A Wright-stained blood smear may show a Maltese cross tetrad within red blood cells, indicating which parasite?

A Wright-stained blood smear may show a Maltese cross tetrad within red blood cells, indicating which parasite?

• A. Babesia sp.
• B. Plasmodium vivax
• C. Plasmodium falciparum
• D. Plasmodium malariae

Answer: (A)

The Maltese cross tetrad inside red blood cells on a Wright-stained smear is a hallmark of Babesia infection. Babesia parasites replicate inside erythrocytes and commonly arrange as four merozoites in a cross pattern, producing that Maltese cross appearance. This feature is not seen with malaria parasites, whose species produce different intraerythrocytic forms: Plasmodium vivax and P. ovale cause enlarged red cells with Schuffner’s dots; P. falciparum shows multiple delicate rings and sometimes banana-shaped gametocytes; P. malariae displays band-form trophozoites and rosette schizonts. So, the presence of the Maltese cross strongly points to Babesia rather than the Plasmodium species listed.

The Maltese cross tetrad inside red blood cells on a Wright-stained smear is a hallmark of Babesia infection. Babesia parasites replicate inside erythrocytes and commonly arrange as four merozoites in a cross pattern, producing that Maltese cross appearance. This feature is not seen with malaria parasites, whose species produce different intraerythrocytic forms: Plasmodium vivax and P. ovale cause enlarged red cells with Schuffner’s dots; P. falciparum shows multiple delicate rings and sometimes banana-shaped gametocytes; P. malariae displays band-form trophozoites and rosette schizonts. So, the presence of the Maltese cross strongly points to Babesia rather than the Plasmodium species listed.