Diagnostic Findings [Last Modified: ]
Malaria
[Plasmodium falciparum] [Plasmodium knowlesi] [Plasmodium malariae] [Plasmodium ovale] [Plasmodium vivax]
Causal Agent Life Cycle Geographic Distribution Clinical Features Laboratory Diagnosis Treatment

Developing trophozoites of P. vivax become increasingly amoeboid, with tenuous pseudopodial processes and large vacuoles.  Schüffner's dots are visible with proper staining.  Pigment tends to be fine and brown.  Infected RBCs are usually noticeably larger than uninfected RBCs.

Plasmodium vivax trophozoites

A

A: Trophozoites of P. vivax in thin blood smears.  Figs. 8-18: Increasingly mature trophozoites of P. vivax.
Illustrations from: Coatney GR, Collins WE, Warren M, Contacos PG. The Primate Malarias. Bethesda: U.S. Department of Health, Education and Welfare; 1971.

Plasmodium vivax trophozoite in thick blood smear Plasmodium vivax trophozoite in thin blood smear
B C

B: Trophozoite of P. vivax in a thick blood smear.
C: Trophozoite of P. vivax in a thin blood smear.  Note the amoeboid appearance, enlarged infected RBC and Schüffner's dots.

Plasmodium vivax trophozoites in thin blood smear Plasmodium vivax trophozoite in thin blood smear
D E

D, E: Trophozoites of P. vivax in a thin blood smear.  Note the amoeboid appearance and Schüffner's dots.

Plasmodium vivax trophozoite in thin blood smear Plasmodium vivax trophozoite in thin blood smear
F G

F, G: Trophozoites of P. vivax in thin blood smears.

 
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