Fascioliasis is infection with the liver fluke Fasciola hepatica, which is acquired by eating contaminated watercress or other water plants.
Flukes are parasitic flatworms that infect various parts of the body (eg, blood vessels, GI tract, lungs, liver) depending on the species.
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
Loss of detectable antibodies occurs 6 to12 mo after cure.
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. In endemic areas, eggs can also be seen in stool after ingestion of infected animal livers. Thus, patients should asked to follow a liver-free diet for several days before their stool is examined.
Treatment of fascioliasis is with triclabendazole (10 mg/kg po once after meals or, for severe infections, twice 12 to 24 h apart); it is available from the Centers for Disease Control and Prevention (CDC) as an investigational drug. An alternative is nitazoxanide 500 mg bid po for 7 days.
Treatment failures are common with praziquantel.