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

Plasmodium ovale: Ring Stage Parasites

P. ovale ring stage

Fig. 1: Normal red cell; Figs. 2-5: Ring stage parasites.
Illustrations from: Coatney GR, Collins WE, Warren M, Contacos PG. The Primate Malarias. Bethesda: U.S. Department of Health, Education and Welfare; 1971.

Smears from patients:

Plasmodium ovale rings have sturdy cytoplasm and large chromatin dots.  Red blood cells (RBCs) are normal to slightly enlarged (1 1/4×), may be round to oval, and are sometimes fimbriated.  Schüffner's dots are visible under optimal conditions.

P. ovale ring - thin smear P. ovale ring - thin smear
A B

A, B: P. ovale rings in thin blood smears.  A shows fimbriation of the infected RBC.  B shows Schüffner's dots.

P. ovale ring - thick smear P. ovale ring - thick smear
C D

C, D: Rings of P. ovale in thick blood smears.
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