April 21, 1969

Dr. Martin Kaplan
World Health Organization
1211 Geneva 27 - Switzerland

Dear Martin:

I have no critical comments on the material with your letter of April 17.
Have you given enough weight to the following idea (implied more weakly at
several places).

The availability of specific antibiotics is the chief barrier against the
threat of natural epidewics of many infectious agents. It may appear advan-
tageous to a national military authority to develop mutant pathogens which
are resistant to all conventiokally available antibiotics save one intended
for protecting the home population. The deployment of such an agent would
plainly imperil the health of many other populations. The home population
will also be imperilled if the multi-resistant strain spontaneously acquires
one further step of resistance, or if the intended antibiotic is net freely
usable, as often happens, for every individual.

Similar remarks about salf{“igdependent cholera and mutant viruses selected
for greater durability in free droplegts.

Sincerely yours,

a

Joshua Lederberg
Professor of Genetics

oe