Table 3 Comparison between P. knowlesi and P. malariae parasites in human infections
P. malariae* | P. knowlesi | |
|---|---|---|
HOST ERYTHROCYTE | ||
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 |
PARASITE | ||
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 |