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Table 3 Comparison between P. knowlesi and P. malariae parasites in human infections

From: Morphological features and differential counts of Plasmodium knowles i parasites in naturally acquired human infections

  P. malariae* P. knowlesi
Size Not enlarged Not enlarged
Shape Rounded, not distorted Rounded, generally not distorted
Stippling Ziemen's stippling under certain staining conditions Irregular dots or stippling in some erythrocytes with mature trophozoites, schizonts and gametocytes
Early trophozoite (ring form) Ring form with dense cytoplasm and single chromatin; sometimes with accessory dot Ring forms are compact with dense cytoplasm; single or double chromatin and rarely triple chromatin; appliqué forms; multiple parasites in single erythrocyte
Late trophozoite Regular and compact cytoplasm; appearance of pigment Dense and thick cytoplasm; Cytoplasm slightly amoeboid and irregular; band forms; varying pigmentation
Mature trophozoite Compact, rounded, heavily pigmented; band forms; not amoeboid Compact and dense cytoplasm, rounded shape with dark brown pigment; band forms; not amoeboid
Schizont Occupies whole erythrocyte, contains 6–12 merozoites, usually 8; merozoites clustered around dark-brown malaria pigment forming rosette pattern Occupies whole erythrocyte; contains up to 16 merozoites; merozoites irregularly scattered or grape-like cluster; malaria pigment scattered or collects into a single mass
Gametocyte Round, compact, occupies whole erythrocyte, scattered malaria pigment; early forms are very similar to mature trophozoites Round, compact, fills whole erythrocyte, scattered or clumped malaria pigment; early forms are very similar to mature trophozoites
  1. *Based on descriptions by Garnham [1], Coatney et al [16] and Warrell & Gilles [12].