Fascioliasis — DTM&H MCQ

Correct answer: D — Triclabendazole

The correct answer is D, Triclabendazole. This patient has fascioliasis (liver fluke infection), suggested by the classic combination of ingestion of wild watercress (the main vehicle for metacercariae in endemic Andean regions), right upper quadrant pain with biliary tract inflammation on ultrasound, marked eosinophilia, and positive Fasciola serology. Triclabendazole is a benzimidazole derivative that is highly active against both immature and adult Fasciola flukes in the liver parenchyma and biliary tree, disrupting the fluke tegument and microtubular function. It is given as a single or split oral dose of 10 mg/kg with food, and remains the only drug with reliably high cure rates in both acute (hepatic/migratory) and chronic (biliary) phases of infection. Why the other options are wrong: C. Metronidazole: this is an antiprotozoal/antianaerobic agent with no activity against trematodes such as Fasciola, so it does not clear the infection despite sometimes being trialled empirically for presumed cholangitis. A. Ceftriaxone alone: this targets bacterial biliary sepsis but has no anthelminthic activity, and the eosinophilia and serology here point to a parasitic, not primarily bacterial, cause. E. Praziquantel: although first-line for schistosomiasis and most other trematodes, Fasciola hepatica is intrinsically resistant to praziquantel because of differences in tegumental drug uptake, so it is ineffective in fascioliasis. B. Albendazole for 3 days: albendazole is a broad-spectrum benzimidazole used for soil-transmitted helminths and some tissue nematodes, but it lacks efficacy against Fasciola and is not a recommended regimen for this fluke. Key point: Praziquantel is the trematocide of choice for most flukes and schistosomes, but Fasciola hepatica is an exception that requires triclabendazole.

Reference: WHO/Oxford Academic (Transactions of the Royal Society of Tropical Medicine and Hygiene): Triclabendazole in the treatment of human fascioliasis: a review, 2019, https://academic.oup.com/trstmh/article/113/12/797/5602280