three and four months after spraying was due to the spraying schedule established, which called for respraying at three-month interval s. In Table II the inspection records are grouped to show the effect of age of DDT deposits and numbers of quadrimaculatus in outbuildings on the percent of houses harboring mosquitoes. Only those houses which contained mosquitoes in the afternoon were considered as positive. These data show in general that for all spray ages the greater the density of quadrimaculatus around the premises the greater is the percentage of sprayed houses positive for mosquitoes. This is prob- ably due in some measure to the likelihood that greater numbers of mosquitoes enter houses in areas of high densities and therefore there is a better chance that some will find non-lethal resting places. It will be noted however that there is a general decrease in effectiveness of DDT deposits with age in each density group except the first. Here the number of zero densities accounted for apparent unifo rmity. In order to fit the inspection routines into usual working hours, inspections were made throughout the day. Since DOT acts slowly, each house in which live quadrimaculatus mosquitoes were found during morning inspections was reinspected during the afternoon, and only afternoon positive houses were considered in making evaluations. Sufficient data have not been accumulated to determine if there is a normally occurring reduction in the percentage of houses positive for quadri- maculatus from morning to afternoon among unsprayed houses. It is assumed that day-long survival of quadrimaculatus may be expected in resting places of this type. Of 508 sprayed houses which contained quadrimaculatus in the morning, survival to afternoon was found in only 30.5 percent. Table III summarizes the records of these reinspections. The gradual lessening of toxicity of the deposits with age, as previously mentioned, is indicated by the decreasing percentage of houses which became mosquito-free by afternoon at successive monthly intervals after spraying. When inspections were made less than one month following spraying, 93 percent of the morning-positive houses were found to be free of live mosquitoes Table II HOUSE INSPECTIONS ON RESIDUAL SPRAY PROGRAM Effect of premise densities and age of spray on percentage of quadrinaculatus positive houses (afternoon inspections). MONTHS FOLLOWING SPRAYING NATURAL RESTING PUCE QUADRIUACULATVS DENSITIES 0-10 11-50 51-100 101-200 201-400 400 + All Less than 1 1 - 2 2 - 3 3 - 4 4 - 5 Percent 0.6 0.9 1.6 0.6 1.5 of Pos] 1.5 2.9 5.4 12.4 12.5 itive Ins 2.3 5.3 7.2 11.1 14.8 ide House 2.8 3.3 ]2.5 22.4 15.0 [nspection 1.0 5.0 14.2 17.2 63.6 s (after 6.0 5.3 32.9 50.0 66.7 noon). 1.1 1.7 4.4 5.4 5.7 Table III HOUSE INSPECTIONS ON RESIDUAL SPRAY PROGRAM Reduction in houses positive for A. quadrimacuI atus from morning to afternoon. MONTHS FOLLOWING SPRAYING NUMBER OF HOUSES WITH A. QUADRIMACULATUS PERCENT REDUCTION MORNING AFTERNOON Less than 1 59 4 93.2 1 - 2 123 13 89.4 2 - 3 206 66 68.0 3 - 4 79 43 45.6 4 - 5 41 29 29.3 i Totals 508 155 Percent 69.5 EXTENDED MALARIA CONTROL 17 in the afternoon. This percentage decreased to 89, 69, 45, and 29 for inspections made one, two, three, and four months, respectively, after spraying. Table IV shows, for those houses found positive at morning inspections, the decrease in total numbers of quadr imaculatus which occurred between morning and afternoon at successive monthly intervals. As in Table III the lessening of effectiveness of the deposits with age is indicated. Concerning the results of the precipitin tests, less than half the samples of quadrimaculat us bloods taken for determination of human feedings have as yet been tested. However, of 21,913 specimens collected on premises where the houses have been sprayed (Table V), only 0.6 percent gave human reactions, while of 9,565 specimens from premises where no spraying had been done the human feeding rate was 3.1 percent. It is believed that these data, which show 80 percent fewer quadr imaculat us with human feedings to be present about premises having sprayed houses, are highly significant as indicating that chances for malaria transmis- sion were greatly reduced. TRAINING AND EDUCATION There was no great need for training supervisory personnel in operational procedure this year since most of them had been adequately trained last year and had had at least one season’s spraying experience. Spray crews were trained by these experienced supervisors, and new recruits occasioned by normal labor turnover were trained on the job by old crew members. Similarly, there was no great need for an extensive program of public education in most states this year in light of the phenomenal success of the previous season's spraying pro- gram in terms of public enthusiasm and cooperation. The amount of local mone- tary and labor contributions to the extended program attested to this. Several of the states conducted health education programs in the schools and institut- ed workshops on malaria sanitation in colleges. Health instruction was given to persons and families affected with malaria, and special concessions, such as offers to spray their homes, were made to those infected if malaria was di- agnosed by a physician. This induced many persons to visit physicians. Field educators held meetings with civic organizations and the general public to ex- Table IV HOUSE INSPECTIONS ON RESIDUAL SPRAY PROGRAM Reduction in numbers of A. quadrimaculatus in houses from morning to afternoon. MONTHS FOLLOWING SPRAYING TOTAL A. QUADRIMACULATUS IN HOUSES PERCENT MORNING AFTERNOON REDUCTION Less than 1 172 6 96.5 1 - 2 290 22 92.4 2 - 3 598 182 69.6 3 - 4 190 74 61.1 4 - 5 106 60 43.4 Totals Percent 1356 344 74.6 Table V RESULTS OF PRECIPITIN TESTS - 1945 (APR. - AUG.) COMPARISON OF SPRAYED VS. UNSPRAYED AREAS. NUMBER SPECIMENS TESTED NUMBER POSITIVE FOR HUMAN BLOOD- PERCENT Sprayed 21913 142 0.6 Not sprayed 9565 293 3.1 Difference - - 80.7 EXTENDED MALAR IA CONTROL plain the use of DDT in household sani- tation, and demonstrations were carried on as part of the county health program. Some states conducted state-wide res- idual spraying projects in which public buildings of various kinds were treated for purposes of demonstration. Consid- erable effort was made in several states to locate discharged servicemen with malaria histories and to instruct them in malaria sanitation. Spray crews were trained by experienced su- pervisors. INVESTIGATIONS AND TECHNICAL DEVELOPMENTS Detailed field tests of dosage and type of spray coverage showed that over-all spraying of a room was preferable to spot spraying of comers, undersides and backs of furniture and pictures, and other resting places of mosquitoes. Also, it was concluded that the extra expense of applying 200 mg. of DDT per square foot in place of 100 mg. was justified by a better percentage of mosquito mortality three to four months after treatment. Laboratory tests showed that the nature of the sprayed surface greatly affected the length of residual effectiveness and that temperature definitely affected the deterioration of DDT on sprayed surfaces. The use of DDT for the control of other insects affecting public health was investigated in detail this year and there were indications that some of the more recently discovered insecticides had advantages over DDT in specialized usage. In Hawaii a DDT-smoke aerosol generator attached to a truck motor exhaust was developed for control of adult mosquitoes. Several investigations centered around studies to determine the efficacy of DDT residual spray in preventing transmis- sion of human malaria and observations were made on the epidemiology of malaria in endemic areas. In Puerto Rico results of a “controlled” residual spray study showed that the malaria rate in one town dropped from 6.3 to 0.91 percent after three sprayings, while the rates in the check, unsprayed area changed only from 4.7 to 3.8 percent in the same period. In all but a few states, federal allocations were augmented by local contributions which ranged from about two percent to over 60 percent of the federal allocation. In addition to augmenting federal allocations by local contributions, there were also other ways in which the various states supplemented extended program spraying. In one instance county-paid crews were put at the disposal of area supervisors to spray border-line counties that would not otherwise have been included in extended program operations. In one state, a proposition was put before civic leaders and county heal th commissioners outlining the possibility of greatly extending the residual spraying program with locally contributed funds and labor. Of the 19 communities approached, 16 subscribed to the first spray period and guaranteed the second on the same basis. Supplementary residual spraying was carried on in another of the states as a private enterprise by individuals trained by working with spray crews on the extended program. As the public interest and demand for DDT residual spraying increased, the local con- tributions increased and it is anticipated that the contributions of many more states may approach 50 percent of the total expenditure by the end of the next fiscal year. FUTURE TREND Typhus Control LEGEND Residual DDT Dusting Ratproofing Typhus Survey Typhus Investigational Program (’niomasville) Murine, or endemic, typhus fever is a disease of increasing public health signifi- cance. Rats are the natural reservoirs of infection and fleas are the probable vectors transmitting the disease from rat to rat, and from rat to man. Other closely related diseases of the typhus group of fevers include the louse-borne or epidemic type, sometimes called “Old World” typhus, and scrub or mite-borne typhus, sometimes called “ field” typhus. Since 1940 there has been so rapid an increase in the number of cases of the murine type reported in this country that typhus fever is now recog- nized as a major health problem in southern and southeastern United States. More than 5,300 cases were reported to public health departments during 1944. This was the greatest number recorded for any one year, but probably represented only a part of the total number of cases occurring because the reporting of actual cases has been far from complete. The fatality rate of endemic typhus is only two to five percent, but the debilitating effect is great. Climatic conditions most favorable for the widespread occurrence of murine typhus fever in this country appear to lie south of 33 degrees north latitude, which crosses the country at about the northern boundary of Louisiana. In areas north of this line the occasional trans- mission of the disease can be traced almost invariably to foci that are business establishments, .especially where food is handled. South of the 33 degree north lati- tude line typhus appears to be contracted about as extensively in residential and rural sections as in business areas of cities and towns. The peak in seasonal inci- 20 TYPHUS CONTROL dence of typhus cases varies in different localities; in many regions it is reached during November or December, but in most places the greatest number of cases are reported during July or August. In July 1942 the Typhus Control Unit of the U. S. Public Health Service was formed. This was an outgrowth of limited federal typhus control activities started earlier, and was used primarily as a field unit for demonstrating ratproofing methods. In those states in which typhus was a problem, ratproofing and poisoning programs were operated with state and local funds under state and local health ordinances. On July 1, 1945 typhus control activities of the U. S. Public Health Service were transferred from the Typhus Control Unit to MCWA and increased federal funds became available for operational control. The various state activities were inte- grated into an over-all MCWA Typhus Control Program, which was characterized by the introduction of EOF dusting as a method of controlling rat ectoparasites. State operations were directed by the respective state health departments in close liaison with the USPHS, and MCWA personnel were assigned to direct typhus control pro- grams in those states which requested it. Most of the federal funds allocated for typhus control were **ear-marked” for DDT dusting as a means of decreasing the ectoparasite population on rats. Although it is uncertain as to which ectoparasites are principally responsible for transmit- ting the endemic typhus fever organism to humans, evidence points to the oriental rat flea, Xenopsylla cheopis, as the most incriminated vector. The Typhus Control Program was justified on the basis of experimental observations which showed that good control of rat ectoparasites could be obtained by dusting EOT along places where rats were known to travel. Fortunately, the rat flea has proved to be more susceptible to control by EOT than rat mites or lice. EKiring this year DDE dusting on an area-wide basis was introduced as an operational measure for typhus control. EPIDEMIOLOGY The immediate problem from an epidemiological standpoint was the determination of those areas in which dusting operations should be conducted. A statistical study undertaken for this purpose indicated in general the following facts: (1) Approxi- mately 5,000 cases of typhus fever are reported in the United States each year; 4,987 cases were reported for the calendar year 1945. Since the death rate is low (two to five percent), mor- bidity statistics are more practical than mortality statistics in determining the extent of the problem. (2) Of these 5,000 cases, over 98 percent are current- ly being reported from nine southeastern states. (3) There were 100 counties in these nine states which re- ported an annual average of MURINE] TOPHUS It ever IN UNITED STATES TOTAL REPORTED CASES 1931*1945 TYPHUS CONTROL (above) Xenopsylla cheopis — rat flea. (left) Mobile typhus control unit. ten or more cases for the five-year period, 1940-1945. (4) There were an additional 40 counties, not included in the 100 above, which reported ten or more cases in 1944 and 1945. (5) Thus, a total of 140 counties in nine southeastern states consti- tuted what was considered to be the nucleus for typhus dusting operations, which could be covered with the funds available. During the fiscal year projects were operated in 11 state health departments, Puerto Hico, and the Virgin Islands with IJSPHS assistance. Ihese involved 167 counties, in which residual dusting was undertaken in 150 and ratproofing in 57. Fat poisoning was also added to these projects if financed by state or local con- tributions. Of the total cost of typhus control during this fiscal year, state and local participation accounted for 62 percent and federal funds for the remainder. In general, three types of operational typhus control programs were conducted, Ihe area-wide dusting program was carried on by the respective state health departments. Organization was similar to malaria control programs. Critical supplies and equip- ment were secured by MCWA. Labor was provided by the counties in which operations were conducted, although the Public Health Service supplied experienced foremen and laborers to work with and train local crews. As soon as the local crews were able to carry on alone, DSPHS labor was withdrawn. A similar arrangement was made for supervisory personnel. Ihe second type of program was ratproofing, which included trapping and poisoning to eradicate the rats inside the proofed premises. Itesides some federal supervision and a limited amount of federal equipment, ratproofing was supported entirely with state and local funds and labor. The third type of program was rat poisoning on an area-wide basis, usually carried on in conjunction with dusting. Poisoning was conducted only in those areas where state or local contri- butions financed it. OPERATIONS RESIDUAL DUSTING. A total of 336,200 premise dustings were completed during the fiscal year, representing an approximate average of two treatments per premise. On the basis of programs proposed by the respective states, the ratio of residences 22 TYPHUS CONTROL EFFECT OF DDT DUSTING ON RODENT ECTOPARASITES to business establishments treat- ed in the areas in which opera- tions were carried on was 11:14. Each premise treatment required an average of 0.68 labor and foreman man-hour to spread 2.4 pounds of ten percent LOT in py- rophyllite. In light of examina- tions of more than 6,000 rats from both undusted and dusted premises, the DDL dusting was found to reduce the oriental rat flea population by 85 percent. A 77 percent reduction was found among all the rat fleas, the somewhat lower figure resulting RESULTS OF ENTOMOLOGICAL EVALUATION OF RAT ECTOPARASITES FROM 6,274 RATS IN NINE STATES FISCAL YEAR - 1946 from difficulty in controlling the “stick-tight” poultry flea. Rat mites were reduced 66 percent in spite of the fact that mites constitute a group of arthropods generally found to be difficult to control with DDT. Only a seven percent reduction was indi- cated in the case of rat lice. An over-all reduction of 43 percent was found among all rat ectoparasites. More than 3,000 blood samples from rats taken from both dusted and undusted premises were submitted for complement-fixation tests. These tests indicated that the number of typhus infections among rats in dusted premises was 40 percent less than those in undusted premises. Dusting programs in the respective states followed similar patterns, with a few variations. Several states combined rodent extermination with practically all of the DOT dusting done, and operated residential and farm programs of typhus con- trol, as well as treating urban and business establishments. In one state supervision of residual house spraying and typhus dusting was combined, although each of these operations constituted a separate program. Due to the intermittent and scattered (below) Dusting an overhead rat run with a small hand duster, (right) Setting traps along rat runs. Trapped rats are bled for complement-fixation tests. TYPHUS CONTROL nature of operations in sections of several states, dusting and other con- trol measures in these sections were carried on by mobile units, each of which circulated in an area of several counties. Another state carried on coun- ty-wide dusting in some areas and spot dusting wherever typhus cases occurred in other counties. Other state innova- tions included a program of dusting and poisoning carried out by local health units in all motion picture theaters each quarter, and mixing DDT dust with flour which was placed in suitable loca- tions in restaurants to kill roaches as well as rat ectoparasites. Typhus control was made an integral part of the routine sanitation program in one of the states in accordance with the policy of the state health department to embody some permanency of organiza- tion in each county health unit where typhus was of public health importance. In several of the states where control of Aedes aegypti and typhus fever were coincident problems, dusting and prem- ise sanitation were combined from the operational standpoint since it required little additional effort to search for rat runs while inspecting for aegypti breeding places, and most aegypti-in- fested premises also required dusting. It is still too early to evaluate the effect of residual dusting in control- ling human typhus cases. RATPROOFING AND POISONING. Approxi- mately 4,000 urban business establish- ments in 57 counties were ratproofed during the year. Each proofing treat- ment required an average of 36.9 labor and foreman man-hours. Both trapping and poisoning were carried on as a sup- plement to ratproofing to eliminate those rodents already within the prem- ises. In one state, rat poisoning in connection with ratproofing was made the responsibility of local project personnel. This state also effected the ratproofing of temporary structures by using treated metal lathes as a sub- (above) Dusting a feed store with a hand pump dust gun. (below) Dusting a rat burrow with a Cyano A foot duster. (below) Rat dying after drinking ‘‘1080” water from paper cup. 24 TYPHUS CONTROL stitute for concrete chain walls. For each establishment ratproofed in another of the states, metal or concrete garbage stands were constructed and the cost of new garbage cans, if required, was computed as part of the over-all cost of ratproofing. A total of 115,100 premise poisonings was completed during the year, both on an area-wide basis and in connection with ratproofing. treatment required 0.56 labor and foreman man-hour to spread 0.63 pound of bait. Most of the area-wide poisoning was carried on in connection with dusting, since the fact that ectopara- sites tend to leave dead rats in search of other hosts may temporarily increase the transmission of typhus fever unless control of ectoparasites is combined with rat poisoning measures. Bed squill was the poison used most because it is slow-acting and allows the rat to carry DDT back to the burrow and other inaccessible places before it dies. Other poisons used included ANTU (alpha napthylthiourea), 1080 (so- dium fluoroacetate) water, and cyanogas “A” dust. A central squill-bait mixing plant was put into operation in one state to furnish mixed bulk and wrapped bait to the state projects. This plant was able to furnish materials to the cities and counties more cheaply than the cost of their buying ingredients and mixing bait themselv.es. In some areas rat poisoning was combined with premise sanitation for the control of Aedes aegypti mosquitoes. To determine the effectiveness of typhus fever control methods, particularly DDT dusting, as they effect the incidence and prevalence of the disease in the human and rodent populations, an investigational project was undertaken in an area in southern Georgia. The incidence of human typhus cases in the study area was determined by a census survey, principally designed to locate mild and unreported cases. The other major aspect of the program involved reservoir and vector studies. Typhus surveys were also made in 21 cities in Arkansas to obtain data on typhus fever cases, ectoparasite populations, and rat blood samples. Technical develop- ments included the combination of ten percent DDT, 50 percent ANTI, and 40 percent pyrophyllite to serve both as a rodenticide and for ectoparasite control. After initial field testing, the mixture was recomnended for more extensive field testing on an area-wide basis by selected states. Preliminary technics were also established for testing panels of various construction materials to d etermine their value in ratproofing. INVESTIGATIONS As more of the respective state and local health department personnel gain ex- perience in the application of typhus control methods, it is anticipated that USPHS participation will be limited to epi- demiological and technical developmental in- vestigations, furnishing specialized equip- ment and materials, and providing technical supervision when requested. Activities in the 11 states concerned with typhus control are now largely being conducted with state and local funds and labor. As time goes on it is expected that this trend will be carried to its logical conclusion — complete state and local financing and operation of typhus con- trol field activities. FUTURE TRENDS Ratproofed garbage stand. Aedes Aegypti Control LEGEND As a continuance of the previous year’s trend, all of the Aedes aegypti control activities this year were integrated into the general sanitation programs of local health departments. It was found that the regular activities of Aedes aegypti in- spectors could be combined with inspection of other sanitary facilities and con- ditions to make a comprehensive sanitation inspection at a great saving in cost. This combining of inspection work also tended to assure continuance of aegypti control as a regular activity of the local health departments. On a number of projects it was found possible to incorporate DDT typhus dusting and some rat poisoning with sanitation inspection, which resulted in an even more complete pub- lic health service with a minimum number of field personnel. Public relations were considerably improved since the public preferred to know and deal with one inspec- tor rather than many, and efficiency was increased. Correction of sanitary vio- lations was obtained primarily by giving the householder a notice at the time of inspection, listing violations and required corrections. In most cases this was sufficient to effect the necessary results. OPERATIONS MCWA participation continued through this fiscal year on a diminishing scale, with the local health departments furnishing at least 50 percent of the personnel. In most cases MCWA supplied the field supervision, together with a few inspectors, and the local municipalities provided the personnel to make up the remainder of 26 AEDES AEGYPTI CONTROL the crews. As shown in the accompanying table, a total of 754,300 premise inspec- tions was made in the continental United States during the year and 31,400 premises were found to be harboring Aedes aegypti breeding places. The average breeding index, or the percentage of total premises inspected where breeding was found, was 4.2 for all inspections, each o± which required 0.12 man-hour of labor. Activities this year were continued in ail of the cities inspected last year, with the exception of Jacksonville, Florida. Although the over-all index of breeding was almost exactly the same as in the preceding fiscal year, several instances of greatly increased breeding indices were noted. In one city in Florida, inspection and control of breeding places was drastically reduced for reasons of economy during this fiscal year, resulting in a rise of more than five percent in infested habitations among those premises in- spected. The marked rise in percentage of infested premises among those inspected in another Florida city during this year was due mostly to the fact that there was no real control program in effect to follow up the inspections made. In one locality in Texas there was no aegypti program in operation during the last part of 1945 because of the negligible amount of infestation the year before. As a re- sult of this over-'bptimistic let-down, the breeding index in this area rose pre- cipitously, necessitating renewed control in 1946. The inspection program through- out Texas was expanded this year to include the surburban towns in the environs of the larger cities regularly inspected. This expansion represented an increase in surveillance rather than an aggravated aegypti problem. The value of inspection and control on a modified county-wide basis may be inferred from the material re- duction in the breeding index over the preceding year in Hidalgo County, Texas. AEDES AEGYPTI SUMMARY PROJECT PREMISES INSPECTED INDEX 1944-45 1945-46 1944-45 1945-46 Mobile, Alabama 69,946 51,846 10.3 4.3 Jacksonville, Florida 17,682 ... 2.0 — Key West, Florida 29,218 10,052 10.1 15.2 Miami, Florida 383,344 240,165 3.7 4.9 Tampa, Florida 22,606 19,440 2.2 15.7 Savannah, Georgia 76,201 28,609 3.1 2.4 New Orleans, Louisiana 92,409 21,059 6.0 8.5 Charleston, South Carolina 66,834 26,281 2.5 3.7 Brownsville, Texas 75,908 68,531 1.4 1.3 Corpus Christi, Texas 86,936 29,026 0.9 1.2 Galveston, Texas 48,880 21,380 1.3 1.6 Hildago County, Texas 54,937 24,283 2.0 0.9 Houston, Texas 147,136 150,164 2.8 2.6 Laredo, Texas 3,971 22,220 0.2 5.4 San Antonio, Texas 55,837 34,549 5.4 5.8 Norfolk, Virginia — 3,673 — 6.2 Portsmouth, Virginia — 3,034 — 3.9 Total 1,231,246 754,312 4.3 4.2 Hawaiian Islands (A. aegypti and albopictus) 222,788^ 335,295 5.0 2.2 Aedes aegypti mosquitoes may be found breed- ing in a variety of containers, such as tin cans in the backyard or in ornamental ponds. In the cities of Norfolk and Portsmouth, Virginia, MCWA carried on a combination survey and control program during the first half of this fiscal year in those sec- tions of the cities where aegypti breeding was most prolific. Local control ac- tivities were included in the over-all mosquito-abatement program of the municipal health departments. MOVA participation in control activities in New Orleans, Louis- iana, was considered unnecessary in 1946 because the local health unit had the situation under effective control. The program in Savannah, Georgia was terminated at the end of March 1946. DENGUE CONTROL IN THE HAWAIIAN ISLANDS The control of Aedes aegypti and albopictus in the Territory of Hawaii con- tinued during this year according to the basic plan of operation established in the fall of 1943 to cope with the out- break of dengue fever. This plan stres- sed inspection of premises, correction of breeding, and education of the house- holder. One positive case of dengue fever was recorded in July 1945, although a number of suspected cases during the year were investigated and anti-mosquito pre- cautions taken. Because of reductions in staff it was impossible to maintain con- tinuous inspection of all zones within cities as previously practiced. Although each zone was inspected, only those zones of high human population density and dem- onstrated hazard from the standpoint of Water barrels should be covered with screen- ing to prevent aegypti breeding. 28 AEDES AEGYPTI CONTROL reintroduction of dengue fever received treatment that approached the desired opti- mum of control. Pioutine inspections were made of 335,300 premises, of which 7,300 were found to be breeding Aedes mosquitoes. Special emphasis was placed on permanent correction wherever possible. In the course of the year 7,500 catch basins and storm drains, 200 ground pools, 60 cesspools, 90 ditches and streams, and 13 swamps were oiled to eliminate mosquito breeding. In addition, 134 fish ponds were stocked with surface minnows, which feed on mosquito larvae. Phenothiazine strips became increasingly important as a means of controlling interior breeding because they were readily acceptible to the householder. An important phase of this year’s program was the development of an alco- holic suspension of DDT in water, which could be used in all breeding containers and served to replace the variety of larvicides previously carried by each inspector Tests were conducteo on the effectiveness of various DDT concentrations in ape plants, lily plants, bamboo stumps, tree holes, and a variety of artificial containers. Close liaison was maintained with agencies concerned with insect quarantine and inspection of airplanes and other forms of transportation in order to prevent the in- troduction of medically or economically important insects into the Territory of liawaii. Also, an extensive program of publicity and education concerned with mosquito control activities was conducted during the year, including news releases, health programs in the schools, numerous public lectures, films, and demonstrations of control technics. The success of the program in the Hawaiian Islands may be judged from the fact that only one positive case of dengue fever was reported this year and the breeding index was decreased from 5.0 in the 1945 fiscal year to 2.2 this year. Inspectors check flower vases in homes and urns in cemeteries for aegypti breeding places. Impounded Wafer Survey In March 1945 the Impounded Water section of the MCWA Engineering Division was established to conduct malaria surveys of existing and proposed impoundments under the jurisdiction of the War Department Corps of Engineers. This was brought about by an agreement between the Office of the Chief of Engineers and the U. S. Public Health Service for the utilization of the trained malaria control personnel of MCWA to assist the engineers in planning for malaria control on the impoundments which they were constructing or planning to construct. Official requests were made by the Corps of Engineers to the U. S. Public Health Service office of Water and Sanitation Investigations in Cincinnati, Ohio, who in turn requested MCWA to make field studies and prepare reports and recommendations. The survey reports were prepared after detailed field study of existing con- ditions. Consideration was given to topography, climate, location, population, and entomological, epidemiological, and other related factors. Impoundments located in the southern states where malaria is endemic were given more complete and in- tensive surveys. Detailed malaria control methods and procedures were recommended for each reservoir if a malaria problem was present. Estimates of the cost of mos- quito control were also furnished so that the engineers could consider this factor as an integral part of the proposed project. The surveys and reports were made with the cooperation of the state health departments. During this fiscal year re- quests were received from 30 district or division offices of the Corps of Engineers for malaria surveys on 188 existing and proposed impoundments located in 34 states. As of June 30, 1946, 94 reports had been completed and field surveys had been made on 40 additional impoundments. In the spring of 1946 a training course was held in Atlanta, Georgia, and at Wilson Dam, Alabama, for the personnel of the Corps of Engineers. Plans for this course were made by the MCWA In-service Training Section of the Training Division and the Impounded Water Section of the Engineering Division. The course was at- tended by 38 engineers representing 31 districts and divisions in 24 states. The first week was devoted to classroom lectures in Atlanta and the last two weeks were spent observing Tennessee Valley Authority field demonstrations, during which time lectures were given by personnel of the Health and Safety Department of the Tenn- essee Valley Authority. Impoundment to create a pond for wild life ref- uge in San t e e-Cooper Reservoir. Water-Hyacinth Survey The Committee on Rivers and Harbors of the U. S. House of Representatives passed a resolution on February 6, 1945 requesting the Board of Engineers for Rivers and Harbors to review the water-hyacinth problem with a view to determining: (1) whether any expansion of the scope of operations or any change in the method now employed for exterminating and removing the hyacinth plants and other marine vegetation from the waters of such states as are affected is advisable at this time, (2) the nature and extent of the various public benefits that would accrue from such ex- termination and removal, and (3) the amount of local cooperation that may be war- ranted by reason of the local benefits. The Fish and Wildlife Service of the U. S. Department of the Interior, the U. S. Department of Agriculture, and the U. S. Public Health Service were to be solicited for cooperation in this study since obstruction of streams by hyacinth growths affects the fishing industry, agricul- ture, and health conditions. In connection with this work the U. S. Public Health Service was invited by the Secretary of War to send a representative to a conference held at Washington, D. C. , on August 24,1945. At this conference plans for USPHS participation in the survey were made. MCWA entomologists were designated who were to meet periodically with the respective water-hyacinth committees of the South Atlantic, lower Mississippi Valley, and southwestern divisions of the Corps of Engineers to discuss the public health implications of any proposed plans of operation and to acquire available information from state health officers on the public health benefits which might accrue from hyacinth eradication in states in which water-hyacinth infestations occur. In addition arrangements were to be made for assistance from specialists of the USPHS office of Water and Sanitation Investigations, Cincinnati, Ohio, in evaluating certain aspects of the public health problems of hyacinth control. Dur- ing the year entomologists assigned to this work met several times with the divi- sional committees, and letters were written to interested state health officers requesting information on the problem. Water-hyacinth cutter of the U. S. Engineer Department cutting aquatic vegetation on the Potomac River. While servicemen benefited by every pre- ventive technic and therapeutic measure known to science before they were dis- charged from active service, it was very possible that cases of malaria, filari- asis, schistosomiasis, leishmaniasis, ancylostomiasis, and other tropical diseases acquired overseas might present themselves to medical practitioners in any state in the country. In order to cope with the potential hazard introduced by the increasing numbers of discharged veterans returning to every corner of the United States, the MCWA program for the training of physicians and medical technicians in the diagnosis of tropical and parasitic diseases was considerably expanded during this fiscal year. In addition, an entirely new training service was inaugurated at the beginning of the year, known as Internship in Public Health, with the basic objective of giving trainees practical experience under competent supervision in the actual work of a local health department. The in- service orientation and training program was continued for operations personnel, and special seminar courses were offered to malaria control consultants, typhus control personnel, members of the Corps of Engineers concerned with malaria con- trol on impounded water, foreign exchange students, and others. Planning and pro- duction of audio-visual materials was accelerated to provide the expanding training programs with ins tr uc ti onalaids , of which the supply previously available was both limited and inadequate. In-Service Training Before 1VOA had completed its first year of operation, it became apparent that an in-service type of training would be necessary to cope with the lack of available trained technical and professional workers and the high rate of turnover among field personnel, both of which were occasioned by the demands of the armed forces. The first orientation and training course in malaria control was conducted in May 1943 for headquarters personnel. During that summer the Training Division was organized to formally administer in-service training. The second course was offered in Decem- ber 1943 for field supervisory personnel. By the end of the 1945 fiscal year 36 orien- tation and training courses in malaria control had been given, in addition to several orientation courses for headquarters clerical personnel. Luring this fiscal year 16 formal courses were offered, including several to specialized workers and foreign s tudents. The first in-service courses consisted chiefly of lectures, with little or no follow-up training in the field. Ihe change to include field work was made gradually until, in 1945, approximately one-third of each course was devoted to intensive field training. 1-Airing this fiscal year the importance of field training and practice was more fully appreciated and an attempt was made to allot at least half the time in each course to field work. MALARIA CONTROL ORIENTATION. Four orientation and training courses in malaria control were offered this year to newly commissioned officers, field supervisory personnel, and professional people newly employed in the headquarters office. General orientation in the organization of the D. S. Public Health Service at the various levels, including MCWA headauarters, was given to all of the trainees. Special orientation in military courtesies was reouired for all newly commissioned officers. Instruction in the medical aspects of malaria included epidemiology and identification of malaria parasites. The entomological phases of malaria control covered mosouito surveys and collections, identification, instruction in completing field forms and records used in program evaluation, and the use and care of entomo- logical eouipment. Ihe engineering phase was studied through reconnaissance surveys, mapping, control methods and technics, crew management, use and care of equipment, records and reports, and administration of control programs. Trainees usually spent the first week of the course in the classroom in order to get the necessary back- ground material preparatory to field training. Ihe last portion of the course was Orientation and training courses for newly commissioned officers includes instruction in mosquito collection and paris green larviciding for mosquito control. IN-SERVICE TRAINING devoted to field observation and practice in applying the control methods and technics discussed in the classroom. Several orientation courses were also held for headquarters office per- sonnel. These courses featured studies of the activities of the U. S. Public Health Service and the organization of the headquarters office. In each course a short period was devoted to adminis- trative procedures which were common to all of the divisional offices within the headquarters organization. MALARIA CONTROL CONSULTANTS. A spe- cial course for malaria control con- sultants was held in August. The five physicians who participated were being trained to act as special consultants in the event of malaria epidemics in their respective states. They received instruction in the identification of malaria parasites and mosquito vectors, malaria survey technics, and malaria control methods. DDT DUSTING FOR TYPHUS CONTROL. Dur- ing September and October three DDT dusting training courses, each of two weeks’ duration, were offered to new personnel recruited by the respective state offices and headquarters in order to get the typhus dusting program under way. The instruction schedule included films and general discussions on the use of DDT in typhus control; consid- eration of typhus fever and other rat- bome diseases; the habits and identi- fication of rats, mice, and other ro- dents, and rat ectoparasites; field practice in the application of DDT dust, and in the setting of all types of traps; and the organization and operation of typhus control programs. RODENT CONTROL. Two intensive, six- week courses in rodent control were held for state supervisory personnel in order to get state ratproofing proj- ects under way as quickly as possible. These courses, given from November through March, included a consideration Trainees usually spend the first week of the course in the classroom in order to get the necessary background prepara- tory to field training. (above) Rat baits and their use are studied on the rat poisoning program, (below) Rodent ectoparasites are remov- ed from trapped rats and identified. IN -SE HVICE TRAINING of the epidemiology of murine typhus fever and other rodent-borne diseases, rodent habits and characteristics, ro- dent ectoparasites and their control, rat poisoning programs, ratproofing programs, fumigants and fumigation, studies of new rodent i ci de s, field prac- tice in estimating, contracting, rat- proofing, and eradication, and adminis- trative procedures in conducting various typhus control programs. A two-week rodent control course was also conducted during January for personnel from marginal states who would be responsible for promoting rodent control programs. Since these men were not concerned with supervising actual projects, their instruction consisted of six days of classroom lectures and four days of field observation rather than field practice. The lectures cover- ed the same subjects as given in the six- week course, although necessarily con- densed. In-service training personnel also Training in malaria control on impounded water includes field surveys. assisted states in conducting two-day typhus and rodent control seminars, held at Savannah, Georgia; Poston, Massachusetts; and Hopkinsville, Kentucky. Assistance of other types was given to states as they requested it. PEST CONTROL. In March a special two-day seminar was held to train members of the Georgia Pest Control Operators Association in the proper methods and precautions in the use of 1080 and ANTE rodenticides. The seminar was attended by 36 members of the Association, as well as by a group of trainees who had previously taken one of the six-week typhus control courses. IMPOUNDED WATER MALARIA CONTROL. A three-week course on malaria control on impounded water was held for personnel of the U. S. Engineering Id.vision, Corps of Army Engineers, during April and May. The USED had many large impoundments under construction and in the planning stages. In order to assist the L. S. Engineer district offices in the field inter- pretation of malaria control principles as included in the reports and recom- mendation of MCWA, key personnel from each division were sent to receive this training. The first week of the course, spent in Atlanta, was devoted to lec- tures in malaria control and discussions of problems and control technics e s- Trainee examining basement for rat signs, as part of rodent control field training. 