From asps to allegations: biological warfare in history.

Biological warfare has been waged intermittently for nearly 2,500 years. The techniques of delivery and weaponization of biological warfare agents have gradually evolved from the catapulting of plague victims to the deliberate use of infected clothes, insect vectors, and specialized weapon systems. Despite advances in immunotherapy and chemotherapy, the threat of biological warfare is increasing, and military health personnel should be acquainted with this area. This paper reviews the history, often controversial, of biological warfare from the Scythian archers through the Russian offensive program in 1994.