What is the history of bioterrorism?

Bioterrorism is the use of toxic biological organisms (as opposed to synthetic, man-made chemicals and other agents) to commit acts of terrorism. While chemical warfare is a relatively recent development, bioterrorism has been around for millennia—at least since 600 BCE.
Ancient people may not have understood the science behind it, but it was apparent that rotten food, decaying corpses, fecal matter, and other contaminants could make an enemy sick. In the Middle Ages, armies would hurl the bodies of their dead soldiers over the enemy’s walls. (This was particularly effective during outbreaks of plague, as the bodies carried the disease as well as normal bacteria.)
A famous example occurred in the 1700s, during the French-Indian War in North America. An outbreak of smallpox among the French troops provided them with the opportunity to infect the Native Americans with a “gift” of infected blankets.
In the twentieth century, bioterrorism techniques became a sophisticated science. Nations raced to develop dangerous, deadly toxins. Thousands of prisoners died as medical researchers used them as test subjects for newer, stronger versions of bacteria and viruses.
In 1972, 103 nations signed the “Convention on the Prohibition of the Development, Production, and Stockpiling of Bacteriological (Biological) and Toxin Weapons and on Their Destruction” (or BWC) treaty, in which they agreed to stop using or producing biological weapons. Though this has not completely eliminated the danger (some countries did not sign the treaty, and others who did have since been found in violation), the practice of bioterrorism is grounds for severe repercussions among most of the global community today.