Biological agents as weapons 1: smallpox and botulism

The use of biological agents as weapons of war is not new. In the 14th-century siege of Kaffa, on the Black Sea, the attacking Tartars catapulted bodies of plague victims at the defending Genoese, who contracted the disease and abandoned the city. Over the past century, many countries have developed the capacity to use biological agents to produce casualties in humans and domestic animals and to damage crops and environmental systems. Some biowarfare programs are known to have continued despite the adoption by 144 countries of the 1972 Biological Weapons Convention, which prohibited development or acquisition of such weapons.