Bubonic plague

Bubonic plague is a bacterial disease caused by the bacterium Yersinia pestis. Bubonic plagues kills two thirds of all people who are infected. It is widely believed that bubonic plague was the cause of 'Black Death'; a plague that killed more than 25 million people in the 1300s.

Bubonic plague is transmitted through the bite of an infected flea. Commonly these fleas are ectoparasites of rats but, should the host die, they will look for other mammals on which to feed. The bacteria inhabit the flea's gut and when it feeds the bacteria are regurgitated in to the body of the animal the flea is feeding on. Once in the body the bacteria move to the lymph nodes and multiply.

A scanning electron micrograph of the bacterium Yersinia pestis. This bacteria casues bubonic plague.
Photograph by the United States Federal Government.

Other names for (or types of) Bubonic plague include:

• Black death

Related terms

• Ectoparasite
• Endoparasite
• Parasite
• Siphonaptera
• Vector

Related groups of terms

• General biology

Related pages on this web site

• Fleas - Order Siphonaptera

See other words beginning with B