What Is The Plague?
Although the term "plague" refers to any contagious epidemic (widespread outbreak) disease, it usually means the bubonic plague, also called the Black Death which occurred during the Middle Ages (A.D. c. 450–c. 1500). This almost-always fatal illness is caused by the bacteria Yersinia pestis and got its name from the swelling of the lymph nodes, or buboes, under the arms. The plague is passed to humans by fleas that have bitten infected rats. In 1343 when the Tartars invaded the Crimea (present-day Ukraine) some of the soldiers had caught the bubonic plague. In an attempt to gain access to an Italian trading post, the Tartars used catapults to launch the dead bodies of their sick comrades over the walls. As a result, many of the enemy became sick and spread the plague to Constantinople (present-day Istanbul, Turkey) and from there to Western Europe. During the mid-1300s, nearly 75 percent of the population in Europe and Asia died from the bubonic plague. Eventually, improved sanitation and antibiotics (substances that kill bacteria, that is germs) reduced the occurrence of the disease, but it still exists, even in the United States, where it was transmitted when plague-infected rats arrived in San Francisco aboard a ship in 1900. Such animals as squirrels, chipmunks, rabbits and prairie dogs became the new hosts for plague-causing fleas. As late as 1992, an epidemic of bubonic plague, this time the kind that infects lungs, known as pneumonic plague, was averted in Arizona by the quick action of doctors.
Further Information: Centers for Disease Control. Plague. [Online] Available http://www.cdc.gov/ncidod/dvbid/plaginfo.htm, November 6, 2000; Corzine, Phyllis. The Black Death. San Diego: Lucent, 1996; Skelton, Rene. "The Great Plague." National Geographic World. March, 1999, pp. 16–20; Yancey, Diane. The Hunt for Hidden Killers: Ten Cases of Medical Mystery. Brookfield, Conn.: Millbrook, 1994.