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

Mature macrogametocytes of P. knowlesi are usually spherical and fill the host RBC.  The cytoplasm stains blue and the eccentric nucleus stains red.  Pigment is coarse and black, and is scattered irregularly in the cytoplasm.  The microgametocyte is often, but not always, smaller than the macrogametocyte.  The cytoplasm usually stains a pale pink, while the nucleus stains a darker red.  The nucleus may make up half the parasite. Coarse, black pigment is scattered irregularly thought the cytoplasm.

Plasmodium knowlesi gametocytes

A

A: Gametocytes of P. knowlesi.  Fig. 24: Mature macrogametocyte (female); Fig. 25: Mature microgametocyte (male).
Illustrations from: Coatney GR, Collins WE, Warren M, Contacos PG. The Primate Malarias. Bethesda: U.S. Department of Health, Education and Welfare; 1971.

Plasmodium knowlesi gametocytes in thin blood smear Plasmodium knowlesi gametocytes in thin blood smear
B C

B, C: Gametocytes of P. knowlesi in a thin blood smear from a human patient that traveled to the Philippines.  Note also a ring-form trophozoite in the lower left of Figure C.  Images courtesy of the Wadsworth Center, New York State Department of Health.

 
Back Top