36 IN-SERVICE TRAINING pecially applicable to impounded water. The last two weeks were spent in the Ten- nessee Valley observing how the Tennessee Valley Authority had resolved the mala- ria problem connected with impoundments and had applied control technics. The field trips were conducted by members of the staff of the TVA Health and Safety Depart- ment. Before each field trip, a short briefing session was held to acquaint the trainees with the particular phases of control to be observed during the day. FOREIGN TRAINEES. In June the first of many trainees from foreign countries, who were studying on fellowships at various colleges in the United States, arrived for training in malaria and typhus control. A two-week course was conducted for seven Latin American trainees, including four sanitary engineers, two doctors, and one entomologist. In training students from Latin American countries, instruction had to be modified somewhat because control operations in these countries were usually under the direct supervision of medical men, as contrasted with the system in this country of placing control operations in the hands of engineers. Since a large number of foreign trainees were expected in the next few years, it was planned to enlarge the scope of the training courses to include instruction in basic sanitation for foreign students at one of the field training areas. SUMMARY. During this year emphasis was placed on actual participation, under close supervision, in field control operations so that the trainees could actually carry out the technics discussed in the classroom. It was also sometimes necessary, particularly for foreign students, to fit the course to the person rather than try- ing to fit the person into a pre-planned course of training. Because of the wide range in educational backgrounds of the trainees, it was not found practical to set up rigid course schedules (with the exception of typhus control training). Instead, the background of each individual was considered in preparing lectures so that each trainee would receive the basic information necessary for gainful par- ticipation in field training. Although the in-service training staff was pre- pared to give various types of instruc- tion on rather short notice, more ef- ficient and thorough training would have resulted in some cases if the trainees had. had proper basic education and ex- perience in the particular field studies. Next year it was anticipated that there would be more decentralized training activities in which groups of public health personnel would be trained lo- cally in the various states. Actual participation in field work is the keynote of the training courses. Here a trainee is dusting a rat burrow with a Cyano A foot pump duster. Internship in Public Health The “ Internship in Public Health” section was established July 1, 1945 in an experimental field training area set up in Savannah, Georgia, to study problems in the training of public health workers. From the studies made, a three-month training course was developed for the various types of public health personnel ordinarily employed in a local health department. The basic objective of this course was to give trainees practical experience under competent supervision in the actual work of a local health department, supplementing academic training offered in schools of public health. Trainees were exposed to the routine problems coincident with the operation of a representative local health department, and the methods of solu- tion of these problems were studied. The Savannah-Chatham County (Georgia) Health Department was selected as the initial training area. Facilities were made available for internship training through the cooperation of the Director of the Savannah-Chatham County Health Department and the Georgia Department of Public Health, through its division of Local Health Organization. Classroom, clinic, laboratory, and field facilities were provided by the local health department. MCWA personnel developed the course, in coopera- tion with the Director of the Savannah-Chatham County Health Department. The teach- ing staff was supplied by MCWA, and the training was closely supervised to prevent interference with the regular work of the health department staff. Training aids, equipment, and supplies used in the course were made available from the Training Division of MCWA. Courses were scheduled at intervals of approximately three months. The first course started on January 1, 1946. The trainees participating In the course fell into one of two general groups: (1) those who had completed or were in the pro- cess of completing formal academic training leading to a degree in public health, and who needed field experience to bridge the gap between academic theory and the practical application of public health methods; and (2) those who required train- ing at a sub-professional level to qualify for positions in health departments. The type of training offered differed somewhat within these groups, since it was determined largely by the background and experience of each individual. The course work was made sufficiently broad in scope to meet the needs of the various types of personnel found in health departments. Each clsss was limited to fifteen per- sons. The training was divided into a three-week period of general orientation in public health organization and methods and a nine-week period of field demonstra- tions and training. The first week and a half was spent in Atlanta studying federal and state public health activities and policies. The organization and functions of the U. S. Public Health Service were explained, as well as its relations with state and local health departments. A brief introduction to the study of communi- cable diseases was given, including etiology, epidemiology, prevention of diseases, and general public health laboratory methods. Lectures were supplemented by a visit to the laboratories of the Georgia Department of Public Health. 38 INTERNSHIP IN PUBLIC HEALTH GENERAL INSTRUCTION. The remainder of the course was conducted at the Savannah- Chatham County Health Department, which operates as a joint city-county health center. A short period of general orientation was given to the group as a whole, without regard to background or experience of the individual members of the class. The orientation began with a general survey of the facilities centered in the train- ing area. The group then received instruction in those phases of public health work common to every job in a health department. Training in public speaking was con- sidered essential, since members of a health department should be capable of ex- plaining health programs to the public. Radio technics were also included. Motion pictures and film strips were shown and discussed, including the proper use of projection equipment and film libraries. The importance of pamphlets and posters in disseminating information to large groups was stressed, and the trainees also prepared news items for release to the press. The basic importance of vital statistics was emphasized, and attention was given to proper organization of records, statistical analysis, and epidemiological data. The trainees prepared and evaluated report forms and individual records, and the correlation between local, state, and federal records was explained. A general course in environmental sanitation was also given to the class so that the trainee might be able to visualize the whole picture of the public health program and the relation of his particular niche to the whole. No formal examinations were given. The work of each trainee was evaluated through his individual preparation of prac- tical health education projects, such as talks, radio programs, panphlets, posters, and news articles. Each trainee presented his material to the class for discussion and evaluation. A conference period was scheduled at the end of each day’s work to discuss the significance of the procedures observed and carried out. SPECIAL STUDIES. After the period of general orientation, the class was divided into special study groups consisting of sanitary engineers, veterinarians, sani- tarians, public health nurses, health educators, and record analysts. Certain mem- bers of each group worked intensively in the different parts of the training area previously surveyed by the entire class, and parts of the instruction given as general orientation were amplified and studied with respect to the particular needs of each group after the class was divided. Separate programs within the course were pursued by each group from this point on. SANITARY ENGINEERS, VETERINARIANS, AND SANITARIANS. The engineer’s activi- ties include primarily the technical planning, supervision, and administra- tion of sanitary works. The sanitarian Interns examine garbage disposal facili- ties. Veterinarian trainees inspect dairy herds, and sanitarians visit eating places to study food handling. carries on the detailed field activities in environmental sanitation. The veteri- narian is concerned chiefly with sanitary problems relating to dairy and meat prod- ucts. The work of these three groups overlaps in certain spheres and, therefore, they were considered together in the training course. The whole class observed the same field activities, but the individual projects carried out by each group dif- fered to some extent. Field inspections were made of dairies, pasteurization plants, ice cream fac- tories, and special freezing units, and complete records and reports were prepared and evaluated. Each intern also made a general survey of the problems involved in retailing food products. The trainees participated in a practical program of malaria control in the training area, including larviciding, drainage, and residual house spraying. Similarly, ratproofing, rat poisoning, and general sanitation pro- grams were observed in regard to the latest procedures and technics in the control of typhus fever. The trainees were informed of modern practices in the field of water purification, and each was given an opportunity to participate in the opera- tion of both a large and a small water plant, and in the essential chemical and bacteriological control testing. The development and plans of sewerage systems and sewage treatment works were studied, as well as the general field of industrial sanitation. Interns also investigated recreational facilities of Savannah Beach and the public swimming pool. Projects were assigned in rural sanitation which would provide a working knowledge of design, installation, and cost of proper sew- age disposal, and of private and semi-private water supplies. Methods of insect control in rural areas were also investigated. The interns were encouraged to answer complaints of sanitary conditions made by citizens in the community. They discussed necessary corrective measures and then followed through to see that the source of the trouble was eliminated. Prem- ise inspections were made of city blocks in widely separated sections of the city. A series of lectures and demonstrations, together with clinic and home visits, gave the trainees a better understanding of the purpose and scope of public health nursing. Veterinarian trainees spent two weeks of the course in a detailed in- vestigation of the physical facilities of abattoirs and the problems of abattoir inspection. The last part of the course for veterinarian trainees concerned the epidemiology of some of the diseases transmitted by animals. The location of dis- ease foci, the importance to the human population, methods of control, and estima- tion of cost of controlling were outlined by the intern. INTERNSHIP IN PUBLIC HEALTH At the completion of the program for sanitary engineers, veterinarians, and sanitarians, each group had not only a detailed working knowledge of its own spe- cialty, but also an understanding and appreciation of the problems of the other groups, as well as a complete picture of the public health program. PUBLIC HEALTH NURSES. Intern nurses were taught the accepted technics of home nursing visits, and each was given a series of cases for clinic or home super- vision. Clinic organization, administration, and procedure were studied, and the interns participated in the activities of both communicable and non-communicable disease clinics. Nurses were also stationed in child health centers in various sections of the city where they observed and helped in the routine work. In addi- tion to care and inspection in the centers, the interns organized and instructed lay groups in public health problems. Frequently they were called upon to lecture before various clubs and to enlist cooperation in stimulating civic action. The interns also worked closely with regular nurses and teachers in promoting and de- veloping a sound health program in the schools. The intern nurses performed the various nursing duties involved in public health programs under the direction of competent, practicing supervisors. HEALTH EDUCATORS. The objective of this training was to provide field experience in public health education, and the course was designed to outline methods and sources of materials. An annotated list was prepared of national, state, and local organizations from which health education materials were available, to be used as a guide in obtaining materials for future work. The importance of maintaining a library of health education materials was stressed, both for use of the health educator and other health department staff members. Studies were also made of the material that should be placed in public libraries. Selected books were reviewed and discussed, and surveys of libraries were made to determine adequacy of avail- able health education materials. Interns were taught proper methods of preparing news articles by conferences with professional news writers, discussions of articles released currently, and by group criticism of articles prepared by individual trainees. Observations were made in clinics and in the field to obtain first-hand knowledge of information Nurse interns partici- pate in the actual work of the clinic and child health center, besides making routine home visits with public health nurses. INTERNSHIP IN PUBLIC HEALTH 41 Health educator interns are taught to evaluate audio-visual and radio technics and materials. which should be made available to the public, and posters, pamphlets, and news articles were prepared by the trainees and released to the public as part of the various health education programs in progress in the area. Trainees also worked in conjunction with the local health department staff in developing lay informa- tion materials on a rabies control program, as representative of an intensive cam- paign against one problem. In this project emphasis was placed on health educa- tion as a joint function of the entire health department staff rather than the sole responsibility of the health educator. Specific instruction was given as to content, composition, layout,'and repro- duction of annual reports. Each trainee prepared a dummy copy of an annual report and solicited bids for reproducing by various methods from local printing firms. Interns also received instructions and experience in organizing study courses and in conducting classes for lay and professional groups. The trainee was held re- sponsible for providing suitable pamphlets, posters, motion pictures, and other materials necessary for such courses and for conducting the meetings of the classes so organized. A well-rounded school health program was developed by the intern through individual conferences with teachers, administrators, PTA leaders, school nurses, and children. The health educator also worked toward the forma- tion of a school health council, de- veloped teachers’ kits of health ma- terials, and placed selected materials in the school library. All during the Studies are also made of health education materials to be placed in schools and pub- lic 1 ibraries. 42 INTERNSHIP IN PUBLIC HEALTH training course, methods of objectively evaluating materials and technics of health education were taught. RECORD ANALYSTS. Record analyst interns reviewed and evaluated records and re- port forms recommended by the state health department to the local health units, and records designed locally for the recording of local health services. Oppor- tunity was given for constructing record and report forms for administrative, ser- vice, and statistical purposes. The interns were trained in the technics of com- puting and applying public health statistics to local health problems, and in using these statistics as a means of interpreting community health records. SUMMARY. It should be strongly emphasized that almost the entire time of the trainee during the twelve-week internship course was spent “working on the job” under close supervision. The practical field work provided experience as a sup- plement to academic training offered in schools of public health. The internship course was made flexible to accomodate both professional and sub-professional people of widely differing backgrounds and experience. Although the internship course was based on and intimately connected with the routine work of the health depart- ment activities, there was no interference with this work, since the teaching load was absorbed by the MCWA staff of instructors working in close cooperation with the health department. Specialized study in each course was based upon the nature of requests from state health departments for assistance in training new personnel to carry on sanitation activities. Record analyst interns review and evaluate records and re- port forms. Diagnostic Laboratory Training In 1944, when the end of the war was in sight, a memorandum was prepared at a meeting of the American Society of Tropical Medicine by the committee on war and postwar problems, calling the attention of the Surgeon General to the possibility that certain exotic parasitic diseases might be introduced into the United States by returning service personnel and by travelers in this air age. The need for ade- quate diagnostic laboratory services was apparent, especially to aid the practic- ing physician in prompt recognition and reporting of such tropical diseases. Accordingly the recommendation was made that the U. S. Public Health Service consider setting up an information service for practicing physicians designed to emphasize the possibility of the introduction of certain exotic species and strain-, of parasites, particularly amoebiasis, schistosomiasis, filariasis, ancylostomiasis echinococcosis, leishmaniasis and trypanosomiasis, and malaria; and to assure that adequate laboratory diagnostic services would be available through health depart- ments for the use of the physicians. FIRST PLAN. Under the direction of the Surgeon General, a plan was proposed in the fall of 1944 to give brief refresher courses in the identification of the prin- cipal tropical parasites at one of the several schools of tropical medicine in this country to interested professional and technical men being discharged from the service and then to assign them to state health department laboratories. These trained technicians were to serve the states both in the laboratory diagnosis of tropical diseases and in training other technicians within the state. A survey was made of all colleges and universities in this country to determine whether any had the facilities and were willing to give such courses. It was found that none of the schools surveyed were able to handle such refresher courses by reason of personnel or equipment limitations. In addition, no qualified veterans could be recruited and this original plan proved impracticable. SECOND PLAN. On February 21, 1945 the responsibility for carrying out a train- ing program was placed with the Office of Malaria Control in War Areas, and it was proposed that a laboratory be established at headquarters in Atlanta, Georgia. To make this plan feasible, it was decided that currently-employed state, city, and municipal laboratory technicians be brought to the MCWA laboratory for brief refresher courses instead of trying to recruit and train new personnel for assign- ment to the states. This plan was presented to the American Society of Tropical Medicine and to state and territorial health officers, and in the spring of 1945 a Professional Information section was set up in the Training and Education Div- ision of MCWA, LABORATORY ESTABLISHED. At first the Professional Information section was es- tablished for the edification of practicing physicians and functioned to build up a fund of specialized information on tropical diseases, including a lantern slide library and an information service. As additional personnel became available plans were put into operation to establish a laboratory. Space was obtained, facilities planned, and equipment was secured - not without considerable difficulty due to DIAGNOSTIC LABORATORY TRAINING war-time shortages. On September 1, 1945 this section was renamed the Diagnostic and Training Laboratory, under the Train- ing and Education Division. The MCWA laboratory was designed to serve three purposes: (1) to offer an intensive train- ing course in the laboratory diagnosis of tropical diseases; (2) to serve as a diag- nostic laboratory for the examination of specimens submitted by state health de- partment laboratories and from various surveys; and (3) to serve as a distribu- tion center for teaching materials. It was obviously impossible for all employed technicians to come to Atlanta for the training course, and it was therefore Lectures precede each day’s laboratory work. decided to send teaching materials to the state, county, city, and municipal lab- oratories for practice diagnosis and instruction. This extension service was started with malaria films. This service was so well - received everywhere and has grown so rapidly that more than 150 laboratories in 48 states and the District of Columbia are now on the mailing list. Sets of prepared slides of fecal material are being sent monthly to about 59 former students in 26 states and Puerto Rico for reviewing the laboratory diagnosis of intestinal parasites. COURSE WORK, Idle first course was announced through the USFHS district offices to the various state health department officials. They submitted lists of persons whom they wished to have attend the first course or a subsequent course. A corrmittee from the Training and Education Division of MCWA selected 21 individuals from these lists, based not so much on the educational background or experience of the individuals as on the wishes of the states. An attempt was made to distribute representation throughout the country and to include individuals from the various USPHS districts. Several MCWA technicians were also included in the first class. On October 1 the first class of 24 students, representing 19 states in eight USPHS districts, reported for instruction. (This was one day after the all-impor- tant microscopes were delivered to the laboratory.) The course work was divided into two sections; the first three weeks were devoted to the laboratory diagnosis of intestinal parasites and the second three-week period to the diagnosis of blood parasites. Weekly topics included: diagnosis of intestinal protozoa (amoebae, flagellates, cultivation and concentration technics); diagnosis of intestinal pro- tozoa and helminths (ciliates, coccidia, nematodes, staining and concentration technics); diagnosis of intestinal helminths (cestodes, trematodes, and concen- tration technics); diagnosis of hemoflagellates, filarial worms, and malarial para- site thin films (leishmaniasis, trypanosomes, filarial worms, four species of plas- modia, and staining of blood films); diagnosis of malarial parasites in thick blood films and arthropods of medical importance; and diagnosis of malarial parasites in thin and thick blood films. Various books on parasitology and tropical medicine and many scientific and technical journals in the library were available for study and laboratory reference, in addition to the several manuals on medical proto- zoology, helminthology, and arthropods of medical inportance supplied to each stu- dent for individual use. The Preparations Laboratory (left) and the Culture Laboratory (right) prepare specimens and material for course instruction and the extension service. INSTRUCTORS. Several individuals participated in the instruction; some were visiting lecturers and others were members of the staff. The Malaria Investigations Office of the National Institute of Health loaned a protozoologist to give the section of the course on microscopical diagnosis of malarial parasites. An engineer and an entomologist were loaned by the in-service training section for that portion of the course devoted to the identification of arthropods of medical importance. The lec- tures and laboratory instruction on the protozoa (except malarial plasmodia) and helminths were shared by two regular staff members. LABORATORY FACILITIES. In addition to class instructors, the assistance of six technicians was utilized during the laboratory exercises. These technicians were permanently assigned to one of the four laboratories maintained as part of the Diagnostic and Training Laboratory. The Preparations Laboratory was responsible for procuring specimens and equipment for instruction and for the preparation of materials for the extension service. The Culture Laboratory maintained strains of intestinal and blood parasites to be used both in the teaching program and for the extension service. The Intestinal Parasite Laboratory participated in intestinal parasite surveys in cooperation with state and local health departments, and re- ceived and checked the identity of intestinal parasite material sent in from var- ious sources for class use. This laboratory prepared the daily practice unknowns for identification by the students as part of the course work. The Blood Parasite Laboratory participated in malaria parasite surveys and hematology studies in co- (left) The Intestinal Parasite Laboratory participates in surveys and identifies specimens sent in for class use. (right) The Blood Parasite Laboratory identifies malaria parasite material received from field surveys, and checks materials for teaching purposes. DIAGNOSTIC LABORATORY TRAINING operation with state and local health departments and was responsible for checking malaria slides obtained for teaching purposes. The Staff Laboratory was main- tained for research projects carried on by members of the Diagnostic and Training Laboratory staff. All of these laboratories were utilized in connection with the clinic service available to MCWA headquarters personnel, and for the diagnosis of materi- al referred to the Diagnostic and Training Laboratory by state and local health de- partments. OBJECTIVES. The objectives of the course were seven-fold: to learn the diagnostic stages of the parasites, including their detailed morphology and the clinical ma- terial in which they are found; to learn the infective stages and where they are found; to learn the life cycles of the parasites and the methods of transmission; to learn the routine laboratory examina- tion procedures; to evaluate the labora- tory procedures and- to learn the signifi- cance of the results obtained with each; to learn the symptoms and geographical distribution of the parasite diseases in order to facilitate the laboratory search for the etiological agents; and to learn the arthropod vectors of parasitic and tropical diseases. COURSE DETAILS. The course was planned from the practical laboratory standpoint. The greatest amount of time and emphasis was placed upon the actual performing of laboratory technics and the microscopical identification of organisms. The students were required to satisfactorily diagnose numerous unknown specimens. A large quan- tity of fresh, living material was avail- able for this course due to the mainten- ance of experimental infections and cultures of various parasitic strains, as well as from surveys that were run concurrently by the Diagnostic and Training Laboratory. Additional material was also obtained through the cooperation of the National Institute of Health, the Army Medical School, and the Georgia and Florida Health ( above) The greatest amount of time and effort is placed on actual laboratory t echni c s. (center and below) Students are required to satisfactorily diagnose numerous unknown specimens. DIAGNOSTIC LABORATORY TRAINING 47 Laboratories. Recently a staff member was assigned to the School of Tropical Med- icine in Puerto Rico for the express purpose of collecting additional material to be used in this course. Hie greatest effort was made to train the students to be able to find and diag- nose parasitic organisms. In addition, it was considered most important that they be capable of interpreting their results and know the values and limitations of the procedures used. In order to assist the lecturers in the presentation of this and more theoretical information, the laboratory staff aided in the preparation of film strips and motion pictures related to parasitology. Some of these were produced specifically for the course, whereas others were designed not only for laboratory use but also for presentation to practicing physicians, medical students, and other professional groups. To provide individual attention, it was found ad- visable to break the class up into small groups for the purpose of holding dis- cussion sessions and oral quizes to determine the progress of each student, and to clear up any questions over which the students might be puzzled. The course was flexible enough to make modifications best suited to each class, although the basic information remains much the same for each group. Enthusiastic comments from the students have been very encouraging. Since October 1945 three six-week courses have been given, and 59 individuals representing 26 states and Puerto Rico participated. Hiose individuals who were deemed to have successfully completed the course were presented with a certificate signed by the Surgeon Gen- eral of the U. S. Public Health Service. OTHER SERVICES. On March 1, 1946 the laboratories were separated from the Train- ing and Education Division, and a separate Division of Laboratory Services was created. This was in line with the reorganization of the Office of Malaria Control in War Areas for its evolution into the new Communicable Disease Center, which was scheduled to occur on July 1, 1946. The Division of Laboratory Services conducted various surveys; blood slides were obtained from North Carolina, Arkansas, and Puerto Rico and, to date, 9,861 have been examined for malaria parasites. Fecal Consultative services are rendered to state and lo- cal health departments and practicing physicians. 48 DIAGNOSTIC LABORATORY TRAINING examinations for intestinal parasites were made oil 450 children from a church clinic in Atlanta, Georgia, and quantitative studies to determine the degree of infection with hookworm were being made of a rural population in South Georgia. Consultative diagnostic services were rendered to state and local health de- partment laboratories and to practicing physicians who requested them. Field in- vestigations were carried on in cooperation with the National Institute of Health during an outbreak of amoebic dysentery in an Alabama institution. A number of studies were conducted to evaluate and possibly inprove various laboratory technics which are used in the diagnosis of parasitic diseases. These included cultivation and staining technics for intestinal protozoa, concentration technics for intestinal protozoa and helminths, and staining methods for malaria parasites. On April 1 the Division of Laboratory Services took over the Rabies Research Laboratory of the Rockefeller Foundation at Montgomery, Alabama for bacteriological and virus in- vestigations. During the next month the complement-fixation work for typhus fever and the mosquito host-preference serology studies were transferred from Washington and Savannah, respectively, to this laboratory. Although much has been accomplished in the past year, the Division of Laboratory Services is still in its infancy. With the establishment of the Communicable Dis- ease Center, this division will be ready to contribute its share to the ever-ex- panding responsibility of guarding the nation’s health, undertaken by this new agency of the U. S. Public Health Service. Field investigations were carried on in co- operation with the National Institute of Health during an outbreak of amoebic dysen- tery in Alabama. T raining Aids Training aids are indispensable to the proper execution of a modem training or educational program, and the production and correct use of these aids are highly important in the organized presentation of such programs. In the logical sequence of producing aids to training, the first step is to plan audio-visual material as an integral part of the training program; the second step is to produce these aids. In actual practice planning must take account of the mechanical and technical limi- tations of any process used, and therefore these two steps are never entirely sepa- rate operations. PLANNING During this fiscal year the planning section of the Training and Edu- cation Division continued its primary function of planning films, film strips, and exhibits for use in the various technical training activities carried on by MCWA. To keep pace with the ever-increasing demand for audio-visual aids as the training program expanded, it became necessary to reorganize the procedures of scrj.pt de- velopment and production processing. A working procedural flow chart was developed to check the progress of individual projects and the program as a whole. The develop- ment of visual materials was sub-divided into the stages of pre-planning, planning, production, release and distribution, and utilization and evaluation. The necessary steps within each stage, and the administration and duties of the participating personnel, were resolved and put into operation. Recruiting personnel to meet the demands of expansion has been a continuing process. The training of project supervisors, who are responsible for all of the stages in the planning and production of a particular film or film strip, was implemented by a workshop on production technics. In the workshop the project supervisors were assigned a subject of their own choice for development into a motion picture or film strip. Under close supervision they carried the subject through all of the steps of pre-planning and planning as if an actual production were under way. Special consideration was given to story conferences, in which all of the technics1used were discussed in detail and where the advantages and limitations of each process were studied. Visual materials already in use were scrutinized at great length with a view toward criticism and improvement of technic. Some of the material so developed in the training workshop was incorporated into the regular program. Technical TRAINING AIDS 50 advisors,, who are consultant scientists, had to be indoctrinated with the principles of presentation and with the special prob- lems of audio-visual production of scien- tific films. This indoctrination was part of the planning section’s work. In anticipation of a long-range, audio- visual production program in preventive medicine and public health, plans were prepared for a preliminary, over-all pro- spectus based upon the three major subject areas: principles of public health, com- municable diseases, and environmental san- itation. During the year both motion pic- tures and film strips were produced in the last two of these three subject areas, but their production was determined largely by the needs of the training and edu- cation programs rather than as a part of a comprehensive program in preventive medi- cine and public health. PRODUCTION. The training aids production section also expanded considerably in personnel and production facilities during this year. Equipment for rush and emer- gency work was installed since competent processing laboratories are located at great distances from Atlanta and long delays were sometimes involved in obtaining service from them. the policy of utilizing the services of commercial lab- oratories in the routine mass production of motion pictures and film strips was still being adhered to. With the equipment available it was possible to turn out the first prints of film strips and recordings on very short notice. Such had frequently been the case during the year when audio-visual material was urgently needed for a new class or where a special foreign-language recording was required for a national or inter- national meeting. Further steps were being taken in this direction to provide MCWA with the latest production equipment, permitting a more finished and profes- sional type of motion picture and film strip. Also, a satisfactory color film strip process was developed and a large majority of the film strips produced were in color, which adds considerable audience interest to the presentation of the subject. During this year 15 motion pictures and 26 film strips were completed and released. The number of motion pictures by subjects were: impounded water, four; laboratory Story boards for film strips are photographed in sequence on an animation machine. Illustrations for publications and films are worked up by the art unit. TRAINING AIDS 51 processes, two; medical aspects of mala- ria, one; dengue and yellow fever, three; malaria control technics, 12; tropical diseases, three; yellow fever and dengue control, three; malaria lay education, two; malaria entomology, one; typhus, four; and milk sanitation, one. Work was also begun and partially completed on nine other motion pictures and 21 film strips. Although these and other projects initi- ated in the past will be completed, the policy of the organization has shifted from the preparation of visual aids for both lay and professional groups to prep- aration exclusively for professional people. The production section also furnished three exhibits for display at major sci- entific meetings in this country and pro- vided photographic and art material for handbooks, field bulletins, and reports released by MCWA. In carrying out the foregoing work, and in supplying services to other divisions of MCWA, this section produced 6,767 black-and-white and 2,774 color photographs, 21,224 black-and-white and 138 color prints, and 662 projection slides. The art unit was called on for a variety of chores, including retouching 300 photographs, 232 art story boards, 105 overlays, 75 film strip and motion picture titles, 55 lettering jobs, 45 general illustrations, 24 maps, 18 charts, 15 cover designs, 15 pictographs, 12 photo-montages, designing 6 exhibits, and 28 miscellan- eous jobs. FILM LIBRARY. For the efficient use of visual aids, especially in light of the planned production expansion, a well-organized film library was a “must.” A member of the staff of the Training and Education Division was assigned to the task of surveying existing audio-visual materials and the facilities for projection, main- tenance, distribution, and exchange. Based on his recommendations, plans were to be drawn for a film library. On November 7, 1945 a memorandum was issued for the establishment of a library which was to serve as a national distribution center for films and other visual aids on tropical diseases. The scope included materials pro- duced by MCWA headquarters, materials ac- quired from other sources for distribution by MCWA, and an in-service library for ex- clusive use by headquarters. Types of ma- terials involved included: 16 mm. motion pictures, sound and silent; film strips, Developing a film in a 16 mm. developing m achine. Editing motion picture film. 52 TRAINING AIDS sound and silent; lantern slides, color and black-and-white; charts and portfolios; projectors; and pertinent literature, such as film lists, circulars, and study guides. Detailed plans were also drawn up for the physical lay-out of the office, library, shipping and receiving room, maintenance and repair room, and the projection thea- ter. A policy of distribution and exchange was tentatively proposed. On April 15, 1946 a film librarian was hired to revise and put into opera- tion the plans previously proposed. The physical lay-out became a reality, includ- ing an air-conditioned theater. Necessary personnel was hired to staff the library. A definite distribution policy was approved and set in motion, including: closer coop- eration with district offices; working arrangements with state, city, and county health departments for the showing of films to the general public; reciprocal aid be- tween this office and other government agencies, both foreign and domestic; agreements with many commercial companies for the use of their films; a loan policy with the U. S. Army and Navy; and exchange arrangements with colleges, universities, and insti- tutions interested in the public health. Cataloging and booking files were devised. A film source file with approximately 1,000 sources from which to procure films was established. Assistance was garnered from commercial distributors located in Atlanta for large-scale repairs of projectors and related equipment. A training course was worked up for personnel concerned with the proper usage and maintenance of audio- visual projection equipment. While only a beginning was made in all of this work, the plans were set and the film library began to expand rapidly toward its goal of becom- ing a national distribution center for visual aids in tropical medicine. PUBLICATIONS. In addition to the use of films, film strips, and exhibits, the training and education programs conducted by MCWA were implemented by various handbooks, bulletins, and reports. Three handbooks on the use of till were prepared during this fiscal year. Two of these were concerned with operational programs: " DDT for Control of Murine Typhus lever," and "DOT Residual Spray Operations." The third handbook was issued in response to requests for information on the use of DDT in homes. The title of this was "DDI for Control of Household Insects Affecting Health." Other handbooks were prepared or extensively revised during the year. These included: "Drainage Maintenance," "That Drainage Job," "Identification of Female Anophelines of the Dnited States," “Larvi- ciding," "Schistosomiasis,” "So You’ve Had Malaria," and "Entomological Field Handbook.” For the efficient utili zation of visual aids, a well-organi zed film library is a “must'’. Tireless research is required to produce hand- books, bulletins, and reports. TRAINING AIDS 53 Five Field Bulletins were issued for distribution to MCWA and other interested personnel. These contained statistics of operations and articles of informative and technical nature concerning program opera- tions. Many of the articles were prepared by field personnel. Field Bulletins aver- aged about 16 pages per issue and contained numerous photographs, drawings, and tables. The Annual Report of MCWA activities for the previous year was prepared and pub- lished. This volume, consisting of 136 pages profusely illustrated with photo- graphs, charts, maps, and drawings, was circulated to members of the organization and other interested persons. In March 1946 a compilation of “History of Malaria Control in War Areas” was begun. This is to be a detailed account of activities of the MCWA office since its inception. It is anticipated that this report will be completed during the current fiscal year. The reports section also supplied scripts for use in the preparation of film strips and motion pictures to be used in connection with the training program. These in- cluded subjects on entomology and engineering. Nearly two million pieces of literature were sent by MCWA to district and state offices during the year to be used in public relations and lay education work. By title, the number distributed to the public, in schools, and at various group meetings was: “Malaria Folder No. 1,” 500,000; “How DDT Spray Keeps Malaria Away,” 300,000; “Spraytime Topics,” 250,000; “Malaria, Lessons on Its Cause and Prevention, For Use in Schools,” by H. R. Carter, 200,000; “Kill That Flea,” 107,000; “DDT For the Control of Household Insects Affecting Health," 78,000; “Mosquito Cut Out,” 75,000; “So You've Had Malaria," 75,000; “Dengue and Yellow Fever are Carried by This Mosquito, Aedes aegypti/’ 75,000; “This Mosquito Carries Dengue and Yellow Fever," 50,000; “Handbook of EOT Residual Spray Operations,” 50,000; “Impida El Dengue Y La Fiebre Amarilla," 35,000; “Entomological Field Handbook,” 30,000; “Mala- ria Education," by Elma Rood, 30,000. REFERENCE LIBRARY. The mainstay of any training, education, or research pro- gram is a comprehensive reference library. When MCWA was first organized most of the professional people brought their own personal collections of books with them for reference purposes, and no central library existed. New purchases of books for use in MCWA work were made on a sectional and divisional basis and a series of small, specialized library collections grew up within each division of MCWA. As training activities expanded, it became neqessary to provide students with reference materials for use in their course work. Most of this material was scattered through- out the divisions and sections of MCWA headquarterjs and it was obvious that a central library system was needed not only for use by students but also to provide more facile reference facilities for headquarters personnel. Accordingly, in October 1945, plans for a library committee were formulated, members to the committee were appointed, and space was provided for a central library to serve the entire MCWA headquarters. On December 6, 1945 the Library The mainstay of any training program is a comprehensive reference library. 54 TRAINING AIDS Board (nee Library Committee) met to formulate a policy. It was decided that the library should contain basic reference or source books in the various sciences related to infectious disease control and a comprehensive collection of the current periodicals in the fields related to infectious diseases. An abstracting service was contemplated for any employee of MCWA requesting it. The library also was to work in close liaison with the National Institute of Health library on an exchange basis to take advantage of its greater facilities. In January 1946 a member of the MCM staff was appointed acting librarian and the actual organization of the library began with the gathering of the reference materials from the various sec- tions and divisions into one central library. A full-time librarian assistant was appointed in April and the huge task of cataloging the books and periodicals on hand and purchasing additional books and periodicals to carry out the original plan of the Library Board was begun. By the end of this fiscal year the library was able to offer efficient reference facilities to both students and headquarters personnel, despite the fact that only a small portion of the proposed total number of books and periodicals had been acquired. An exchange service was established with the colleges, universities, and medical schools in Atlanta and vicinity to supply reference materials not yet pos- sessed by the library. Its resources were made available on a short or long term loan basis to other departments, institutions, and individuals interested in public health. At the present time the library is expanding to include those services offered .elsewhere only by the library of the London School of Hygiene and Tropi- cal Medicine. Training aids are the result of innumerable conferences on planning, production, and utilization. 