Bubonic plague is the most common form of the plague, named for the characteristic buboes – buboes are enlarged lymph nodes (“swollen glands”) – in the groin which are usually very tender and painful. Lymph nodes may be similarly affected elsewhere such as in the armpits and neck. Common but less specific features of the disease include headache, fever, chills, and weakness. The bubonic plague is caused by bacteria called Yersinia pestis. The bacteria are transmitted from infected rats to the oriental rat flea to people. The rats are a “reservoir” for the disease. The fleas are the “vectors” that carry the bacteria from the rat reservoir to the human host.
The Black Death, or the Black Plague, named for the color of flesh infected by Yersinia pestis, was one of the most deadly pandemics in human history. It probably began in Central Asia and spread to Europe by the late 1340s. The number of deaths worldwide is estimated at 75 million people; there were as many as 50 million deaths in Europe. The Black Death is estimated to have killed 60% of Europe’s population. The same disease is thought to have returned to Europe every generation with varying strength until the 1700s. During this period, more than 100 plague epidemics swept across Europe. For example, In 1603 the plague killed 38,000 Londoners. The 14th century eruption of the Black Death changed Europe’s social structure. It was a serious blow to the Roman Catholic Church and resulted in persecution of minorities such as Jews, foreigners, beggars, and lepers. The uncertainty of daily survival created a general mood of morbidity, influencing people to “live for the moment.”
Yersinia pestis is endemic in the rat / flea populations of New Mexico, Arizona, and Colorado. There is no way to completely eradicate it. On November 1, 2002, a married couple traveled from Santa Fe County, New Mexico, to New York City where they both became ill with fever and bubonic plague was diagnosed. Each year around 15 people are infected with plague in the U.S. and usually one of them dies.