Clinical Features:
During the acute phase (caused by the migration of the immature fluke through the hepatic parenchyma), manifestations include abdominal pain, hepatomegaly, fever, vomiting, diarrhea, urticaria and eosinophilia, and can last for months.  In the chronic phase (caused by the adult fluke within the bile ducts), the symptoms are more discrete and reflect intermittent biliary obstruction and inflammation.  Occasionally, ectopic locations of infection (such as intestinal wall, lungs, subcutaneous tissue, and pharyngeal mucosa) can occur.

Laboratory Diagnosis:
Microscopic identification of eggs is useful in the chronic (adult) stage.  Eggs can be recovered in the stools or in material obtained by duodenal or biliary drainage.  They are morphologically indistinguishable from those of Fasciolopsis buski.  False fascioliasis (pseudofascioliasis) refers to the presence of eggs in the stool resulting not from an actual infection but from recent ingestion of infected livers containing eggs.  This situation (with its potential for misdiagnosis) can be avoided by having the patient follow a liver-free diet several days before a repeat stool examination.  Antibody detection tests are useful especially in the early invasive stages, when the eggs are not yet apparent in the stools, or in ectopic fascioliasis.

Diagnostic findings

• Microscopy
• Antibody detection
• Morphologic comparison with other intestinal parasites.

Treatment:
Unlike infections with other flukes, Fasciola hepatica infections may not respond to praziquantel.  The drug of choice is triclabendazole with bithionol as an alternative.  For additional information, see the recommendations in The Medical Letter (Drugs for Parasitic Infections).