56 Knowledge gained from laboratory and field investigations is the foundation upon which operational control of disease is based. A large part of the investiga- tional work this fiscal year was con- cerned with the objective of at least main- taining malaria at its present low level of morbidity and possibly eliminating it entirely from the United States. To this end, operational control was concen- trated on DDT residual house spraying in endemic areas to protect the civilian population against the possibility of contracting malaria from carriers returning from malarious areas overseas. Another important phase of investigation pertained to DDT dusting' for the control of rat ectoparasites and typhus fever. Related investigational studies, car- ried on in cooperation with the National Institute of Health, several universities, and state health departments, included; anopheline bionomics studies*, determina- tions of the infectivity of foreign malari- as for native mosquito vectors; epidem- iologic and entomologic evaluations of DDT residual house spraying; the residual dura- bility of EOT under various conditions; evaluations of DDT as a mosquito larvicide, and its possible effects on fish and wildlife’1; the design and testing of spray equipment; anopheline host-preference studies; and DDE dusting in relation to human typhus prevalence. Other investiga- tional studies this year were concerned with the implication of insect vectors in the transmission of certain virus infections. Technical Developments During the year the residual house spraying technics developed at Carter Memorial Laboratory in Savannah, Georgia, were put into operation on the Extended Malaria Con- trol Program of MOVA. With the acceptance of these technics in large-scale application, the work of the laboratory was directed toward the solution of other EDI problems. Em- phasis was placed on developing an acceptable technic for using DDT as an anopheline larvicide, and observing the effects of such larviciding on fish and fish-food organ- isms. Detailed investigations were made of some of the factors affecting the residual effectiveness of DDT wall spray. Further studies were carried out on the use of DDT in premise sanitation, particularly from the standpoint of control of houseflies in a variety of food-processing and food-handling establishments. An investigational pro- gram for the control of rodents and their ectoparasites was initiated this year. As in years past the development and testing of new and improved equipment for mixing and applying insecticides formed an important part of the work of the laboratory. ANOPHELINE LARVICIDING Extensive studies on the control of "quad” larvae resulted in the development of a technic for hand larviciding involving the application of DDT in an oil-mist spray. An atomizing nozzle such as is used in fuel oil burners was fitted to an air pressure sprayer similarly to those already in use in residual spraying. At a pressure of 30 to 50 pounds per square inch the nozzle delivered three gallons of No. 2 fuel oil per hour as a fine mist spray. At a convenient pace of about 75 feet per minute an acre could be covered by one gallon, assuming the effective swath width to be about 30 feet. This is a treatment rate of 20 minutes per acre spraying time. Total actual spraying time is more likely to be nearer 1.7 hours per acre, including pumping and refilling. To insure a positive spreading pressure, and thus a more uni- form distribution of the surface film, the addition to the DDT-oil solution of one-half of one percent of a spreading agent was recommended. Carter Memorial Laboratory, Savannah, Georgia 58 TECHNICAL DEVELOPMENTS When HOT in an oil-mist spray was used routinely on the control project, material and labor cost from $1.15 to $1.35 per acre and required 1.7 man-hours per acre. On paris green hand dusting programs the cost per acre for material and labor was from $2.25 to $2.75, and 3.1 man-hours were required. Fuel oil applied by hand cost from $8.50 to $11.50 per acre for labor and material and required three to six man-hours. It was found in using the DDT oil-mist technic that 0.05 pound of EDI per acre was adequate to insure 90 per- cent control of all instars of anopheline larvae and most culicine larvae and was reasonably safe from the standpoint of damage to fish and fish-food organisms. Extensive field testing by a regular MCWA larviciding crew during the 1945 season proved so satisfactory as to permit rec- ommendation of this technic for large- scale testing by the individual states. Field trials of DDT oil-mist larviciding. EFFECTS OF DDT LARVICIDING ON OTHER ORGANISMS Results of studies of the effects of a larvicide upon fish and upon the major groups of organisms known to he important as fish-food may well be the determining factor in its use. Accordingly a study of the effects of DDT on fish, on surface organisms, on bottom organisms, and on plankton was initiated during this fiscal year. Studies in small, shallow ponds showed that DDT was least harmful when ap- plied as a dust and most harmful when applied as a tight emulsion. A surface film of DDT-oil solution was relatively safe to fish in single doses of up to 0.1 pound of DDT per acre. Even this dosage killed numerous surface insects. Dosages of 0.5 pound and more of DDT per acre was definitely harmful to fish. Single applications of 0.1 pound DDT per acre killed many surface Hemiptera and Coleoptera. Repeated weekly applications resulted in appreciable reduction in pop- ulations of Chironomidae, Ephemeroptera, and the larger members of the families Gyrinidae, Dytiscidae, Haliplidae, Hydrophilidae, Corixidae, and Gerridae. Oligo- chaeta, Nematoda, and Copepoda were appar- ently not affected. No significant re- ductions in populations were noted in any of the plankton organisms as a result of as many as 18 routine weekly treatments with 0.05 pound of DDT per acre. Bottom samples were taken, but have not yet been classified and counted. Fish apparently suffered no direct effects from single surface applications of 0.1 pound DDT per acre, although crawfish were killed. After from ten to 13 routine TRENDS IN THE POPULATION OF OLIGOCHAETA. INSECTS AND CHIRONOMIOAE IN A POND ROUTINELY TREATED FOR 17 WEEKS AT THE RATE OF ONE GALLON OF FUEL OIL AND O.l POUND OF DOT PER ACRE. TECHNICAL DEVELOPMENTS 59 Proper application of a DDT spray emulsion is shown on the left, and treatment to the point of “run-off” is shown on the right. applications at this dosage, dead and sick fish were noted. At a dosage of 0.05 pound DDT per acre, dead fish were first found at about the thirteenth to fifteenth weekly treatment. The actual number of treatments required to start killing fish seemed to depend upon the size and depth of the test pond. Since all of these ponds were smaller and more shallow than those normally of importance for fish, it was con- sidered that 0.05 pound of CUT per acre may be safely used for mosquito control in larg- er ponds containing deep water. This is especially true if only the margins are treated. During the year, in cooperation with the Fish and Wildlife Service of the De- partment of the Interior, a series of tests were begun using airplane applications of COT both as a spray and as a thermal aerosol, using Velsicol NR-70 as the sol- vent. This experiment was to extend over one full season and possibly a second season, so that results will not be available for some time. Effects on aerial insects; birds, and small maimals were also being studied in this experiment. RESIDUAL SPRAYS With the initiation of large-scale use of residual-type DDT sprays on the Ex- tended Malaria Control Program, it was possible to devote a greater proportion of effort to inproving formulae and investigating the more basic problems affect- ing residual spray effectiveness. Considerable time was spent both in the chemical laboratory and in field trials in testing a large variety of solvents to find some- thing more satisfactory than xylene. Availability, ability to dissolve DDT, ex- plosibility, toxicity of the vapors to man, effect upon various surfaces, and emulsifiability were all considered. So far a better solvent has not yet been found. Similarly a wide variety of commercially available emulsifiers was tested. More detailed field tests of dosage and type of coverage have shown that the over-all spraying of a room is preferable to spot spraying of corners, undersides and backs of furniture and pictures, and other preferred resting places of mos- quitoes. Also it was concluded that the extra expense of applying 200 mg. DDT per square foot in place of 100 mg. is justi- fied by a better percentage of kill from three to four months after treatment. Laboratory tests have shown that the nature of the sprayed surface will great- ly affect the length of residual effective- ness. Unfinished pine plywood was used as Age of MG. DDT PEB SQUARE FOOT Residue 100 200 (months) Percent Knockdown Percent Mortality Percent Knockdown Percent Mortality 0 94 100 86 100 1 47 85 81 95 2 55 80 75 90 3 23 75 35 80 4 - - - - 5 14 50 35 75 Percent knockdown and 48-hour mortality of A.quadr imaculatus adults from 60-minute ex- posures to deposits of 100 and 200 mg. DDT per square foot from a xylene-DDT spray at 0 to 5 months after application. TECHNICAL DEVELOPMENTS a standard for comparison. Results equal to or better than this standard were obtained on fabrics (mohair, canvas, cotton goods, and window-shade materials), on wallpaper, and on rubbing varnishes that had dried for at least one month previous to spraying. Somewhat inferior results were obtained on rubbing varnishes that had dried only ten days prior to spraying, and on casein-water paint, weathered gloss enamel, fiberboard, and wire screen. Much poorer results were obtained on whitewash, spar varnish, and on gloss and flat paints that had dried for from one to 17 weeks. Very little residual toxicity was obtained on linoleum, and practically none on adobe-like clay panels. Chemical recovery of EOT from test panels showed that temperature definitely af- fected the loss of technical DOT. Thus, after one month at 40 degrees F., 76 percent of the DOT applied in kerosene solution was recovered from glass panels. When similar panels-were held at room temperature, 63 percent of the DOT was recovered after one month. At 140 degrees F., the recovery was only nine percent. Not more than half of one percent of the COT could be flaked off a panel by a total of 42 severe, standard- ized Jars over a period of one month. The exposure of test panels to a large number of houseflies was shown to reduce the residual effectiveness of DDT much more rapidly than similar exposure to mosquitoes (A. quadrimacnlatus.) Test panels used for studies of chemical recovery of DDT- INSECT PREMISE SANITATION Further studies were made in the use of DOT for the control of houseflies in a va- riety of food-processing and food-handling establishments, such as dairies, pasteur- izing plants, abattoirs, sea food plants, markets, and restaurants. New problems were encountered in the control of blowflies around abattoirs and sea food plants. Blow- flies of the calliphorid group do not rest inside of buildings at night, so that inte- rior residual sprays were not too effective. Studies of their nighttime resting habits resulted in the application of EOT to the exteriors and to the vegetation within a radius of 30 feet around the building. Preliminary results indicate that some of the newer “candidate” may have some advantage over DDT for this type of (below) Calliphorid flies used the oak out- side the oyster house as a night resting place. (right) The DDT spray is applied to the edges of the overhead beams where the flies rest in the dairy barn. TECHNICAL DEVELOPMENTS exterior residual spray. Limited studies on the use of DDT in controlling bedbugs indicated that the sinplest treatment tried, i. e., thoroughly spraying the mat- tress on both sides and around the edges with 2.5 percent DDT in xylene, resulted in apparent eradication of bedbugs for at least 16 weeks following treatment. The most satisfactory treatment for control of German roaches proved to be a combination of a spray and dust. A five percent DDT-xylene spray was used to drive the roaches out of hiding, thus dis- closing their daytime resting places. This was followed by an application of ten percent ECT-pyrophyllite dust to the hiding places revealed by the spray. With this technic the greatest mortality occurred during the first three or four days. Roaches were apparently eliminated in from two to eight weeks in most cases and no rein- festation had occurred 16 weeks after treatment. Panels of asbestos board, gypsum board, insulbrick, and masonite were tested to determine their values in ratproofing construction. RODENT AND ECTOPARASITE CONTROL A new project concerned with the control of murine typhus fever and other dis- eases transmitted by rat ectoparasites was undertaken during the year. The fact that ectoparasites tend to leave dead rats in search of other hosts may temporarily increase the transmission, of typhus immediately after the instigation of rat poi- soning measures. Although rats themselves may act as disease reservoirs, trans- mission from rat to rat and from rat to human is largely dependent upon the ac- tivity of ectoparasites. The control of ectoparasites, therefore is especially important before or at the same time that rodent control measures are applied. Ten percent DDT in pyrophyllite effectively controlled ectoparasites, espe- cially Xenopsylla cheopis. A combination of ten percent DDT, 50 percent ANIU (alpha naphthylthiourea), and 40 percent pyrophyllite served as an excellent rodenticide CONTROL OF X. CHEOPIS FLEAS WITH 10 PERCENT DDT DUST TECHNICAL DEVELOPMENTS 62 and ectoparasite control. After initial field testing, this procedure was recom- mended for more extensive field testing on an area-wide basis by selected state programs. Preliminary technics were also established for testing panels of con- struction materials to determine their values in ratproofing. EQUIPMENT DEVELOPMENT AND TESTING During the year extensive tests were conducted on a wide variety of equipment. Several sprayers for specialized purposes were developed and tested. An aluminum hand-sprayer designed for residual house spraying on a small scale had the ad- vantage of being light in weight and therefore less tiring to use. For larger buildings a portable five-gallon sprayer mounted on rubber tires was developed, using a gear pump driven by a small, directly-connected electric motor. This sprayer weighed about 50 pounds, was readily stored, and was easily transported in a pickup truck. A wheelbarrow-type exterior sprayer was developed for use by the Dysentery Control Project in Texas. It was made up of two surplus U. S. Army oxygen con- tainers, one of which contained the spray material and the other compressed air. The spray chamber had a capacity of nine gallons and the pressure chamber was charged with 100 pounds per square inch air pressure. The pressure dropped to 40 pounds per square inch in the course of spraying the nine gallons. Numerous modifications and improvements were made on equipment previously developed. (left) A wheelbarrow-type exterior sprayer was developed for use by the Dysentery Control Proj- ect in Texas. (right) An improved DDT power mixer developed by Carter Laboratory. Malaria Bionomics Observations Emory University Field Station, Newton, Georgia. The objective of MCWA activities at the Emory University Field Station, Newton, Geor- gia, waste maintain an up-to-date appraisal of malaria morbidity in the United States. Observations of the factors responsible for the natural occurrence of human malaria had been made since 1939. MCWA participation was begun in 1944 to utilize the backlog of information on malaria epidemiology collected previously. With the extensive infor- mation available, this station was able to serve as one of the principal outposts for the observation of malaria and the factors accountable for its occurrence. Malaria morbidity in the area under study was declining in comformity with the recession observed generally in North America. During initial periods of observa- tion, appreciable amounts of malaria were encountered. Malaria morbidity rates gradually became negligible, and the last blood-positive malaria cases were ob- served in 1944. No malaria control measures were intentionally applied nor were significant changes discerned which could have been responsible for the apparent elimination of malaria from this area. This year’s observations, which were con- tinued to detect as promptly as possible any factors which might contribute to an accelerated transmission of malaria, were included in three general categories: epidemiological, biological, and hydrological. EPIDEMIOLOGICAL OBSERVATIONS Epidemiological data were collected from approximately 1,000 persons residing in an area which was formerly highly malarious. In past years all persons living in the area were visited at frequent intervals by competent public health nurses 64 MALARIA BIONOMICS OBSERVATION and accurate individual case histories were maintained. Upon manifestation of any clinical symptoms suggestive of malaria, thick-film blood slides were obtained. Diagnosis of malaria was contingent upon demonstration of the parasites. In con- sideration of negligible malaria rates for the past three years, routine nursing visits to persons in the experimental area were discontinued. Periodic observations were conducted in the area to apprehend cases had they occurred. Blood parasite surveys were made in schools and in se- lected groups in the experimental section. No cases of malaria were detected dur- ing the year. Epidemiological data were collected from approximately 1000 persons in the area. BIOLOGICAL OBSEBVATIONS Measurements of Anopheles density were maintained for use in connection with investigations of Anopheles bionomics. Because of the sustained depression of anopheline populations observed for the past two years, efforts were concentrated in selected areas. In the environs of the five ponds where intensive observations were being conducted, weekly quantitative measurements of adult mosquito densities and qualitative appraisals of larval mosquito populations were obtained. OBSERVATIONS ON OVERWINTERING OF ANOPHELES. Studies to determine the manner in which Anopheles pass the winter were continued. Results obtained from work of the previous year pointed to the possibility of * quads” overwintering in the egg stage. Efforts were made to recover eggs from breeding places during the winter months when larvae could not be detected. Since the harboring places of anopheline eggs are not well known, the work was only partially successful. The first male mosquito collected at the beginning of the season is assumed to indicate emergence of the first generation of spring. No male anophelines were collected during the period between December 20, 1945 and March 15, 1946, indicating the probable ab- sence of Anopheles emergence throughout this period. During the first week in March an attempt was made to recover “quad” adults from favored resting places by fumigation. No specimens were obtained, confirming observations of the previous year that a progressive decline in mos- quito population occurs during the winter until adult mosquitoes are virtually or actually absent by spring. It is believed that oviposition occurs throughout the winter when atmospheric conditions are favorable to anopheline activity. Review of physical data accumu- lated suggested that “quad" populations are adversely affected by humidity below Collecting adult mosquitoes from artificial resting place to measure Anopheles density. MALARIA BIONOMICS OBSERVATION 65 40 percent and temperatures below 70 degrees F. Requirements for mosquito egg development are not well known; indications are that eggs are extremely resistant to low temperatures, but that develop- ment of the embryo occurs only when the temperature is above a “development zero,” which is 50 degrees F. according to the experience of other investigators. Much additional information is necessary, but the continued accumulation of data under natural conditions together with information obtained in the insectary would probably permit a much better understand- ing of the manner in which “quads” pass t he winter. ANOPHELES ACTIVITY STUDIES. Attempts were made to modify tne “New Jersey” light trap to make it attractive to “quads.” From results obtained, it seems that the light waves shorter than those of the visible spectrum may be more effective in attracting “quads” than visible light. It was found that very intense light attracted a greater number oiAnopheles than did the 25-watt bulbs ordinarily used. If a more satisfactory light trap can be devised, many problems concerning nocturnal activity of anophelines could be investigated. For the study of mosquito migration, a technic of marking adults with particles of fluorescent compounds had previously been worked out at the field station. Fur- ther studies along this line were aimed at finding suitable fluorescent materials, ingestible by the larvae without harm, which would persist in the adult stage. Five compounds showed promise, but further work was contingent upon an adequate supply of mosquitoes from the insectary. Typical anopheline breeding place in environs of the field station. HYDROLOGICAL OBSERVATIONS Hydrological observations were conducted with the continued cooperation of the Water Resources Branch of the U. S. Geological Survey. Observations of physical factors related to Anopheles breeding included measurements of precipitation at 12 points in the area, records of pond stages at 15 ponds, and records of stage and discharge from seven stream gaging stations. Three of these stations were lo- cated on large streams and the others were on small streams typical for the area. Data on ground-water variations were obtained by neasurements of 90 observation wells. These observations were made over the entire experimental area. During the. year an effort was made to intensify measurements in selected areas in order to obtain more precise information on the physical factors related to Anopheles breeding. Making measurements with tape gage at observation well. MALARIA BIONOMICS OBSERVATION PONDS. Four ponds were selected for an intensive study. At these locations hy- drological observations included measure- ments of water level, surface-water tem- perature, precipitation, wind movement, and atmospheric temperature and humidity. Most of these data were collected on con- tinuous recording instruments so that a record was preserved of intensity and dura- tion rather than maxima, minima, or means. Further work on the analyses of factors contributing to storage of water in ponds indicated that prediction of pond levels could be made with considerable accuracy if such influences as run-off and precipitation were known. The present concept of the role of ponds in the hydrological picture may be considerably revised as a result of detailed information collected in the immediate vicinity of ponded areas. The possibility was evident that ponds in the region under observation might be contained in relatively impervious basins, separate from underground water. If this is proved correct, factors responsible for the occurrence of ponds would be simpler than previously believed, and the collection of data for predicting the amount and extent of surface water storage would be materially simplified. EVAPORATION. An evaporation station was established during the year to permit more critical evaluation of factors responsible for water losses from ponds. Meas- urements were made of the same factors being measured in the pond; i. e., water surface temperature, wind movement, precipitation, and atmospheric temperature and humidity. Since a record of the water level in the pond was also maintained, the linear amount of water loss from the pond was determinable and could be compared with evaporation loss from an artificial container. Thus, water loss due to seepage and transportation could be approximated. Records from the evaporation station were available from the beginning of 1946. These included measurements of evapora- tion from a standard type of Weather Bureau evaporation pan and from an insulated pan of the same size. The length of the record did not include the season of maxi- mum evaporation, nor were correlations of data from the evaporation stations and ponds complete. Preliminary analyses did indicate however that evaporation and possibly transpiration could be calculated indirectly from the factors under ob- servation. Studies along these lines were being continued. Recording hydrothermograph. (left) Stream flow gaging station above a small dam at Emory University Field Station. (right) Evaporation station for determining amount of water loss from ponds. Malaria Field Studies Investigations carried on by the Malaria Field Research Station, Manning, South Carolina, in cooperation with the South Carolina State Board of Health, centered around a study to determine the efficacy of DDT residual spray in preventing trans- mission of human malaria. In addition observations were made on the epidemiology of malaria in an area. The area chosen for study of the effect of DDT residual spray was located in the only known highly endemic malaria region in the United States, the Santee- Cooper reservoir area in the coastal plain of South Carolina. The Santee Reservoir is 30 miles long and about three and a half miles wide with a total water-surface area of 97,000 acres and a shore line of over 497 miles at the 75-foot contour. The smaller Pinopolis Reservoir, connected with the Santee by a diversion canal, is about 12 miles long and ten miles wide and has a total water-surface area of about 65,000 acres and a shore line of 151 miles at the same contour elevation. Records taken over a ten-year period in the vicinity of the Santee River showed that malaria increased after water was impounded in the Santee and Pinopolis basins in 1941. Minor epidemics occurred during the seasons of 1942 and 1943 in Clarendon County near the Santee Reservoir. SANTEE - COOPER RESERVOIRS AND VICINITY WMOXWUTt SCALE Of NLCS 68 MALARIA FIELD STUDIES The study area was divided into two approximately equal parts; one part was set aside for spraying, the other left unsprayed. Each of the areas had a population of about 1,500 people, of whom 90 percent were Negroes. Most of the people worked on farms. Ninety percent of the houses were not mosquito proofed. The majority of malaria in the area was caused by Plasmodium falciparum. Houses were sprayed with residual DDT during the last two weeks of April 1945 and again three months later. The methods of spraying were the same as those used on the Extended Malaria Control Program of MCWA. A residuum of 100 mg. of DDT per square foot was left on the sprayed surface of the walls and ceilings of each room in the house. Porches and privies were treated, but other outbuildings were left unsprayed. EPIDEMIOLOGICAL STUDIES The parasitemia prevalence during the pre-spraying period showed a continuous downward trend from October 1944 to April 1945, as might be expected over the winter months. In October 1944 the prevalence was 20.7 percent in the sprayed area and 16.3 percent in the unsprayed. In April 1945 it was respectively 6.1 and 5.1 percent in the same areas. Thick film blood smears were obtained at monthly intervals during the post-spraying period, beginning the first of June 1945. More than 90 percent of the 3,000 people in the entire study area were tested during each survey. A graphical comparison of gross parasit- emia prevalence percentages in the sprayed and unsprayed areas from June 1945 to January 1946 is shown in Figure 1. Hie data are adjusted for population changes due to births, deaths, immigration and emigration, a s we 11 as moving from one area to the other. The parasitemia prevalence during the post-sp raying period was higher in the unsprayed area than in the sprayed area. Detailed analyses by sex, race, age groups, and species of Plasmodium served to confirm the statistical significance of the difference between the gross para- sitemia prevalence of the two areas. Fur- ther refinements of the data to allow comparison of incidence rates in the two areas, computed from all individuals with parasitemia against all tested individuals with the same number of monthly smears, also corroborated the gross parasitemia prevalence percentages as a satisfactory representation of the parasitemia occurrence in the two areas. On the basis of the analyses of the parasitemia data, it was determined that LDT residual spray was found to be effective in reducing malaria transmission in humans. Although evidence of the occurrence of new infections of malaria in the sprayed area was seen, it was at a significantly lower rate than in the unsprayed area. A clinical study of the people in the area was carried out between June and Decem- ber 1945. This study consisted of semi-monthly sickness screenings of the entire population and follow-up medical studies on reported sick persons. Severe clinical manifestations of malaria were rare in 1945. The majority of cases seen were of Fig. 1. Parasitemia prevalence, June 1945-January 1946. Percentage of thick blood smears positive for plasmodia. First spray period April 15-30, 1945. Second spray period July 15-30, 1945. MALAHIA FIELD STUDIES 69 the mild localizing type, only rarely con- fining the individual to bed or house. The most frequent complaints were irregular night fever, headache, backache, and mal- aise. Typical proxysms were infrequent. Cer- tain human host factors were examined and measured for tendencies which might affect the parasitemia prevalence. The observed infection rates were considered in relation to the total tested population: well per- sons, sick persons, individuals with para- sitemia, and those without manifest para- sitemia. Crude quantitative effects of cer- tain human host factors, such as prevailing illness and frequency of anti-malarial self-medication, were determined. The comparability of the two areas as to certain human host factors was demonstrated and the effects of some important host- parasite relationships on the monthly parasitemia rates were presented. It was shown how parasitemia prevalence rates are functions of biological phenomena acting prior to the taking of blood smears, and how sickness from all causes might affect the parasitemia rates by increasing self-medication with anti-malaria drugs. It was also shown that the effects of these human host factors may cause minor fluc- tuations in monthly parasitemia prevalence. Typical housing in the Santee-Cooper area. ENTOMOLOGICAL STUDIES Entomological observations were made in the study area during the entire season of 1945. These consisted of: (1) the recording of anopheline populations at selected “index stations,” approximately 20 percent of the occupied homesteads; (2) the dissection of anophelines for sporozoites in the salivary glands; and (3) the testing of the blood meals in the anophelines to determine the hosts upon which they had fed. Population studies showed that anopheline density distribution, although uneven within the areas and unequal between the areas, conformed in general with the domi- cile distribution of the parasitemia infections. The seasonal trend of the Anopheles quadrimaculatus populations in stables showed a rfse from June to September and October 1945. November showed an abrupt decline in A. quadrimaculatus population, although A. crucians was present in some numbers throughout most of this month. Throughout the post-spraying period, houses in the sprayed areas were generally free of mosquitoes during the daytime. Terrain of the Santee-Cooper area favors anopheline breeding. 70 MALARIA FIELD STUDIES A. quadrimaculatus were collected for dissection, beginning May 29, 1945, until this species virtually disappeared about the first of November, after which time some A. crucians were also dissected. The sporozoite rate increased with the advanc- ing season, conforming in general with the fall rise of the parasitemia prevalence. For the entire season, ten infected “ quads,” or 0.14 percent, were found in 6,963 dissected from the sprayed area, while 20, or 0.19 percent of the 11,862 from the unsprayed area showed sporozoites. HOST PREFERENCE AND INFECTIVITY STUDIES Determination of host preference by precipitin tests of engorged mosquitoes showed that 12, or 0.76 percent of 1,577 tested from the sprayed area had fed on human blood, while 210, or 7.5 percent of 2,793 tested from the unsprayed area had fed on humans. The latter percentage included specimens caught in houses, whereas mosquitoes were not found in houses in the sprayed area. When the out-building samples were com- pared for the two areas, there was virtually no difference in the percentage of human feedings; 0.76 percent for the sprayed area and 0.75 percent for the unsprayed. In cooperation with the National Institute of Health Malaria Investigations Labor- atory at Columbia, South Carolina, studies were carried out to determine the infec- tivity to native mosquitoes of native cases of malaria in Negroes. Results of these investigations are given in the “imported Malaria Studies" section immediately following. (left) A. quadrimaculatus were dissected, (right) Precipitin testing to determine number of mosquitoes which had fed on human blood. Imported Malaria Studies Imported malaria studies were continued during this year by the Malaria In- vestigations Laboratory, National Institute of Health, Columbia, South Carolina, in cooperation with MCWA. Four laboratories were operated to determine the public health significance of returning malaria carriers. These laboratories had access to troops in about 12 Army and Navy hospitals and the cooperation of six mental hospitals for study of malaria infections. Studies conducted during the previous year indicated that foreign malarias relapsing in returning troops could be spread by our native vectors and that control measures were necessary against these foreign malarias in returning carriers. During the course of studies on foreign malarias, it was found that an infec- tion with a foreign strain of Plasmodium vivax gave little or no immunity against a subsequent infection with a domestic strain (St. Elizabeth). The reverse was also true. Over 200 patients were observed in delayed primary attacks. These at- tacks followed soon after the discontinuation of suppressive dosages of atabrine and were characterized by lower parasite densities than the later relapses. How- ever when treatment was denied, comparably high parasite density levels were reach- ed. The observations on the delayed primary attack were compared with similar ob- servations on induced primaries and the similarities indicated that the delayed primary more nearly resembles the natural primary than the relapse attack. Relapses tended to follow a pattern, according to individuals. An individual with a high parasite count during one relapse would be likely to show high para- site counts during other relapses. Similarly, in some individuals gametocytes are produced more consistently than others. Little difference in parasite levels was exhibited during early and late relapses. Parasite levels were similar in Pacific and Mediterranean cases, but in the latter high gametocyte counts were noted. ASYMPTOMATIC PARASITEMIA The parasitological patterns of relapsing malarias were of three general types: (1) most patients showed parasites up to a week, or rarely longer, preceding the onset of fever (relapse); (2) a small percentage of patients exhibited transient asymptomatic parasitemias between clinical relapses; and (3) following the last clinical attack, a small number of patients exhibited terminal asymptomatic para- sitemias which lasted for months. The asymptomatic parasitemias showed a low para- site density on the average. Gametocyte production appeared to be in proportion to the total parasite count. One hundred eighteen lots of mosquitoes were applied to 34 individuals with asymptomatic parasitemias. Twenty-eight percent of the mosquito lots showed some infection, and 12 percent of the patients at some time infected mosquitoes. The highest incidence of infection was obtained just before onset of fever. This clear- ly indicated that patients with asymptomatic parasitemias could infect native mos- quitoes, although to a lesser extent than clinical relapsing cases. However because of the absence of symptoms and the consequent greater likelihood of exposure to mosquitoes, such persons might be more of a public health hazard than the clinical relapsing cases. THE INFECTIVITY TO ANOPHELES OF MALARIAS OF FOREIGN ORIGIN OUADR/MACULATUS MOSQUITOES PROBABLE ORIGIN OF INFECTION PATIENTS UPON WHOM MOSQUITOES WERE FED MOSQUITOES FED ON PATIENTS NUMBER NUMBER INFECTIVE TO MOSQUITOES DISSECTED INFECTED PERCENT INFECTED SOLOMON ISLANDS 72 42 2,871 789 27.5 NEW HEBRIDES 2 1 169 14 8.3 NEW GUINEA 44 23 1 ,846 640 34.7 MEDITERRANEAN 40 30 1 ,256 467 37.2 LIBERIA 1 1 47 10 21.3 BURMA 2 1 89 38 42.7 CARIBBEAN 6 4 147 20 13.6 TOTAL ALL AREAS 167 102 6.425 1,978 30.8 IMPORTED MALARIA STUDIES 73 In cooperation with the Malaria Field Hesearch Sta- tion, studies were made at Manning, S. C., to determine the infectivity to native cases of malaria, principally asymptomatic, in Negroes. A total of 115 lots of mos- quitoes were fed on 96 pa- tients. Out of eight cases of P. malariae, two were infec- tive to mosquitoes. Out of 106 cases of P. ealciparum, 16 infected mosquitoes. The single feeding on P. vivax did not infect mosquitoes. The infections were produced in mosquitoes during the win- ter as well as in the summer. The patients infecting mos- quitoes showed a very low gametocyte count. All were below 34 per cram., and 11 of the 18 had a count below ten gametocytes per cmm. Con- versely, some gametocyte carriers with 121 and 165 per cmm. did not infect mosquitoes. During the course of the investigations it was learned that neuro-syphilitic American Negroes shoved a general resistance to foreign P. vivax as compared to white neuro-syphilitic patients, who were virtually non-immune. The difference was statistically significant. RELATIONSHIP OF NUMBER OF RELAPSES TO MONTHS SINCE FIRST ATTACK, TO MOSQUITOES INFECTED, AND TO GAMETOCYTES PER 100 WHITE BLOOD CELLS AVERAGE NUMBER MONTHS FOR EACH RELAPSE NUMBER (I6Z CASES) (NUMBERS AT POINTS ARE NUMBER CASES TESTED) PER CENT MOSQUITOES INFECTED GAMETOCYTES PER IOO WHITE BLOOD CELLS DELAYED PRIMARY ATTACKS = P AVERAGE NUMBER OF RELAPSES » B.O'I AVERAGE NUMBER OF MONTHS = 15. IJ USPMS - CDC ATLANTA. GEORGIA JUNE . 1947 Fourteen species of native mosquitoes were fed on a patient infected with Wuch- ereria bancrofti from Bora Bora in the French Society Islands. Microfilariae were present in the peripheral blood stream. Culex pip tens and C. quinquefasciatus were highly susceptible. Low grade infections were found in C. erraticus, C. salinarius. Anopheles punctipennis, Aedes triseriatus, A. aegypti, A. atropalpus, and Mansonia per turbans. Anopheles walkeri was found to be moderately to highly susceptible, but the number of dissections was small. No infections were found in Anopheles quadrimaculatus, A. freeborni, Aedes atlanticus (or tormentor?), and Psorophora ferox. FILABIASIS STUDIES A periodicity of the microfilariae was demonstrated. The larvae were most numerous in the peripheral blood stream during the afternoon daylight hours. Larvae were present throughout the day and night, the ratio between the mean high and low counts being 3.2. Seven papers resulting from the cooperative work between NIH and MCWA were published in scientific journals during the fiscal year. DDT Investigations As in past years, MCWA and the Office of Malaria Investigations, National In- stitute of Health, participated in a cooperative program of research. In return for the benefits derived from studies in the Menphis, Tennessee, laboratory, MCWA supported certain phases of the work by allocation of funds and personnel. A field experiment involving an area of 24 square miles was designed to determine whether a two percent solution of DDT in oil applied at the rate of 6,5 gallons per acre at ten-day intervals would suffice to control mosquito production. Results indicated successful control, with a 40 percent reduction in over-all cost of the larviciding as compared to using oil alone; however, the dosage of two percent DDT in oil was above that which other experiments showed could be utilized routinely and safely for fish and fish-food organisms. To ascertain whether a reduction in mos- quito production could be effected under unusually difficult conditions, an experi- ment was devised whereby a two percent solution of DDT in oil was applied at 1000- foot intervals to a large, slow-flowing drainage ditch at the rate of six gallons per acre at ten-day intervals. The operation was successful from the standpoint of mosquito control, and a reduction of 80 percent in cost was obtained. Another phase of the investigations concerned field experiments with COT residual spray. The methods of spraying were the same as those used on the Extended Malaria Control Program of MCWA. Results showed that a single application of DDT residual spray in inhabited houses controlled mosquitoes for a period of 17 weeks. Examinations of 13,812 thick film blood smears from the southeastern United States and Puerto Rico were made during the fiscal year as part of the MCWA ma- laria incidence survey. Of these slides, 0.36 percent were positive for malaria parasites. The greater number of smears were taken in the southeastern states and only 0.18 percent of these were positive. The much smaller number of slides from Puerto Rico showed 2.2 percent positive. Three technicians were trained in the thick film method at the Menphis laboratory, and a member of the laboratory staff conducted four classes for the training of technicians in cooperation with MCWA. (left) Slow-flowing drainage ditch of the type used for experimental larviciding with DDT in oil. (right) Thick film blood smears from southeastern United States and Puerto Rico were examined as part of the malaria incidence survey. Typhus Investigations A proposal to institute a Typhus Investigation Program in south Georgia was in- itiated in August 1945, and its organization was begun during that month. Plans out- lining the proposal, scope, and operating procedures were approved by representatives of the Georgia Department of Public Health and MCWA as of October 1, 1945. Oper- ating out of headquarters in Thomasville, actual investigations have been under way since September 24, 1945. The study area selected included Brooks, Thomas, Grady, Cook, and Decatur counties; Grady County served as a control area for the project. The purpose of this study was to determine the efficacy of murine typhus fever control methods, particularly LOT dusting, as they affected the incidence and prev- alence of the disease in human and rodent populations. In order to obtain accurate information on the incidence of human typhus cases within the study area, it was considered necessary to carry out a census survey designed to locate mild or unre- ported cases. By the end of this fiscal year 18,262 premises had been surveyed. Typhus cases appearing since January 1, 1945, were investigated in detail, as well as any other illness which might possibly be typhus fever. Up to July 1, 1946, 278 possible typhus cases had been examined. Case histories were taken of 281 individuals who supposedly had “suspicious” illnesses but who were considered to be negative for typhus. Blood specimens from 273 individuals were sent to the laboratory for the Weif-Felix and complement-fixation tests. The other major aspect of the investigation program was concerned with rat- reservoir and ectoparasite-vector studies. Through the end of the fiscal year a total of 5,642 rats were trapped. Blood specimens from 3,346 rats were sent to the laboratory, of which 3,170 were found satisfactory for complement-fixation test- (right) It was necessary to carry out a census survey designed to locate mild or unreported typhus cases. (left) 72,260 rat ectoparasites were collected an*i identified. 