Fascioliasis

Fascioliasis is a zoonotic liver fluke infection caused by Fasciola hepatica (worldwide) and Fasciola gigantica (Africa, Asia).

• Humans acquire infection by eating freshwater plants (watercress, water caltrop) or drinking water contaminated with metacercariae. Sheep, cattle, and other ruminants are reservoirs.
• Endemic regions: Bolivia and the Andes, Egypt, Iran, Vietnam, and parts of East Africa and Europe; estimated 2.4 to 17 million infected.
• Phases: acute (migratory) and chronic (biliary).

• Acute (1 to 3 months after infection): fever, right upper quadrant pain, hepatomegaly, urticaria, and marked eosinophilia due to larval migration through the liver.
• Chronic (months to years): intermittent biliary colic, cholangitis, cholecystitis, obstructive jaundice, pancreatitis, and anaemia.
• Ectopic fascioliasis: subcutaneous nodules, and abdominal or pulmonary involvement.
• Halzoun (pharyngeal fascioliasis) with ingestion of raw liver.

• Stool microscopy for eggs (after 3 to 4 months; repeat samples needed; eggs are large and operculate).
• Serology (ELISA, immunoblot) in the acute phase, when eggs are not yet shed.
• Eosinophilia, raised liver enzymes (cholestatic pattern), and anaemia.
• Imaging: CT or MRI shows hypodense tracks or subcapsular lesions in the acute phase; ultrasound, ERCP, or MRCP shows biliary dilatation or flukes in the biliary tree.
• Exclude hepatic abscess, hydatid disease, clonorchiasis, opisthorchiasis, cholangiocarcinoma, and viral hepatitis.

• Triclabendazole 10 mg/kg orally as a single dose with food (repeat after 12 to 24 hours, total 20 mg/kg, for severe or relapsed infection); active against both immature and adult flukes.
• Alternative: nitazoxanide 500 mg twice daily for 7 days (adults; children 100 to 200 mg twice daily); bithionol 30 to 50 mg/kg on alternate days for 10 to 15 doses.
• Praziquantel, albendazole, and mebendazole are ineffective.
• Biliary obstruction: ERCP with extraction of worms and sphincterotomy; antibiotics for cholangitis.
• Follow up stool examination at 1 and 3 months; treatment failures are increasingly reported (resistance).
• Prevention: avoid raw aquatic plants, treat drinking water, livestock deworming, and mass preventive chemotherapy in endemic communities.