Fasciolopsiasis

Fasciolopsiasis is an intestinal infection caused by Fasciolopsis buski, the largest trematode fluke infecting humans, acquired by eating raw aquatic plants (water chestnut, water caltrop, lotus, bamboo shoots) contaminated with metacercariae.

• Endemic in South and Southeast Asia (China, India, Bangladesh, Thailand, Vietnam, Laos, Taiwan), mainly in rural communities where pigs share the water.
• Reservoir host: pigs. Snail intermediate hosts (Segmentina, Hippeutis).
• Heavy burdens cause illness; light infections are asymptomatic.

• Epigastric or abdominal pain, diarrhoea alternating with constipation, nausea, vomiting, and anorexia.
• Heavy infection: malabsorption, protein losing enteropathy, anaemia, facial and generalised oedema, ascites, and intestinal obstruction.
• Rarely death from exhaustion in the severely infected.
• Eosinophilia is modest; leucocytosis occurs.

• Stool microscopy for large operculated eggs (130 to 140 by 80 to 85 micrometres, indistinguishable from Fasciola eggs); concentration methods improve yield.
• Adult flukes are occasionally seen in stool or vomitus.
• Blood: eosinophilia, anaemia, hypoalbuminaemia.
• Exclude fascioliasis, echinostomiasis, giardiasis, and other intestinal helminthiasis; check serology for confirmation where needed.

• Praziquantel 25 mg/kg three times in one day (at 4 to 6 hour intervals), or 15 mg/kg as a single dose in mass campaigns; cure rate over 90%.
• Alternative: niclosamide 2 g single dose, albendazole 400 mg daily for 3 days (less effective), tetrachloroethylene.
• Supportive care: correction of anaemia and hypoalbuminaemia, nutritional support.
• Repeat stool tests at 2 to 4 weeks; re-treat if eggs persist.
• Prevention: boil or peel water plants, avoid use of night soil and pig manure in water plant cultivation, and health education.