83: Opisthorchiasis

Classification: ICD-9 121.0; ICD-10 B66.0

Syndromes and synonyms: Cat liver fluke disease, food-borne trematodiasis

Agent: Small (6–18 mm long) trematode liver fluke of dogs, cats, and some other fish-eating mammals: Opisthorchis felineus in Europe and northern Asia, O. viverrini in Southeast Asia. Both species live in bile ducts.

Reservoir: Humans and fish-eating mammals.

Vector: Freshwater snails (Bithynia spp.).

Transmission: Consumption of raw, undercooked, dried, salted, or pickled freshwater fish. There is no direct person-to-person transmission.

Cycle: Eggs excreted by the mammalian host in the feces into freshwater are ingested by the snail vector. They hatch and in 2 months pass through various stages in the snail to produce motile cercariae, which leave the snail and penetrate freshwater fish. In 6 weeks the cercariae encyst, and when the fish is eaten by another mammalian host, they exit the cyst and penetrate the bile duct, where in a month they mature into adult worms and start to produce eggs.

Incubation period

Only gold members can continue reading. Log In or Register to continue