76 TYPHUS INVESTIGATIONS (left) Blood specimens from 3,346 rats were sent for complement fixation tests. (right) An endemic typhus vaccine was given to operational personnel. ing. Of these, 1,387, or 43.4 percent, gave positive typhus complement-fixation reactions. Ectoparasite examinations were made on 4,098 rats, and 72,260 ectoparasites were collected and identified. One round of DDT dusting was completed in Brooks, Cook, and Thomas counties prior to the end of the fiscal year. At the same time a county-wide rat poisoning campaign was conducted in Decatur County. Results are not yet complete enough to report the effectiveness of these operations. TYPHUS VACCINATION PROGRAM With the inauguration of the typhus program as a part of MOVA activities, methods of protecting operations personnel from the hazards of contracting the disease were considered. An endemic typhus vaccine was being manufactured by a commercial biologi- cal supply house. Since this vaccine was still in the experimental stage, it was not being offered on the open market. However, a quantity sufficient to vaccinate about 650 employees was made available to this office, and this material was distrib- uted to the various states conducting typhus control programs. Blood samples were taken before and after vaccination and sent to the company in order to study the efficacy of the vaccine. A consistent increase in antibody titre was noted among personnel on this project who received the murine typhus vaccine. Encephalitis Studies In connection with investigations being conducted on the epidemiology of en- cephalitis by the Hooper Foundation of the University of California at Berkeley, two entomologists, one ornithologist, and one assistant were assigned to that or- ganization by the U. S. Public Health Service to aid in an attempt to determine the importance of wild birds and their bloodsucking parasites as reservoirs and vectors of encephalitis. The proposed investigation included the searching of birds’ nests for mosquitoes, mites, and ticks, and the identification and testing of these arthropods for the presence of the encephalitis virus. Smears for avian malaria and mosquito dissections were planned to obtain data to serve as an index of certain bird-mosquito relationships, particularly in respect to Culex tarsalis, the most incriminated vector of encephalitis. “Wild" tarsalis resting and feeding habits were to be investigated for the first time and determinations made of the flight range of this species. These studies were important as a supplement to those already completed or being conducted on domestic fowl by the Foundation. It was essential to determine the principal source from which C. tarsalis mosquitoes derive their encephalitis infections in order to provide the most effective mosquito control measures. If wild birds were the important source rather than domestic fowls, DDT residual sprays for mosquito control around human habitation would be a less effective mea- sure since there would be little probability of the infected mosquitoes resting on sprayed surfaces. If domestic fowls were of greater importance as reservoirs of infection, such measures as DDT spraying of chicken houses would be a most ef- fective control. The transfer of mites and ticks from wild to domestic birds could also be of importance in establishing domestic reservoirs of infection. This study was not begun until April, and results of the work are not sufficient to warrant reporting at this time. Dysentery Control Studies Throughout this fiscal year MCWA and the National Institute of Health cooper- ated in an investigational program design- ed to determine the role of flies in the transmission of dysentery and diarrhea. Fly control operations were the respon- sibility of MCWA, and NIH had charge ol the epidemiological phases of the work. The program, operating out of Pharr, Texas, was begun in the fall of 1945. Hidalgo County was chosen as t he site of the dysentery and diarrhea con- trol operations because of the high incidence of these two diseases there. Actual work was being conducted in five towns, while five comparable towns were being used as controls. In the towns where fly reduction operations were being carried on, DPT residual and space sprays were used against the adult flies, and orthodichlorobenzene was used as a larvicide. (top) Inoculating Klegler's agar slant with picked colonies in epidemi- ological studies, (middle) DDT residual spray on foliage, (bottom) DDT space spraying. Alabama BURTON F. AUSTIN, M. D. State Health Officer LEGEND War Malaria Control - 1945 Season War Malaria Control - Con- tinued in 1946 i Extended Program Residual I Spraying Extended Program Larvicid- ing, Surveillance, and/or Drainage Typhus Control Residual Dusting -Typhus Control Ratproofing Aedes aegypti Control Virus Laboratory, Montgomery (Montgomery County) During the course of the fiscal year the emphasis of MCWA activities in Alabama shifted from war malaria larviciding for the protection of military establish- ments to extended program residual house spraying for the protection of the ci- vilian population against the possible introduction of foreign malarias. Typhus control operations were initiated during the early part of the fiscal year and continued on an increasing scale throughout the year. The Aedes aegypti control unit maintained routine operations. An average of 128 U5PHS employees spent 181,852 man-hours during the year on all types of MCWA activities in 36 counties of the s tate. WAR MALARIA A total of 17 counties had war malaria operations, including 19 war areas con- taining 33 zones, in which 74 war establishments were protected. TTie great majority of these operations were terminated by the end of the 1945 control season as a result of the ending of the war. In 1946 larviciding was continued only around Maxwell and Gunther Fields in the Montgomery area and inspections were continued around Tuskegee Army Airfield in the Tuskegee area, Brookley Field in the Mobile area, and Craig Field in the Selma area. 81 ALABAMA Former Anopheles breeding pond completely filled in with saw dust. LARVICIDING. Sixteen war establishments in 11 zones were protected by oiling or dusting. To do this job, 4,753 gallons of oil were sprayed over 174 acres and 500 pounds of paris green were used to cover another 373 acres. Supplementary activities included the clearing of 48 acres of aquat- ic and land vegetation and the cleaning of 264,804 linear feet of ditching to maintain drainage. No new drainage opera- tions were carried out this year. ENTOMOLOGICAL SURVEILLANCE. Since the bulk of the mosquito-producing areas had been eliminated during previous years by major drainage operations, most of the war establishments this year were protected by entomological surveillance. Of the total of 74 war establishments, 58 in 22 zones were kept under constant inspection to apprehend high “quad" breeding indices. In those areas which re- mained active after the end of the war, entomological surveillance indicated the necessity for only a relatively small amount of larviciding and ditch main- EXTENDED PROGRAM The Extended Malaria Control Program was expanded during the year to include all or part of 21 counties. The areas in which malaria control work was done were chosen from a consideration of malaria statistics and entomological findings. The general policy was to apply DDT residual spray to all occupied rural residences in these areas, and to determine by entomological surveys the necessity for doing control work in the towns. In the larger towns larviciding and minor drainage meas- ures were utilized rather than residual spraying for reasons of economy. The or- ganization for residual house spraying was set up under seven area headquarters. Four of these areas were comparatively large; Montgomery area contained six coun- ties, Mobile area had five counties, Greene had five counties, and Selma had three. The other two areas — Geneva and Colbert — were one-county operations geograph- ically detached from other control areas. An area supervisor was in charge of the program in each of the six areas, aided by an assistant area supervisor in two areas. The entomological inspectors in the four larger areas were under the tech- nical direction of the state entomologist, but were otherwise responsible to the area supervisor. In each of the two smaller areas, the area supervisor made the routine entomological inspections. SPRAYING. During the first half of the fiscal year, spraying operations were carried out in six counties, in which 21,964 house spray applications were ac- complished. An average of 0.76 pound of COT was used per house spray application, and 1.40 spray crew man-hours were expended per application. After the end of the war the extended program expanded to include 21 counties and 45,711 house spray ap- plications. Experience gained by previous spraying lowered the number of man-hours ALABAMA per house application to 1. 15, and the amount of DDT per application was in- creased to 0.80 to obtain greater re- sidual effectiveness. The personnel for spraying crews was recruited in the various counties, consideration being given to the location of the homes of the crew members with reference to the working areas. In many cases it was more practicable for crews to pro- ceed routinely to work from the fore- man’s home rather than to report to a central headquarters each day. Three- man spraying crews — foreman and two laborers — proved to be the most ef- ficient operating unit. In a few in- stances it proved profitable to add a fourth man temporarily when working in a thickly populated area, where a com- plete additional crew was not justi- fied. Air compressors mounted on truck motors supplied pressure for spray cans fitted with valve stems. Spraying was done with a number of different makes of knapsack pressure spray- ers, none of which proved entirely satisfactory for che purpose. Ten crews were equipped with engine driven compressor units adapted to Dodge Vi- ton military ve- hicles and Lofstrand sprayers modified by replacing the sprayer pumps with caps and tire valves. This arrangement proved successful because it eliminated all troub- le connected with the sprayer pump. Time saved by eliminating hand-pumping was rather insignificant. No other attempts were made to modify the spraying equip- ment but it is apparent that there is a definite need for a better hand-pressure sprayer. Vehicles of %-ton or %-ton capacity proved best for the work. The four- wheel-drive feature was advantageous in some localities and in wet weather but considerable mechanical difficulty was experienced with the old model Army vehicle (%-ton truck). LARVICIDING. At the beginning of the fiscal year the cities of Montgomery, Prattville, and Fort Deposit were given extended protection by larviciding and minor drainage operations, while Selma, Entaw, and Demopolis were kept under en- tomological surveillance. In 1946 larviciding protection was continued in the three above-mentioned cities while surveillance was increased to include 16 cities in 13 counties. No major drainage was considered necessary during the year. EXTENDED PROTECTION. More than half a million residents of Alabama received malaria protection in one form or another through extended program operations. A total of 67,675 house spray applications were made during the course of the year, requiring the use of 53,430 pounds of DDT and 83,502 spray crew man-hours to pro- vide this protection. TYPHUS CONTROL Typhus control was initiated during the first part of the fiscal year and oper- ated in a total of 11 counties. Rodent extermination was combined with practically all of the HT dusting activities and rat-stoppage was promoted wherever possible. ALABAMA 83 Approximately three-quarters of a million residents of Alabama were accorded typhus protection through the services of 32 USPHS employees during the year. Treatment of some 58,800 residences and business establishments required the expenditure of 93,650 local and MCWA labor man-hours. The program was well received this year both in urban and rural areas, which was not the case during its inauguration. RESIDUAL DUSTING. Inspections for rats and ectoparasites were carried out in 42,931 premises in 28 cities and 32,091 premises were found to be infested. Ala- bama was one of the few states which carried on residual dusting in rural areas this year; Crenshaw, Covington, Geneva, Houston, and Dale counties contained rural dusting beats. Approximately 9,144 business establishment dustings were accom- plished as against 23,915 residence dustings; some of the premises required more than one application. In carrying out the fore-going work, 144,133 pounds of ten percent MIT were used, averaging 4.3 pounds per premise dusting. Labor and fore- man man-hours per application averaged 0.86 during the year. RATPROOFING AND POISONING. Three cities — Mobile, Dothan, and Eufaula — had ratproofing campaigns in which a total of 120 business establishments were treat- ed. An average of 22.5 labor and foreman man-hours were needed to treat each es- tablishment, Rat poisonings were carried out in approximately 24,940 premises in conjunction with both residual dusting and ratproofing. About 29,555 pounds of bait and 5,211 pounds of cyanogas were used, requiring 0.43 labor man-hour to dis- tribute 1.19 pounds of bait per premise poisoning. EPIDEMIOLOGY. An analysis of reported cases of typhus fever for the period January 1 to July 1, 1946 did not allow any definite conclusions when compared to the number of cases occurring for a like period during past years. Complement- fixation tests did not show a reduction in the number of positive rats as the res- ervoir of infection. The ectoparasite index showed a considerable reduction in the number of fleas, although seasonal conditions might have been a contributing factor. A more thorough examination for parasites and infected rats was antici- pated during the fall months. AEDES AEGYPTI CONTROL The Aedes aegypti control unit continued its routine operations in Mobile dur- ing this fiscal year. A monthly average of six MCWA employees inspected 51,850 premises and found 2,250 to be infested, an aegypti breeding index of 4.34. As an incidental result of these control measures, the 201,000 residents of the city benefited from the rubbish collections and general improvements in premise sani- tation. (left) Inspecting for rat signs in a basement, (below) Aedes aegypti inspectors checking water containers for mosquito breeding. Arkansas T. T. ROSS, M. D. State Health Officer The number of residual house spray applications in Arkansas exceeded that of any other state in the country during this fiscal year, and the war malaria lar- viciding program was surpassed only by one other state. As in other states, the end of the war caused a marked curtailment in war malaria control operations and an increase in other phases of the program. During the year a monthly average of 367 USPHS employees worked 571,366 man-hours on all phases of MCWA activities, including typhus control. LEGEND War Malaria Control - 1945 Season War Malaria Control - Continued in 1946 | Extended Program Residual Spraying Extended Program Larviciding, Surveillance, 'and/or Drainage Typhus Control Ratproofing Typhus Surveys ARKANSAS 85 WAR MALARIA War malaria activities were carried on in a total of 22 counties during the year, including 53 zones in 20 areas, and protected 40 war establishments and 17 housing and recreational areas connected with them. Residual spray operations were utilized as a war malaria control expedient in 12 of these establishments and two housing projects where it was impractical to carry out larviciding. Approximately 319,000 man-hours were expended to accomplish the larviciding, residual spraying, clearing and cleaning, and drainage necessary to maintain war malaria control dur- ing the year. Since the great majority of the military installations terminated soon after the end of the war, only six — Fort Smith and Camp Chaffee in Sebas- tian County; Shoemaker Ordnance Plant and a Camden installation in Ouachita Coun- ty; the Army-Navy Hospital and Lake Catherine Rest Camp in Garland County — were protected by larviciding during the second half of the fiscal year, and Lake Hamil- ton Rest Camp in Garland County was kept under entomological surveillance. LARVICIDING. During the first half of the fiscal year 37 war establishments and 13 war housing and recreational areas in 39 zones were protected by larvicid- ing operations. These numbers dropped to six in each case with the curtailment of war malaria control operations at the beginning of 1946. Larviciding problems were intensified by the fact that the majority of larvicidal zones were located in sec- tions of the state affected by the four successive floods in 1945. Many new breed- ing areas were created, and many others usually easy to control were rendered inac- cessible because of high water. Routine oiling covered 9,927 acres and required 167,360 gallons of oil. Paris green dust, 2,447 pounds, was spread over 1,564 acres. To facilitate larviciding, 426 acres of aquatic vegetation and 369 acres of land vegetation were cleared out. DDT-OIL LARVICIDING. Reports submitted from 11 areas where the new DDT-mist type oil larvicide was used experimentally were very encouraging. It proved to be equally or more effective in control than the older-type of larvicides, with the added advantages of greater ease in application, increased spray swath, great pen- etration of vegetation, and savings in labor and material costs. In all areas, supervisors reported a reduction in man-hours and material used. Savings in ma- terial ranged from 63 percent in Mississippi County to 90 percent observed in six areas. Savings in labor ranged from a 20 to 50 percent reduction in St. Francis County to 80 percent in Lee County. The new larvicide was popular with the crews because of its easier methods of application brought about by use of a lighter can and less frequent refilling. COT mist-type oil larvi- cides proved equally or more effective than the older-type larvicides. 86 ARKANSAS DRAINAGE. Certain areas in the state required drainage operations to effec- tively control mosquito-breeding. Drainage work undertaken as a part of the war malaria program was completed during the first half of the fiscal year. In all, 93,242 linear feet of hand ditching and 1,500 feet of dynamite ditching were ac- complished. Approximately 637,743 linear feet of old ditching were cleaned and 2,295 feet were lined with cement slabs. Fifteen acres of water surface were elim- inated as breeding places. ENTOMOLOGICAL SURVEILLANCE. All zones where larviciding was carried on were kept under entomological surveillance to detect any increases in the mosquito breeding index. In addition, entomological inspections were used to determine when to start and stop larviciding and the extent of the control zone. After the war those war establishments which were not terminated were protected by larvicidal operations, which included regular entomological inspections. THERMAL AEROSOL EXPERIMENT. This experiment, based upon work done by the Ten- nessee Valley Authority and others, consisted of spraying rice fields with DOT ther- mal aerosol by airplane. Its purpose was to determine if damage to the rice would result from a weekly application schedule heavy enough to control malaria mosquito breeding. A 220 horsepower PT-17 made flights at a height of 20 feet, spraying in 100-foot swaths. The thermal aerosol equipment was calibrated to discharge 0. 12 pound of EOT per acre using a 20 percent EOT mixture in Velsicol NR-70. Two fields at Stuttgart, one of 32 acres and the other 40 acres, received a total of eight weekly treatments from July 28 to September 18; three other fields served as controls. These treatments covered the period from the second flooding of the rice until the water was drained off for harvest. All flights were made at day- break so as to take advantage of the low wind velocity generally found at this time of day. Larval population were sampled weekly by 200 random dips in each of the five fields under observation; very few or no larvae were found in the treated field. An agronomist from the U. S. Department of Agriculture visited the rice fields three times: after the first, fifth, and eighth sprayings. The rice appeared to be developing normally at these times. The rice pathologist of the University of Arkansas examined samples of the harvested rice and confirmed observations that there was no discemable injury to the rice as a result of these DOT treatments. EXTENDED PROGRAM At the beginning of the program, house spraying activities were hampered by lack of equipment — both transportation and sprayers — and because of the diffi- culty in obtaining and maintaining a supply of DOT concentrate in all areas. After the program had been in operation for a time, adequate equipment was obtained for all crews. A central supply house was set up in Little Rock and a regular delivery system to all areas was established. With crews properly equipped and supplied, houses were sprayed with a minimum expenditure of man-hours. SPRAYING. A total of 32 counties had all or part of the county under residual spraying control, eight of these 32 counties were added to the program in 1946. Approximately 88,915 residual spray applications were completed during the first half of the year, requiring an average of 1.09 labor and foreman man-hours to spray 0.39 pound of DOT per application. The spraying program expanded during the second half of the year to accomplish 135,327 house spray applications. Labor and fore- ARKANSAS 87 man man-hours per house spraying decreased to 1.05 as a result of experience gain- ed and public education. The amount of DDT per application was increased to 0.65 pound to obtain a longer-lasting residual effectiveness. Spraying was done by three-man crews — two sprayers and a lead man. Each crew was equipped with a Vr ton truck carrying two five-gallon cans for DDT concentrate, a drum for water, three sprayers, cover cloths, and a foot-locker containing replacement parts. SPRAY CREW TRAINING. The crews in each area were trained by the area super- visors and malaria control assistants. They were shown the training film strips, “ Hand Spraying of DETT'’ and “ Safe Practices in the Use of DDT, " and were given considerable time for supervised practice spraying before going into houses. They were also given a brief training course in the basic facts about malaria and its control so that they might be able to answer questions asked of them by people whose houses they sprayed. The lead man was trained to make contacts immediately ahead of the spray crew and see to it that the house was prepared for spraying. Previous information as to how houses should be prepared was given through com- munity meetings and radio and newspaper publicity. The monthly publication “Ar- kansas Malaria Bulletin" was first issued in April 1945. The purpose of this bul- letin was to present a coordinated account of the work to field personnel and to provide a stimulus for malaria control activities by exploiting the spirit of com- petition of field personnel. Monthly tabulations of results of entomological, oper- ational, and educational activities were published. LARVICIDING AND DRAINAGE. According to the recommended practice, 26 cities in 11 counties were given extended malaria protection by larviciding operations dur- ing the first half of the year, Tliis number was later increased to 27 cities in 16 counties to meet the requirements of an expanding extended program; six of the original cities larvicided in 1945 were dropped while seven additional cities were added to the extended larviciding program in 1946. One major drainage proj- ect around the McGehee Housing area in Desha County was conpleted during the first half of the fiscal year. PUBLIC EDUCATION. Considerable attention was given to health education of children in the schools, with the cooperation of the teachers. Short courses or workshops in four Arkansas colleges helped prepare and train instructors to teach malaria sanitation. Attention was also given to adult lay education for the pur- pose of creating an awareness to the malaria problem and the formation of perma- nent malaria control organizations. Talks were made at meetings of numerous social and civic groups. Proper instruction of persons and families affected with malaria was an important part of the education program. Tliese persons were usually inter- ested and provided an ideal means of promoting malaria control sanitation. This work was directed through the medium of the county or district health office to the physicians attending cases. Malaria control assistants contacted physicians to explain the methods and objectives of the program and to work out with the doc- tor procedures for handling case reports. The people were urged to go to a phy- sician for treatment of malaria. As an inducement, the offer was made to spray the house of each person whom a physician reported as having malaria, provided the house had not been sprayed within 30 days previously. As part of the program for apprehending malaria cases, attempts were made to locate discharged service- men who had malaria while in service. Local draft boards cooperated by question- ARKANSAS ing each veteran reporting for reclassification. Personal contacts are being made with these men to inform them in methods of malaria sanitation. In both the promotional work and in the program of general malaria control edu- cation, the educator worked closely with school superintendents, health offi- cers, home demonstration agents, and various organizations already existant in each county which were interested in the malaria control programs. Twenty-four towns in the extended program area contributed a total of $37,500 for malaria control work. This local financial participation was partially the result of promotional work of the educational section. ENTOMOLOGICAL SURVEILLANCE. Entomological surveillance on the extended pro- gram consisted of regular inspection in all larvicidal zones and surveys of spray- ed and unsprayed houses with nearby adult resting places in the residual spray area. Of 3,102 sprayed houses inspected in the first quarter of the fiscal year, 6.67 percent had mosquitoes in the afternoon as compared with 48.04 percent in unsprayed houses. In the last quarter 0.82 percent of 6,738 sprayed houses in- spected had mosquitoes in the afternoon as compared with 33.07 percent in unspray- ed houses. Entomological inspectors collected 1,535 engorged anophelines during the last quarter, 11 of which showed a positive test for human blood. EXTENDED PROTECTION. Approximately 772,000 residents of Arkansas were accorded extended malaria protection. To provide this protection 239,191 labor and foreman man-hours were expended on 224,215 residual house spray applications and 122,977 pounds of EOT were used, in addition to larviciding in a number of towns. TYPHUS CONTROL Typhus control operations in Arkansas consisted mainly of rat poisoning and ratproofing campaigns in the cities of Little Rock and North Little Rock. In ad- dition, typhus surveys were made in 30 other cities in 21 counties to obtain data on typhus fever cases, ectoparasite populations, and rat blood samples. Hie sur- vey got underway in October and continued until malaria control personnel return- ed to their regular assignments. Early in January a ratproofing program was ini- tiated in Little Rock; in June a similar program was started in North Little Rock. During this period an average of 22 employees were engaged in surveys, rat poi- soning or ratproofing, and approximately 186,000 residents of the state were pro- tected by typhus control activities. RAT ERADICATION. In the two cities where rat poisoning or ratproofing were car- ried on, 408 premise poisonings were acconplished with 21,183 Red Squill torpedoes and 3,126 pints of ** 1080” poisoned water used to supplement the bait. An aver- age of 7.1 labor and foreman man-hours were required to spread approximately 52 torpedoes of bait per premise treatment. One hundred eighty-nine establishments were ratproofed during the year, requiring 2,896 local and MCWA labor and foreman man-hours. This was an average of 29.2 man-hours per establishment. Surveys were made to obtain data on typhus fever cases, ecto- parasite populations, and rat blood samples. California WILTON L. HALVERSON, M.D. Director of Public Health LEGEND War Malaria Control - 1945 Season A War Malaria Control - Continued V in 1946 Japanese '* B” Encephalitis Control The emphasis of MCWA activities in the state of California during this fiscal year was placed on measures di- rected toward the control of pre- hibernation migration of female Anoph- eles freeborni, the western malaria vec- tor. This migration directly affected the control measures because the peak of reported cases of malaria occurred during this period of migration. Emphasis was also placed on the use of DDT larvicide in connection with control measures aimed at preventing the establishment of Japanese “B” encepha- litis in areas adjacent to international airports of entry. DDT was used to control the breeding areas of Culex tar salts, the most incriminated vector of indigenous mosquito-borne virus encephalitis in California. (left) Northern California mobile unit dusting within control area of airfield, (riaht) Typical pools in Los Angeles River, very suit* able for A. freeborni breeding. Southern California mobile unit area. WAR MALARIA A total of 25 war establishments in 22 zones was protected by larviciding or surveillance during 1945. After the end of the year only five military installations were protected: Merced Army Air Base near Merced; Hamilton Field and the Fair- field— Suisun and Mather Array Air Bases in the area of the Northern California Mobile Unit with headquarters in Marin County; and Hammond General Hospital near Modesto. Approximately 22,450 man-hours were expended on various war malaria ac- tivities during the year. MOBILE UNIT OPERATIONS. During the first half of the fiscal year, both the North and South California Mobile Units conducted malaria control operations. The northern unit carried on entomological surveilLance, larviciding, and minor drainage in nine zones in four counties—Alameda, Marin, Sacramento, and San Joaquin—and protected 12 military establishments. The southern unit operated in six zones in five counties—Riverside, Santa Barbara, San Diego, San Bernardino, and Los An- geles—and protected six war establishments. In 1946 only the North California Mobile Unit was active. In addition to routine malaria control activities, emphasis was placed on the control of Japanese **B” encephalitis around the international airports of entry - Hamilton, Fairfield, and Mather Airfields. LARVICIDING. Anopheline breeding occurred in irrigation canals, irrigation spillage and seepage water, and also in large acreages of rice fields adjacent to control zones in the Great Central Valley of California. Much of this area was controlled by the drainage work accomplished during past years. Larviciding and minor drainage effectively reduced adult mosquito populations during the sunmer months. Oiling was most extensively utilized during the year; 10,951 gallons of oil were used to larvicide 1,003 acres. Supplementary dusting with paris green covered an additional 11 acres. Nineteen acres of vegetation were cleared to facilitate larviciding operations. DRAINAGE. Some new ditching operations were carried on during the year. In the vicinity of Marysville and Yuba City a dragline was used to excavate 1,800 feet of new ditching in 1945. Some 600 feet of hand ditching was accomplished during the 1946 season by the Northern California Mobile Unit. Altogether, 42 acres of water surface were eliminated by the ditching operations and the cleaning and main- tenance of 64,500 feet of existing irrigation drainage ditches. CALIFORNIA 91 ENTOMOLOGICAL SURVEILLANCE. Twelve war establishments in 11 zones were under entomological surveillance during the first half of the fiscal year. Inspections were carried on at five military establishments in 1946, four of which required larviciding as a malaria control measure. CONTROL OF MIGRATION OF ANOPHELES FREEBORNI Although larviciding and minor drainage can control mosquito populations during the summerr an incredible number of mosquitoes are produced in rice fields during the fall and winter months. These mosquitoes migrate from the fields, owing perhaps to overcrowding or to their seeking suitable winter shelters. ENTOMOLOGICAL EVALUATIONS. Each year during mid-September, the migration of A. freeborni is most pronounced in those areas adjacent to rice culture in the Great Central Valley. Three resident MCWA zones located there have experienced this migration. The entomological records from each of these zones have constantly shown that during the fall and winter months, when breeding is at a minimum or has stopped completely, counts of adult females have averaged better than 30 per station in control-zone resting places for this entire period. PHYSICAL LIMITATIONS. The rice fields are at various distances from the control zones. In one area they are five to six miles away; in another, three to four miles; and in still another, the rice fields border on the control zone. It would be im- practical to larvicide these areas of intensive freeborni breeding because of the great extent of the rice field acreage involved. Moreover, inside the control zones during the summer months there is no noticeable increase in adults that might be attributed to rice field breeding. DDT—SPRAY CONTROL. The measures undertaken against the migration of A. freeborni consisted of two EOT residual spray projects, in both of which the WIT was applied prior to the migration. One project was an attempt to prevent the migration into the control zone; the other was to determine if the early fall and over-wintering population of freeborni within the control zone could be reduced once the migration had reached that point. MARYSVILLE AREA PROJECT. The project attempting to prevent migration into the control zone was undertaken in the Marysville Area. A “barrier" of DDT residual spray was placed between the rice fields, and the control zone. Some of the rice fields were adjacent to the control zone; others were from three to six miles dis- tant. The “ barrierwhich traversed the border of the rice fields and was approximately a mile in depth toward the control zone, was not continuous but concentrated in the separate farm- steads staggered throughout the one-mile zone. CUT residual spray was deposited A “barrier” of DDT residual spray was ap- plied to the interior of all buildings except dwellings. CALIFORNIA 92 on the interior surfaces of 937 buildings in this zone, with the exception of dwell- ings. The spray was a DDT-Triton-xylene-water emulsion applied at the rate of 100 mg. of DDT per square foot with a 50-gallon power sprayer equipped with two con- ventional fan-type DDT residual spray nozzles. A 100-foot hose connected each nozzle to the power sprayer which was operated at 60 pounds per square inch pressure. All the equipment was mounted on a %-ton pickup truck and was handled by a three-man crew. Although the spray was applied prior to the migration (the first two weeks in August), and the reduction of freebomi was practically 100 percent in the sprayed shelters, nevertheless there was no apparent decrease of A. freeborni within the control zone stations during the fall and winter months. MERCED AREA PROJECT. In the second project, to determine whether the immigrant population could be reduced after it had reached the control zone, DDT residual spray was applied to the interior surfaces of all buildings, except dwellings, within the Merced Area control zone. The DET was applied in the same manner and at the same rate as for the Marysville Project. During the first two weeks of September 825 buildings were sprayed. The results were excellent, for the adult population was practically reduced to zero from the time of the spraying until February 1946 in all of the buildings that had been treated. The cantonment area of the protected military establishment in this zone was also treated with DDT residual spray by the Post forces prior to the start of this project. OVER-ALL RESULTS OBTAINED. The over-all effectiveness of spraying EOT inside the protected area can best be shown by the results obtained. As indicated by a comparison of this year's weekly larval collections with those of last year for the same period, the first observed breeding of freeborni during the spring of 1946 was delayed approximately one month. IMs may have resulted from the great reduc- tion of the adult population of freeborni. JAPANESE “B” ENCEPHALITIS DOT larvicide was used in connection with control measures aimed at preventing the establishment of Japanese “B” encephalitis in areas adjacent to the international airports of entry into this country. Hamilton, Fairfield - Suisun, and Mather Air- fields, in the Northern California Mobile Unit area, were the destinations of much of the military air-traffic arriving from endemic areas in the Pacific. Inspection and spraying of inbound planes were performed by the Division of Foreign Quarantine. MCWA activities were designed to prevent the possible spreading of the disease to native vectors. DDT-Diesel oil plus an emulsifier-spreader was used as a mosquito larvicide from mid-April of 1946 on. DDT-OIL LARVICIDE. Thus far the results indicate that when this larvicide was applied as a mist spray it was equal to straight Diesel oil in effectiveness of larval kill. The path of the mist, however, was so dependent upon every slight change in wind direction that complete coverage, and hence 100 percent larval kill, were not always obtained. Nevertheless, with good entomological inspection following closely behind the larvicide application, excellent control could be obtained. The cost of the labor in applying the DDT-oil mist larvicide was so greatly reduced as compared to the use of straight Diesel oil that even if an area needed retreatment this method was still more practical and economical. The proper dosage per acre and the frequency of application still remain to be determined, but it is hoped that these data will become available as more use is made of the larvicide. Florida WILSON T. SOWDER, M. D- State Health Officer LEGEND War Malaria Control - 1945 Season ❖War Malaria Control - Continued in 1946 XyXvX| Extended Program Residual Spraying p. Extended Program Larvicidin^, Surveillance, and/or Drainage | Typhus Control Residual Dusting Typhus Control Ratproofing yfa Aedes aegypti Control Malaria control activities in Florida operated directly under the Bureau of Malaria Control. The different activities functioning under the Bureau included administration, engineering, entomology, and public relations and education. All issuance of supplies, major repair work on automotive equipment, and EOT mixing were performed at the central headquarters in Jacksonville. WAR MALARIA Ninety-one war establishments in 82 zones received malaria protection of one kind or another during the year. Programs in the 37 counties included larvicid- ing, major drainage, and entomological surveillance. In accordance with established policy the end of the war caused a drastic curtailment in the extent of war ma- laria operations. During the second half of the fiscal year only 19 war establish- ments, distributed among 18 zones in ten arfeas, were protected by war malaria con- FLORIDA 94 trol measures, and the scope of operations was narrowed down to nine counties. Over the course of the year 136,979 man-hours were expended on war malaria con- trol alone. LARVICIDING. A total of 21,191 gallons of oil and 6,008 pounds of paris green were used to effectively control the 4,801 mosquito-producing acres around the 49 war establishments protected by larviciding during the year. Only three war establishments remained to be guarded by oiling or dusting during the latter part of the fiscal year, after the war had ended; the other 16 remaining active were protected by entomological surveillance. DITCHING AND DREDGING. Several drainage projects were carried out during the 1945 season. In the Gainesville area the ditch lining project on the University of Florida campus, begun during the previous fiscal year, was finished. This proj- ect eliminated a malaria hazard around the campus and served as a malaria control demonstration for engineering students. Ditch linings were also installed around the city of Leesburg Housing and Recreation Project in the Leesburg area. In ad- dition, the elimination of the large marsh area adjacent to the city by hydraulic dredging, begun two years ago, was completed. This removed the most serious A. quadrimaculatus breeding area around the city. The Gainesville and Leesburg proj- ects accounted for 9,444 feet of permanent ditch lining. In the Gainesville, Lees- burg, and Lake City areas a total of 79,900 linear feet of hand ditching and 10,676 feet of dynamite ditching were accomplished, and 30,000 cubic yards of watered places were filled in. Maintenance of existing ditching included the cleaning of 1,168,497 linear feet to remove silt and debris. HERBICIDING. The use of herbicidal chemicals was continued around Lake City to cope with the water hyacinth problem in connection with malaria control. Last year experiments proved that 2,4 dichlorophenoxyacetic acid was effective in com- bating growth of water hyacinths. This year effective control was maintained by power-spraying a solution of 2,4-D. from a boat. On the large canals in the Lake Okeechobee region, experimental airplane spraying of 2,4-D. was carried out by agencies interested in the Everglades drainage hyacinth problem. TTie results ob- tained by this method were excellent. Elimination of a large marsh adjacent to Leesburg, begun two years ago, was completed. A channel was cut around the area to be dredged. The dredge can be seen to right of center. FLORIDA EXTENDED PROGRAM For operational purposes under the Extended Malaria Control Program, the state was divided into three districts, each under the supervision of an engineer. Dis- trict I included Jackson, Walton, Holmes, Washington, Calhoun, and Gulf counties; District II contained Leon, Madison, Gadsden, Wakulla, Jefferson, Dixie, Lafayette, Gilchrist, and Taylor counties; and District III encompassed Hamilton, Marion, Levy, Sumter, Hernando, Suwannee, Citrus, and Alachua counties. Each engineer was directly responsible for all spraying and entomological operations in his district, and was in charge of all personnel. The districts were sub-divided into areas with an area supervisor in charge of each. Two or three counties comprised the area unit, depending upon the number of houses sprayed. The area supervisor was respon- sible for the assignments and activities of the spray crews and the crew-leaders' reports. He was often called on to solve problems of either public relations or operational nature arising from the previous day's activities. EPIDEMIOLOGICAL FACTORS. In the absence of entomological records extending over a period of years, equitable apportionment of a state-wide control program had to be based primarily on epidemiological histories. The counties which were selected for DDT residual house spraying were those which, in the last malaria peak years (1933-37), had malaria death rates in excess of 25 per 100,000 popu- lation. In order to minimize the mathematical misrepresentation possible with low numbers such counties must also have had, during some year on record, more than five malaria deaths and a malaria death-rate of over 50 per 100,000 population. Of the 29 counties which fell into the above classification six were deleted due to low vector densities. Within a county the recent and current anopheline den- sities were used to indicate the need for control operations. EXTENDED CONTROL OPERATIONS. Ten counties received DDT residual spray appli- cations in the 1945 season. Of the 24,113 house spray applications, monthly con- trol inspections on a random sample basis of sprayed, unscreened houses and un- sprayed outbuildings showed an average *1 quad" vector ratio of 1:550. Further, the monthly series of vector-positive percentages derived from 100 mg. per square foot applications, deposited one to six months previously, demonstrated a defi- Around Palatka the navigation problem vas solved by the use of hyacinth saw boats, which were equipped with front and outrigger booms of circular saw blades. 96 FLORIDA nite loss of protection after the third month. During the second half of the fis- cal year 27,516 house spray applications in 23 counties were accomplished. The number of man-hours per house application was reduced from 1.62 for the 1945 sea- son to 1.18 for the 1946 season by reason of the increased experience of spray crews. As recommended for cities having more than 2,500 population, Marianna, Live Oak, Monticello, and Madison were given extended protection by larviciding during the 1945 mosquito-breeding season. In 1946 further control around Madison was con- sidered unnecessary, but Tallahassee, Gainesville, and Perry were added to the list of towns which required larviciding operations. Entomological surveillance was maintained throughout the state where control operations were not being car- ried on. Approximately 188,000 residents of Florida were protected from malaria by operations on the extended control program, which expended 71,569 man-hours of labor and 43,094 pounds of DOT. TYPHUS CONTROL Eleven cities in six counties had typhus control programs in operation during the past fiscal year. Approximately 29,400 residual dusting applications were car- ried out in business establishments and residences in nine cities, and 0.56 labor and foreman man-hour was expended to spread 1.7 pounds of ten percent DDT dust per premise application. Ratprooiing a total of 411 business establishments in the cit- ies of Pensacola, Jacksonville, Tampa, Bartow, and Haines City required an average of 20 man-hours for each establishment. To acconplish 320 premise poisonings, a total of 181 pounds of bait and 38 pints of “ 1080" water were used, and 0.56 man-hour was expended per premise poisoning. In addition to 13,930 man-hours of local labor, a monthly average of 14 MCWA employees worked 21,658 man-hours during the year on the various kinds of typhus control activities and afforded typhus protection to 579,800 residents of the state. AEDES AEGYPTI CONTROL Aedes aegypti control projects were operated in Key West, Miami, and Tampa. In the city of Key West 10,052 premises were inspected for aegypti breeding places and 1,528 were found infested; an index of 15.20. In,Miami 11,826 premises out of 240,165 were found to be infested; an index of 4.89. Tampa showed 3,060 infested premises out of 19,440 inspected, or an index of 15.74. An average of 23 USPHS employees worked full-time on aegypti control operations and public education work, effecting the protection of half a million people in Florida against the re-in- troduction of dengue and yellow fever. AIRCRAFT DISINSECTIZATION The inspection for insects and spraying of all commercial planes arriving at Miami from quarantine areas was continued during the 1946 fiscal year under the Division of Foreign Quarantine of the U. S. Public Health Service. The cessation of hostilities was followed by a steady increase in commercial air traffic and more than 40 different airlines were operating into the Miami airport during this fiscal year. The aerosol formula used to spray planes consisted of five percent pyrethrum extract, three percent EOT, five percent cyclohexanone, two and a half percent deobase, and 84.5 percent dichloro-difluoromethane (Freon 12). Georgia T. F. ABERCROMBIE, M. D. Director of Public Health LEGEND War Malaria Control - 1945 Season War Malaria Control - Continued in 1946 Extended Program Residual Spraying Typhus Control Residual Dusting Typhus Control Ratproofing Aedes aegypti Control Thomasville Typhus Investigation Projects Thomasville Typhus Investigation Office (Thomas County) Carter Memorial Laboratory, Savannah (Chatham County) Emory University Field Station, Newton (Baker County) GEORGIA Malaria mortality in Georgia during the calendar year 1945 reached an all-time low of 0.8 per 100,000 population, and the reported morbidity for the first six months in 1946 was also the lowest on record. The Extended Malaria Control Pro- gram was received with wholehearted and almost unanimous approval by the general public and interested local authorities. Numerous requests were received to ex- pand the program to include rural outbuildings and practically every type of build- ing occupied for portions of a day. WAR MALARIA War malaria larviciding and minor drainage operations were conducted in 11 areas and an additional four areas were controlled by entomological surveillance during the calendar year 1945, protecting 85 war establishments. During the second half of the 1946 fiscal year, after the war had ended, only three war establishments — Robins Field in the Macon area, Oliver General Hospital in the Augusta area, and the Naval Hospital in the Dublin area — continued to function. The five remain- ing full-time employees confined their operations to larviciding and inspection wotk» with the exception of minor bulldozer-filling operations at Augusta. LARVICIDING AND INSPECTION. Most of the larviciding was accomplished with paris green; 9,802 pounds were used to dust 7,553 acres. An additional 241 acres were lar- vicided with 2,182 gallons of oil. To insure maximum larval kill and to eliminate fa- vorable breeding places, 143 acres of land and aquatic vegetation were cleared out. Twenty-eight war establishments were pro- tected by entomological surveillance dur- the first half of the fiscal year. During 1946 entomological inspections were carried on in connection with larviciding activities around the remaining three war establish- ments. . DRAINAGE AND FILL. Some minor drainage operations were undertaken in 1945 to eliminate mosquito-breeding areas. Manual labor accounted for 6,229 linear feet of new ditching, and 113 feet were dug by machines. Near Augusta 23,062 cubic yards of earth were moved in filling operations. A total of 24 acres of water surface was eliminated during the year by draining and filling operations. Paris green larviciding with rotary duster. EXTENDED MALARIA CONTROL In the first half of the fi seal year operations were conducted in 14 counties grouped in four areas. In the latter half operations were conducted in 36 counties grouped in 11 areas and three districts. The state office and warehouse at Macon served as the central office and distribution center. Warehouse facilities were am- ple for storage of chemicals, equipment, and supplies, mixing of concentrate, repairs to vehicles and equipment, and other services necessary to the program. GEORGIA OPERATIONAL PROCEDURE. A supervisor was employed, trained, and assigned to each county and was responsible for all county operations. In multiple crew coun- ties one to two assistants were employed to assist the county supervisor in lay- ing out crew routes, advising the house- holders concerning operational procedures, recording sanitation data, and revising maps. In the latter half of the fiscal year all spray-crew personnel, spray- crew vehicles, and office and warehouse facilities were furnished by county health authorities at a cost amounting to ap- proximately $73,000, or an average of $0.81 per unit spraying. Operational pro- cedures followed were designed to perform the residual spraying operations with a maximum of efficiency and to record and assemble data of public health impor- tance. Weekly operational reports embody- ing all pertinent data were prepared and submitted by all county supervisors. These reports were reviewed and analysed by area and district supervisors and by state office personnel, who summarized these reports and, during the subsequent week, furnished all supervisory personnel with county, area, and district rankings based on operations data. EQUIPMENT, Each crew used a 30- to 55-gallon container, equipped with a quick- opening outlet for mixing, transporting, and storing emulsion. After June 1945 tests demonstrated the practicability and desirability of using stored compressed air as a source of air power in lieu of hand pumping. All crews were equipped with 60- to 80-gallon compressed air tanks which were filled at service stations at no cost. All hand sprayers were modified by removing the hand pumps and installing air-filling valves for delivery of air from the storage tanks. This procedure eliminated all pump maintenance and also considerably reduced manpower requirements for maintaining proper air pressure in the sprayers. Using this equipment, hand spraying operations were more efficient, (above) Filling spray can with DDT emulsion from drum on truck. Air compressor behind drum provides pressure through valve stem on spray can. (below) Mobile DDT residual spray unit working in Terrell County. 