🦠microbiology review

Babesiosis

Written by the Fiveable Content Team • Last updated September 2025
Written by the Fiveable Content Team • Last updated September 2025

Definition

Babesiosis is a parasitic infection of the red blood cells caused by protozoa of the genus Babesia, commonly transmitted through tick bites. It primarily affects the circulatory system and can result in hemolytic anemia.

5 Must Know Facts For Your Next Test

  1. Babesiosis is primarily transmitted by Ixodes scapularis ticks, which are also vectors for Lyme disease.
  2. The most common species causing human babesiosis in the United States is Babesia microti.
  3. Symptoms include fever, chills, sweats, fatigue, and hemolytic anemia; severe cases can be life-threatening.
  4. Diagnosis often involves blood smear microscopy to identify parasites within red blood cells or PCR testing for Babesia DNA.
  5. Treatment typically includes a combination of atovaquone and azithromycin or clindamycin and quinine.

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