Question:hard
A 15-year-old boy presented with fever and chills for 3 days. On examination he had a delayed skin pinch time and dry oral mucosa. A peripheral blood smear revealed the following picture. Identify the pathogen involved.
A 15-year-old boy presented with fever and chills for 3 days. On examination he had a delayed skin pinch time and dry oral mucosa. A peripheral blood smear revealed the following picture. Identify the pathogen involved.
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Banana-shaped gametocytes and several delicate rings in one red cell point to one species.
Updated On: Jun 23, 2026
- Babesia
- Plasmodium vivax
- Plasmodium falciparum
- Salmonella typhi
Show Solution
The Correct Option is C
Solution and Explanation
Read the smear like a checklist. Banana or crescent gametocytes, fine ring forms only one-sixth the cell size, double-chromatin headphone rings, two or more parasites crammed into one normal-sized red cell, and applique rings sitting on the cell edge all spell Plasmodium falciparum.
Important key note: the crowd-recall answer says B, but the same recall text names falciparum and the morphology it describes is purely falciparum. Since falciparum is listed as option C here, the medically correct choice is C, not B.
Elimination: P. vivax enlarges the red cell, stipples it with Schuffner dots and forms big amoeboid trophozoites, none of which is shown. Babesia produces a tetrad Maltese cross and never makes gametocytes or malarial pigment. Salmonella typhi is a blood-culture organism and is invisible on a Giemsa malaria film. The dehydration (delayed skin pinch, dry mucosa) is just from the febrile illness. Ref: Paniker's Textbook of Medical Parasitology, 8e, p.73; Jawetz Medical Microbiology, 27e, p.721.
Important key note: the crowd-recall answer says B, but the same recall text names falciparum and the morphology it describes is purely falciparum. Since falciparum is listed as option C here, the medically correct choice is C, not B.
Elimination: P. vivax enlarges the red cell, stipples it with Schuffner dots and forms big amoeboid trophozoites, none of which is shown. Babesia produces a tetrad Maltese cross and never makes gametocytes or malarial pigment. Salmonella typhi is a blood-culture organism and is invisible on a Giemsa malaria film. The dehydration (delayed skin pinch, dry mucosa) is just from the febrile illness. Ref: Paniker's Textbook of Medical Parasitology, 8e, p.73; Jawetz Medical Microbiology, 27e, p.721.
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