III.

Biological Warfare

Several major nations have worked to some degree on the development of biological agents for use in warfare. Selected or adapted from pathogens causing various diseases that attack humans, domestic animals, or vital food crops, such agents include bacteria, fungi, and viruses or the toxins they produce. The pathogens causing botulism, plague, anthrax, foot-and-mouth disease in animals, and stem rust in wheat are among the many that could be directed against opposing armies or the civilian economies supporting them. Genetic engineering also offers the possibility of developing new virulent strains against which an opposing force could not be prepared in advance. Unlike chemical weapons, which become less potent as they disperse, biological weapons can become more potent, sometimes mutating into even more virulent forms.

Large-scale biological warfare has thus far remained theoretical, although in the 1980s it was learned that Japan used biological agents against the Chinese in the 1930s and early 1940s. In the early 1980s, controversial claims were also made that the Soviets, in Afghanistan, and the Vietnamese, in Laos and Cambodia, were using fungal toxins—in a form called “yellow rain”—as biological weapons.