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 abdominal pain, cholelithiasis, cholangitis, obstructive jaundice, or pancreatitis. Heavy infection can cause sclerosing cholangitis and biliary cirrhosis. Ectopic lesions may occur in the intestinal wall, lungs, or other organs. Pharyngeal fascioliasis has been reported after consumption of infected raw liver in the Middle East.
CT frequently shows hypodense lesions in the liver during the acute stage of infection. Ultrasonography, CT. MRI, ERCP, or cholangiography can detect biliary tract abnormalities in chronic disease. Antibody detection assays are useful in the early stages of infection before eggs are produced. In chronic infections, eggs may be recovered from the stool or from duodenal or biliary materials. The eggs are indistinguishable from those of Fasciolopsis buski.
Treatment is with triclabendazole (10 mg/kg po once after meals or, for severe infections, twice 12 h apart); it is available from the Centers for Disease Control and Prevention (CDC) as an investigational drug. Alternatives include nitazoxanide 500 mg bid po for 7 days and bithionol 30 to 50 mg/kg po every other day for 10 to 15 doses. Treatment failures are common with praziquantel.
Last full review/revision July 2013 by Richard D. Pearson, MD
Content last modified October 2013