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

Comparison of Plasmodium Species Which Cause Malaria in Humans

Plasmodium species Stages found in blood Appearance of Erythrocyte (RBC) Appearance of Parasite
P. falciparum

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Ring

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normal; multiple infection of RBC more common than in other species; Maurer's clefts (under certain staining conditions) delicate cytoplasm; 1 to 2 small chromatin dots; occasional appliqué (accolé) forms
Trophozoite

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normal; rarely, Maurer's clefts (under certain staining conditions) seldom seen in peripheral blood; compact cytoplasm; dark pigment
Schizont

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normal; rarely, Maurer's clefts (under certain staining conditions) seldom seen in peripheral blood; mature = 8 to 24 small merozoites; dark pigment, clumped in one mass
Gametocyte

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distorted by parasite crescent or sausage shape; chromatin in a single mass (macrogametocyte) or diffuse (microgametocyte); dark pigment mass
P. vivax

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Ring

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normal to 1.25×, round; occasionally fine Schüffner's dots; multiple infection of RBC not uncommon large cytoplasm with occasional pseudopods; large chromatin dot
Trophozoite

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enlarged 1.5 to 2×; may be distorted; fine Schüffner's dots large amoeboid cytoplasm; large chromatin; fine, yellowish-brown pigment
Schizont

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enlarged 1.5 to
2×; may be distorted; fine Schüffner's dots
large, may almost fill RBC; mature = 12 to 24 merozoites; yellowish-brown, coalesced pigment
Gametocyte

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enlarged 1.5 to 2×; may be distorted; fine Schüffner's dots round to oval; compact; may almost fill RBC; chromatin compact, eccentric (macrogametocyte) or diffuse (microgametocyte); scattered brown pigment
P. ovale

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Ring

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normal to 1.25×, round to oval; occasionally Schüffner's dots; occasionally fimbriated; multiple infection of RBC not uncommon sturdy cytoplasm; large chromatin
Trophozoite

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normal to 1.25×; round to oval; some fimbriated; Schüffner's dots compact with large chromatin; dark-brown pigment
Schizont

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normal to 1.25×, round to oval, some fimbriated, Schüffner's dots mature = 6 to 14 merozoites with large nuclei, clustered around mass of dark-brown pigment
Gametocyte

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normal to 1.25×; round to oval, some fimbriated; Schüffner's dots round to oval; compact; may almost fill RBC; chromatin compact, eccentric (macrogametocyte) or more diffuse (microgametocyte); scattered brown pigment
P. malariae

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Ring

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normal to 0.75× sturdy cytoplasm; large chromatin
Trophozoite

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normal to 0.75×; rarely, Ziemann's stippling (under certain staining conditions) compact cytoplasm; large chromatin; occasional band forms; coarse, dark-brown pigment
Schizont

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normal to 0.75×; rarely, Ziemann's stippling (under certain staining conditions) mature = 6 to 12 merozoites with large nuclei, clustered around mass of coarse, dark-brown pigment; occasional rosettes
Gametocyte

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normal to 0.75×; rarely, Ziemann's stippling (under certain staining conditions) round to oval; compact; may almost fill RBC; chromatin compact, eccentric (macrogametocyte) or more diffuse (microgametocyte); scattered brown pigment
P. knowlesi

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Ring

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normal to 0.75×; multiple infection not uncommon. delicate cytoplasm; 1 to 2 prominent chromatin dots; occasional appliqué (accolé) forms
Trophozoite

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normal to 0.75×; rarely, Sinton and Mulligan's stippling (under certain staining conditions) compact cytoplasm; large chromatin; occasional band forms; coarse, dark-brown pigment
Schizont

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normal to 0.75×; rarely, Sinton and Mulligan's stippling (under certain staining conditions) mature = up to 16 merozoites with large nuclei, clustered around mass of coarse, dark-brown pigment; occasional rosettes; mature merozoites appear segmented
Gametocyte

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normal to 0.75×; rarely, Sinton and Mulligan's stippling (under certain staining conditions) round to oval; compact; may almost fill RBC; chromatin compact, eccentric (macrogametocyte) or more diffuse (microgametocyte); scattered brown pigment

 

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