100 GEORGIA even in urban areas, than conventional power spraying. The major item of equip- ment developed in 1946 was a 300-gallon concentrate mixer made entirely from sal- vaged Army equipment. This was a rectangular vat in which agitation was secured by means of a four-blade paddle wheel, with supplementary agitation by a one-and- a-half or two-inch pump. The temperature of the solution could be raised by forcing hot air along one side of the tank, or by use of submerged electric heating ele- ments. RESULTS, [hiring the first half of the fiscal year 44,733 house spray applica- tions were completed, using approximately 0.75 pound EOT per house. From January through June 1946, 90,314 house spray applications were completed. The applica- tions were completed. The application rate was doubled in 1946 to 200 mg. per square foot, increasing the DDT used to 1.38 pounds per house. Labor and foreman man-hours per house were reduced from 1.08 in 1945 to 0.61 in 1946, mostly by de- velopment of the compressed air spraying technic and the preparation of house- holds for spraying before the arrival of spray crews. Written comments from health officials and members of the medical profession, in the absence of reliable mor- bidity data, generally credited the extended program with reducing malaria mor- bidity and with substantially reducing the incidence of enteric diseases among the approximately 500,000 residents of the sprayed counties. In small towns, al- though no business establishments were sprayed, an almost complete absence of flies was noted. TYPHUS CONTROL During the fiscal year a total of 54 counties participated in the residual dusting program either on a full-time or intermittent basis. Of the 23 counties which had full-time dusting programs, four — Bibb, Colquitt, Fulton, and Jenkins — also had ratproofing activities. (The city of Atlanta in Fulton County also had a dusting and ratproofing program separate from county activities.) Due to the intermittent and scattered nature of operations in some sections of the state, dusting and rat eradication control measures in these sections, located in parts of 31 additional counties, were carried on by mobile units operating out of the Macon field office. OPERATIONS. Rat harborages were found in almost all of the 82,654 premises inspected in 54 counties. An average of 0.88 labor and foreman man-hour was util- ized to spread 4.2 pounds of ten per- cent DDT dust in each of the 77,567 prem- ise dustings completed during the year , mostly in business establishments. Some 325 business establishments in the cities of Macon, Moultrie, Millen, and Atlanta were ratproofed, requiring an average of 58.3 man-hours per treatment. Ap- proximately 23,675 premise were treat- Dusting DDT into rat hole with hand pump dust gun. GEORGIA ed with rodenticides, requiring 298 gallons of “ 1080” water, 17,419 pounds of red squill bait, ten pounds of “ANm", and 12 pounds of cyanogas dust. EVALUATION AND INVESTIGATIONS. Biologic and entomologic activities were con- ducted in each of the 23 counties having full-time dusting programs by three crews, each consisting of a biological aide and a trapper, under the immediate super- vision of the field entomologist. A total of 2,324 rats were trapped from both dusted and undusted premises. The flea index (all species) of rats trapped in dust- ed premises was 2.1 percent as compared to 7.7 percent in undusted premises, in- dicating 72.7 percent control. Out of a total of 1,670 rat-blood specimens exam- ined, 608, or 36 percent, were found positive for typhus fever by the complement- fixation test. Typhus and rodent control investigational studies were conducted in Brooks, Thomas, Cook, Grady, and Decatur counties by MCWA personnel operating out of head- quarters in Thomasville, with joint administrative responsibilities shared by MCWA and the Georgia Department of Public Health. A county-wide experimental rat poi- soning program was carried on in Decatur County. Brooks, Cook, and Thomas coun- ties had county-wide residual dusting investigations. Rodent ectoparasite and blood surveys were conducted in Grady County, which served as the control county of the project. TRAINING PROJECT. A project to train typhus control personnel from the vari- ous states was carried on under supervision of MCWA training personnel in cooper- ation with the City of Atlanta Health Department and the Georgia Department of Public Health. The training consisted of classroom and field work, involving rat- proofing of buildings, rat eradication, and residual DDT dusting. The project also served as a typhus control program for the City of Atlanta Health Department. TYPHUS PROTECTION. In addition to 55,268 man-hours of local labor, a month- ly average of 43 MCWA employees spent a total of 65,338 man-hours to protect ap- proximately 2,000,000 residents of Georgia from the ravages of murine typhus fever during this fiscal year. Since rat ectoparasites serve as the vectors of human infection, most of the protection afforded was by means of residual DDT dusting. AEDES AEGYPTI CONTROL MCWA Aedes aegypti control operations in Savannah terminated at the end of March 1946. Up to that time five inspectors examined 28 , 609 premises for aegypti breeding places and found 680 premises infested; an index of 2.4. Approximately 150,000 residents of the city enjoyed protection against the re-introduction of dengue and yellow fever, and an improve- ment in general sanitation as a result of this program. An inspector shows a housewife Aedes aegypti larvae which he found in water plant container. Illinois ROLAND R. CROSS, M. D. Director of Public Health The war malaria control program in Illinois was operated under the jur- isdiction of the state department of public health until late in October 1945, after which activities were directed by USFHS District No. 3 per- sonnel in close liaison with the state department of public health. Entomo- logical surveillance, larviciding, and major and minor drainage activi- ties were accomplished in nine coun- ties during the first part of the fis- cal year. In 1946 necessary surveil- lance around the war establishments which remained active was maintained by the military authorities in coop- eration with local health departments and District No. 3 personnel. ACCOMPLISHMENTS. During the fiscal year a total of 1,563 pounds of paris green was used to dust 1,287 mosquito- producing areas and 5,165 gallons of oil were used to larvicide an addi- tional 181 acres. A small amount of brush and aquatic vegetation clearing, 3 acres, was necessary to facilitate larviciding. A considerable amount of previously constructed ditches requir- ed cleaning and many new ditches had to be dug, totalling 28,245 feet of ditch clean- ing, 4,145 feet of hand-ditching, and 5,090 feet of dynamite ditching. Seven acres of water surface were eliminated by these methods, requiring a total of 10,366 man-hours. War Malaria Control - 1945 Season LEGEND LARVICIDING AND DRAINAGE Eight projects in three counties required larviciding and minor drainage during 1945 and one-major drainage project was completed around Scott Field, St. Clair County. A request was received for assistance in controlling a mosquito problem in the vicinity of the Navy Spare Parts Warehouse in Joliet, Will County. After inspection the problem was found to be mostly one of pest mosquitoes. Larviciding of the Illinois-Michigan Canal by two Navy men with Navy equipment under MCWA technical guidance effected good control. Water-emulsifiable DDT was sprayed from a boat with a four-gallon Myers sprayer. ILLINOIS 103 SCOTT FIELD ZONE. The Silver Creek flopd-plain with its numerous sloughs, me- andering intermittent streams, and many low areas represented the greatest problem to malaria control. The bottom lands were inundated every spring and during the fall of 1945 they were also flooded several times. A close entomological check was kept on all breeding areas and only those areas harboring **quad” larvae were oiled under the selective larviciding program in effect. As in previous years many drainage ditches had to be reopened and in a few instances new ones had to be dug. A major drainage program was begun July 9 to permanently drain Leibrock's Slough. These areas were completely drained and were dry for a short period in August, but floods from September on damaged drainage ditches considerably and additional ditching was again required, Future ditching work will depend in great measure on floods along Silver Creek. Entomological surveillance was maintained in Scott Field by military personnel during the 1946 mosquito-breeding season. ILLINOIS ORDNANCE AREA. The principal source of A. quadrimaculatus breeding in this area in Williamson County, which included the Illinois Ordnance Plant, the Veterans' Hospital, an FHA Housing Project and the city of Marian, and an FHA Project and the city of Carterville, was a 1,000-acre area of the upper portion of Crab Orchard Lake. This is an artificial impoundment which had not been properly cleared before impounding. It was noted that larvae were found only in a narrow zone 20 to 50 feet wide along the shoreline early in the season and that as the season advanced the growth of aquatic plants gradually caused the widening of the breeding zone. Early in the season the shoreline zone was treated with paris green larvicide by means of a large Root power duster mounted on a sled and pulled by a small crawler- type tractor. As the season advanced and mosquito breeding became general over the extensive shallow lake areas, it was necessary to employ airplane paris green dusting to adequately treat the main portion of the lake. Use of the ground unit was con- tinued along the narrow bays and irregular shoreline areas which were impractical and uneconomical to treat by airplane. ENTOMOLOGICAL SURVEILLANCE In addition to the inspections carried on in conjunction with the above-mentioned larviciding and drainage projectsr ten war establishments in seven counties were kept under entomological surveillance to discover and control conditions .favorable to malaria transmission. Reconnaissance surveys of natural resting place stations were made in extra-cantonment areas and New Jersey light traps were also used to collect data on mosquito populations. Inspections on the military posts were con- ducted by military personnel under MCWA guidance. In 1946 surveillance was continued in the military installations by military personnel in cooperation with district and local health department personnel. LAWRENCEVILLE AREA. George Army Air- field and the city of Lawrenceville are both located in the Lawrenceville area in Lawrence County. During 1945 the MCWA pro- New Jersey-type light traps were used to collect data on mosquito populations. 104 ILLINOIS gram around the city of Lawrenceville consisted of inspections of natural resting place stations and light trap collections in the northern part of the city. Anoph- eline breeding was recorded rather early in this fiscal year because of heavy rains throughout July, August, and September. Although malaria statistics show a mild rate of endemic malaria in this region over the last ten years, state or federal control was not believed to be warranted; the most satisfactory solution of the situation was felt to be an abatement program by the local government in cooperation with the state health department. The principal “quad” breeding areas around George Field were drainage ditches and gravel pits. Since July, August, and September were wet months, the rate of flow in the ditches remained high. For this reason, and also because vegetation was slow in developing, breeding was kept below normal. After July 31 post personnel took over the inspectional work and no further MCWA activity was necessary. Post personnel also carried out a DDT residual spraying program in George Field during 1945. OTHER AREAS. A reconnaissance survey around the city of Savanna in Carroll County indicated that there was a low number of A. quadrimaculatus present throughout this area. From previous experience with this area together with the reduction of ac- tivities at the Savanna Ordnance Depot, it was decided that no further work, either control or inspectional, was justified. The Naval Ordnance Plant in the Cairo zone of Alexander County was accorded malaria protection through entomological surveil- lance during the first part of the fiscal year. A series of ponds constituted the major “quad" breeding problem around the Army Engineers Depot in the rezoned Granite City area of Madison County. Control measures were never considered necessary during the 1945 season, but since “quads” were present surveillance was continued during the 1946 season by post personnel. In addition to large numbers of Army personnel at Camp Grant in Winnebago County, there was also present a considerable number of prisoners of war. For this reason it was felt best to maintain entomological sur- veillance in this zone, although the number of “quads” taken from natural resting place stations was very low throughout the 1945 season. Post personnel continued surveillance in 1946, An inspection of 23 natural resting place stations around Mayo General Hospital in Knox County at the beginning of the fiscal year yielded a total of 31 adult “quads”. No further action was taken since neither malaria nor mosquitoes were a problem in this zone. Actual control operations and collection work in the Great Lakes zone in Lake County were under the direct jurisdiction of the Great Lakes officials and were carried out by their personnel with technical assistance from MCWA personnel. Because of the large amount of drainage work completed in 1944, the over-all malaria mosquito problem on the post was materially reduced, although pest mosquito control proved a difficult problem. No cases of local transmission of malaria were recorded in spite of the large number of malaria patients in the Naval Hospital. Surveillance was continued in 1946 by Navy personnel. SCHICK GENERAL HOSPITAL Although Schick General Hospital is located across the Mississippi River in Clinton County, Iowa, one survey of natural resting places was made at the beginning of the fiscal year by Illinois MCWA personnel. Results of this survey showed no significant numbers of “quads” within one mile of the hospital and no further surveys were made. Because of the large numbers of veterans and service-men located at this hospital who had malaria histories, post personnel continued surveillance in 1946. Indiana L. E. BURNEY, M. D. State Health Commissioner During the 1945 mosquito-breeding season larviciding operations were carried on in the Terre Haute, Fort Harrison, and Evansville zones. A to- tal of 333 acres were treated with 4,621 gallons of oil and an additional 65 acres were dusted with 52 pounds of paris green. Approximately 3,400 feet of ditches were cleaned of debris during the season. Six additional zones containing military installa- tions and industrial plants were kept under entomological surveillance to locate and eliminate any areas that showed signs of becoming serious mos- quito-breeding places. Surveys of five new prisoner-of-war camps revealed a situation at one, near Morristown, which favored local malaria trans- mission. This breeding area, in an old gravel-pit lake, was effectively controlled by weekly larviciding with a 50-gallon Hardie power sprayer mounted in a boat. All MCWA opera- tions in Indiana were concluded in October 1945. Control measures carried on in 1946 were initiated and financed locally. LEGEND War Malaria Control - 1945 Season TERRE HAUTE During 1945 the Terre Haute zone in Vigo County, which included two towns, an ordnance plant, an airport, and several industrial plants, was reorganized. Many new larval and adult stations were established and many of the old ones discon- tinued. A more adequate indication of A. quadrimaculatus breeding places in the zone was thus secured. Control operations were begun in June, when counts in adult stations reached significant numbers. The major breeding places in the Terre Haute zone were roughly classified as: (1) the Wabash bottom area, (2) the ornamental ponds, and (3) the old excavations. WABASH BOTTOM AREAS. The most important mosquito-breeding places in the Terre Haute zone lie in the bottom areas. A flood at the end of June filled the low areas and depressions and provided optimum conditions for heavy “ quad” breeding. Con- over Marsh, the most favorable breeding habitat, is a low-lying area of about 15 (above) Conover Marsh, looking toward the Wabash River, during July 1945. Hie levee, extending from the hill in the left background to the right background of the picture, is obscured by heavy vegetation. (lower left) Spraying breeding areas on Indian Lake by means of the paddle- wheel -propelled boat. The paddle wheel may be raised or lowered in the water thus regulating the speed of the boat. It is steered by manipulating a sweep in the bow. (lower right) Power spraying in one of the steep-banked borrow pits. These could not be treated by hand because of the great difficulty in coming within range of the breeding areas. INDIANA 107 acres, separated from the river bottom proper by a levee. This extensive breeding area, overgrown with vegetation, could be controlled effectively only by pumping all the water over the levee with a six-inch centrifugal pump. The Ellis Pond area between Taylorville and West Terre Haute was another source of extensive “quad” breeding. This area is filled when the river bottom rises and then dries up dur- ing the summer. In the late summer the area was surveyed for possible drainage routes to the river. Dynamite was used with good effect to regrade an old 850- foot slough, providing for quick drainage of this extensive swamp when the Wabash River fell to low stages. ORNAMENTAL PONDS. In 1934, the Isaac Walton League constructed a series of fish-breeding ponds in Deming Park at the east edge of Terre Haute. The ponds form a good “ quad" larvae habitat. Breeding was well controlled by hand and power lar- viciding. THE EXCAVATIONS. Numerous old strip-mine, gravel, and shale pits are distrib- uted throughout the control zone, mostly west of the Wabash River. Conditions in these pits vary considerably but entomological data indicated that moderate breed- ing occurred in some of them during the summer months. The 600-gallon Bean power sprayer was used effectively to larvicide the steep-banked pits and small ponds. Substituting a %-inch hose for the %-inch hose on the sprayer resulted in an ef- fective spraying distance of about 125-150 feet from the nozzle tip. FORT HARRISON On the basis of past entomological records and reconnaissance during 1945, it appeared that the only significant breeding place around a war establishment in Marion County was Indian Lake, an impoundment of about 58 acres, one-half mile north of the Fort Harrison and Billings General Hospital zone. A thick mat of veg- etation covered approximately 20 acres of the surface of the lake and formed' an excellent habitat for “ quad” breeding. Larvicide was applied by a 50-gallon Hardie power sprayer mounted in a boat. Good control was obtained with this equipment, but hand-paddling of the boat through the vegetation was slow and exhausting. To remedy this, a stern paddle-wheel powered by a small motor was mounted in the boat and successfully propelled it through the surface growth. The larvicide formula used consisted of 18.2 gallons of No. 2 Diesel oil, one gallon of two percent py- rethrum solution, 9.6 gallons of water, and 0.15 gallon of B-1956 emulsifier. This stock solution was diluted 1:10 and sprayed at the rate of 50 gallons per acre. EVANSVILLE The most significant A. quadrimaculatus breeding places in and near Evansville in Vanderburgh County were two ponds in Garvin Park and a series of small ponds in the golf course. Under the existing favorable conditions, moderate numbers of mosquitoes developed in these places. At the beginning of August joint efforts with the city of Evansville resulted in a program of hand-larviciding with Diesel oil. Since the breeding places were limited in area and easily accessible, good control was obtained. An Army airfield and several industrial plants in this zone received routine entomological inspections in 1945. In light of the adult-mosquito and larvae counts, no further control was found to be necessary. Kentucky PHILIP E. BLACKERBY, M. D. State Health Commissioner NOVA activities in Kentucky were con- siderably modified during the second half of the fiscal year as a result of a thor- ough study of operations over the 1945 mosquito-breeding season. The war malaria program diminished in scope from ten counties to operations in four counties after the end of the war. The extended program was reorganized along more effi- cient and economical lines, based on the experience of the previous season’s spray- ing operation. Over the course of the year, an average of 40 USPHS employees spent 68,321 man-hours on war malaria and extended program activities of various kinds. LEGEND War Malaria Control - 1945 Season War Malaria Control - Continued in 1946 Extended Program Residual Spraying Extended Program Larviciding, Surveillance, and/or Drainage WAR MALARIA During the first half of the fiscal year 38 war establishments in 16 zones were protected by larviciding and four military installations in three zones were con- trolled by periodic entomological surveillance. In the course of this work, 14,667 gallons of oil were expended in oiling 683 mosquito-breeding acres and an additional 89 acres were dusted with 132 pounds of paris green. Supplementary work included clearing out 33 acres of vegetation and maintenance-cleaning of 5,383 linear feet of ditches. In 1946 only three military establishments remained active-Camp Campbell, Fort Knox, and the South Louisville Zone Medical Depot - and a modified malaria KENTUCKY 109 control system was put into effect. The necessary larviciding work was combined with entomological inspecting so that both operations were carried on by a com- bination sprayer-inspector. In addition, a new larvicide consisting of DDT-Diesel oil spray was used in place of the older larvicides. Results showed that this new larvicide was easier to apply and reduced the cost of application to about one-third the cost of the old method. EXTENDED PROGRAM During the first half of the fiscal year 16,838 house spray applications were completed in six counties, using a total of 6,956 pounds of DDT in the process. An average of 1.15 labor and foreman man-hours was necessary to carry out each house- spray application. The city of Fulton in Fulton County was given extended protection by larviciding as recommended for cities of more than 2,500 population. At the end of the 1945 mosquito-breeding season a thorough study was made of this first ex- perience in residual house spraying in Kentucky. As a result of this study several improvements in procedure were incorporated into the following season's operations. PUBLIC EDUCATION. Because of the intensive program of malaria education carried on during the previous season and the favorable public reaction arising as a result of the homes already sprayed, the educational phase of the extended program was considerably reduced in 1946. Local county health departments and other agencies were encouraged to carry on this work. The cooperation of home owners was obtained to a much greater extent during the 1946 season, and the furniture was more fre- quently covered before the spray crew arrived. It was learned from experience during the first season that various pieces of furniture in the homes were not damaged when left uncovered during spray operations and considerable time and effort were saved by covering only necessary pieces of furniture. SPRAY CREWS. Since most of the men employed in the spray operations had previously received adequate training, they were left to operate with much less direct super- vision. The area supervisor was thus left free to spend most of his time as advance or contact man for at least two spray crews, in addition to his other duties. After using both two-man and three-man crews, it was concluded that the two-man crew was more efficient. Also, it was found that one man, by properly planning the work, was adequate to perform the duties required at the central mixing plant. Two men had originally been assigned to this work. PRIVATE ENTERPRISE SPRAYING. Various individuals requested information about residual DDT spraying of homes as a private enterprise. Since this presented an opportunity for a number of homes to be sprayed in addition to those included on the extended program, permission was given for these persons to obtain training in the proper spraying technics by working with spray crews on the extended program. Also, a limited amount of technical guidance was furnished to them. The result was the spraying of approximately 4,800 homes, a substantial contribution to the malaria control program in Kentucky. MALARIA INCIDENCE RECORDS. The contact man, or spray foreman, secured information concerning malaria cases by asking the home owner a number of standard questions. The area office tabulated the information thus obtained and maintained a permanent record of malaria incidence throughout the counties sprayed. The Paducah office KENTUCKY used this data to keep spot maps, show- ing malaria cases and deaths, up to date. EXTENDED PROTECTION. During the sec- ond half of the fiscal year 9,206 house spray applications in 11 counties were accomplished on the extended program. Spray crew man-hours per application were reduced to 0.70 as a result of the experience gained during the pre- vious season. Extended control larvi- ciding operations in 1946 were con- tinued in the environs of the city of Fulton, and also expanded to include the cities of Paducah and Mayfield. A total of 93,500 residents of Kentucky benefited from extended malaria control operations. WORKSHOPS With the advent of DDT and new roden- ticides, the Division of Sanitary Engi- neering received numerous requests for information relative to the proper use of these materials. In answer to these requests, district and state MCWA per- sonnel conducted DDT and rodent work- shops throughout the state for the benefit of city and county health departments as well as other groups interested in the promotion of public health work. To date there have been ten such work- shops, with an attendance of approximately 450 people. (top) Insect and rodent control demonstration unit, (center) Larviciding typical “quad” breeding place in Paducah area, (below) Paris green dusting from boat in Paducah area. Louisiana DAVID E. BROWN, M. D. State Health Officer LEGEND War Malaria Control - 1945 Season War Malaria Control - Continued in 1946 Extended Program Residual Spraying Extended Program Larviciding, Surveillance, and/or Drainage Typhus Control Residual Dusting - Typhus Control Ratproofing Aedes aegypti Control At the beginning of this fiscal year the number of war establishments in Louis- iana had already been reduced from that of the preceding year. By 1946 only a small fraction of the total number continued in operation and required malaria control operations. Coincident with the minimizing of war malaria activities, the extend- ed control program grew more than fourfold according to the number of residual house spray applications. In the early fall of 1945 MCWA residual typhus dust- ing and ratproofing were inaugurated as a supplement to the extensive state rat eradication program which had been in operation for the preceding several years. edes aegypti control in New Orleans, begun in April 1943, was terminated at the end of Over the course of the year an average of 229 MCWA personnel worked a total of 340,364 man-hours on the various phases of control activities. 112 LOUISIANA WAR MALARIA During the first part of the year a total of 71 war establishments (26 less than in the preceding fiscal year) in 23 parishes received malaria protection through surveillance, larviciding, and minor drainage activities. After the end of the war only nine installations remained active and required control — the Naval Ammunition Depot in Plaquemines Parish; the Naval Hospital, the USPHS Marine Hospi- tal, and Jackson Barracks in Orleans Parish; Barksdale Army Airfield and the city of Bossier in Bossier Parish; Selman Army Airfield in Ouachita Parish; Camp Polk in Vernon Parish; and the Veterans' Hospital in Rapides Parish. ACCOMPLISHMENTS. Louisiana lies entirely within the endemic malarious area along the Gulf Coast and has extensive swanp areas which cannot be drained. For this reason a tremendous larviciding program was necessary to effect malaria control — larger than in any other state. Altogether, 302,711 gallons of oil were used to spray 12,563 acres of mosquito-breeding surface and an additional 1,720 acres were dusted with 1,780 pounds of paris green. A sizable amount of brush and aquatic growth, 143 acres, was cleared to facilitate larviciding control. Minor drainage totalled 8,805 feet of hand-dug ditches and about 40 feet of dynamite ditching. Approximately 310,800 feet of previously constructed ditches were maintained aod cleaned! EXTENDED PROGRAM During the first part of the fiscal year residual spraying was carried on in eight parishes — Bossier, Caddo, Catahonla, Concordia, Madison, Morehouse, Nat- chitoches, and Red River — in the northern part of the state, including the six parishes which were sprayed the preceding season. A total of 9,761 house spray applications were completed during this period, requiring an average of 1.38 labor and foreman man-hours to apply 0.60 pound of DDT per house application. Extended larviciding protection was accorded the cities of Tallulah in Madison Parish, Bas- trop and Mer Rouge in Morehouse Parish, Natchitooches and Carapti in Natchitooches Parish, Benton in Bossier Parish, and Conshatta in Red River Parish. In 1946 the residual house-spraying program was enlarged to embrace seven other parishes — Bienville, East Carrol, West Carroll, Jackson, Tensas, Union, and Webster — in addition to the original eight. From January through June a total of 36,141 house spray applications was accomplished. Spray crew efficiency increased as evidenced by the considerably less average time required for each house spraying - 0.98 man-hour. The amount of COT per applica- tion remained about the same as in the pre- ceding season. Extended larviciding control was discontinued in Mer Rouge, Campti, Benton, and Conshatta, and was begun in Minden (Webster Parish), Lake Providence (East Carroll Parish), and the Jonesboro- Hodge Zone (Jackson Parish). Approximately Inspecting for mosquito larvae in swampy area. LOUISIANA 113 301,000 residents of Louisiana be nefited from extended malaria control. SPRAY CREW COMPOSITION. Two or three men were employed in the actual house spraying operations, depending upon local conditions. In several places the local authorities furnished one or more men to contact the occupants and prepare the houses ahead of the spray crews. This very materially facilitated the work and resulted in increased spray crew effi- ciency. Between mosquito-breeding seasons, skeleton field forces were employed in making field surveys and locating all houses in the areas to be included in the 1946 spraying program. To facilitate this work and to provide a permanent record of the character, size, and location of the houses, large scale maps were prepared on which were also included essential topo- graphical features and roads. SPRAY CLARIFYING TANKS. Since house spraying activities were begun in Louis- iana in April 1945, field spray crews experienced considerable lost time because of spray nozzles clogging up due to insolu- ble impurities in the DDT concentrate. To obviate this difficulty, a 500-gailon, steel, oil storage tdnk was modified for use as a settling tank. An 18-inch manhole was cut in one end and fitted with a wooden weather-cover. A two-inch outlet was welded into the center of the other end of the tank, which was to be the bottom. Then a one-inch outlet was welded into the side of the tank six inches above the bottom. The tank was set on end, with the pipe outlets on the bottom, on a pedestal raised high enough to get gravity-flow from the one-inch outlet into drums via a hose. The two-inch bottom outlet was used to draw off the lighter sludge which settled to the bottom. A cloth strainer, attached to a pulley above the tank, was placed inside the tank covering the bottom. This strainer prevented the bottom outlet from being clogged and was used to lift out the heavy sludge-sediment before filling the tank again. A 1,000-gallon tank was similarly modified. Spray-clarifying tanks of 590 and 1,000 gallon capacities were used to settle out nozzle-clogging sediment. JEEP-TRAILER COMBINATION. A combination of jeep, for motive power and person- nel carrier, and a trailer, for a spray and equipment carrier, was tried out dur- ing the past year to ascertain if it had any actual superiority over a single ve- hicle such as a weapons carrier. The trailer carried a standard oil drum fitted with a lock-type faucet for the spray mixture. A standard box with compartments contained two five-gallon “ GI” cans of concentrate, four spray cans, rags, pails, etc. Another box, on the other side of the trailer, contained cover cloths, tools, repair parts, etc. The whole trailer was protected with a canvas cover. The jeep- trailer combination showed decreased cost qf operation, a lower center of gravity for safety, better traction, and greater mobility. The jeep could be used by the LOUISIANA 114 advance man, while the crew worked out of the trailer. This combination proved more efficient than any vehicles previously used. MOBILE POWER-SPRAY UNITS- During house spray work in the summer of 1945 it was noted that mechanical pumps were of eco- nomical use only when the houses were thickly grouped. To make most efficient use of the three 50-gallon and two 100- gallon Dobbin spray pumps on hand, each was mounted on a Jeep trailer as a mobile unit. The units could be assigned to any crew when they were spraying in a thickly- populated neighborhood, and then, when ordinary conditions prevailed, could be assigned to another crew. This arrangement worked out most advantageously; each power sprayer could be operated by a regular crew, and was kept busy at maximum efficiency. A combination of jeep, for motive power and personnel carrier, and a trailer, for a spray and equipment carrier, was tried out. TYPHUS CONTROL In the past several years state and local funds had supported on extensive rat poisoning program in cooperation with the Fish and Wildlife Service of the U. S. Department of Interior. At the beginning of the 1946 fiscal year an MCWA typhus control program was inaugurated in Louisiana as a supplement to, and in coopera- tion with, state typhus control activities. The combined program consisted of parish-wide, rural and urban, residual dusting in the four parishes of Orleans, Caddo, Calcasieu, and Iberia, and 1‘spot’’ dusting wherever typhus cases appeared in Tangepahoa and Washington parishes. Infested business establishments in five cities were ratproofed, and poisoning activities were carried on both indepen- dently and as an adjunct to dusting and proofing. Approximately 907,000 residents of Louisiana benefited directly as a result of MCWA and state typhus control ac- tivities. In addition to an extensive dusting, proofing, and poisoning program carried on with state and local funds, 24 cities were included in the MCWA-state residual dusting program. Of these, four cities - New Orleans, Shreveport, Lake Charles, and New Iberia - also had ratproofing programs. In the city of Hammond, ratproofing alone was the means of combating the typhus menace. EPIDEMIOLOGY. There were 425 cases of typhus fever in the state in the year 1945, which was an increase of approximately 100 percent over 1944. In 1945, through September, there were 305 cases in the state, 60 of which occurred in New Orleans. Over the same period in 1946 there were 213 cases, 76 of which were in New Orleans. This was a decrease of approximately 30 percent over last year, disregarding the better reporting of the disease by physicians. The typhus complement-fixation blood tests showed a reduction from approximately 68 percent positive to 34 percent pos- itive for rat bloods on a state-wide basis. SQUILL MIXING PLANT. In the latter part of April a central squill-bait mixing plant was put into operation to furnish mixed bulk and wrapped bait to the state projects. This plant was able to furnish materials to the cities and parishes more LOUISIANA 115 cheaply than the cost of their buying ingredients and mixing bait themselves. Also, as a result of this plant's operation, the amount of time the supervisor spent in an area was reduced considerably. By the use of Bed Squill ‘ * torpedoes," the poisoning and dusting crew was able to do two operations at once, obviating the necessity of a return trip to each place dusted. After the dust had settled, Red Squill torpedoes were placed in rat “runs. ” Squill, being a slow-acting poison, allowed the rats to carry the DDT into their burrows and other inaccessible places before causing the death of rats. DUSTING INNOVATIONS. In dusting restaurants, the ten percent DDT was mixed with flour, which not only killed rat fleas but also did a very good job of ex- terminating roaches. To obtain a sufficient amount of DDT dust without expend- ing considerable effort, the dust-outlet holes in the hand-dust gun between the dust chamber and the delivery spout were punched out. A program of theater dust- ing and poisoning was carried on quarterly, by local parish health units, in 39 parishes that had typhus cases. PROOFING AND POISONING PRACTICES. For each establishment ratproofed, metal or concrete garbage stands were constructed. New garbage cans, if required, were fig- ured in with the cost of ratproofing. Permanent ** 1080" poisoning stations were used wherever safe in food-outlet places. These stations were completely protect- ed as a safety precaution. Clean-up campaigns were carried on routinely on each rat eradication project. ACCOMPLISHMENTS. In the MOVA-state typhus program, a total of 25,667 premises were inspected during the year for rat infestations and 23,588 premise dustings were completed. Each dusting treatment required an average of 0.42 labor man-hour to dust 1.7 pounds of ten percent DOT. Approximately 270 buildings were ratproofed, each of which required 51.3 man-hours of labor. Some 23,172 premise poisonings were completed, requiring an average of 0.29 man-hour of labor to spread 0.23 pounds of bait per premise treatment. Use was also made of " 1080 ” poisoned water as a supplement to the bait; 548 pints were consumed during the year. AEDES AEGYPTI CONTROL The control of the yellow fever and dengue mosquito had been in effect in New Orleans since April 1943. In the 1945 fiscal year Aedes aegypti control was com- bined with general sanitation activities. This integrated program, under which aegypti control was supervised by USPHS personnel, continued until the end of 1945. In 1946 further MCWA participation was considered unnecessary because effective control was being maintained by the local health unit. During the year 24,667 prem- ises were inspected and 1,794 were found to contain aegypti breeding places, an index of 8.51. The 540,000 residents of the city benefited not only by these con- trol measures but also by the general sanitation improvement throughout the city. TYPHUS FEVER CASES Mississippi FELIX J. UNDERWOOD, M. D Secretary and Executive Officer LEGEND War Malaria Control - 1945 Season War Malaria Control - Continued in 1946 Extended Program Residual Spraying Typhus Control Residual Dusting Typhus Control Ratproofing During 1945 a maximum number of MCWA zones were in operation in Mississippi. After the end of the war rapid curtailment of war es- tablishments relegated the war malaria phase of control to a relatively minor activity, while the extended malaria program expanded to major proportions. Typhus control activi- ties were inaugurated and carried out in four approved areas in the southern part of the state. An average of 214 USPHS employees participated in MCWA activities of various kinds during the year. All control operations of both malaria and typhus were conducted under the supervision of the State Division of Sanitary Engineering, with field work organized as an integral function of the county health departments. This form of organization resulted in wholehearted cooperation by county officials. WAR MALARIA In 1945 war malaria operations protected 59 war establishments in 40 zones in Mississippi. After the end of the war only three military installations— the sep- aration center at Camp Shelby in Forrest County, the Veterans' Hospital in Hinds County, and Kaye Field in Lowndes County — received control and entomological sur- veillance measures. CONTROL OPERATIONS. During the course of the year wide-spread use was made of both oil and paris green larvicides. Approximately 2,760 acres of water surface were treated with 68,219 gallons of oil and an additional 2,621 acres were dusted with 4,492 pounds of paris green. Clearing of 488 acres of aquatic and land vege- MISSISSIPPI 117 Power dusting from a wagon at Lake Washington. tation facilitated the larviciding work and rendered some areas unfavorable for quadrimaculatus breeding. Drainage operations included 1,000 feet of hand ditching and the cleaning of 254,145 feet of existing ditches. EXTENDED CONTROL Public interest and enthusiasm in the residual spraying program have been evident throughout the year. In the borderline counties of Yazoo, Holmes, Carroll, Talla- hatchie, and Panola, which would normally be only partly included in the residual spray program, county-paid crews were placed at the disposal of the various area supervisors to assure complete coverage of these counties. Full-time malaria edu- cators assisted in the public relations phases of the extended program which offered protection to more than 459,000 residents of the state. ACCOMPLISHMENTS. Since the beginning of the extended spraying program in Mis- sissippi, 201,369 house spray applications have been accomplished. Of this number, 61,949 in 13 counties were achieved by a maximum of 48 crews during July, August, and September 1945. The average number of man-hours per spraying for this period was 1.07, and 0.47 pound of EDI was used for each house application. It was neces- essary to employ a 2Yz percent spray due to the critical shortage of xylene, DDT, and Triton emulsifier. During the winter months only key personnel were retained for making maps, numbering houses, and preparing for renewed activities in the spring. From March through June of 1946 a maximum of 60 crews worked in 17 counties to perform an additional 104,041 house spray applications. The man-hours per house- spraying dropped to 1.00 because of increased spray-crew experience and the amount of DDT per application was increased to 0.70 pound. 118 MISSISSIPPI SPRAY CREWS. The work crew used in Mississippi consisted of one sprayer-foreman and three laborers. The use of the four-man crew was begun early in 1945 and has been continued in the belief that it is an efficient operational unit in view of the shortage of vehicles. Under conditions existing in this state, it has been observed that a four-man crew usually sprayed 15 to 20 percent more houses per day than a three-man crew could accomplish without using extra equipment. MATERIALS AND EQUIPMENT. The Greenwood warehouse served as the distribution center for all materials and equipment. All kinds of major and minor repair work on automotive and sprayer equipment, as well as DDT mixing, was done at this ware- house. A mixing procedure was developed at the warehouse which doubled the output of concentrate from a single mixer. To each of 30 empty 55-gallon drums of the re- movable-head type (originally used for Triton emulsifier), 125 pounds of IX/I and 31.5 gallons of xylene were added, the covers replaced, and the drums allowed to stand overnight. By morning most of the DDT was dissolved and what remained was more or less in suspension. The “mix" was then pumped into the mixer, became clear in about two or three minutes, emulsifier was added, and the mixing was complete. A more versatile spray can was the result of installing a valve stem on the filler cap of the Lofstrand sprayer and on the cover plate of the Hudson sprayer. The pumps on both cans were left in place so that pressure could be obtained from either a compressor or the hand pump. Twenty-five compressors were used during the year to provide air pressure for the spray cans. Each compressor tank was fitted with a valve so that air could be delivered from a filling-station air supply in the event of breakdown of the compressing unit. The use of a faucet-equipped, 55-gallon drum on each truck for carrying diluted five percent spray was continued this year. Some areas constructed large, overhead tanks for mixing the diluted spray in order to facilitate the filling of the drums on the spray trucks each morning. The tank at Cleveland had a 500-gallon capacity and the one in the Clarksdale area held 420 gallons. A general utility man mixed the five percent spray in the tank each morning and had the drum in each truck filled by the time the crews re- ported for work. The movement of the truck kept the spray in the drum agitated during the day. ENTOMOLOGICAL INSPECTION. All of the inspection work was accomplished by four full-time inspectors and one part-time inspector, who also acted as an assistant supervisor. In 1945, when a 2Vi percent spray was used, 4. 