A splenectomised farmer from Assam presents with high fever and dark urine after working in cattle fields. Peripheral smear shows intraerythrocytic parasites, but unlike falciparum malaria there is no malarial pigment, and several erythrocytes contain tetrads of merozoites arranged in a Maltese cross pattern. The distinguishing feature that separates this organism from Plasmodium species is:
- A Formation of banana-shaped gametocytes in peripheral blood
- B Presence of Schuffner dots and 48-hour periodicity
- C Absence of hemozoin pigment formation and transmission by a hard tick rather than a mosquito ✓
- D Cytoadherence mediated by PfEMP1 binding to ICAM-1
Correct answer: C. Absence of hemozoin pigment formation and transmission by a hard tick rather than a mosquito
Explanation
Babesia species are intraerythrocytic protozoa transmitted by Ixodes ticks. The Maltese cross tetrad and absence of hemozoin pigment distinguish them from Plasmodium, which digests haemoglobin and deposits malarial pigment. Babesiosis occurs in splenectomised individuals and can be acquired transfusionally. Schuffner dots, banana-shaped gametocytes, and PfEMP1-mediated cytoadherence are all features of Plasmodium species and therefore exclude the other options.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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