Common name. Cattle liver fluke
Geographic distribution. Europe, Africa, Asia, Australia, South and Central America
Infection rate. Human infection is not common, but occurring worldwidely.
Life cycle. The adult worms live in the bile ducts of the final hosts. The eggs are passed into the environment with the feces. The miracidia hatch in freshwater and infect snails (first intermediate hosts). Stages of sporocyst, redia, and cercaria undergo in snails. Mature cercariae encyst on water vegitation, i.e., watercress to make metacercariae. The final hosts are infected by ingestion of undercooked aquatic vegetation or raw cattle liver. The important final hosts are cattle, sheeps and goats.
Morphology. Adult worms are large leaf-like, 20 to 30 mm in length. At the anterior end, distinct conical projection is observed. The ceca and testes are highly branched. The tegument contains spines. The eggs measure about 140 by 80 ㎛.
Pathology and clinical symptoms. The triad of fever, hepatomegaly, and eosinophilia in endemic area suggests fascioliasis. Symptoms and signs are associated with biliary obstruction and cholangitis. Acute epigastric pain, pruritus, and jaundice are common. Worms in human infections may be frequently found in ectopic foci.
Diagnosis. Detection of eggs in feces. Enzyme-linked immunosorbent assay (ELISA) are also used for diagnosis of ectopic fascioliasis. Radiologic techniques can provide indirect evidences of fascioliasis.
Prevention. Avoiding ingestion of raw watercress grown in endemic areas.
Egg of Fasciola hepatica, human case.
Transverse section of Fasciola hepatica.
Transverse section of Fasciola hepatica showing multiple intestinal lumen.