1 percent of the sprayed houses inspected were found positive for “quads" as compared with 87.2 percent pos- itive for unsprayed houses. In 1946 only 2.1 percent of sprayed houses were found positive. This lower figure might have resulted from the use of a five percent spray since there was some indication that the greatest proportion of positives among the sprayed houses occurred in counties which had used the smallest amount of DDT per house application. Observations in houses sprayed in late summer and fall of 1945 indicated that some degree of control of flies and mosquitoes was attained during the early summer of 1946. TYPHUS CONTROL The policy of the Mississippi State Board of Health regarding the control of typhus has been to embody some permanency of organization in each county health unit where the disease is of public health importance. To this end, five sanitarians were placed in county units, permitting typhus responsibilities to become an integral part of the routine sanitation program. (top) Central mixing plant. DDT and xylene were placed in drums to stand overnight be- fore being run through mixer. Hose leads to outdoor mixer. (center) Filling drum in truck with five percent DDT spray from over- head mixing tank. Spray cans were filled from drum through faucet in the side of the truck, (left) Valve stems installed in Lofstrand and Hudson spray cans. Air pressure could be obtained from compressor or regular hand pump. 120 MISSISSIPPI State-wide eradication work was carried on by a full-time, state board of health- paid employee working with the State Plant Board and assisted by members of the State Division of Sanitary Engineering. Poisoning operations in connection with ratproofing were the responsibility of local project personnel, who also cooperated with campaigns conducted by the State Plant Board. Such cooperative, county-wide poisoning campaigns were carried out in several counties where vent-stoppage and residual dusting were employed as control measures in urban communities. Over the course of the year, in addition to 12,254 local labor man-hours, a monthly average of 11 MCWA employees worked a total of 19,712 man-hours to offer protection against typhus fever to approximately 196,650 residents of Mississippi. RESIDUAL DUSTING- In Jackson County residual dusting in areas of concentrated popu- lations throughout the county continued through USPHS assistance during the year. A dusting project in Harrison County was started early in the fiscal year and continued with excellent evidence of ectoparasite control. Analysis of results showed approxi- mately 89 percent control of fleas and 77 percent control of total ectoparasites in some ten days after dust application. In Laurel, Jones County, a ratproofing project was supplemented by residual dusting. After completion of the initially-planned dusting cycle, the incidence of typhus in rats, based on 33 sanples, was approximately 12 percent. During the last half of the fiscal year, 3,250 applications of EOT dust were reported from this area. Residual dusting operations were begun also in the cities of Hattiesburg, Forrest County, and Jackson, Hinds County, in 1946. In general, the scope of the residual dusting operations extended along the coastal highway strip, including the cities of Bioloxi, Gulfport, Pass Christian, Mississippi City, Pas- cagoula, and Laurel. A total of 15,383 premise dustings was accomplished during the year, and 0.75 labor and foreman man-hour was expended for each dusting application. RATPROOFING AND ERADICATION. In Jackson and Marion Counties, cooperative rat- proofing and rat eradication projects were completed for this fiscal year. A rat- proofing project in Laurel was organized with the services of an experienced DSPHS supervisor and continued, after the initial organizational period, without further assistance. Promotional work on two additional large projects in the cities of Jackson and Hattiesburg was accomplished and plans completed for inauguration of ratproofing work to begin about July 1946. The “1080” poisoning campaigns in busi- ness districts in Jackson and Harrison counties were so effective that originally proposed evaluation procedures for DDT dusting were found to be impracticable be- cause of inadequate samples of rats obtainable by trapping. One-half man-hour of labor was required to place 0.36 pound of bait in each of the 2,065 premise poisonings accomplished. A total of 172 establishments in the cities of Gulfport, Pascagoula, Laurel, and Columbia were ratproofed, requiring 46.3 labor and foreman man-hours for each job. For buildings of a temporary nature, ratproofing was made possible by using treated metal lathes as a substitute for concrete chain walls. The lathe was placed 18 inches in the ground and had a shelf of fr<5m eight to 12 inches. Metal laths were used as a substitute for concrete chain walls on temporary buildings. Missouri R. M. JAMES, M. D State Health Commissioner LEGEND War Malaria Control - 1945 Se a s on War Malaria Control - Con- tinued in 1946 [Extended Program Residual Spr aying Extended Program Larvicid- ing, Surveillance, and/ or Drainage The extent of war malaria operations in Missouri decreased sharply after the war’s end; only three war establishments out of a total of 26 remained active dur- ing the last half of the fiscal year. Conversely, the Extended Malaria Control Program increased in scope from three counties to ten during the course of the year as emphasis shifted to the protection of the civilian population against the possible introduction of foreign malarias. During the course of the year an aver- age monthly total of 103 MCWA employees worked some 171,000 man-hours on war ma- laria and extended program operations. At the beginning of the fiscal year 26 war establishments in 20 counties were protected by larviciding, minor drainage, and surveillance. No major drainage proj- ects were found necessary this year, since vertical drainage of the “ Frisco Ponds,” the LeMay Sink Hole, and the sinkholes around Jefferson Barracks in previous years had eliminated or brought under control many of the serious “ quad” breeding areas. During 1946 only three war establishments — Lambert Field and Jefferson Barracks in the St. Louis area, and the Fort Leavenworth reservation in the Fort Leaven- worth area - remained active and required malaria control. At Lambert Field, ento- mological surveillance indicated no need for control operations, while at the other two installations larviciding was necessary to effect control. WAR MALARIA LARVICIDING. Based on last year’s DDT-larvicide experiments at Duck Lake in the Fort Leavenworth area, routine DDT larviciding of small ponded areas, ditches, and streams was inaugurated this year in the Jefferson Barracks zone and the Fort Leavenworth Zone on the Missouri side of the river. A mixture of DET, No. 2 Die- sel oil, and a spreading agent was sprayed through an atomizing nozzle at the rate 122 MISSOURI of 0.05 pound DDT per acre. DDT larviciding saved a great deal of time when small ponds, ditches, and streams constituted the principal water areas treated. It took about the same amount of time to treat an area with EOT as with oil, except that it was not necessary to obtain refills constantly with DDT as it was with oil lar- viciding. Inspectors reported very good kills after larviciding with DDT. From the results of work performed, it appeared likely that a trained sprayer-inspector could provide adequate control over the scattered limestone sinks in the Jeffer- son Barracks area without additional labor help. However, at Fort Leavenworth it was still necessary to continue extensive paris green larviciding over the large water areas in addition to the DDT larviciding activities. During the course of the fiscal year, 15,864 pounds of paris green were used to dust 7,482 acres, and 36,115 gallons of oil were sprayed over 2,127 acres. Sixty acres of land and aquatic vegetation were cleared to facilitate control operations, and 14,240 linear feet of ditches were cleaned and otherwise maintained. Minor drainage activities included 2,000 linear feet of hand ditching, 6,600 feet of dynamite ditching, and 600 feet of ditch linings. EXTENDED PROGRAM During the 1945 season three counties — Dunklin, Pemiscot, and New Madrid — were included in the residual house spraying program. In addition, according to recommended practice, 16 towns of over 2,500 population received extended protec- tion through larviciding. A total of 19,760 house spray applications were accom- plished, requiring an average of 0,97 man-hour to apply 0.56 pound DDT per spray application. In the second half of the fiscal year the 39,000 house spray appli- cations accomplished extended over ten counties — the three sprayed in 1945, and Mississippi, Butler, Wayne, Bollinger, Ripley, Scott, and Stoddard. Man-hours per application decreased to 0.78 because of increased efficiency of crew operation, and the amount of DDT per house spraying was increased to 0.77 pound to obtain greater residual effectiveness. Over the course of the year approximately 459,000 residents of Missouri benefited from the extended program. SURFACE SPRAY RATES. When smoothly-painted surfaces were sprayed it was nec- essary to increase the spraying rate to approximately 400 square feet per minute When smoothly painted surfaces were sprayed it was necessary to decrease the spraying rate to prevent run-off. MISSOURI 123 to prevent run-off. When very rough, course surfaces were sprayed the rate was reduced to about 100 square feet per minute in order to secure a surface residuum of 200 mg. of COT per square foot and still allow for losses due to absorption. SPRAY CREW COMPOSITION. In order to obtain a better man-hour ratio per house spray application, two-man crews were inaugurated insofar as automotive vehicles permitted. An operational unit of three two-man crews headed by a contact-man supervisor was found to be most economical and efficient. For the sake of economy, the contact man was utilized as an "operations individual" during the active spray months. He made the house spraying arrangements for three crews so that crew time was not consumed with contacting houses where the owner was away or refused to have the spray applied. During the winter months the contact man was assigned to malaria education activities. By having first-hand spray operations experience his value as an educator was greatly increased. SPRAYING EQUIPMENT. Each crew was provided with a 55-gallon drum of mixed con- centrate and water, which was prepared at the warehouse or storage area before leaving for the day’s work. This system proved far superior to measuring and add- ing water and concentrate to each individual spray can as it was needed. Contin- uous agitation of the mix was effected by the jostling of the truck over the road. The use of air compressor units proved more satisfactory than the old hand pump- ing method not only in saving energy but in saving spray can maintenance. Much difficulty was experienced with the hand-spraying units due to inferior construc- tion and the cori'osive effect of the spraying materials. Considerable time was spent in preparing large scale maps of residual spray areas showing exact house locations and spraying progress. It is believed that the extra work entailed in the preparation of these maps has paid dividends in facilitating operations and insuring a high standard of accuracy of spray records. AUTOMOTIVE EQUIPMENT. Although certain definite stations were designated as area headquarters, there were times when all trucks but one were based at an aux- iliary station and the crews were transported there in one truck from the main base. This practice saved considerable wear on automotive equipment, particularly when the spraying area was far from the regular base. Governors were installed on tactical vehicles at the beginning of the 1946 spraying season and have re- sulted in a considerable reduction of accidents, A practice was instituted in the garage of keeping a rotating motor pool so that each vehicle was completely check- ed before it was released from the central garage. As a result of experience gain- ed from the operation of mobile-units engaged in DDT spraying of poliomyelitis endemic areas, an additional truck carrying extra concentrate, repair parts, and supplies was added to each unit of contact man and three spray crews. This truck also served as a conveyance for the contact man in the area to be sprayed. INSECT CONTROL As a result of the extensive use of DDT, health authorities in Missouri have begun to think more and more in terms of the use of DDT for general sanitation rather than malaria control alone. While it is understood that DDT will not re- place good municipal housekeeping or general sanitation, nevertheless the tre- mendous reduction in flies, bed bugs, and mosquitoes on a countywide scope has emphasized that DDT spraying is extremely effective as a sanitation device. North Carolina CARL V. REYNOLDS, M. D. State Health Officer ihe malaria control progr-am underwent drastic changes during the course of the fiscal year as a result of the ending of the war and the consequent inactivation of 71 out of the total of 77 war establish- ments previously protected. War malaria activities were diminished almost to the vanishing point, while residual spraying operations were greatly expanded. Typhus control was incorporated as part of MCWA activities at the beginning of the fiscal year and the program was considerably LEGEND War Malaria Control - 1945 Season War Malaria Control - Continued in 1946 j Extended Program Residual Spraying Extended Program Larviciding, Surveillance, and/or Drainage Typhus Control Residual Dusting - Typhus Control Ratproofing expanded by the introduction of residual dusting operation. The number of MCWA per- sonnel employed on malaria control decreased from 188 in July 1945 to 67 in June 1946 due mainly to the virtual termination of war malaria projects and the increasing amount of local participation in the extended control program. Approximately 160,000 man-hours were expended on all types of MCWA activities during the year. WAR MALARIA During the first half of the fiscal year 58 war establishments in 30 zones were protected by larviciding, minor drainage, and major drainage operations, while conditions around an additional 19 war establishments in 11 zones necessitated only periodic entomological inspections. After the end of the war only six proj- ects — the city of Fayetteville, Fort Bragg and the Veterans’ Hospital in the Fort NORTH CAROLINA 125 Bragg area of Cumberland County, the Cherry Point Marine Base and the Pollocks- ville Marine Air Base in the Newburn area of Craven County, and Moore General Hos- pital in the Asheville area of Buncombe County — remained active and malaria pro- tection was continued in all of these areas by surveillance, larviciding, and drain- age activities. LARVICIDING. Oil was the larvicide of choice in North Carolina during the past fiscal year; 27,862 gallons were sprayed over 1,382 mosquito-breeding acres. An additional 71 acres were dusted with 270 pounds of paris green. Supplementary ex- tensive clearing was accomplished by the removal of 167 acres of aquatic vegeta- tion and 378 acres of land growths. DRAINAGE. Major drainage was carried on in four zones during the first half of the fiscal year. In Buncombe County, a project to drain abandoned gravel pits in the vicinity of Moore General Hospital was initiated early in 1945 and was com- pleted at the end of March 1946. Although the hospital was in the mountains and* not near any endemic malaria section, it had special significance in that a great number of malaria and other tropical disease cases were being cared for and con- siderable “ quad” breeding was found in the gravel pits. Since the hospital was a permanent installation it was felt that permanent drainage was the preferable malaria control method. In the Jacksonville zone of Onslow County a large swamp in the vicinity of the city of Jacksonville, Camp Lejeune and the Marine tent-camp area, the Naval Hospital, and the Midway Housing Project was drained by ditching operations. Three swamps in the vicinity of the Oak Grove Marine Airfield barracks area in Jones County were drained by dynamite ditching. Ditching was also required around the Cherry Point Marine Base and the adjacent war housing project in Craven County because the average elevation above the Neuse River was only 18 feet and numerous swamps had developed through lack of proper drainage outlets. Altogether a total of 69,194 linear feet of hand ditch- ing, 27,280 feet of dynamite ditching, and 1,597 feet of underground ditching was nec- essary to accomplish major and minor drain- age projects in 1945. Approximately 1,206,000 linear feet of existing ditches were cleaned and 7,839 cubic yards of earth were filled in to eliminate, in all, a total of 50 acres of water surface. EXTENDED PROGRAM During the first half of the fiscal year 2,488 residual house sprayings were performed in 13 counties, including 24 towns. In 1946 residual spraying was ex- tended to 36 counties, including 92 towns, and a total of 20,605 house spray ap- plications were completed. Spray crew effi- ciency increased, as shown by the aver- age of 0.86 man-hour per application re- quired in 1946 as compared to 1.08 during Major drainage was carried on in four zones during the first half of the fiscal year. 126 NORTH CAROLINA the previous season. To obtain increased residual effectiveness the amount of DDT per house application was increased from 0.38 pound to 0.65 pound in 1946. One extended program major drainage project was begun in February 1946 and continued to the end of the fiscal year. In Craven County, just outside the city of Newburn, a series of ponds around the Washington Fork community were eliminated by hand- dug ditches. HOUSE SPRAYING PRIORITY. In determining the homes to be sprayed with DDT, top priority was given to veterans with malaria histories. The order of priority after infected veterans was: homes of individuals with current positive blood smears, communities in which a high incidence of malaria had been established by blood- slide surveys, and lastly, communities in which malaria was established by other epidemiological data. All homes of individuals found to be positive for malaria on current blood slide surveys were sprayed as well as those homes in the immed- iate vicinity. LOCATING VETERANS' HOMES. In some cases it was very difficult to locate dis- charged servicemen with malaria histories and to ascertain their desires to have their homes sprayed. The cooperation of the local health officers was enlisted in this project. A circular fetter was mailed to health officers explaining the program for spraying veterans’ homes and asking that they submit lists of infected veterans in their counties who wanted their homes sprayed. The industry of the health officers in compiling these lists contributed materially to the success of the programs; in one county alone 175 homes of veterans with malaria histories were located and sprayed. ENTOMOLOGIST-EDUCATORS. Due to the scattered nature of the program in North Carolina no one area had sufficient work either for a full-time entomologist or a full-time educator. As the personnel on these two activities were capable of performing the dual function, education and entomology were combined and placed under the supervision of the state entomologist, thus saving in personnel and trav- el expenses. This system worked out very satisfactorily. FISH POND BREEDING CONTROL. Under a program sponsored by the U. S. Soil Con- servation Service a large number of fish ponds were built on farms in the state. The State Board of Health required a permit before construction was allowed. Embodied in the application for the permit was an agreement to maintain the pond in such a manner that it would not breed malaria mos- quitoes, thus becoming a nuisance dangerous to the public health. County soil conserva- tionists cooperated with the health depart- ment by helping the farmers to fill out the applications, obtain the permits, and plan and construct the ponds, thus assuring con- formance with required regulations. During May and June of 1946, 107 and 101 proposed ponds, respectively, were inspected. Ponds had to be maintained to prevent mosquito breeding. 127 NORTH CAROLINA (above) Distributing 1080 water in “souffle” cups, (right) Combing a rat for ectoparasite counts. TYPHUS CONTROL In September of 1945 typhus control activities in North Carolina were incor- porated into the MCWA program and operations were considerably expanded by the inauguration of residual DDT dusting. Besides 46,424 man-hours of local labor, a monthly average of 19 MCWA employees spent a total of 33,239 man-hours on various types of typhus control during the year, offering protection to some 371,400 res- idents of the state. RESIDUAL DUSTING. Eighteen cities in the counties of New Hanover, Craven, Gran- ville, Wilson, and Sampson had residual dusting programs. About two-thirds of the 36,176 premise dustings were in residences, and the other third were in businees establishments. An average of 0.60 labor and foreman man-hour was required to spread 1.5 pounds of 10 percent DDT for each premise application. RATPROOFING. Ratproofing campaigns were carried out in the cities of Moores- ville in Iredell County, Charlotte in Mecklinburg County, Winston-Salem in Forsyth County, Elkin in Surrey County, and Dunn in Harnett County. In all, 601 business establishments were treated requiring 53. 3 labor and foreman man-hours for each establishment. RAT POISONING. Poisoned bait was spread around premises as a supplementary ac- tivity to both residual dusting and ratproofing, since it required little more time and effected additional rat control. A total of 2,079 premise poisonings were com- pleted, requiring 0.36 pound of bait and 1.20 labor and foreman man-hours for each premise treatment. Oklahoma GRADY F. MATHEWS, M. D. Commissioner of Public Health LEGEND War Malaria Control - 1945 Season War Malaria Control - Continued in 1946 i) Extended Program Residual Spraying Extended Program Larviciding, Surveillance, and/or Drainage Malaria control activities in Oklahoma, as in other states, were transitional in character during this fiscal year, with gradual reduction of war malaria control to a minimum and coincidental expansion of the DDT residual spray program. The extended program in this state was unique in that the scope of spraying operations was depen- dent directly on the amount of local participation furnished by each county. ENTOMOLOGICAL RECORDS Routine entomological inspections were supplemented by a flexible system of light trap locations, shifted so as to eventually complete the collection records in every county in the state. So far seven new locations were operated in 1945, and 27 were added in April 1946. The method of operation of the light traps re- quired cartons of sufficient size (one-half pint) for one night's “run". Collec- tions were handled by local cooperators at each station. The cartons were picked up during monthly service visits to each light trap, and specimens were stored for winter study. Entomological inspection indicated that 1945 was the most serious malaria mos- quito-breeding season yet recorded in Oklahoma. Collections commonly included more OKLAHOMA 129 than 100 Anopheles quadrimaculatus at representative stations, and the species was widely distributed throughout the state. High catches along the Red River ex- ceeded 1,000. Adult collections in some few stations continued from past seasons reached 25 to 50 times any previous records. WAR MALARIA During the first part of the fiscal year 69 military establishments in 25 coun- ties were protected by malaria control activities. Entomological inspection of 41 installations indicated no need for further ministrations, while 28 required larviciding and minor drainage to effect control of mosquito breeding. In 1946 only one military establishment, the Veterans' Hospital in Muskogee County,was functioning during the malaria mosquito season. LARVICIDING. Most of the larviciding was done with oil; 86,740 gallons were sprayed over 5,054 acres of water surface. An additional 966 acres were dusted with 1,500 pounds of paris green. Approximately 21,000 linear feet of existing ditches were cleaned out, and 35 acres of brush and vegetation were cleared. Minor drainage activities consisted of hand-digging 18,000 linear feet of ditches. EXTENDED PROGRAM During the 1945 season the residual spraying program operated in Choctaw, Mc- Curtain, and Pushmataha counties. The cities of Hugo and Bowell in Choctaw Coun- ty, and Idabel and Broken Bow in McCurtain County received extended protection through larviciding, since they had populations exceeding 2,500. LOCAL PARTICIPATION PLAN. In the early part of 1946 a proposition was placed before civic leaders and organizations in 19 communities of 100 houses or more, Applying DDT residual spray to house interior. Larviciding small, swampy pond. OKLAHOMA 130 and before the commissioners of five counties, outlining the possibility of great- ly extending the residual spraying program with locally contributed funds and labor. The desired pro-rated contributions from the communities to the state ma- laria control fund were computed at $1.00 per house - approximately one-half of the actual field costs or one-third of the total over-all costs. The counties were urged to contribute an equivalent amount of labor. The response to this proposal for local participation was, in most cases, favorable and enthusiastic. Of the 19 communities approached, 16 subscribed to the first 1946 spray period (March - June 1946) and guaranteed the second spray period on the same basis. The counties contributed less labor than requested due to impending end of the fiscal year bud- get, but all guaranteed action during the second spray period. The local partici- pation program will mean expansion during the next fiscal year into at least three additional, malarious counties. The plan furnished a striking example of neigh- borly effort in public health. PUBLIC RELATIONS. Two field educators and state office personnel promoted the local participation plan by utilizing to full advantage the printed and projec- tion materials supplied by MCWA headquarters. Meetings were held in almost every schoolhouse before and during the inauguration of the program. Meeting With civic organizations several nights each week was a regular part of the weekly field schedule. The significance of DDT in household sanitation was thoroughly emphasiz- ed throughout the state. A county demonstration program was inaugurated following a general meeting of health unit personnel in Tulsa on December 3-4, 1945. Sta- tions were established for issuance of DDT to county sanitarians and other author- ized individuals for demonstration purposes, and report forms were devised to keep the state office informed of the progress and effectiveness of this work. Over 60 demonstrations, with more than 1,300 attendance, have been reported so far. ACCOMPLISHMENTS. From July through December 1945, 9,735 house spray applica- tions were performed in the three counties covered by the program. Spray crews worked a total of 9,283 man-hours to spray 4,127 pounds of DDT. In 1946 as a re- sult of the local participation plan, residual spraying was extended to cover five counties — the three previously sprayed, plus Haskell and Sequoyah counties. The number of spray applications increased to 17,060 during the second half of the fiscal year, requiring 14,554 labor and foreman man-hours to spray 14,911 pounds of DDT. Spray crew efficiency increased; only 0.85 man-hour was required to spray a house in 1946 as compared to 0.95 in 1945. The amount of DDT per house was more than doubled during the second half of the fiscal year to obtain greater resid- ual effectiveness. In all, some 102,000 residents of Oklahoma received extended control protection. SPECIAL RECONNAISSANCE SURVEYS The state office cooperated extensively with the U. S. Engineer Corps and the USPHS Impounded Water Section in organizing and carrying out reservoir survey work. At Tishomingo, on Lake Texoma, the state also furnished supervision and in- spection for the U. S. Engineer control project. Other reconnaissance responsi- bilities at the many POW camps and military hospitals were continued through the 1945 season, utilizing the services of an entomologist from the staff of the Uni- versity of Oklahoma, who could thus become available to the state as an experi- enced worker in field malaria control. Oregon H. M. ERICKSON, M. D. State Health Officer LEGEND War Malaria Control - 1945 Season War Malaria Control - Continued in 1946 In the summer of 1945 only one larviciding and minor drainage project was con- ducted in Oregon. Located in the valley of the Rogue River near Medford, this project included one zone surrounding Camp White and another zone enclosing Medford Army Airfield. In addition, several entomological surveys were completed in the western part of the state. In 1946 entomological inspections were carried on around Camp White and Medford Airfield until the middle of May, when the project was terminated owing to the imminent closing of the installations. SPECIES DIFFERENTIATION Although most of the malaria in Oregon has occurred in the Willamette River Valley where punct ipennis is the predominant Anopheles, the situation is reversed near Medford where freeborni has been found to be the most abundant species. In 132 OREGON July, August, and September of 1944, freeborni constituted 95 percent of the adult anophelines found near Medford. During the same period of 1945, this species made up 93.6 percent of the total. In contrast to the preceding year, however, puncti- pennis was more common (4.0 percent) than pseudopunctipennis franciscanus (2.3 percent). This past year was the second in yhich the occurrence of franciscanus was confirmed north of California on the West Coast. CONTROL FACTORS The larviciding and drainage control project was not initiated until July 1944, when a survey showed that large numbers of adult Anopheles freeborni were present, and that anopheline larvae were breeding abundantly, especially in natural pools along the permanent streams and in waste irrigation water. Within one-quarter mile of perhaps the most productive breeding area were barracks housing prisoners of war, among whom at that time there were from 15 to 20 malaria relapses each week. LARVICIDING. Control measures, begun May 5 in 1945, were continued through Sep- tember 6, after which no breeding was found in the controlled area, and practically none outside. The larviciding was done by prisoners of war provided from Camp White. The same.crew was also used for mosquito control within the reservation. A total of 1,635 gallons of Diesel oil was applied to over 66,000 feet of ditches and 30 acres of other breeding places after the first of July. ENTOMOLOGICAL INSPECTIONS. Whereas the average number of adult freeborni per inspection station did not fall below ten until mid-September of 1944, this number never exceeded ten throughout the summer of 1945. Inspections of adult stations were continued through the winter and into the middle of May 1946, when the project was terminated owing to the imminent inactivation of Camp White. As in the previous winter, some adults of freeborni and punctipennis were found at each inspection until Aprils punctipennis was relatively more abundant during the winter. RECONNAISANCE SURVEYS In the latter part of 1945 several surveys were made in the western part of the state. One survey was made near Grant’s Pass in Josephine County, where there were two proven cases of malaria transmission the preceding year from a returned soldier having malaria. Another survey was an investigation of the mosquito situation in Roseburg, Douglas County. The vicinity of Klamath Falls and zones around the nearby Marine Barracks and Naval Air Station were inspected in July, but no extra-cantonment malaria control was deemed necessary. In the vicinity of Portland, no adults of freeborni were collected or reared, and in view of these and other factors no special emphasis on the control of an- ophelines was recommended for this area. Several entomological surveys were made in the western part of the state. South Carolina BEN F. WYMAN, M. D State Health Officer LEGEND War Malaria Control - 1945 Season War Malaria Control - Continued in 1946 Extended Program Residual Spraying Extended Program Larviciding, Surveillance, and/or Drainage Typhus Control Residual Dusting Typhus Control Ratproofing Aedes aegypti Control NIH Malaria Field Research Laboratory, Manning (Clarendon County) NIH Imported Malaria Studies Labora- tory, Columbia (Richland County) Significant features of the MCWA program in South Carolina during the past fis- cal year were the combined supervision of typhus control dusting and residual house spraying in seven counties and the addition of typhus dusting to the activities of the Aedes aegypti unit in Charleston. As in the preceding year, aegypti control was integrated with general sanitation work. Malaria control activities were diminished markedly immediately after the end of the war in order to permit the financing of residual spraying operations, which were almost doubled in scope in 1946. During the year an average of 295 MCWA employees'worked a total of 415,746 man-hours to provide health protection of various kinds to more than half a million residents of the state. WAR MALARIA During the first part of the fiscal year 109 war establishments in 19 counties received protection against malaria by a combination of entomological surveillance, larviciding, and drainage operations. In 1946 the malaria control unit in the Charles- ton area confined its activities mostly to anopheline mosquito control around the SOUTH CAROLINA Port of Embarkation Hospital, which was used as a temporary camp for laborers imported from the Caribbean islands for redistribution to various parts of the country. Small crews were continued around Fort Jackson in the vicinity of the city of Columbia in Hichland County and Shaw Army Airfield in Sumter County because these two per- manent installations were maintaining mosquito control within the respective bases and desired that some control be carried on around the bar- racks area outside the base. ACCOMPLISHMENTS; Maintenance of previously constructed drainage ditches and larviciding were the chief methods of war malaria control of this fiscal yea£. Approximately 54,000 gallons of oil were sprayed over 2,750 acres, and 1,733 pounds of paris green were used to control an additional 1,337 mosquito-breeding acres. Exten- sive removal of aquatic and land vegetation was performed, accounting for some 700 acres cleared. More than 2,100,000 linear feet of drainage ditch- es were cleaned and otherwise maintained during the year. Approximately 42,110 feet of new ditches were dug by hand and 78 feet of ditch linings were installed. A small amount of underground drainage, 1,000 feet, was also completed. In all, a total of 42 acres of water surface were elimi- nated by the foregoing operations and approxi- mately 6,200 cubic yards of fill. EXTENDED PROGRAM. During the first part of the fiscal year 34,918 house spray applications were completed in 12 counties, requiring 1.40 labor and foreman man-hours to spray 0.46 pound of DDT per house application. Extended larviciding protection was offered to 11 towns in eight coun- ties, as recommended for communities having more than 2,500 population. In 1946 the program was expanded to include 23 counties, in which 55,582 house spray applications were completed. More efficient spray crew operation decreased the man- hours required for each spraying to 1.21. The average amount of COT per application increased during this period to 0.59 pound. Larviciding on the extended program was" not considered necessary in 1946. EQUIPMENT. Power-spray units were used in 17 of the total 23 counties operated during Clearing and larviciding a sw amp. EOT residual spray crew prepar- ing to power spray a house interior. Oiling an old cistern for Aedes aegypti control. SOUTH CAROLINA 135 the year. These units proved very efficient and economical when used in areas in which houses were close together, but were not well-suited for use in isolated, large farm houses or in very small tenant houses. Trucks equipped with pneumatic pressure tanks for furnishing air pressure to the hand sprayers saved considerable labor in those areas in which power sprayers were not suitable. INVESTIGATIONAL PROJECTS. A special study was organized in Calhoun County to determine the effectiveness of COT premise spraying as compared to house spraying alone as a means of controlling anopheline mosquitoes. The area chosen for this study had had relatively high mosquito densities in previous years. In one-half of the area residences were sprayed in the usual manner with EOT emulsion. In the other half all out-buildings or parts of out-buildings in which animals were housed were sprayed as well as the residences. Preliminary indications pointed to premise spray- ing as the more effective means of controlling mosquitoes around the homestead. In conjunction with the Malaria Field Research Station, special studies in Clarendon County to ascertain the worth of residual house spraying in the control of human malaria was continued for a second year. On the basis of the analyses of the para- sitemia data it was indicated that EOT residual spray was capable of reducing the incidence of human malaria. A detailed report of the study appears in the “Investi- gations"'section of this volume, under “Malaria Field Research, Manning, S. C.* TYPHUS CONTROL Supervision of residual house spraying and typhus control dusting was very ef- fectively combined in seven counties during the year. Addition of typhus dusting to the activities of the Aedea aegypti unit in Charleston furnished a very efficient service without undue duplication since a great many of the premises inspected by the “ aegypti" men also needed dusting for rat-flea control. ACCOMPLISHMENTS: Sixty-nine cities in 11 counties had residual dusting activities during the past year, in which 14,222 premise treatments were made. Each dusting treatment required 1.59 labor and foreman man-hours, and 3.6 pounds of ten percent EOT dust. Ratproofing was completed in 654 buildings in 13 cities in 12 counties, of which four —the cities of Charleston, Florence, Bamberg, and Mullins — also had residual dusting programs. The working time required to ratproof each establishment averaged 35.8 man-hours. Bat poisoning was carried on in conjunction with proofing to eliminate those rats already on the premises. In all, a total of 953 premise poisonings were carried out, in which 2.92 labor man-hours were required to place an average of one pound of bait for each treatment. Due to the intermittent and scattered nature of operations in some sections of the state, dusting and other control measures in these sections were carried on by mobile units, each of which circulated in an area of several counties. AEDES AEGYPTI CONTROL Aedts atgypti control in Charleston continued throughout this entire fiscal year as an integral part of the general sanitation program. The new feature of thin year’s activities was the addition of typhus dusting to the combined aegypti - sanitation program. This integration of activities provided a more complete service to 145,000 residents of the city and proved very satisfactory and economical. Of tne 26,281 premises inspected in Charleston during the year, aegypti breeding places were found in only 980, for an index of 3.73. Tennessee R. H. HUTCHESON, M. D. Commissioner of Public Health LEGEND War Malaria Control - 1945 Season War Malaria Control - Continued in 1946 Extended Program Residual Spraying Extended Program Larviciding, Surveillance, and/or Drainage Typhus Control Residual Dusting Typhus Control Ratproofing The MQVA program in Tennessee was continued during this fiscal year as a function of the State Department of Public Health, Division of Preventable Diseases. Activities were concentrated in the western part of the state where topographic and climatic con- ditions were very favorable for mosquito production. War establishment zones were pro- tected by an intensive program of larviciding, while other sections having high mor- tality rates received DDT residual spraying treatment aimed at killing adult mosqui- toes. Typhus control activities under the MCWA program began late in the year when residual dusting programs were started in three counties. During the year an average of 101 USFHS employees worked an aggregate of 152,216 man-hours on all types of MCWA activities and afforded protection to approximately 420,000 residents of the State. VAR MALARIA A total of 134 war establishments in eight counties received malaria protection during the first part of the fiscal year, of which 124 required larviciding and minor drainage operations and ten required only surveillance. In 1945 an unusually late flood on the Mississippi River inundated a large section of the delta, creating vast areas of slow-flowing, float age-covered water in which “quads” bred so prolif- ically as to render the usual larvicidal methods entirely ineffective. To prevent a possible outbreak of malaria, several war industry plants in Memphis and the Thayer General Hospital in Nashville were sprayed with EXIT. In 1946 only four mili- tary installations —the Kennedy General Hospital, the Naval Reserve Base, and the Ferry Command Base in Shelby County, and the Thayer General Hospital in Davidson TENNESSEE 137 County — remained active and required malaria protection. The mosquito-breeding season was not accompanied by more than the usual amount of precipitation. Breeding started late, but prolifically. The new larvicide, consisting of 2.5 pounds of DDT per 50 gallons of No. 2 Diesel oil, was applied by hand sprayers through a mist nozzle at the rate of one to two gallons per acre with amazing results. Consequently, "quad” counts were kept well within the "safety” limits of under ten adults per station. LARVICIDING. The larviciding system employed, known as the ** blanket” system, consisted of treating all Anopheles breeding places of ordinary size routinely every eight to ten days. Larger breeding areas involving more than one-half acre were inspected routinely and treated only when the need was indicated. During the year a total of 43,981 gallons of oil were used to spray 1,787 acres and 552 pounds of paris green were dusted over 207 acres. Supplementary clearing effected the removal of vegetation and brush from 27 acres. INSPECTION ACTIVITIES. The inspection force worked in close cooperation with larviciding crews. Usually a team of three inspectors was used, one inspector being assigned specifically to adult mosquito collection. The two "larval” inspectors were used primarily as** trouble shooters” for investigating unusually high adult counts whenever they occurred, in addition to routine checking following larvicidal treatment. Larvae and adult mosquito reports were analyzed each day in order that prompt action could be taken where indicated. Inspectors were equipped with small hand-sprayers charged with a DDT and oil solution to enable them to treat small, miscellaneous breeding places at the time of their discovery, thus saving the larvi- ciding crews the necessity of making special trips. DRAINAGE No war malaria drainage work was undertaken during the active control season. IXiring the winter, or “off season" months, larviciding crews were diverted to drainage activities. Entomological rec- ords were used as a basis in planning all drainage projects. During the year 18,368 linear feet of ditches were dug by hand and 16,743 feet of ditch linings were in- stalled. Approximately 3,000 cubic yards of earth were used as fill and 59,317 feet of existing ditches were cleaned and otherwise maintained. AUTOMATIC LARVICIDING DEVICES In Shelby County experimental larvi- ciding work was carried on as a supplemen- tary duty of the inspection force. One project involved the charging of 50 leach- ing cans of one-gallon capacity with one percent solution of CDT in oil, and placing them along low, bottom areas in anticipation of their being picked up and providing treatment for flood water conditions. In the areas so treated good results were DDT oil-mist larviciding. 