Fascioliasis — DTM&H MCQ

Correct answer: D — Triclabendazole

The correct answer is D, triclabendazole, because this vignette describes acute hepatic fascioliasis: fever, right upper quadrant pain, marked eosinophilia and migrating hepatic lesions following ingestion of wild watercress contaminated with Fasciola hepatica metacercariae. Watercress and other aquatic plants are the classic vehicle for human infection with this liver fluke, and the acute (hepatic/invasive) phase reflects larval migration through the liver parenchyma before the flukes reach the biliary tree. Current UK expert guidance for eosinophilia in returning travellers recommends triclabendazole (10 mg/kg/day for two days) as first line, with rapid clinical response and low rates of resistance in humans despite widespread resistance in livestock. No other agent listed has reliable activity against migrating or adult Fasciola flukes. Why the other options are wrong: B. Praziquantel: effective against most flukes (schistosomes, most other trematodes) but Fasciola hepatica has a thick tegument relatively resistant to praziquantel, so it is not used for fascioliasis. A. Chloroquine: an antimalarial with no activity against trematodes; irrelevant to a helminth causing eosinophilic hepatitis. E. Metronidazole: active against protozoa and anaerobic bacteria (eg amoebiasis, giardiasis) but has no anthelmintic activity against Fasciola. C. Ivermectin: effective against many nematodes and ectoparasites but has no efficacy against trematodes such as Fasciola hepatica. Key point: Watercress ingestion plus eosinophilia and migrating hepatic lesions signals acute fascioliasis, treated with triclabendazole, not praziquantel.

Reference: UK guidelines for the investigation and management of eosinophilia in returning travellers and migrants, Journal of Infection (ScienceDirect): recommends triclabendazole 10 mg/kg/day for 2 days for fascioliasis, with rapid response and rare human resistance. https://www.sciencedirect.com/science/article/pii/S0163445324002627