Fascioliasis is infection with the liver fluke Fasciola hepatica, which is acquired by eating contaminated watercress or other water plants.
F. hepatica is the sheep and cattle liver fluke. Incidental human fascioliasis, acquired by eating watercress contaminated by sheep or cattle dung, occurs in Europe, Africa, China, and South America but is rare in the US.
In acute infection, immature flukes migrate through the intestinal wall, the peritoneal cavity, the liver capsule, and the parenchyma of the liver before entering the biliary ducts where they mature to adulthood in about 3 to 4 mo.
Acute infection causes abdominal pain, hepatomegaly, nausea, vomiting, intermittent fever, urticaria, eosinophilia, malaise, and weight loss due to liver damage. Chronic infection may be asymptomatic or lead to intermittent biliary tract obstruction. Ectopic lesions may occur in the intestinal wall, lungs, or other organs.
CT frequently shows hypodense lesions in the liver. Antibody detection assays are useful in the early stages of disease. Eggs may be recovered in the stool or, during chronic infection, in duodenal or biliary materials.
Treatment is with triclabendazole (10 mg/kg po once or twice) where it is available. Alternatively, nitazoxanide 500 mg bid po for 7 days or bithionol 30 to 50 mg/kg po every other day for 10 to 15 doses may be used. Treatment failures are common with praziquantel.
Last full review/revision December 2009 by Richard D. Pearson, MD