Mycology/Parasitology USMLE Step 1 Practice Question
A 28-year-old male returns from rural Brazil with unilateral periorbital edema (Romana sign), fever (38.5°C), tachycardia (102 bpm), and generalized lymphadenopathy. Thin blood smear reveals C-shaped trypomastigotes with prominent kinetoplasts. Serology is positive for anti-Trypanosoma cruzi antibodies. He denies recent insect bites. Which of the following best describes the chronic phase pathophysiology of this infection?
Answer choices
- AToxic metabolite accumulation from persistent parasitemia
- BAutoimmune destruction of myocardium and colon due to molecular mimicryCorrect answer
- CParasitic destruction of autonomic nerve ganglia in the myenteric plexus
- DImmune complex deposition in cardiac tissue leading to inflammation
- EDirect parasitic invasion causing fibrosis of cardiac myocytes
- FPersistent intracellular parasitic replication within cardiomyocytes causing progressive myocyte necrosis
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