138 TENNESSEE obtained for one entire high water period which persisted for approximately three weeks. Another experimental project was begun in a large drainage creek five miles long and containing approximately ten acres of breeding surface. The possibility of the automatic treatment of this canal was investigated in cooperation with the Office of Malaria investigations. National Institute of Health. A pellet consisting of 100 grams of EDf (100 percent technical grade), 200 grams of para-dichloro-benzine, and 20 cc. of oleic acid was submerged in the creek at 1,000-foot intervals and anchored by means of wires. These pellets dissipated very slowly when submerged in water at temperatures below 110 degrees F. and it was anticipated that control could be maintained for three to four months in the channel of the creek. Side pockets, however, had to be located and treated individually. EXTENDED PROGRAM Six counties —Dyer, Lake, Lauderdale, Obion, Shelby, and Tipton—were included in the residual spraying program during the /irst half of the fiscal year. During this period 12,162 residual house sprayings were completed, using three-man spray crews. In 1946 the program was expanded to include the additional counties of Crock- ett, Fayette, Gibson, Hardeman, Haywood, and Weakley, and 21,578 house applications were performed in the 12 counties, using two-man spray crews. Comparison of the efficiency of the three-man versus the two-man spray crews revealed startling results. The threC-man crews averaged 5.8 houses per man-day and 1.02 man-hours per house appli- cation, while the two-man crews averaged 11.5 houses per man-day and 0.77 man-hour per house application. The amount of DDT per application was increased from 0.42 pound in 1945 to 0.75 pound in 1946 in light of the studies on increased residual effectiveness with heavier deposits of EOT, A short-time investigation of one-man spray crews revealed the even more unexpected results of an average of 16.7 houses per man-day. Detailed studies of the efficiency of one-man crews will be undertaken in the next fiscal year. EQUIPMENT. Each crew was provided with a one-half ton truck equipped with a small air compressor unit and hand sprayers or power spraying apparatus. DDT emulsion was mixed and transported in 50-gallon drums fitted with a lock-type faucet. The Filling hand sprayers with DDT emulsion from 50-gallon drum equipped with a lock- type faucet. TENNESSEE 139 movement of the truck kept the emulsion agitated. IDT concentrate for the entire state program was mixed in a central warehouse. Hie conventional 50-gallon, barrel- type, mechanical mixer was modified so as to permit the mixing of DDT isomers, DDT-oil solutions, and pyrethrum emulsion larvicides. INSPECTION CHECK- In order to determine the efficiency of the residual spraying program, one to two percent of the DET-treated houses were inspected monthly for three months after spraying. Hie data collected indicated the number of ** quads'* in sprayed houses as compared to adjacent, unsprayed natural resting places. Engorged specimens were collected for feeding preference studies. Other data gathered included the distribution of DDT crystals on sprayed surfaces, the number of houseflies present, and the general reaction of the public toward the spraying program. LARVICIDING AND DRAINAGE. In 1945 extended malaria control protection through larviciding was accorded the cities of Memphis and Collierville in Shelby County, Newbcrn and Dyersburg in Dyer County, Tiptonville and Ridgely in Lake County, Rip- ley in Lauderdale County, and Covington in Tipton County. During the second half of the fiscal year larviciding was continued only in Memphis and its environs, Collier- ville, Bipley, Covington, and Dyersburg. Three extended major drainage projects were carried on during the year. Operations consisted of installing ditch livings and supplementary grading and sodding around the outskirts of the city of Memphis, in Dyersburg, and in Halls. TYPHUS CONTROL Hie MCWA typhus control program in Tennessee started late in 1945. Residual dust- ing activities were inaugurated in the cities of Chattanooga in Hamilton County, Nashville in Davidson County, and Knoxville in Knox County and were continued through- out the fiscal year. Chattanooga also has an MCWA ratproofing campaign as well as local ratproofing under the city ordinance. Typhus control in Memphis was operated entirely with local supervision, funds, and labor. Of the 16,450 premises inspected for rats and ectoparasites, 15,336 were found to be infested and were treated with DDT dust. An average of 0.45 labor and foreman man-hour was required to spread 2.4 pounds of ten percent DDT dust per premise application. Drainage ditch in Memphis lined with salvaged masonry. Texas GEORGE W. COX, M. D. State Health Officer LEGEND War Malaria Control - 1945 Season War Malaria Control - Continued in 1946 Extended Program Residual Spraying Extended Program Larviciding, Surveillance, and/or Drainage Typhus Control Residual Dusting Typhus Control Ratproofing Aedes aegypti Control Fly Control Project Headquarters, Pharr (Hidalgo County) The over-all magnitude of MCWA activi- ties in Texas during this fiscal year ex- ceeded that of any other state in the coun- try, During the course of the year, war ma- laria operations were relegated to a minor role, while'cxtended control activities were expanded to include more than five times the number of counties previously sprayed. Extensive typhus control activities continued unabated during the year. Aedes aegypti control, in addition to being integrated with general sanitation work as in the preceding year, was also combined this year with re- sidual typhus dusting in several cities. A monthly average of 312 USPHS employees work- ed a total of 511,075 man-hours during the year on all types of MCWA control projects. TEXAS 141 LIGHT TRAPS. The program for obtaining information on the distribution and a- bundance of individual mosquito species in the state, inaugurated during the pre- vious fiscal year, was continued this year. Mosquito light traps were operated in non-MCWA counties through the cooperation of the Division of Entomology of the state health department. Information obtained from this program will further aug- ment existing data on mosquito-borne diseases. WAR MALARIA During the first half of the fiscal year, 130 war establishments located in 15 areas in 39 counties received malaria protection. Of these, 97 required larvicid- ing and minor drainage control measures and 33 were kept under surveillance. A special airplane larviciding project was completed on the small river separating the Arkansas and Texas portions of the city of Texarkana. In 1946, after the end of the war, only four war malaria areas remained in operation, all of which re- quired some larviciding and minor drainage control. These included the Brownsville International Airport in Cameron County, the city of Marshall in Harrison County, Texarkana in Bowie County, Fort Worth Army Airfield in Tarrant County, and the Love Army Airfield, the Naval Air Station, and Hensley Field in Dallas County. LARVICIDING. A total of 69,659 gallons of oil were sprayed over 3,140 acres, and 1,896 pounds of paris green were dusted over 1,458 acres of mosquito breed- ihg areas by hand and power spraying and dusting equipment. To facilitate larvi- ciding, and to eliminate favorable mosquito breeding conditions, 391 acres of a- quatic vegetation and 88 acres of land growths were cleared out. DRAINAGE. One major drainage project was completed in 1945 in the outskirts of the city of Tyler in Smith County, where a railroad embankment has caused the formation of a 40 acre marsh in the Caddo Lake area. Two thousand feet of dyna- mite ditching, supplemented by 100 feet of hand digging, created proper drainage facilities. Including minor drainage operations throughout the state, a total of 31,543 linear feet of hand ditching, 26,656 feet of machine ditching, and 2,080 feet of dynamite ditching was accomplished. These activities, combined with the cleaning and maintenance of 1,028,461 feet of previously constructed ditches, elim- inated 136 acres of water surface. (left) Aquatic vegetation being removed from shore line after having been pushed there by an outboard-powered barge, (right) Adult collecting station near Brownsville. Animal sheds make good alb inarms catching stations. 142 TEXAS EXTENDED PROGRAM During the latter part of 1945, six counties - Bowie, Cameron, Hidalgo, Lamar, Red River, and Willacy — had county-wide residual house spraying programs. Ap- proximately 75,850 residual applications were completed, requiring an average of 0.42 pound of DDT per house spraying. In 1946, the program was extended to offer residual protection to 33 counties which had potential malaria problems. To ef- fectively handle this more than five-fold increase in scope of activities, spray- ing operations in each county were confined as far as possible to those areas where protection was indicated on the basis of available entomological, epidemiological, and topographical data. In keeping with this policy, 46,184 house spray applications were accomplished during the second half of the fiscal year. The amount of COT per house application was increased to 0.58 pound in order to comply with the latest knowledge on increasing residual effectiveness. Extended malaria control by larvicid- ing was carried on in nine cities in Hidalgo County — Mercedes, Donna, Weslaco, Alamo, San Juan, Pharr, McAllen, Mission, and Edinburg — throughout the entire fiscal year. SPRAY CREW EFFICIENCY. In 1945 an average of ],.25 labor man-hours were required for each house spray application. This was decreased to 1.12 man-hours in 1946 mainly by having the house occupants cover their own furniture and furnishings while the spray crew was preparing to spray the house. This result- ed in saving time in each residence which otherwise would have been wasted on extra-spraying activities. Operational time was also saved by means of installing on each vehicle a tank or barrel of sufficient size to furnish an inmediate and con- tinuous supply of water for an entire day’s spraying needs. The maintenance of automotive and spraying equip- ment was greatly facilitated in at least one area by the employment of personnel with mechanical knowledge, who were able to do minor repairs in addition to per- forming their regular spraying duties. Spraying trash and garbage with 5 percent DDT emulsion at Pharr, Texas. TYPHUS CONTROL During the past fiscal year, recommended procedures in regard to dusting, poi- soning, and ratproofing programs were maintained in order to continue or initiate typhus control operations in as many counties as possible. However, since it was noted in several counties that there was a high number of typhus cases among the rural population, and also in certain residential areas of several cities, the de- cision was made that a residential and farm program of typhus control should also TEXAS 143 be inaugurated. These rural and residential projects represented a departure from the accepted practice of treating mostly business establishments in the larger cities. Due to the intermittent and scattered nature of operations, especially in rural sections, dusting and other control activities in 38 of the 49 counties op- erated were carried on by eight mobile units, each of which circulated in an area of several counties. Another feature of this year's typhus control program was the integration of residual dusting, and in some cases rat poisoning, with Aedes aegypti and general sanitation work, wherever applicable. During inspections for aegypti breeding places, it required little additional effort to search for rat “signs” and to dust .and drop poisoned bait in appropriate places. RURAL AND RESIDENTIAL PROJECTS. Thirteen counties participated in the farm ty- phus control program, and seven cities were included in the residential program. The first requirement was the passage of resolutions by the counties or cities involved, stating that they would adhere to the general features of the program outlined by the state health department. Secondly, a local supervisor, employed and paid by local funds, was assigned for training with one of the mobile dusting and poisoning units. V\hen the lo- cal supervisor finished his training, a supply of DDT was furnished to the city or coun- ty involved. After an exten- sive publicity campaign, out- lined by the state health de- partment, the local supervisor was authorized to conduct either a rural or residential program, whichever the case might be. A small charge was required of each premise treated by the city or county in order to defray the cost of the labor and materials used in dusting and eradica- tion. Complete monthly re- ports were submitted by the local supervisor to the state health department, where they were reviewed and checked. Mobile typhus crew ratproofing buildings ACCOMPLISHMENTS. Of the 169,964 premises in 49 counties inspected for rats and ectoparasites, 90,300 in 181 cities received residual dusting treatments. Each premise treatment required an average of 0.56 labor and foreman man-hour to dust 1.2 pounds of 10 percent DDT. Ratproofing programs were carried out in 20 cities in 16 counties, and 1,254 business establishments were rendered impervious to rat invasions. Modifications in each building required an average of 31.2 labor and foreman man-hours. Rat poisoning operations were carried out as an adjunct to both dusting and proofing activities. In all, 37,516 premise poisonings were accom- plished, each of which required an average of 0.50 man-hour to spread 0.32 pound of bait. Supplementary eradication with ‘* 1080’’poisoned water accounted for a total of 1,888 pints during the year. In addition to 146,972 man-hours of local 144 TEXAS labor, a monthly average of 62 USPHS personnel worked a total of 82,009 man-hours to offer typhus protection to more than 2,500,000 residents of the state. AEDES AEGYPTI CONTROL Aedes aegypti control operations continued as an integral part of the general sanitation program, which included also rat poisoning, pest control, and fly con- trol. During this fiscal year, residual typhus dusting was likewise incorporated into the general sanitation-aegypti control program. In addition to local labor, 23 DSPHS inspectors participated in aegypti control, which benefited more than 1,200,000 residents of the state. The cities of Mercedes, Weslaco, Donna, Alamo, San Juan, Pharr, McAllen, Mission, and Edinburg in Hidalgo County averaged the lowest percentage of mosquito-breeding places to premises inspected in the state. Of the more than 24,280 premises inspected only 220 were infested, for an index of 0.89. On the other hand, San Antonio in Bexar County had the highest index — 5.77. Approximately 2,000 premises of the 34», 550 inspected were infested. Laredo in Webb County, where control measures were not begun until the second half of the fiscal year, ran a close second with an index of 5.4. Between these extremes were Houston in Harris County, 2.61; Galveston in Galveston County, 1.58, Browns- ville in Cameron County, 1.33; and Corpus Christi in Neuces County, 1.15. Through- out the entire state 8,919 of the 350,153 premises inspected had aegypti breeding places, for an average index of 3.06. Aegypti — sanitation inspection activities were expanded this year to include surburban towns in the environs of the larger cities mentioned above. This expansion represented an increase in surveillance rather than an aggravated aegypti problem. The city of Kingsville in Kleberg Coun- ty was also accorded surveillance this year. Inspector dusting empty battery cases with paris green to prevent aegypti breeding. Virginia I. C. RIGGI N, M. D. State Health Commissioner LEGEND During the first half of this fiscal year the MCHA program in Virginia continued on the same scale as in the preceding year since no one knew how much longer the war would last. Mai aria control emphasis was placed on prisoner of war camps and installations where returning military personnel were stationed. With the end of the war all activities around military in- stallations began to be curtailed. Only key men were retained to carry on malaria control during the 1946 season, to conduct the typhus control dusting program, and to man a demonstration EDI residual spraying project. The number of MCWA employees decreased steadily from 137 in July 1945 to 30 in June 1946. Over the year a total of 105,423 man-hours were expended on the various phases of the program. War Malaria Control - 1945 Season A War Malaria Control - Continued V in 1946 t. iExtended Program Residual Spraying Typhus Control Residual Dusting Aedes aegypti Control WAR MALARIA Of the 107 war establishments in 18 counties which were protected by surveillance, lar- viciding, and minor drainage during 1945, only seven —Oceana Navy Airfield, the Little Creek Zone, and the FPHA Lousing Project in Princess Anne County; Langley Field, fort Mon- roe, and the Copeland Park FPHA [lousing project in Elizabeth City County; and Fort Fust is in Warwick County — remained active and required malaria control after the end of the war. Luring the year 49,794 gallons of oil and 2,409 pounds of paris green were used to larvi- cide 1,493 and 1,347 acres respectively. A total of 184 acres of aquatic and land vegetation were cleared to facilitate larviciding and to discourage anopheline breeding. Minor drainage operations throughout the state totalled 160,131 linear feet of hand-dug ditches, 1,563 feet of ditch linings, and 3,806 cubic yards of fill. Approximately 414,370 feet of previously constructed ditches were cleaned and repaired. 146 VIRGINIA ARTIFICIAL RESTING PLACES. In evalu- ating malaria control activities ex- perience had shown that a good natural resting place for collecting adult Anophe- les quadrimaculatus did not always exist where it was desirable to obtain sam- ples. Boxes and nail kegs were tried as artificial resting places in pre- vious years with inconsistent results. During the 1945 season “ quad houses,” based on those used in North Carolina, were built. These consisted of a de- mountable shed, three feet by three feet by six feet high, with the front enclosed to about half way down. They were bolted together and so could be set up in a few minutes in any desired location. The resulting catches proved this type of collecting station more dependable than the smaller boxes or kegs and gave very satisfactory results in lieu of natural resting places. Power iarviciding a pond from a jeep equipped with pressure equipment. LARVICIDING BOATS. Small boats were designed and built for paris green dust- ing of the shallow shoreline of municipal reservoirs. To meet the specialized re- quirements of this type of work the boats were constructed of Juniper, with wide beams, and gradually-sloping, scow bows to veer off stumps and yet provide am- ple space for large forward loading decks. The boats were ideal for the purpose and required only two- or three-horsepower outboard motors to make sufficient headway. PEST MOSQUITO CONTROL. At Fort Story, Princess Anne County, Army personnel were greatly annoyed by the presence of pest mosquitoes. The Army therefore arranged with the Virginia MCWA organization to ditch the salt marsh for an area of five miles around the Fort. In addition an entomological survey of the Seashore State Park was made to ascertain how great a mosquito problem this area presented to the Army activities. Work was done with prisoner-of-war labor under the direction of USPHS personnel. Privy-type artificial resting place used as an adult collecting station. CONTRACT SERVICES. The U. S. Public Health Service contracted with the Fed- eral Public Housing Authority, on a reimbursable basis, to do complete mos- quito control work around six of their major housing developments in the Hampton Hoads area in Norfolk County. This con- tract was extended into the 1946 season. At Hiverdale, Norfolk County, the main ditches around the FHA housing devel- opment were lined with concrete, on a contractual bases. This work was com- pleted during the fiscal year. VIRGINIA 147 POND IMPOUNDMENTS. It has become common practice in Virginia for owners of larger farms to impound streams, thus creating small ponds for irrigation purposes. At one such pond, located about one-quarter mile from a Navy Airfield, quadrimacu- latus were found to be breeding quite heavily. Although the state board of health had regulations concerning impoundments it was felt that a demonstration pond would aid farmers in developing their proposed ponds. Therefore the above-mentioned pond was modified at the property-owner’s expense with a spillway and regulating baffle boards for raising and lowering the water elevation. This project will be of per- manent benefit to future malaria control work in the state. PERMANENT MOSQUITO CONTROL PROGRAM One of the main objectives in the state of Virginia’s activities was to conduct the MCWA program in such a fashion that when the war was over the local authorities, real- izing the benefits, would provide local funds to carry on the work. During World War I much mosquito-control work was done in the Hampton Roads area, but when the war ended no efforts were made to continue and the initial work was soon wasted. Virginia author- ities were determined that such would not be the case again. After “V-J Day” direct work was started to promote local programs. Three new mosquito-control districts were estab- lished and four other conmunities made substantial appropriations to initiate work. In addition to local funds the 1946 State Legislature appropriated a portion of the state’s funds to be used as contributions to local districts. Several other local jurisdictions were slated to inaugurate programs at an early date. RESIDUAL SPRAYING A limited amount of DDT residual house spraying was performed in New Kent and Norfolk counties during the 1945 mosquito season. However the feeling existed that there was a definite place, at least in public institutions, for the proper use Crew cutting hand ditch from swampy pond to outlet drainage ditch. 148 VIRGINIA of CUT residual spray. For this reason as well as to clear up a great deal of confus- ing information released on the use of DDT, a state-wide project was inaugurated in 1946 for the purpose of spraying certain public buildings as a demonstration service. To accomplish these sprayings a crew was trained and equipped, thus making them avail- able at any time to be dispatched to any section of the state in the event of a mala- ria outbreak. Thirty institutions throughout the state were sprayed including prisons, hospitals, jails, welfare homes, farms, etc., and from reports received this has been one of the most beneficial projects undertaken in the state. TYPHUS A review of the health records revealed that there had been 64 cases of typhus fe- ver in the city of Norfolk since 1937 and that the number of cases reported each year was on the increase. Justified by these data a DDT dusting program was inaugurated in 1946 to control rat fleas and other ectoparasites. Rats, trapped before dusting, were combed and the ectoparasites counted. Also, blood samples were taken to determine in- cidence of typhus among the rats. After dusting similar samples were taken to check the efficiency and effectiveness of the program which affected 200,000 residents of the city. Approximately 450 premise dustings were completed, each of which required an average of 1.06 labor man-hours to spread 13.2 pounds of ten percent DDT dust. AEDES AEGYPTI CONTROL During the first part of the fiscal year a combination aegypti survey and con- trol program was carried out in the cities of Norfolk and Portsmouth. Of the 3,673 premises inspected in Norfolk, 229 were found to be harboring breeding places, for an index of 6.31. In Portsmouth only 119 of the 3,034 inspected premises were in- fested, the index here being 3.92. No regular MCWA aegypti control program was undertaken in these two cities because existing local mosquito-abatement efforts were coping with this problem which affected some 195,000 residents of the state. (left) Rats, trapped before dusting, were combed and the ectoparasites counted.(below) This boat served as an excellent aegypti breeding place. district programs HC«A ACTIVITIES CAR« •« m «V ” 0 " H# T « E STATE OR District No. 1 Headquarters: New York, New York LEGEND War Malaria Control - 1945 Season War Malaria Control - Continued in 1946 The states encompassed by USPHS District No. 1 include Maine, New Hampshire, Vermont, Massachusetts, Rhode Island, Connecticut, New York, Pennsylvania, New Jersey, and Delaware. Although these states are relatively far-removed from the normally malarious regions of the United States, they are well within the range of distribution of the eastern malaria vector, Anopheles quadrimaculatus. A mala- ria potential had been introduced into this district early in the war years by the establishment of prisoner of war canps, military hospitals, and cantonment zones in which were housed many cases of malaria contracted in endemic areas throughout the world. An MCWA program was therefore instigated in these states to forestall the possibility of malaria gaining a foothold in a presently non-malarious region. Since the problem was essentially one of prevention, major reliance was placed on the entomological phases of the work and the data so obtained were used as a guide to control operations and their effectiveness. It was not considered neces- sary to carry on an extensive program with actual control operations around each DISTRICT NO. 1 151 war establishment and therefore MCWA activities were conducted under the general supervision of the district office in cooperation with the respective state health departments and military authorities. Reconnaissance surveys were conducted by the district entomologist, and three mobile units did the necessary larviciding and minor drainage wherever indicated. In those zones where conditions required con- tinued control, fixed units consisting of prisoner of war labor, Army personnel, or local laborers were established under general district supervision. On the basis of entomological surveys conducted in the previous year no malaria control activ- ities were deemed necessary during the past fiscal year in Maine, New Hampshire, and Vermont. In the other seven states a total of 55 war establishments in 41 coun- ties were accorded some type of military protection and four additional military posts had pest mosquito control projects. In 1946, after the war had ended, only 14 military establishments in six states remained active and required control measures. DISTRICT OFFICE ACTIVITIES The District No. 1 office, located in New York, N. Y., exercised general supervision over all field units in the ten states comprising the district in cooperation with the state health departments and military authorities. Entomological activities during the year included surveys to determine the prevalence of mosquitoes, identification to establish the presence of the malaria vector, and impounded water surveys to determine the possibilities of malaria hazards. All MCWA public relations material in the dis- trict originated from the district office. An extensive training and educational pro- gram was carried out including a course in mosquito identification for Army techni- cians in the Second Service Command, instruction and information on the public health uses of EOT for officers of the Second and Third Service Commands, conferences and demonstrations on DDT for health department personnel in the district, lectures on rodent and insect control for War Shipping Administration, state, and local health department personnel, and laboratory training and field methods in malaria control for the Army Specialized Training Program and Navy medical students. ENTOMOLOGICAL SURVEYS Upon the request of state health department or military authorities the dis- trict entomologist made a preliminary reconnaissance survey in the zone in ques- tion to determine the need for further control activities. In those zones where uncertainty existed as to the need for additional control measures even after the preliminary survey had been made, the district entomologist or mobile units made occasional inspections to check on the situation. In “ borderline” zones, where conditions were favorable for malaria transmission but larviciding was not in- dicated, mobile units carried on regular routine inspections. During the first half of the fiscal year reconnaissance surveys were conduct- ed in ten zones in Massachusetts, two zones in New Jersey, six zones in New York, and ten zones in Pennsylvania. Occasional check inspections were carried on around the West Roxbury and Northampton Veterans’ Hospitals in Massachusetts; the England General Hospital and the Belle Meade Service Forces Depot in New Jersey; Fort Ni- agara, the Rhoads and Halloran General Hospitals, Mitchell Army Airfield, and pris- oner of war Side Camp in New York; and the Valley Forge and Deshon General Hos- pitals, Middletown Air Service Command, and Camp Reynolds in Pennsylvania. In 1946 only one reconnaissance survey was requested, around the Castle Point Veterans’ 152 Hospital in New York. Occasional check in- spections were continued around the two Veterans' Hospitals in Massachusetts. Rou- tine inspections were begun by mobile units around the Tilton General Hospital at Fort Dix in New Jersey and Camp Shanks in New York, both of which had required larvicid- ing the previous season. The Valley Forge and Hal lor an General Hospitals were also put under routine inspections because previous sur- veys had classed them as “borderline” cases. MOBILE UNITS Three mobile units operated in District No. 1 during the past year. Mobile Unit 1, based in Cushing General Hospital, Framing- ham, Mass., operated in Massachusetts. Unit 2 was based in Camp Kilmer, New Jer- sey, and operated in Delaware, New Jersey, New York, and Pennsylvania. The third unit functioned mainly in Rhode Island from its headquarters in Davisville. Entomologists made preliminary recon- naissance surveys to determine need for further control activities. MOBILE UNIT 1. During the first half of the fiscal year this unit carried on larviciding and minor drainage projects around Camp Myles Standish Station Hospi- tal in Bristol County and Waltham Regional Hospital, Cushing General Hospital, Fort Devens Station Hospital, Lovell General Hospital, and a prisoner of war camp in Middlesex County. Occasional inspections were conducted around the West Rox- bury and Northampton Veterans’ Hospitals in Norfolk and Hampshire Counties. In addition to these control activities this unit also carried on field training in malaria control for the Army Specialized Training Program, Navy medical students, and several communities in Massachusetts. A special study was also made of the hibernation of A. quadrimaculatus during the winter months. There was little change in the activities of Unit 1 in 1946 since most of the installations protected were hospitals which did not cease operations after the end of the war. Camp Myles Standish Station Hospital was the only establishment around which activities were discontinued in the second half of the fiscal year. MOBILE UNIT 2. In 1945 larviciding was performed by this unit in New Jersey around Tilton General Hospital and Fort Dix in Burlington County, Princeton University Naval Station in Mercer County, and Camp Kilmer in Middlesex County. In New York, Camp Shanks in Rockland County and the Pawling AAF Rehibilitation and Power larviciding from a mobile unit truck. DISTRICT NO. 1 153 Convalescent Center in Duchess County required larviciding control. During the winter months Unit 2 supervised pest mosquito control projects around Fort Miles in Delaware and the Carteret Ordnance Depot in New Jersey. These projects were con- ducted with Army funds and prisoner of war labor. Occasional check inspections were made in New Jersey around the AAF Redistribution Center and England General Hospital in Atlantic County and the Belle Meade Service Forces Depot in Somerset County. In New York, the Halloran General Hospital in Richmond County was the sub- ject of check inspections, as was the Valley Forge Hospital in Chester County in Pennsylvania. This unit also gave demonstrations and training in the use of DDT residual spraying to interested communities and military installations. In 1946 larviciding was continued only around Camp Kilmer and the Pawling Convalescent Center. Tilton General Hospital at Fort Dix and Camp Shanks did not require con- tinued larviciding but they were routinely inspected during the remainder of the fiscal year. Conditions around the Halloran and Valley Forge General Hospitals made it advisable to begin periodic, routine inspections instead of occasional checks but no larviciding was thought necessary up to the end of the fiscal year. A residual spraying project for fly control was begun by Unit 2 around Fort Miles in Delaware in the latter part of the year. MOBILE UNIT 3. The third mobile unit carried out larviciding operations in Rhode Island around the Naval Construction Training Center and the Advance Base Depot in Davisville and the Naval Air Station in Quonset Point. In Connecticut, after July 17, this unit took over larviciding control from Unit 1 around the Old Farms Convalescent Hospital in Avon and continued the work for the remainder of the year. Unit 3 also assisted Unit 2 in providing larviciding control around the Pawling AAF Convalescent Center. One major drainage project was completed around the Naval Construction Training Center in the first half of the fiscal year. In 1946 Unit 3 was dissolved. ACCOMPLISHMENTS. Over the course of the fiscal year mobile unit operations accomplished dusting over 557 acres with 1,488 pounds of paris green to control anopheline larvae and 349 acres larvicided with 2,930 gallons of oil where pest mosquito control was also desirable. Drainage included 230 feet of hand ditching, and 1,650 feet of machine-dug ditches. The greatest part of the 7,475 man-hours expended by the mobile units during the year was spent in entomological surveil- lance around war establishments, since the problem in District 1 was essentially one of prevention rather than actual control. u FIXED ’* UNITS Several zones in New Jersey and Delaware required more extensive control mea- sures and it was considered advisable to establish “ fixed” control projects in these zones rather than to tie up a mobile unit. These projects were set up under district supervision in cooperation with military authorities, and labor consist- ed of Army personnel, locally-hired workers, and prisoners of war. All but one of these ” fixed” projects was terminated by the end of 1945. In Cape May County, New Jersey, larviciding and major drainage operations were conducted around the Naval Air Station in Wildwood. Larviciding and DDT residual spraying projects were completed in the Fort Miles Coast Artillery Outpost and the Coast Guard Station on Cape May Point. A pest mosquito control project was DISTRICT NO. 1 Power spray equipment mounted on a “Weasel.” Larviciding with water- oil emulsion at U. S. Naval Air Station, Wild- wood, N. J. carried out in the Carteret Ordnance Depot during the winter months in coopera- tion with Mobile Unit 2. Delaware had three pest mosquito control projects opera- ted with prisoner of war labor furnished by the Army. These projects consisted of minor drainage work around the Dover Army Air Base, Fort Saulsbury and Fort Miles; the latter was conducted in cooperation with Mobile Unit 2. Airplane dusting with paris green, hand larviciding, and minor drainage were carried on around Fort Du- Pont in Delaware City and New Castle Army Air Base in New Castle. Field training in malaria control for the Army Specialized Training Program and Naval medical students was also given by personnel attached to the Delaware project. In 1946 a residual spray project for the control of flies was operated by prisoner of war labor under the supervision of Mobile Unit 2 personnel. ACCOMPLISHMENTS. Larviciding with paris green was carried out wherever con- trol of anopheline mosquitoes was necessary. Supplementary oiling was done around those installations where pest mosquito control was also desired. Over the course of the fiscal year fixed units used a total of 9,966 gallons of oil to larvicide 654 acres and 17,048 pounds of paris green to dust 8,645 acres of mosquito-pro- ducing surfaces. Eight acres of brush and aquatic vegetation were cleared, and 122,422 linear feet of previously constructed ditches were cleaned and otherwise maintained. Major and minor drainage accomplished by " fixed'* projects included 45,856 feet of hand-dug ditches, 6,535 feet of machine ditching, and 310 feet of ditch linings installed. In all, a total of 490 acres of water surface were eliminated as sources of mosquito breeding, requiring an expenditure of 13,488 MCWA man-hours. German prisoners of war cleaning and ditching near U. S. Naval Air Station, Wildwood, N. J. District No. 2 Headquarters: Richmond, Virginia LEGEND War Malaria Control - 1945 Season USPHS District No. 2 includes the states of South Carolina, North Carolina, Virginia, West Virginia, Maryland, and the District of Columbia. The first three states mentioned had MCWA programs operating under the general direction of their respective state health departments in cooperation with the district office and are discussed elsewhere in this volume under **state-operated*' programs. West Vir- ginia had no MCWA program operating during this fiscal year. In Maryland and the District of Columbia, both being on the border of the normally malarious region, it was not deemed necessary to carry on an extensive program with actual control operations around each war establishment. Major reliance was placed on the ento- mological phases of the work and the data obtained from inspections were used to guide control operations as well as to evaluate their effectiveness. This work was conducted under the general supervision of the District No. 2 office in coop- eration with the respective state health departments. District entomologists and engineers performed the necessary inspection and supervision. MARYLAND During the first part of the fiscal year malaria control activities were con- ducted around 30 war establishments in Maryland. Of these 25 required only periodic 156 DISTRICT NO. 2 entomological surveillance to check on mosquito production. Larviciding and ditch- ing were required around the Navy Powder Factory, the Potomac Heights War Housing Development, and another war housing project in the Indian Head zone in Charles County. The ditching completed totalled 500 feet dug by hand and 1,068 feet blast- ed by dynamite. In addition approximately 1,000 feet of previously constructed ditches were cleaned to facilitate drainage. WATER CHESTNUT CONTROL. In the previous fiscal year extensive cutting of wat- er chestnut by the Navy in the Stump Neck (Charles County) and Fort Washington (Prince Georges County) zones had greatly reduced breeding of A. quadrimaculatus. Only fringes of this aquatic plant had been left after cutting, and breeding had been successfully controlled by paris green dusting from boats. During the first part of this fiscal year, around the Navy Proving Ground in the Stump Neck zone and the Veterans' Administration Hospital in the Fort Washington zone, continued effective breeding control was maintained by paris green dusting. Some additional cutting was required this year, amounting to 14 acres, to prevent this aquatic plant from again establishing itself. SURVEILLANCE. Many of the military installations around which drainage proj- ects had been completed in previous years required no further control besides entomological inspection during this fiscal year. These included among others the numerous prisoner-of-war camps located throughout the state, the Forest Glen Annex and the Advance Reconditioning Center of the Walter Reed General Hospital, and the Camp Springs Army Airfield. TERMINATION OF THE PROGRAM. The MOVA program was discontinued in Maryland on Decem- ber 1, 1945. This step was decided upon since the principal problem encountered, water chestnut in the Potomac River, had been virtually eliminated. It is anticipated that the U. S. Engineers will maintain patrol activities in future years to insure that this aquatic plant does not again obtain a foothold. In addition the end of the war, with the consequent great reduction in the number of military establishments, removed practically all of the necessity for the type of work which had been carried on. DISTRICT OF COLUMBIA As in previous years the MCWA program in the District of Columbia during the first half of this fiscal year consisted entirely of entomological surveillance since virtual elimination of significant mosquito production had been accomplish- ed two years ago by the removal of water chestnut from the Oxon Run Zone. SURVEILLANCE, Periodic inspections as a malaria control measure were maintained around 22 war establishments in ten zones during the first half of the fiscal year. Among the establishments protected were the Naval Research Laboratory in the Oxon Run zone, the Army War College in the North Anacostia zone, the Naval and Wave Barracks in the Lower Potomac zone, the Naval Observatory in the Zoo zone, Walter Heed Hospital in Rock Creek zone, Georgetown University in the Upper Potomac zone, and the Navy Yard, Marine Barracks in the South Anacostia zone. Other installations were located in the Benning, Kingman Lake, and Soldiers’ Home zones. D, C, HEALTH DEPARTMENT CONTROL, Inspectors from the Bureau of Sanitation of the District of Columbia Health Department had been operating in coordination with and under the supervision of USPHS personnel in the control of mosquitoes in non-military areas and it is anticipated that in the future anti-malaria and anti-mosquito work will be continued in the District of Columbia under the direction of the health department. District No. 3 Headquarters: Chicago, Illinois USPHS District No. 3 includes the states of Wisconsin, Michigan, Illinois, Indiana, Ohio and Kentucky. Indiana and Kentucky had MCWA programs operating under the general jurisdiction of the respective state health departments in cooperation with the district office and are discussed elsewhere in this volume under “state- operated” programs. Illinois had an MCWA program operating under state health de- partment direction until late in October and then supervision of activities was transferred to the district office. Illi- nois is also discussed under “ state- operated” programs. There were no malaria control activities carried on in Wisconsin during this fiscal year. Consultant services were offered by the district office to the respective states and local communities, and a training course was given in Madi- son, Wisconsin late in November for state personnel on the use and application of HU, and on rodent control measures. This course was attended by approximately 75 employees from the various state public welfare institutions. MICHIGAN. During the first part of the fiscal year, in addition to entomo- logical surveillance in the Fort Custer area, district mobile unit personnel carried on larviciding around the Percy Jones General Hospital in Battle Creek, Calhoun County, and the Hospital Annex on Gull Lake in Kalamazoo County. A total of 845 pounds of paris green was used to dust 274 mosquito-producing acres. Four acres of aquatic vegetation were cleared to facilitate larviciding and to eliminate fa- vorable breeding conditions. At the request of the state health department several mosquito surveys were made in communities in Macomb and Wayne counties. OHIO. With the exception of entomological surveys in 1945 around Cule General Hospital in Cuyahoga County, Fletcher General Hospital in Guernsey County, Camp Pe rry in Ottawa County, and Lockbourne Army Air Base in Franklin County, there were no malaria control activities in Ohio during the year. Consultant services were offered by the district office to the state department of health and local agencies and several meetings were held with state and local officials in the in- terest of mosquito control. LEGEND War Malaria Control - 1945 Season District No. 6 Headquarters: San Juan, Puerto Rico LEGEND War Malaria Control - 1945 Season War Malaria Control - Continued in 1946 Extended Program Residual Spraying Typhus Control Ratproofing The MCWA program in the three Caribbean islands was operated directly out of the USPHS District No. 6 office located at San Juan, Puerto Rico. Projects for the protection of military personnel were carried on in seven extra-cantonment areas in Puerto Rico, and one in Jamaica, Rritish West Indies. In addition, sur- veillance programs in Puerto Rico were operated cooperatively with the Navy in two areas and with the Army in one area. Under the Extended Malaria Control Pro- gram three projects for the civilian population were carried out in cooperation with the Puerto Rico Insular Health Department. Typhus control activities became DISTRICT NO. 6 159 part of the general MCWA program on July lf 1945. These activities were continued in Puerto Rico in cooperation with the Insular Health Department until December 1945, when practically the entire program was turned over to the Insular authori- ties. U. S. Public Health Service activities were then transferred to St. Thomas, Virgin Islands. During the fiscal year, an average of about 230 persons per month were employed on MCWA projects, representing an average monthly reduction of about 95 employees from the 1945 fiscal year. A total of 413,713 man-hours were expended on all types of control activities. CARIBBEAN JOINT ARMY-NAVY-PHS MALARIA CONTROL COMMITTEE. On May 6, 1946 the Tenth Naval District Medical Officer called a meeting of Army, Navy and Public Health Ser- vice malaria control personnel to evaluate the then current malaria control problem and to develop measures for continuing adequate control activities with available appropriations and personnel. As a result of this meeting there was created an organi- zation designated “Joint Aimy-Navy-Public Health Service Malaria Control Committee, ” approved by both the Antilles Department of the Army and the Tenth Naval District. Under provisions of the conmittee, the control of military malaria in the Caribbean area was considered a joint responsibility of the three agencies concerned. Based on appraisal of the over-all problem, each agency was allocated functions commensurate with available funds and materials. The areas where control operations were indicated were divided into those requiring “ conventional ” control measures, plane spraying with DDT, and experimental larviciding. These areas were then assigned to the re- spective agencies for control on the basis of location, extent, and type of control required. The committee was to begin functioning July I, 1946. PUERTO RIGO A. Fernos Isern, M> D* Insular Commissioner of Health The malaria rate among military personnel in Puerto Rico declined steadily dur- ing the period of MCWA activities, dropping from 21 per thousand per year in 1943 to five per thousand per year in 1945. During this time there was a substantial decrease in personnel engaged in larvicidal control, although the consumption of larvicide indicated a gradual rise in efficiency of operations. A great part of the increase in efficiency was attributable to drainage projects which not only permanently eliminated some breeding areas but also increased the accessibility of others not eliminated. Other contributing factors included the selection of bet- ter labor and the introduction of some mechanization. ENTOMOLOGICAL FACTORS. Malaria control operations in Puerto Rico and Jamaica differ from those in the United States in that animal bait traps and light traps (and not the daytime resting places of A. quadrimaculatus, A. freeborni, or even A. a Ibimanus in the low Rio Grande Valley) are the primary source of information as to the A. albimanus populations. Dipping records and adult population studies, based on weekly animal bait trap and nightly light trap collections, were used to locate breeding areas, to watch trends in mosquito populations, and to check on effectiveness of control operations. Frequently, entomological data furnished the reason and justification for extensive engineering operations. Surveillance programs were operated in collaboration with the Navy in two areas and with the Army in one area during the fiscal year. Navy installations included the Roosevelt DISTRICT NO. 6 160 Roads Fleet Anchorage and the U. S. Navy Air Base in the Ceiba area and the U. S. Navy Radio Station in the Carolina area. The Army installations included the U. S. Army Auxiliary Air Base and the Coast Artillery encampments in the Ceiba area. LARVICIDING. IXiring the first part of the fiscal year, larvicidal and minor drainage activities were carried on in eight military areas, three of which also had major drain- age operations. Later, two of the control areas were placed under surveillance and two other areas — Camp Tortliguerno and Camp _____ O’Reilly — were reduced from full control to surveillance and subsequently closed. DDL was first used as a larvicide in Puerto Rico as five percent DDT in kero- sene at Fort Buchanan in December 1945. A blocked canal within the control area, with a larval population of about ten to 15 anopheline and ten to 15 culicine lar- vae per dip, was selected. Five gallons of the solution were applied to a section of the cailal, comprising about three acres. On the day following treatment no anopheline larvae could be found although there was no apparent reduction in the culicine population. The treatment remained effective for almost three weeks; 21 days elapsed before anopheline larvae were again found. D0T isomer, 2.5 percent in kerosene with 0.5 percent B-1956 spreader, was first used as a larvicide in January 1946 at Camp O’Reilly. It was found that effective control could be ob- tained in a stream, even one with considerable flow, for about two weeks. When used on streams and rivers more than ten feet wide, a rate of 1.5 to 3.0 gallons of solution per acre was found effective. Field tests with a new larvicide con- taining 1.25 percent DDT and 0.5 percent spreader by weight in oil showed consid- erable promise. It gave excellent control and reduced costs of routine labor and materials. The efficiency of DDT larvicide was also expressed in the reduction of adult A. albimanus populations. During the four-month test period at Camp O’Reilly, animal bait trap catches in the inner zone showed a reduction from an average of 0.6 per night in December 1945 to 0.2 per night in March 1946. Animal bait trap near Ft. Buchanan, P.R. AIRPLANE SPRAYING. At Fort Bundy the military population was not of sufficient size to warrant an MCWA control program. The only ground control measure in reg- ular use was the oiling done by Post Engineer crews within the Post area. Animal bait traps and light traps were maintained and operated by MCWA, and as the trap catches indicated the need an Army C-47 plane sprayed the area, usually with ten percent DDT in Diesel oil. Adequate control was evidenced by a zero malaria rate among the military personnel. Near Fort Buchanan and the San Patricio Navy Housing Unit is a large swamp, locally termed the “ Brugal ” swamp. The area covers about 180 acres, most of which was economically inaccessible except by air. The area was first brought under control by airplane dusting with 33 percent paris green. Later the Navy furnished, equipped, and operated a light biplane for thermal-aer- osol spraying. Excellent results were obtained against not only the anopheline larvae population but also against both anopheline and culicine adults as well. Treatments were made at intervals of from one week to ten days. DISTRICT NO. 6 DRAINAGE. An outstanding contribution in the field of civilian malaria control was made through a demonstration major drainage project at Ponce, Puerto Rico, inaugurated cooperatively by the Malaria Control Division of the Insular Department of Health and the U. S. Public Health Service. The primary purpose of the project was to demonstrate the feasibility of building malaria out of a large urban area by permanent elimination of breeding places. The town of Ponce, with a population of 105,116 and a high malaria rate, located on the south coast of Puerto Rico, was selected as the control area. The initial phase of planning and field surveys was started during the latter part of April 1945. Because of administrative delays, con- struction work was not started until late August. Considerable progress was made during the remainder of the fiscal year. Near Losey Field, a breakwater composed of mangrove poles and rough oak planks was constructed to protect a gravity-flow sea outlet from one of the drainage sys- tems. The breakwater has functioned in an excellent manner since it was installed in February of 1946. Previous to its instal- lation, it was necessary at frequent inter- vals to assign a laborer to clear the sand from the mouth of the outlet. The breakwater protected the outlet from wave action and released the laborer for other tasks. More important, construction of the breakwater resulted in better drainage for the area served by the outlet. A mojor drainage project at Fort Buchanan, consisting of 2,600 feet of dynamite ditching, was completed in 1945. RESIDUAL HOUSE SPRAYING. In collaboration with the Insular Health Department and the School of Tropical Medicine, an extensive residual spray program was carried out in the areas of Humacao Playa, Santa Isabel, and Loiza Aldea. Records to date indicated that in at least one area, Humacao Playa, considerable success was obtained by spray- ing 520 houses three times each over a period of a year. Malaria rates in this treated area were reduced from 6.3 percent before spraying to 0.91 percent after the Replacing an open drainage ditch with 24*inch subsurface pipe. The open ditch was a convenient garbage disposal place. (above) Construction of breakwater prevent- ed formation of sandbar which blocked drain- age ditch outlet to sea. (below) House to house survey prior to DDT residual spraying. 