Encyclopedia of Parasitology

2016 Edition
| Editors: Heinz Mehlhorn

Opisthorchiasis, Man

Reference work entry
DOI: https://doi.org/10.1007/978-3-662-43978-4_2229
 Clonorchiasis, an infection with the Chinese liver fluke, and Opisthorchiasis, an infection with any of several  Opisthorchis spp. are bile duct infections after ingestion of undercooked fish or crustaceans containing the metacercariae. Luminal infections of the bile duct with a small parasite burden may be asymptomatic ( Pathology, Fig. 22b). The worms are attached to the wall of the bile ducts with their 2 suckers giving rise to local inflammation. Large numbers of parasites may introduce heavy biliary obstruction, with resultant jaundice and secondary infection leading to cholangiohepatitis, liver abscesses, cholecystitis, and pancreatitis. The worms survive for 20 years or longer, accompanied by adenomatous  hyperplasia of the bile ducts, increased mucus production, and sometimes adenocholangiocarcinoma, usually mucin-producing. In the pancreatic ducts both squamous metaplasia and adenomatous hyperplasia may occur. Eggs pass out of the bile duct and are found in the stools.
  • Main clinical symptoms:  Abdominal pain,  oedema,  diarrhoea, icterus.

  • Incubation period: 2 weeks.

  • Prepatent period: 2–4 weeks.

  • Patent period: 20 years.

  • Diagnosis: Microscopic determination of eggs in faecal samples or PCR – marker for coproscopic analyses.

  • Prophylaxis: Avoid eating raw freshwater fish in endemic regions.

  • Therapy: Treatment: praziquantel, see  Trematodocidal Drugs.

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© Springer-Verlag Berlin Heidelberg 2016