Overview
Plague is an infectious disease caused by bacteria called Yersinia pestis. These bacteria are found mainly in rodents, particularly rats, and in the fleas that feed on them. Other animals and humans usually contract the bacteria from rodent or flea bites.
Historically, plague destroyed entire civilizations. In the 1300s, the "Black Death," as it was called, killed approximately one-third (20 to 30 million) of Europe's population. In the mid-1800s, it killed 12 million people in China. Today, thanks to better living conditions, antibiotics, and improved sanitation, current World Health Organization statistics show there were only 2,118 cases in 2003 worldwide.
Approximately 10 to 20 people in the United States develop plague each year from flea or rodent bites-primarily from infected prairie dogs-in rural areas of the southwestern United States. About 1 in 7 of those infected die from the disease. There has not been a case of person-to-person infection in the United States since 1924.
Worldwide, there have been small plague outbreaks in Asia, Africa, and South America.
Transmission
Y. pestis is found in animals throughout the world, most commonly in rats but occasionally in other wild animals, such as prairie dogs. Most cases of human plague are caused by bites of infected animals or the infected fleas that feed on them. In almost all cases, only the pneumonic form of plague can be passed from person to person.
Diagnosis
A health care provider can diagnose plague by doing laboratory tests on blood or sputum, or on fluid from a lymph node.
Treatment
When plague is suspected and diagnosed early, a health care provider can prescribe specific antibiotics (generally streptomycin or gentamycin). Certain other antibiotics are also effective.
Left untreated, bubonic plague bacteria can quickly multiply in the bloodstream, causing septicemic plague, or even progress to the lungs, causing pneumonic plague.
Prevention
Antibiotics
Health experts recommend antibiotics if you have been exposed to wild rodent fleas during a plague outbreak in animals, or to a possible plague-infected animal. Because there are so few cases of plague in the United States, experts do not recommend taking antibiotics unless it's certain a person has been exposed to plague-infected fleas or animals.
Vaccine
Currently, there is no commercially available vaccine against plague in the United States.
|