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Clonorchis sinensis2
Liver flukes are Platyhelminthe parasites of the class Trematoda and order Opisthorchiata. Three species of liver flukes, Opisthorchis viverrini, Clonorchis sinensis, and Opisthorchis felineus, are involved in malignancy, particularly biliary cancer.
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Clonorchis sinensis2
Liver flukes generally reside in the bile ducts, hepatic ducts, pancreatic ducts, and gall bladder. Infection with liver flukes can lead to non-malignant conditions such as gallbladder or liver enlargement, presence of sludge, chronic inflammation and fibrosis of the bile ducts, and opisthorchiasis5. Chronic infection is also associated with greatly increased risk of cholangiocarcinoma, a normally rare cancer. While their primary host is humans, they have demonstrated the ability to additionally infect numerous other mammals.
Opisthorchis viverrini, Clonorchis sinensis, and Opisthorchis felineus are all endemic to different parts of Asia.
Geographic Distribution2
These liver flukes are hermaphroditic parasites with complex lifecycle involving two intermediate hosts (snails and fish). The flukes again access to the body by the consumption of raw fish and can live within the body for up to thirty years. An effective drug for killing liver flukes, praziquantel, has been available for ten years, but has not decreased the incidence of cholangiocarcinomas11. Since treatment has not been effective at preventing cancers, efforts must focus on preventing infection instead. Such techniques include sufficient cooking of fish to kill parasites and establishing an uninfected water supply.
[Lifecycle] [O. viverrini] [C. sinensis] [O. felineus] [Carcinogenesis and Pathology] [Cholangiocarcinoma] [Treatment and Prevention] [Links] [Literature Cited]