Bubonic Plague Cause
Bubonic plague is caused by a bacterium called Yersinia pestis. Once inside the body, Yersinia pestis travels to the lymph nodes and begins to multiply. This eventually causes the symptoms of bubonic plague, usually within two to six days. Approximately 10 to 20 people in the United States develop Yersinia pestis infections each year from flea or rodent bites.
These bacteria are found mainly in rodents, particularly rats, and in the fleas that feed on them. Other animals known to carry Yersinia pestis include mice, fleas, lice, and prairie dogs.
(Click Causes of Bubonic Plague for more detailed information on bubonic plague and the bacterium that causes it.)