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Epidemiology and pathogenesis of babesiosis

Edouard G Vannier, PhD
Jeffrey A Gelfand, MD, FACP
Section Editor
Johanna Daily, MD, MSc
Deputy Editor
Elinor L Baron, MD, DTMH


Babesiosis is a zoonotic infectious disease caused by protozoa of the genus Babesia that invade and lyse red blood cells, causing hemolytic anemia in some cases. Most cases of human babesiosis are reported from the United States and Europe. The epidemiology of human babesiosis depends on the Babesia species, the density of vertebrate reservoirs and ticks, and the risk of exposure of humans to ticks. Babesia parasites also can be transmitted via blood transfusion and from mother to fetus.

The epidemiology and the pathogenesis of human babesiosis will be reviewed here. Clinical manifestations, diagnosis, treatment, and prevention of babesiosis are discussed separately. (See "Clinical manifestations, diagnosis, treatment, and prevention of babesiosis".)


Species characteristics — Babesia species have the following life cycle characteristics [1-4]:

Vertebrate host reservoirs

Transmission via tick bite


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Literature review current through: Aug 2017. | This topic last updated: Nov 05, 2015.
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