Warmatrix

Bio-agents are biological weapons that can be industrially produced. The danger of them attacking both friend and foe has made the great majority of countries ban their use.
More primitive biological weapons have been used since ancient times. Hunters put poison on the tips of their arrows and spears to kill animals. Such poisons, or alternatives like snake venom and feces, were used in warfare too. Poisoning wells in dry areas was a common tactic to deprive enemies of clean drinking water. The Hittites drove tularemia victims into enemy territory; in some Medieval sieges rotting carcasses and victims of the bubonic plague were catapulted over the walls. Sometimes biological warfare was unintentional but effective nonetheless, like the cocktail of infectious diseases that Europeans brought with them to America from the the 15th century CE onward, which killed a staggering 90% of the native Americans. When realization of the killing power of diseases dawned in the 18th century CE, at least two times Europeans handed out blankets that had been exposed to victims of smallpox to them. During World War I Germany did some research into bio-agents and used anthrax on a small scale.
Both biological and chemical weapons were prohibited by the Geneva protocol of 1925 CE. However the first versions of the protocol did not cover research, production or storage of them. During the buildup to World War II Britain, the USA and especially Japan developed biological weapons. The infamous Japanese 'Unit 731' experimented with them on Chinese prisoners, both military and civilian, killing several thousands. It also caused small outbreaks of typhoid and the bubonic plague in northern China and eastern Siberia, which continued to kill people up to two years after the war.
Traditional biological weapons like the bubonic plague were used by taking advantage of existing victims of the diseases. The research just before World War II produced 'bio-agents', biological weapons that can be produced in laboratories. Early bio-agents like the bubonic plague, tularemia and brucellosis are very dangerous to use because they can easily backfire, killing both friend and foe. This is illustrated by several accidents at research facilities that caused outbreaks of infectious diseases. Other bio-agents, like anthrax, are only mildly infectious but lethal nonetheless. Biological agents include bacteria, rickettsiae, viruses, fungi and toxins. Some kill, others debilitate. Most bio-agents target humans, others plants or animals to deprive the enemy of food.
Bio-agents are relatively cheap and easy to produce, with the potential of hurting many people. They can be spread by aerosols, to a limited degree by bombs and also by sneaking them into food or water supplies. They are hard to detect and in many cases hard to defend against. For this reason they are often called a 'poor man atomic bomb'.
In 1972 CE the research, mass production, stockpiling and use of biological weapons was outlawed in the Biological Weapons Convention, which is currently signed by around 170 countries. Several countries, including signatories, continue to experiment with bio-agents, which is not prohibited by the treaty. Especially the USSR set up "Biopreparat", a large biowarfare research project that did not only produce lethal weapons, but killed several Russian civilians and researchers themselves in accidents. The program was largely dismantled after the end of the Cold War. Today the largest biological threat does not come from powerful states but from terrorists, some of whom have no compunctions about using biological weapons.