Botulinum Toxin in Biowarfare

To the Editor: A historical incident illustrates a number of features of botulinum toxin not discussed in the review of bioweaponry by Dr Arnon and colleagues.¹

During World War II, the US Office of Strategic Services (OSS) developed a plan for Chinese prostitutes to assassinate high-ranking Japanese officers with whom they sometimes consorted in occupied Chinese cities. Concealing traditional weapons on the women at the appropriate time would obviously be difficult. Therefore, under the direction of Stanley Lovell, the OSS prepared gelatin capsules "less than the size of the head of a common pin"² containing a lethal dose of botulinum toxin. Wetted, a capsule could be stuck behind the ear or in scalp hair, later to be detached and slipped into the officer's food or drink. The OSS recognized that the normal background of botulism cases would deflect suspicion from the women.²

The capsules were shipped to Chunking, China. The Navy detachment there, taking nothing for granted, tested the capsules on stray donkeys. The donkeys lived. Lovell was informed that the capsules were faulty, and the project was abandoned. Much later, Lovell learned of the donkey test with, one imagines, some consternation, since "donkeys are one of the few living creatures immune to botulism."²

This incident has been retold in other publications.^{3 - 4} No source for the donkey-resistance information is ever given. More recent experience shows that botulism can occur in mules⁵ and donkeys (R. H. Whitlock, DVM, PhD, written communication, April 27, 2001).

Nevertheless, this incident raises 2 points: (1) botulism need not occur in epidemics when it is being used as a bioweapon, and (2) botulism in animals may be a sign of biowarfare.