Fascioliasis — DTM&H MCQ

Correct answer: D — Triclabendazole

The correct answer is D, Triclabendazole. This woman has acute fascioliasis (Fasciola hepatica), acquired from ingesting metacercariae on wild watercress, presenting with fever, right upper quadrant pain, marked eosinophilia and migratory hepatic lesions during the parenchymal (hepatic migration) phase, before adult flukes reach the biliary tree and start shedding eggs, which explains the negative stool ova at this stage. Triclabendazole is active against both immature migrating flukes and adult biliary flukes, given as a single or split oral dose, making it the only agent effective in this pre-patent phase. This benzimidazole derivative is recognised as the treatment of choice for fascioliasis at all stages of infection. Why the other options are wrong: B. Praziquantel: effective against most other flukes (Schistosoma, Clonorchis, Paragonimus) but Fasciola hepatica has an unusual tegument that renders it inherently resistant to praziquantel, so it fails clinically. E. Albendazole: a benzimidazole used for soil transmitted helminths and some tissue nematodes (eg hydatid, neurocysticercosis) but has no reliable activity against Fasciola flukes. A. Metronidazole: targets protozoa and anaerobic bacteria (eg amoebic liver abscess, giardiasis) and has no anthelmintic activity against trematodes. C. Ceftriaxone: a cephalosporin antibiotic with no role in parasitic fluke infection; it would be considered only if a bacterial hepatic abscess were suspected, which the eosinophilia and exposure history argue against. Key point: marked eosinophilia plus migratory hepatic lesions after eating watercress, with stool ova absent, points to acute hepatic phase fascioliasis, treated with triclabendazole regardless of praziquantel's usual fluke efficacy.

Reference: WHO, Report of the WHO Informal Meeting on use of triclabendazole in fascioliasis control, 2007: triclabendazole is the treatment of choice for fascioliasis, effective against both migrating immature flukes and adult flukes in the bile ducts. https://www.who.int/publications/i/item/WHO-CDS-NTD-PCT-2007.1