Which malaria parasite typically has ameboid trophozoites and Schuffner's dots in infected red blood cells?

Which malaria parasite typically has ameboid trophozoites and Schuffner's dots in infected red blood cells?

• A. Plasmodium knowlesi
• B. Plasmodium falciparum
• C. Plasmodium malariae
• D. Plasmodium vivax

Answer: (D)

This question tests how parasite forms in red blood cells help identify the species. The combination of ameboid-looking trophozoites and Schuffner's dots (fine stippling in the RBC cytoplasm) is a classic clue for Plasmodium vivax. In P. vivax infections, RBCs are enlarged and the trophozoites take on irregular, amoeboid shapes, while the cytoplasm shows Schuffner's dots on staining. Other malaria species don’t typically show this pattern: P. falciparum usually has small, delicate ring forms and does not display Schuffner's dots; P. malariae has band-shaped trophozoites and a different staining appearance; P. knowlesi can mimic other species but the described combination is most characteristic of P. vivax.

This question tests how parasite forms in red blood cells help identify the species. The combination of ameboid-looking trophozoites and Schuffner's dots (fine stippling in the RBC cytoplasm) is a classic clue for Plasmodium vivax. In P. vivax infections, RBCs are enlarged and the trophozoites take on irregular, amoeboid shapes, while the cytoplasm shows Schuffner's dots on staining.

Other malaria species don’t typically show this pattern: P. falciparum usually has small, delicate ring forms and does not display Schuffner's dots; P. malariae has band-shaped trophozoites and a different staining appearance; P. knowlesi can mimic other species but the described combination is most characteristic of P. vivax.