bubonic plague

Yersinia pestis bacteria. Bubonic Plague ravaged Europe in the 15th century, wiping out one third of the population. Symptoms include a large bluish-black cyst, and a blackening of the skin, which earned it the name the Black Death. Carried by fleas, it became prominent when fear of witches caused the large-scale elimination of cats, allowing rats to run rampant. Variations include an airborne variety that is carried by the mucus in a victim's cough. There are still cases today but modern anti-biotics can effectively treat the disease. Resistent strains of this bacteria are an extremely large threat. Scientists are investigating the possibility that decendents of plague survivors are resistent to AIDS because the Yersinia bacteria attacks the same macrophages that the HIV does.

Bubonic plague gets its name for the way it causes severe swelling in the lymph nodes, a condition called boubon in Greek. The swelling actually damages surrounding blood vessels, causing intense black bruises that made it known as the Black Death.

The plague was a central theme in The Decameron by Giovanni Boccaccio, who wrote it after losing much of his family when the Black Death hit Florence, Italy in 1348. Two excellent contemporary books about the plague include The Black Death and the Transformation of the West (1997) by David Herlihy, and The Black Death (1979) by Philip Ziegler.

The severity of the disease and its relative ease of transmission (just find a few fleas) made the bubonic plague a natural choice for countries experimenting with biological warfare. After successfully exposing prisoners of war to the plague in WWII, Japan launched a series of biological attacks against China, including dropping plague-infested bombs on Manchuria.