Diagnostic Findings [Last Modified: ]
[Babesia divergens] [Babesia microti]
Causal Agent Life Cycle Geographic Distribution Clinical Features Laboratory Diagnosis Treatment

Microscopy

Babesia parasites resemble Plasmodium falciparum, however Babesia has several distinguishing features: the parasites are pleomorphic (vary in shape and size), can be vacuolated, and do not produce pigment.

Babesia sp. in thick blood smear Babesia sp. in thick blood smear
A B

A, B: Babesia sp. in thick blood smears stained with Giemsa.

Babesia sp. Babesia sp., tetrad forms
C D

C, D: Babesia sp. in a thin blood smear stained with Giemsa.  Note the tetrad, a dividing form pathognomonic for Babesia, in D.

Babesia sp. in a thin blood smear, extracellular forms Babesia sp. in a thin blood smear, extracellular forms
E F

E, F: Babesia sp. in a thin blood smear stained with Giemsa.  Note the clumped extracellular forms indicative of Babesia in E.  F also has extracellular forms as well as intra-erythrocytic forms, one of which is vacuolated.

Babesia microti in a thin blood smear
G

G: Babesia microti in a thin blood smear stained with Giemsa.  Note the intra-erythrocytic vacuolated forms in G (black arrows).

 
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