162 DISTRICT NO. 6 third spraying. Rates in the “ check" area, Loiza Aldea, were 4.7 percent and 3.8 percent respectively, Loiza Aldea was sprayed once at the end of the- year, after having served as a ** check" on operations in Humacao Playa. It was found that for approximately $1.00 per capita per year in a moderate- sized Puerto Rican town, the malaria rate can be reduced substantially. The mini- mum effective rate of application in the coastal region of Puerto Rico was found to be 200 mg. DOT per square foot. The DOT-kerosene solution meets with much favor among the native population. However, the DOT-isomer-xylene emulsion was definite- ly not popular and many people refused to have their houses sprayed with it. TYPHUS CONTROL. During the first part of the fiscal year a ratproofing proj- ect was inaugurated and carried on in San Juan directly under DSPHS supervision, in cooperation with the Insular Health Department. By December 1945 the entire program, with the exception of supervision* of the activities oT one trap operator, was turned over to the Insular authorities. The catches made by this trap opera- tor were delivered to the School of Tropical Medicine where an investigation was being conducted on the ectoparasites of rats. JAMAICA, B. W. I. The MCWA project at Fort Simonds, Jamaica Base Command, was unique in that it was the only project operating on foreign soil. The base was a lend*lease airfield entirely surrounded by British-owned or Jamaican-owned land. The area supervisor not only directed the regular off-Post MCWA activities but also, acting for the Post Engineer and Post Surgeon, directed on-Post control. Owing to the agricul- tural uses of the land in the off-Post zone, paris green dusting, cleaning, and clearing were the control measures in use. A residual spray program was maintain- ed in the surrounding native villages. The on-Post control program consisted of oiling for larvae control, minor drain- age, inspection, residual spraying of all buildings, and the servicing of the C-47 spray plane which was used for general EOT spraying when the need was indicated. Owing to the rapid turn-over of military personnel it was often necessary for the resident officer to ride the spray mission to serve as a guide for the pilot. Hand- operated equipment was u$ed generally on the project. Attenpts to introduce mech- Dusting albitanui breeding places in Jamaica, B.W.I., with paris green. Concrete-products manufacturing plant which turned out approximately 35 miles of inverts, slabs, and pipes during the year. anized equipment did not prove successful. This was partly due to the unfamiliarity of the available laborers with mechanical equipment and partly to the inaccessi- bility of much of the A. albimanus breeding area. One section of the control zone was an area of about seven square miles. Two sides were bordered on parts by paved roads and gravelled surface; one side had a partially gravelled road; the fourth side had a dirt road that was usable only in dry weather. Cattle trails provided the best routes within the area. VIRGIN ISLANDS Knud Knud - Hansen, M. D. Commissioner of Health The MCWA program in the Virgin Islands consisted mainly of USPHS promotion and supervision of a ratproofing canpaign in the city of Charlotte Amalie on St. Thomas Island. Work on this project progressed slowly due to labor shortages. Cki the is- lands of St. Thomas and St. Croix, entomological and engineering surveys were made by MCWA personnel to combat filariasis and the Aedes aegypti vector. Recommenda- tions were made for eliminating the aegypti breeding places and for DDT residual spraying of the islands. DISTRICT NO. 6 SUMMARY The malaria rate for military personnel continued to decrease in the protected areas. Many cases of malaria occurred on some posts among troops returning from combat zones, but this appeared to have no effect on permanent personnel. 164 DISTRICT NO. 6 PLANNING. Approximately 7,300 acres were included in topographic surveys dur- ing the year. The design and preparation of detailed plans for two pumping sta- tions, one combination office and warehouse, and 12 separate drainage and fill units were completed. Entomological studies were made to determine the significant breeding places, and to establish priority of construction units. OPERATIONS. Paris green was the most extensively used larvicide during the past fiscal year. A total of 61,663 pounds were used to dust 38,891 acres. An additional 1,320 acres were covered with 18,702 gallons of oil. Approximately 100 acres of aquatic and land vegetation were cleared out supplementary to larvicidal work. Principal drainage items included approximately 45,000 cubic yards of hand exca- vation, 31,000 cubic yards by drag-line, 22,000 cubic yards sub-surface and back fill, and 22,000 cubic yards of fill material. Approximately five miles of inverts with side slabs, nine miles of four-inch side drain pipe, and four miles of six to 30 inch pipe were installed and 18 miles of open-earth ditching and two miles of earth dikes were constructed. A total of 1,670,000 linear feet of existing ditch- es were cleaned of silt and debris. CONSTRUCTION. Items constructed by the close of the fiscal year included one temporary and one permanent combination office-warehouse and concrete-products manufacturing plant, one complete pumping station with inlet and discharge canals, and one under construction. Manufacture of concrete products included approximately eight miles of Panama inverts, ten miles of side slabs, nine miles of four-inch pipe, 1.5 miles of six-inch pipe, and one mile of eight-inch pipe, 2.5 miles of ten-inch pipe, and three miles of 12- to 30-inch pipe. FUTURE ACTIVITIES. Operations for the 1947 fiscal year are expected to con- tinue at about the same level as existed at the close of this year. It is probable that, for routine operation, more emphasis will be placed on DDT aerosols and the new DDT-oil larvicide. Discharge side of Losey Field USPHS pumping station. This station, which drains a 430 acre swamp, has a 30,000 gpm capacity. District No. 7 Headquarters: Kansas City, Missouri LEGEND War Malaria Control - 1945 Season War Malaria Control - Continued in 1946 Nine states comprise USPHS District No. 7—North and South Dakota, Minnesota, Nebraska, Iowa, Kansas, Missouri, Oklahoma, and Arkansas. Of these, Arkan- sas, Oklahoma, and Mis- souri had MCWA programs operating under the juris- diction of the respec- tive state health departments in cooperation with the dis- trict office and they are discussed separately under “state-operated” programs. North Dakota had no MCWA program in operation during the fiscal year. Activities in the other five states, supervised by the district office in cooperation with the respective state health departments, included the entomological surveillance and inspection of war areas in the marginal malaria states and malaria control projects in Clarinda, Iowa and Fort Crook, Nebraska. A total of 28 reconnaissance surveys were completed by the district entomologist around war areas to determine the need for further control activities, and 38're-inspections of war establishments for malaria densities were made. Control efforts by the district mobile unit at the two projects mentioned above included considerable minor drainage work as well as larviciding. In 1946 only three states—Minnesota, Nebraska, and Kansas —had active war establishments which required surveillance or control. 166 DISTRICT NO. 7 DISTRICT SUMMARY During the first part of the fiscal year a total of 51 war establishments in 41 counties had malaria control activities. Most of these were branch prisoner of war camps which were established throughout the district in order to make prisoners of war available for harvesting work. The great majority of these installations were kept under entomological surveillance and required no further control measures. Only two projects, one each in Iowa and Nebraska, required larviciding and minor drainage control. In 1946 larviciding and minor drainage was continued around the Nebraska project, and entomological surveillance was maintained in three zones in Kansas and one zone in Minnesota. MCWA activities around the remainder of the installations were terminated soon after the war ended in 1945. NEBRASKA. Entomological surveillance was carried out around prisoner of war camps in the counties of Buffalo, Dawson, Franklin, Hall, Harlan, Hitchcock, Keith, Morrill, Phelps, and Scotts Bluff. In addition inspections were made in the en- virons of Kearny Army Airfield in Buffalo County, Harvard Army Airfield in Clay County, Winslow Army Airfield in Dodge County, Fort Omaha in Douglas County, Fair- mont Army Airfield in Fillmore County, Grand Island Army Airfield in Hall County, McCook Army Airfield in Red Willow County, and Braning Army Airfield in Thayer County. One larviciding and minor drainage project was carried on throughout the fiscal year around Fort Crook in Sarpy County. SOUTH DAKOTA. One prisoner of war camp in Yankton County was kept under ento- mological surveillance during the first half of the fiscal year to check on the possibility of a malaria hazard. This camp was terminated soon after the end of the war. IOWA. During the first part of the fiscal year entomological surveillance was maintained around prisoner of war camps in the counties of Bremer, Floyd, Fremont, Hardin, Kossuth, Monona, and Page, and around Schick General Hospital in Clinton County (in conjunction with District No. 3), the Veterans' Hospital in Knoxville in Marion County, Fort Des Moines in Polk County, and the Sioux City Army Airfield in Woodbury County. Larviciding and minor drainage was required around the prisoner of war camp near Clarinda in Page County. None of the installations which remained active in 1946 required malaria control. MINNESOTA. Two prisoner of war camps, in Faribault and Martin counties, required surveillance during the first part of the fiscal year. These were terminated in 1946, and surveillance was begun around Fort Snelling in Ramsey County. KANSAS. Only one prisoner of war camp, in Cloud County, was active and required surveillance during the latter part of 1945. However, entomological inspections were made around many other types of establishments including Great Bend City and the Army Air Base in Barton County, Jayhawk Ordnance Plant in Cherokee County, Arkansas City in Cowley County, Fort Riley in Geary County, the city of Gardner and the Naval Air Base in Johnson County, the Federal Housing Project and the Kansas Ordnance Plant in Labette County, the city of Coffeyville and the Coffeyville Army Air Base in Montgomery,County, Camp Phelps in Saline County, and Winter General Hospital in Shawnee County. In 1946 surveillance was continued only around Fort Riley, Camp Phillips, and Winter General Hospital. DISTRICT NO. 7 167 MOSQUITO COLLECTIONS In addition to the surveillance and inspections mentioned above the major ento- mological activities included intensive studies of the malaria mosquito breeding places in and around high “quad" producing areas in Kansas. Some of these studies were made by light trap operations in four previously unsampled areas in Kansas. Records from these trap catches were used in implementing distributional knowledge of various species of mosquitoes in the middle west. INSECT CONTROL DEMONSTRATION ACTIVITIES In the late summer of 1945 DDT-isomer concentrate was made available to the district office with the suggestion that it be used to conduct demonstrations illus- trating the proper use of this insecticide in the control of insects affecting health. Because of the many requests from state and local health departments for demonstrations it was planned to conduct an exhibition in each of the state health departments in the district and in as many local health departments as possible before distributing the DDT-isomer in order to arouse a keener stimulation for demonstrational activities on the part of state and local health workers. A total of 109 showings were held by district personnel in the states of Missouri, Kansas, Oklahoma, Nebraska, North and South Dakota, Minnesota, and Iowa, at which a total of 2,723 individuals, mostly public health workers, received practical instruction in the proper uses of EOT for the control of insects affecting health. Following this series of demonstrations and the distribution of the DDT-isomer concentrate to the states a total of 372 demonstrations was reported by seven of the above- mentioned states, with a total attendance of 3,979. Complete reports have not yet been received from all of the states. These latter demonstrations required a total of 134 55-gallon drums of DDT-isomer concentrate distributed to the various state and local health departments. Mobile equipment for insect control demonstrations. District No. 8 Headquarters: Denver Colorado LEGEND War Malaria Control - 1945 Season War Malaria Control - Continued in 1946 The range of distribution of the west- ern malaria vector, Anopheles freeborni, includes the northern tip of Montana, the southwestern corner of Wyoming, the western half of Colorado, and all of Idaho and Utah. However, these states, comprising USPHS District No. 8, are not within the normally malarious regions of the United DISTRICT NO. 8 169 States and it was considered unnecessary to maintain separate control projects around each of the war establishments in this district. Instead surveillance was maintained by the district entomologist in close cooperation with military au- thorities and state and local health departments, and district mobile unit per- sonnel were dispatched to those areas where control measures were required. UTAH. Two larviciding and minor drainage projects were carried on during the fiscal year in Utah, around Bushnell General Hospital in Brigham City, Box Elder County, and in the zone including the Army Service Forces Depot and a prisoner of war camp in Weber County. Entomological surveillance was maintained during the course of the year in the environs of the Naval Supply Depot in Davis County and Hill Army Airfield in Weber County. During the 1945 mosquito season periodic in- spections were made of the Ordnance Depot and prisoner of war camp in Tooele County. OTHER STATES. The Ruppert prisoner of war camp in Minidoka County of Idaho was inspected periodically and occasional spot larviciding was done by the inspector. This camp closed after the end of the war. In Cascade County of Montana, Gore Field and East Base in the Great Falls area were under surveillance during the first half of the fiscal year. Check inspections were also made during this period around the Fort Warren (Laramie County) and Douglas (Converse County) prisoner of war camps in Wyoming. In Denver, surveillance was carried on ar.ound the Fort Logan Convalescent Hospital and Fitzsimmons General Hospital in Denver County and Camp Carson Hospital in Colorado Springs, El Paso County. No actual MCWA program as such was continued in these states in 1946. (below) District No. 8 mobile unit in opera- tion. (right) Surveil- lance was maintained by the district entomolo- gist. District No. 10 Headquarters: Honolulu, Oahu LEGEND Aedes aegypti Control Operations Aedes aegypti Surveillance The control of Aedes aegypti and albopictus in the Hawaiian Islands continued during this fiscal year according to the basic plan of operation established in the fall of 1943 to cope with an outbreak of den- gue fever. This plan stressed inspect ion of premises — correction of breeding —education of the householder. On October 31, 1945, all Army personnel assigned to the Mosquito Control Division were withdrawn and activities were continued with 22 federal civil ser- vice employees, supported by funds from the U. S. Pub- lic Health Service. Notification was received in March 1946 that USPHS funds would not be available beyond the end of May. On June 2, 1946 the Mosquito Control Division was completely trans- ferred to the Bureau of Sanitation of the Board of Health, with 29 positions sup- ported with territorial money from the Governor’s contingent fund. CONTROL OPERATIONS One positive case of dengue fever was recorded in July 1945, although a number of suspected cases during the year were investigated and anti-mosquito precautions taken. Routine premise-to-premise inspections were carried on in Hilo, Honolulu, and rural Oahu, and surveys were made on the islands of Kauai, Maui, Lanai, and Hawaii as conditions indicated. An experimental, specially constructed DDT-smoke aerosol attachment to the exhaust of a motor vehicle was developed and proved val? uable in the control of adult mosquitoes. INSPECTING PROCEDURE, It was impossible with the reduced staff to maintain con- tinuous inspection of all zones within cities at the same frequency as previously practiced. Although each zone was inspected, only those zones of high human popu- lation density and demonstrated hazard from the standpoint of re-introduction of DISTRICT NO. 10 dengue fever received treatment that approached the desired optimum of control. The use of EDI, with its high residual toxicity, aided in pre- venting some adverse effects resulting from the lengthening of the inspection cycle. The small, mobile crew of inspectors who had been func- tioning in Hilo proved invaluable as a nucleus for a fly-control problem subsequent to the tidal wave disaster of April 1, 1946. Routine inspections were made of 335,295 premises dur- ing the year, of which 7,268 were found to be breeding Aedes mosquitoes. Special emphasis was placed on permanent correction wherever possi- ble. The use of EOT suspensions, applied to all potential and actual breeding containers with a special “squirt” oil-can applicator, increased the efficiency of the inspectors. LARVICIDING AND FILLING. The borrowed mili- tary motorcycle larviciding units were replaced by a jeep (%-ton truck) equipped with a pres- sure tank and spray equipment. This truck was used for larviciding storm drains, manholes, ground pools, swamp areas, ditches, and cess- pools. During the year a source of breeding was completely eliminated by the removal of the bomb shelters erected during the war. The large swamp area adjacent to Kapiolani Boulevard was filled in, permanently removing one of the largest sources of Culex breeding within the city of Honolulu. A regular inspection cycle of known swamp and pond areas of mosquito breeding was established. When breeding was discovered, im- mediate treatment was made. This proved quite effective in reducing the numbers of Culex mos- quitoes within Honolulu. ACCOMPLISHMENTS, In the course of the year 7,425 catch basins and storm drains, 207 ground pools, 62 cesspools, 89 ditches and streams, and 13 swamps were oiled to eliminate mosquito breed- ing. In addition, 134 fish ponds were stocked with surface minnows, which fed on mosquito lar- vae. Phenothiazine strips became increasingly important as a means of controlling interior breeding. They have been readily accepted by the householder and are in constant demand. During the year approximately 85,000 packages, each containing 12 phenothiazine strips, were dis- tributed in the Territory of Hawaii to schools, in cemeteries, and at public lectures. Military motorcycle larviciding units were replaced by a jeep equipped with pressure tank and spray equipment. (above) When breeding was discovered, in- spectors provided immediate treatment, (below) Inspector’s kit. Bottles contain an alcoholic suspension of DDT in water. “Oil-can” squirt gun in lower center. DISTRICT NO. 10 DDT-ALCOHOL LARVICIDE An important phase of the program in Hawaii was the development of a method for using an alcoholic suspension of DDT in water, which could be used in all contain- ers, replacing the variety of larvicides previously carried by each inspector. A conveniently handled oil-can “squirt" gun to apply the DDT suspension insured adequate treatment of all potential and actual breeding containers. Tests were conducted on the effectiveness of various DDT concentrations in ape plants, lily plants, bamboo stumps, tree holes, and a variety of artificial containers. ENTOMOLOGICAL ACTIVITIES The study of the life history and habits of mosquitoes was the basis for the development of effective control measures. The distribution, flight range, egg- laying habits, types of containers used as breeding places, effective larvicide concentrations, etc., were studied to obtain the necessary knowledge for adequate control measures. AIRPLANE QUARANTINE. Close liaison was maintained with agencies concerned with insect quarantine and inspection of airplanes and other forms of transportation in order to prevent the introduction of medically or economically important in- sects. During the past fiscal year approximately one-fourth of all arriving and departing*planes were inspected for insects and 133 aircraft were found to be car- rying mosquitoes. A total of 364 mosquitoes of 19 different species were discover- ed. The species included five Anopheles, six Aedes, five Culex, and one each of Mansonia, Psorophora and Culicidae. Only four mosquitoes were found alive, none of them Anopheles. Intensive measures were taken by the agencies concerned to se- cure adequate disinsectization of the planes upon arrival and departure. PUBLIC EDUCATION In the course of the fiscal year 254 column-inches of news releases directly concerned with mosquito control activities appeared in the English-language news- papers. In addition, 108 column-inches appeared in the foreign language newspapers, including Japanese, Chinese, and Filipino. HEALTH PROGRAMS. During the 1945-46 school year the Division of Health Educa- tion in the Department of Public Instruction of the Territory of Hawaii prepared a series of monthly health programs. The first program, entitled “Mosquitoes and their Control, “ was prepared with the assistance and review of the Division of Mosquito Control. The program consisted of a package of prepared articles, post- ers, and information concerning teaching aids, available films, references, etc., which assisted the teacher in presenting health subjects in an interesting and factual manner. By this means health subjects of local interest were included in courses in biology, hygiene, and home economics without departing too greatly from the standard curriculum. LECTURES AND FILMS. Numerous public lectures and talks to schools were given during the year, which included presentations of the films, “ Aedes aegypti Con- trol”, “Miss Keeter Goes to Town“, “The Life History of the Yellow Fever Mos- quito and “ Winged Scourge". Demonstrations of control techniques were also given using live exhibits wherever possible. Eighty-three showings of the film on mos- quito control were given to a total estimated audience of 16,843. i x appendix MCWA MALARIA CONTROL PERSONNEL ON DUTY Table Fiscal Year 1946 July Aug. Sept. Oct. Not . Dec. Jan. Feb, Mar. Apr. May June Monthly Average A1ab ana 96 88 59 77 58 42 41 36 102 151 166 174 90 Arkansas 477 501 480 323 203 189 167 152 386 416 408 442 345 Dist. of Col. 2 6 2 2 1 1 1 1 1 1 — — 2 California 26 29 28 27 21 17 16 11 11 16 17 14 20 Florida 300 317 307 307 120 111 106 86 95 193 189 184 193 Georgia 196 198 193 173 138 75 73 59 97 172 108 107 132 I11inois 32 25 14 10 3 8 3 1 — — — — 12 Indiana 13 13 13 6 6 6 6 2 — — — — 8 Kentucky 94 98 89 28 18 17 17 18 34 32 31 1 40 Louisiana 345 341 317 2 75 112 123 120 89 133 183 178 206 202 Maryland IT- nr- 13 5 3 8 1 — — — — — 9 Miss iss ippi 335 349 255 131 81 59 66 70 258 277 290 261 203 Missour i 207 184 187 122 49 65 29 30 81 86 98 99 103 N. Carolina 188 185 165 97 87 7-9 58 72 73 68 68 67 100 Oklahoma 145 150 123 123 81 44 39 31 44 43 41 43 75 Oregon 1 —r 1 1 1 1 1 1 1 1 1 — 1 S. Carolina 497 493 468 385 187 124 112 127 83 238 239 235 266 Tennessee 145 141 113 80 62 76 74 71 86 84 90 93 93 Texas 367 377 373 224 201 106 121 101 115 230 245 264 227 Virginia 137 135 122 103 76 32 30 29 29 28 30 30 65 Dist. 6 303 310 452 273 293 281 214 186 170 148 143 117 280 Dist. 10 32 36 35 34 34 39 37 34 33 31 30 27 34 MCWA AEDES AEGYPTI CONTROL PERSONNEL ON DUTY Table II Fiscal Year 1946 July Aug. Sept. Oct. Not . Dec. Jan. Feb. Mar. Apr. May June Monthly At erage A1ab ana 10 6 6 6 8 6 5 6 4 6 6 6 6 Florida 25 28 24 24 24 23 23 23 22 22 20 15 23 Georgia T 6 6 6 6 6 5 2 - 2 - - 5 Louisiana 9 10 10 9 10 10 11 10 9 8 2 - 9 S. Carolina 8 8 8 8 7 7 7 7 7 7 6 6 7 Texas 36 37 39 34 24 14 15 16 16 15 14 14 23 Table III MCWA TYPHUS CONTROL PERSONNEL ON DUTY July Aug. Sept. Oct. Nov. Dec. Jan. Feb. Mar. Apr. May June Monthly Average A1ab ana 10 9 11 20 26 39 42 41 49 46 47 45 32 Arkansas 30 30 31 3? 29 — 1 4 22 22 California 0 1 1 1 1 0 — — — — — — 1 Florida 2 2 8 12 17 16 17 19 20 21 19 20 14 Georgia 1 2 1 22 24 42 48 72 61 92 76 70 43 Louisiana 1 1 —r 12 7 20 20 17 23 31 35 40 18 Mississippi 2 2 2 7 4 18 19 20 19 19 2 15 11 N. Carolina 5 4 12 ! 18 19 21 24 26 26 24 24 27 19 S. Carolina 7 7 14 21 22 20 21 26 31 33 33 34 22 Tennessee 1 0 _ — 6 6 11 11 17 19 16 11 8 Texas 18 25 48 47 77 81 73 73 78 74 89 62 62 VirKini a 1 1 — — — — — 2 1 District 6 1 1 1 1 — 1 — — — 1 1 1 1 Fiscal Year 1946 1st Half F.Y. 2nd Half F.Y, Total F.Y. Man-Hours F.Y. 1st F. Half Y. 2nd F Half Y Total F V Man-Hours Alabama Co’s Areas Zones Est. Towns 25 19 33 74 28 4 5 5 36 19 33 74 44 181,852 Mississippi Co’s Areas Zones Est. 30 23 40 59 24 3 4 4 32 23 40 59 365,112 Arkansas Co* s Areas Zones Est' Towns 29 20 53 57 35 3 7 7 39* 20 53 57 35* 571,366 Missouri Co’s Areas Zones Est. Towns 21 15 24 26 12 2 3 3 28 15 24 26 Id 16 170,979 California Co's Areas Zones Est. 14 6 22 25 5 3 5 5 15 6 23 26 22,454 North Carolina Co’s Areas Zones Est. Towns 39 14 41 77 41 3 5 6 48 14 41 77 160,042 Florida Co’s Areas Zones Est. Towns 45 37 55 3 244,136 24 36 82 91 10 18 19 6 82 91 21 Oklahoma Co’s Areas Zones Est. 28 15 38 69 6 1 1 1 29 15 38 69 118, 336 Georgia Co* s Areas Zones Est. Towns SO 15 53 85 62 3 3 3 78 15 53 85 U9 241,095 Oregon Co’s Areas Zones Est. 5 2 8 8 1 1 1 1 5 2 8 8 344 Illinois Co’s Areas Zones Est. 10 9 12 19 * - - 10 12 19 10,366 South Carolina Co’s Areas Zones Est. Towns 30 23 33 109 29 3 3 3 34 23 33 109 90 415,746 Indiana Co’s Areas Zones Est. 7 7 9 19 - - 7 7 9 19 5,947 Tennessee Co’s Areas Zones Est. 13 6 22 134 15 2 4 4 19 6 22 134 152,216 Kentucky 14 15 19 68,321 Towns 12 Areas Zones Est. Towns 6 19 42 4 4 3 19 42 3 Texas Co’s Areas Zones Est. 72 15 78 130 77 4 6 7 95 15 78 130 10^ 511,075 Louisiana Co s Areas Zones Est. Towns 21 8 44 71 24 5 8 9 33 8 44 71 36 340 , 364 Virginia Co’s Areas Zones Est. 19 6 30 107 4 3 6 7 19 6 30 107 3 105,423 TOTAL 1st Half F-Y, 2nd Half F.Y. Total F.Y. Man F ■Hours .Y. Co's Areas Zones Est. Towns 478 245 641 1202 415 54 83 87 601* 245 642 1203 663* 3,685, 174 y Does not include 30 additional towns in 21 countie* in Arkansas which had Typhus Surreys. Table IV " STATE-OPERATED" PROGRAM SUMMARY - FISCAL YEAR 1946 Total Counties. Areas. Zones, Establishments, and Towns for all MCWA Programs Operating in Each State 1st Half F.Y. 2nd Half F.Y. Total F.Y. Man-houfs F.Y. INCLUDED STATES District 1 Go's Zones Est. 43 59 60 11 14 14 43 59 60 20,963 Connecticut, Delaware, Massachusetts, New Jersey, New York, Pennsylrani a, and Rhode Island included in district totals. (No MCWA operations in Maine, New Hampshire or Vermont.) District 2 Co ’ s Areas Zones Est. 15 4 35 52 - 15 4 35 52 3,120’ Maryland and the District of Columbia included in district totals. (No MCWA operations in West Virginia. Virginia, North and South Carolina had ** s t at e-ep er a t e d " MCWA programs. District 3 Co ’ s Areas Zones Est. 8 8 9 10 - 8 8 9 10 2, 441 Michigan and Ohio included in district totals. (No MCWA operations in Wisconsin, Illinois, Ind- iana, and Kentucky had " state-operated” MCWA programs, ) District 4 Alabama, Florida, Georgia, Louisiana, Mississippi, and Tennessee, all had " state-operated” MCWA p ro g r a ms. District 5 Arizona, Nevada, and Washington had no MCWA opera- tions. California and Oregon had “ state-operated” MCWA programs. District 6 Co ’ s (i s1ands) Areas Zones Est. Towns 12 9 11 20 12 7 11 11 13 9 11 20 2 413,713 Puerto Rico, Virgin Islands, and Jamaica, B.W.I. included in district totals. District 7 Co's Are as Zone s Eat. 41 42 51 51 5 5 5 5 42 42 52 52 Iowa, Kansas, Minnesota, Nebraska, and South Dakota included in district totals. (No MCWA operations in North Dakota. Arkansas, Missouri, and Oklahoma had " state-operated” MCWA programs.) District 8 Co's Areas Zones Est. 10 8 13 14 3 3 3 5 10 8 13 14 3, 100 Colorado, Idaho, Montana, Utah, and Wyoming in- cluded in district totals. District 9 No MCWA operations in New Mexico. Texas had a “ state-operated” MCWA program. District 10 Co's (ialands) 5 5 5 Hawaiian Islands included in district totals. District 11 No MCWA operations in Alaska. TOTAL Co' s Areas Zones Est. Towns 131 71 178 207 36 15 31 35 T36 71 179 20 8 2 443,337 Table V “ DISTRICT-OPERATED” PROGRAM SUMMARY - FISCAL YEAR 1946 Counties, Areas, Zones, Establishments, and Towns for all MOVA Programs Operating in Each District WAR MALARIA AEDES AEGYPT1 WAR MALARIA AEDES AEGYPTI 1st Half F.Y. 2nd Half F.Y. Total F.Y. F.Y. 1946 1st Half F.Y. 2nd Half F Y Total F.Y. Alabama Co’s Areas Zones Est. Towns 17 19 33 74 4 4 5 5 17 19 33 74 1 1 Mississippi Co’s Areas Zones Est. 21 23 40 59 3 3 4 4 21 23 40 59 1946 Arkansas Co's Areas Zones Est. 22 20 53 57 3 3 7 7 22 20 53 57 Missouri Co’s Areas Zones Est. 20 15 24 26 2 2 3 3 20 15 24 26 California Co’ 8 Areas Zones Est. 14 6 22 25 5 3 5 5 15 6 23 26 N. Carolina Co's Areas Zones Est. 26 14 41 77 2 3 5 6 26 14 41 77 Florida Areas Zones Est. Towns 37 36 82 91 9 10 18 19 37 36 82 91 3 3 Oklahoma Co’s Areas Zones Est. 25 15 38 69 1 1 1 1 25 15 38 69 Oregon Co’s Areas Zones Est. 5 2 8 8 1 1 1 1 5 2 8 8 Georgia Co' 8 Areas Zones Est. Towns 23 15 53 85 3 3 3 3 23 15 53 85 1 1 S. Carolina Co’ 8 Areas Zones Est. Towns 19 23 33 109 3 3 3 3 19 23 33 109 1 1 Illinois Co’s Areas Zones Est. 10 9 12 19 - 10 9 12 19 Indiana Co’s Areas Zones Est. 7 7 9 19 * 7 7 9 19 Tennessee Co’s Areas Zones Est. 8 6 22 134 2 2 4 4 8 6 22 134 Kentucky Co’s Areas Zones Est. Towns 10 6 19 42 4 4 4 3 10 6 19 42 1 1 Texas Co’s Areas Zones Est. Towns 39 15 78 130 5 4 6 7 39 15 78 130. 8 30 Louisiana Co’s Areas Zones Est. 1 23 8 44 11 6 5 8 2 23 8 44 LL Virginia Co’s Areas Zones Est. Towns 18 6 30 107 3 3 6 7 18 6 30 107 1 TOTAL WAR MALARIA \EDES AEGYPTI 1st Half F. Y. 2nd Half F.Y. Total F.Y. F.Y. 1946 Co’s Areas Zones Est. Towns 344 245 641 1202 56 54 83 87 345 245 642 1203 16 39 Table VI SUMMARY OF ** STATE-OPERATED" MCWA WAR MALARIA PROGRAMS Fiscal Year 1946 WAR MALARIA AEDES AEGYPTI 1st Half F.Y. 2nd Half F.Y. Total F.Y. F.Y. 1946 INCLUDED STATES District 1 Go's Areas Zones Est. 43 59 60 11 14 14 43 59 60 Connecticut, Delaware, Massachusetts, New Jersey, New York, Pennsylvania, Rhode Island included in district totals. (No MCWA operations in Maine, New Hampshire and Vermont.) District 2 Go’s Are as Zones Est. 15 4 35 52 - 15 4 35 52 Maryland and District of Columbia included in district totals. (No MCWA operations in West Vir- ginia, Virginia, North and South Carolina had " state-operated” MCWA programs. District 3 Go's Areas Zones Est. 8 8 9 10 - 8 8 9 10 Michigan and Ohio included in district totals. (No MCWA operations in Wisconsin, Illinois, Ind- iana and Kentucky had ** s tat e-operated ” MCWA p rograms. District 4 Alabama, Florida, Georgia, Louisiana, Mississippi and Tennessee all had ” state-operated"MCWA pro- grams. District 5 Arisona, Nevada and Washington had no"MCWA opefa- tions. California and Oregon had ” state-operated” MCWA programs. District 6 Go's Areas Zones Est. 9 11 20 7 9 11 9 11 20 Puerto Rico, Virgin Islands, and Jamaica, B.V.I., included in district totals. District 7 Go's Areas Zones Est. 41 42 51 51 5 5 5 5 42 42 52 52 Iowa, Kansas, Minnesota, Nebraska, and South Dakota included in district totals. (No MCWA operstions in North Dakota, Arkansas, Missouri and Oklahoma had ** atate-operated” MCWA programs. District 8 Go’s Areas Zone s Est. 10 8 13 14 3 3 3 5 10 8 13 14 Colorado, Id,aho, Montana, Utah, and Wyoming in- cluded in district totals. District 9 No MCWA operations in New Mexico. Texas had a ** s ta te - op e ra te d ” MCWA program. District 10 Go's (islands) 5 Hawaiian Islands included in district totals. District 11 No MCWA operations in Alaska. TOTAL Co ( 8 Areas Zones Es t. 126 62 178 20 7 26 8 31 35 127 62 179 208 5 Table VII SUMMARY OF “ DISTRICT-OPERATED” MCWA WAR MALARIA PROGRAMS Fiscal Year 1946 LARVICIDAL WORK DRAINAGE OPERATIONS LARVICIDE USED SURFACES TREATED CLEARING CLEANING NEf DITCHING —LIN. FT. Ditch Lining Linear Feet Under- Ground Drain- age Lin.FY. Fill C. Y. Water Surf. Elimi• nated Acres TOTAL MAN HOURS Oil Gals. Paris Green Lbs. ACRES ACRES Lin. Ft. Hand Mach. Dyna- mite Total Oiled Dus ted A1abama 4,753 500 174 373 39 9 264,804 — — — — — — — 3 4,701 Ar kansas 167,360 2,447 9,927 1,564 426 369 637,743 93,242 — 1,500 8,101 2,295 — — 15 319,158 California 10,951 35 1,003 11 9 10 64,487 600 1,800 — 2,030 — — — 42 22,454 Florida 21,191 6,008 1.091 3. 710 64 49 1,168,497 79,903 — 10.676 12,270 9,444 58 30,075 37 136,979 Georg i a 2,182 9,802 241 7,553 60 83 158,335 6,229 113 — 823 — — 23.062 24 41,263 111 ino is 5,165 1,563 181 1,287 2 1 28,245 4,145 — 5,090 4,050 — — — 7 10,366 Indiana 4,621 52l 333 65 — — 3,400 — — 850 900 — — — — 5,947 Kentucky 14,667 132 683 89 25 8 5,383 — — — — — — — — 43,479 Louis i ana 302,711 1, 780 12,563 I. 720 56 87 310,812 8, 805 — 40 1,388 — — 293 — 247,382 Mississippi 68,219 4,492 2,761 2, 621 205 283 254,145 1,000 — — 23 — — — 1 162,253 Missouri 36,115 15,864 2,127 7,482 4 59 14,240 1,965 — 6,600 5,205 600 — 4 50 121,435 N. Carolina 27,862 270 1,382 71 167 378 1,205,888 69,194 27,280 36,133 — 1,597 7,839 50 59,908 Oklahoma 86,740 1,500 5,054 966 6 29 21,018 18,047 — — 2,001 — — 15 8 94,499 Oregon 1,635 — 30 — — — — — — — — — — — — 344 S. Carolina 54,064 1,733 2,754 1.337 431 271 2,116,420 42,118 — — 4,882 78 1.075 6,262 48 219,362 Tennessee 43,981 552 1,787 207 5 22 59,317 18,368 — — 4,570 16,743 — 3,054 12 112,225 Texas 69,659 1,896 3,140 1,458 391 88 1,028,461 31,543 26,656 2,080 13,502 — — 417 136 135.252 Virginia 49,794 2,409 1,493 1,347 62 122 414,370 160,131 — — 12,511 1,563 — 3,806 — 104,635 District 1 12,896 18,536 1,003 9,2 02 5 5 122,422 46.086 8,185 36,914 310 700 490 20,963 District 2 — — — — 14 — 1,000 500 — 1,068 900 — — 382 10 3,120 District 3 — 845 — 2 74 4 — — — — — — — — — — 2.441 District 6 18,702 61.663 1,320 38.891 34 57 1.668,868 53,380 11,286 3,2 63 24,819 — 1,045 91 413,713 Distr ict 8 250 195 54 569 — — — 695 — — 18 — — — — 3,100 TOTAL FISCAL YR. 1,003,518 132,274 49,101 80,797 2,008 1,930 9,547,855 635,951 48,040 58,447 173,040 31,033 2,730 76,954 1,024 2,284,979 SUB-TOTAL 1st HALF FISCAL YR. 900,973 116,329 43,858 70,132 3,45 7 7,269,718 478.088 37,962 36,214 122,009 20,203 2,210 58,028 418 SUB-TOTAL 2nd HALF FISCAL YR. 102,545 15,945 5,243 10,665 482 2,278,137 157,863 10,078 22,233 51,031 10,830 520 18,926 606 Table VIII MCWA LARVICIDAL AND DRAINAGE OPERATIONS Fiscal Year 1946 RESIDUAL SP RAYING LARVICIDING, DRAINAGE 1st Half F. Y. 2nd Half F. Y. Total F. Y. 2nd Half F. Y. 2nd Half F. Y. Total F. Y. 1st Half F. Y. 2nd Half F. Y. Total F. Y. 1st Half F. Y. 2nd Half F. Y. Total F. Y. Alabama Go’s Towns 6 21 21 6 6 16 19 16 19 Missouri Go’s Towns 3 10 10 3 16 - 3 16 Arkansas Go’s Towns 23 31 32 11 26 "IT" 27 17 33 N. Carolina Co’s Towns 13 36 36 - 1 1 1 1 Florida Go's Towns 10 23 23 4 4 6 6 7 7 Oklahoma Go’s Towns 3 5 5 2 4 ‘ . 2 4 Georgia Co’s Towns 14 36 36 - - - S. Carolina Go’s Towns 12 23 23 8 11 8 11 Kentucky Co* s Towns 6 11 11 1 1 3 3 3 3 Tennessee Go's Towns 6 12 12 5 8 4 6 5 9 Louisiana Co’s Towns 8 15 15 5 7 6 6 8 10 Texas Co’s Towns 6 33 33 1 9 1 9 1 9 Mississippi Go’s 13 17 17 - - - les not include experimental residual spraying in counties in Puerto Rico, or state-wide demonstration raying in Virginia. TOTAL* RESIDUAL SPRAYING LARVICI DING.DRAINAGE 1st Half F. Y. 2nd Half F. Y. Total F. Y. 1st Half F. Y. 2nd Half F. Y. Total F. Y. * Dc Q Co’s 123 273 274 46 53 71 o Towns 92 77 122 sp Table IX SUMMARY OF MCWA EXTENDED MALARIA CONTROL PROGRAMS Fiscal Year 1946 No. House Spray Appli- cations Lbs. EOT Used Lbs. DDT per House Appl. Man Hours Man Hours per House Appl. Man Hours per Pound DDT No. House Spray Appli- cations Lbs. DDT Used Lbs. DDT per House Appl. Man Hours Man Hours per House Appl. Man Hoars per Pound DDT Alabama 21,964 16,658 0.76 30,848 1.40 1.85 45,711 36,772 0.80 52,654 1.15 1.43 Arkansas 88,915 34,524 0.39 96,683 1.09 2.51 135,327 88,453 0.65 142,508 1.05 1.61 Florida 24,113 19,393 0.80 39,164 1.62 2.02 27,516 23,701 0.86 32,405 1.18 1.37 Georgia 35,087 26,574 0.76 28,810 1.08 1.08 90,314 118,490 1.44 50,416 0.61 0.43 Kentucky 16,838 6,956 0.41 18,415 1.15 2.88 9,206 5,756 0.63 6,427 0.70 1.12 Louisiana 9,761 5,840 0.60 13,441 1.38 2.30 36,141 23,322 0.64 35,392 0.98 1.52 Mississippi 61,949 28,724 0.46 66,087 1.07 2.30 104,041 83,245 0.79 104,806 1.00 1.25 Missouri 19,760 11,133 0.56 19,090 0.97 1.72 39,001 30,006 0.77 30,454 0.78 1.01 N. Carolina 2,488 .951 0.38 2,678 1.08 2.81 20,605 13,291 0.65 17,793 0.86 1. 34 Oklahoma 9,735 4,127 0.42 9', 283 0.95 2.24 17,060 14,911 0.87 14,554 0.85 0.98 S. Carolina 34,918 16,211 0.46 48,950 1.40 3.02 55,582 32,829 0.59 67,483 1.21 2.06 Tennessee 12,162 5,068 0.42 12,363 1.02 2.42 21,578 16,115 0.75 16,626 0.77 1.03 Texas 75.850 31,707 0.42 94,977 1.25 2.99 46,184 26,784 0.58 51,865 1.12 1.94 SUB-TOTAL 413,450 207.866 0.50 480,789 1.15 2.31 648,266 513,675 0.79 623,383 0.96 1.21 TOTAL — FISCAL YEAR Number House Spray Applications Lbs. DDT Used Lbs. DTT per House Application Man- Hours Man-Hours per House Application Man-Hours per Pound DDT 1,061,806 721,655 0.68 1,104, 172 1.04 1.53 Table X SUMMARY OF RESIDUAL DDT HOUSE SPRAYING OPERATIONS Fiscal Year 1946 xv i ii Table XI SUMMARY OF MCWA TYPHUS CONTROL PROGRAMS Fiscal Year 1946 Residual Dusting Ratproofing Total Typhus USPHS Man-Hours Worked » Other Man-Hours Worked * Total Man-Hours Worked » Alabama Co * 8 11 28 3 3 11 28 56, 549 37,100 93,649 Arkansas Co’s - 1 2 1 • 2 * 400 12,617 13,017 Florida ~G7T 5 9 4 5 6 11 517658 13,930 35, 588 Georgia 543 169 4 4 5T3 162 65, 338 55,268 120,606 Louisiana Co’s 6 24 5 5 6 25 19, 540 24,609 44,149 Mississippi Co* s 12 5 6 6 13 19,712 12,254 31,555 N. Carolina Co’s Towns 5 18 5 5 10 23 33. 239 46,424 79,663 S. Carolina Co* s —n 69 15 13 19 u 78 34,277 45,674 79,951 Tennessee Co's 3 1 3 3 10,945 57 11,002 Texas Co’s 45 181 16 20 50 182 82,009 146,972 228,981 Virginia Co's 1 1 1 , -.1 628 160 788 TOTAL Co’s Towns no 514 57 64 167 • ± 535 • 344,295 495,065 739,360 # Include* supervision, travel, leave, aickneaa, mi ace 11aneous, etc. * Does not include 21 counties and 30 towns in Arkansas which had Typhus Surveys. +, Does not include Thomasville Typhus Investigational Program in Georgia, consisting of experimental residual dusting in three counties, rat eradication in one county, and one control county. Table XII SUMMARY OF RESIDUAL DUSTING TYPHUS CONTROL OPERATIONS Fiscal Year 1946 Premises Inspected Premises Infested Premises Treated Lbs. 10% DDT IXist Used Lbs. 10% DDT Dust Per Prem. Treat. L and LF ft Man-Hours L and LF ft Man-Hours per Prem. Treat. Alabama 42.931 32.091 33.747 144. 133- 4. 3 29.084 0.86 Florida 31.097 22.729 29. 408 51. 129 1.7 16.383 0. 56 Georgia 82.654 71,889 77.567 308.867 4.2 61.160 0.88 Louisiana 25.667 23.572 23.572 39.112 1. 7 9.800 0.42 Miss issipp i 25 833 14,866 15.383 23.935 1. 6 11.000 0.72 N. Carolina 39.312 34. 637 36.175 53.110 1. 5 21.530 Q_i_60 S. Carolina is! 247 11.211 14.222 50.668 3. 6 22.601 1. 59 Tennessee 16.450 15. 336 15.347 37.134 2. 4 6.968 C. 45 Texas 169.964 98.479 90.300 104.359 1.2 50.215 0. 56 Virginia 512 455 453 5,985 13.2 • ... 1.06 TOTAL 449,667 325,265 336,161 818,432 2.4 228,741 0.68 ft L and LF • labor and labor foremen * per premise (includes several treatments) Table XIII SUMMARY OF RATPROOFING AND POISONING TYPHUS CONTROL OPERATIONS Fiscal Year 1946 RATPROOFING RAT POISONING Estab. Treated L and LF# Man-Hours L and LF Man-Hours Per Treat. Premise Poison- ings Lbs. Bait Used Lbs. Bait Per Prem. Poisoning Pts. " 1080" Water Used L and LF* Man-Hours L and LF Man-Hours Per Prem. Poisoning A1 abama 120 2,696 22. 5 24,936 29.555 1. 19 10.67 1 0. 43 Arkansas 149 5.511 29. 2 408 5. 356 13.12# 524 2.896 7. 1 # Fl orid a 411 8. 375 20. 4 321 181 0. 56 38 1.421 4.4 Georgia 325 14. 405 58. 3 23. 675 17. 441 0.86 298 18.216 0.88 Louisiana 272 13.955 51. 3 23.172 5. 379 0.23 548 6.779 0. 29 Mississippi 172 7.970 46. 3 2.065 742 0. 36 150 1.025 0.50 ,N. Carolina 60 1 32. 152 53. 3 2.079 7 50 0.36 • • • 2. 488 1. 20 S. Carolina ~6l4 23.413 35. 8 953 993 1.04 219 2.778 2.92 Tennessee ... • • « ... 4 80 . • - Texas 1.254 39.158 31. 2 37.516 12.168 0. 32 1.888 18.790 0. 50 total 3,998 147,635 36.9 115,129 72, 565 0. 63 3, 665 65,144 0. 56 # P*r precise (several treatments to eliminate rats in * L and LF * labor and labor foremen premises ratproofed)