Coccidioidomycosis historical perspective

Biological Warfare
C. immitis was investigated by the United States during the 1950s and 1960s as a potential biological weapon. The Cash strain received the military symbol OC, and original hopes were for its use as an incapacitant. As medical epidemiology later made clear, OC would have lethal effects on several segments of the population, so it was later considered a lethal agent. It was never standardized, and beyond a few field trials, it was never weaponized. Most military work on OC was on vaccines by the mid-1960s.