Yersinia pestis infection overview
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Assistant Editors-In-Chief: Esther Lee, M.A.
Overview
Yersinia pestis infection is an infectious disease of animals and humans caused by a bacterium named Yersinia pestis. Human yersinia pestis infection takes three main forms: pneumonic, septicemic, and the notorious bubonic plagues.All three forms are widely believed to have been responsible for a number of high-mortality epidemics throughout human history, including the Plague of Justinian in 542 and the black death that accounted for the death of at least one-third of the European population between 1347 and 1353. It has now been shown conclusively that these plagues originated in rodent populations in China.
Historical Perspective
It is suggested that yersinia pestis infection was a contributing factor in some of (though possibly not all) the European plagues. The earliest account describing a possible plague epidemic is found in I Samuel 5:6 of the Hebrew Bible (Tanakh). In this account, the Philistines of Ashdod were stricken with a plague for the crime of stealing the Ark of the Covenant from the Children of Israel. These events have been dated to approximately the second half of the 11th century BC.
Pathophysiology
A person can get plague from flea bites or another individual when the other person has plague pneumonia and coughs droplets containing the plague bacteria into air that is breathed by a non-infected person.
Causes
Yersinia pestis, a rod-shaped facultative anaerobe with bipolar staining (giving it a safety pin appearance)[1] causes the infection in mammals and humans.
Risk Factors
Outbreaks in people occur in areas where housing and sanitation conditions are poor. These outbreaks can occur in rural communities or in cities. They are usually associated with infected rats and rat fleas that live in the home.
Natural History, Complications and Prognosis
If plague patients are not given specific antibiotic therapy, the disease can progress rapidly to death. About 14% (1 in 7) of all plague cases in the United States are fatal.
Diagnosis
History and Symptoms
The typical sign of the most common form of human plague is a swollen and very tender lymph gland, accompanied by pain. The swollen gland is called a "bubo." Bubonic plague should be suspected when a person develops a swollen gland, fever, chills, headache, and extreme exhaustion, and has a history of possible exposure to infected rodents, rabbits, or fleas. A person usually becomes ill with bubonic plague 2 to 6 days after being infected.
Treatment
Medical Therapy
According to treatment experts, a patient diagnosed with suspected plague should be hospitalized and medically isolated. Laboratory tests should be done, including blood cultures for plague bacteria and microscopic examination of lymph gland, blood, and sputum samples. Antibiotic treatment should begin as soon as possible after laboratory specimens are taken. Effective antibiotics are streptomycin, gentamicin (Used when streptomycin is not available), tetracyclines and chloramphenicol. (Used for critically ill patients, or rarely for suspected neuro-involvement)
Primary Prevention
A plague vaccine is not currently available for use in the United States. Preventive measures are directed to home, work, and recreational settings where the risk of acquiring plague is high.
References
- ↑ Collins FM (1996). Pasteurella, Yersinia, and Francisella. In: Baron's Medical Microbiology (Baron S et al, eds.) (4th ed.). Univ. of Texas Medical Branch. ISBN 0-9631172-1-1.