Chinese liver fluke
| Chinese liver fluke | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
Chinese liver fluke ( Clonorchis sinensis ) |
||||||||||||
| Systematics | ||||||||||||
|
||||||||||||
| Scientific name of the genus | ||||||||||||
| Clonorchis | ||||||||||||
| Looss , 1907 | ||||||||||||
| Scientific name of the species | ||||||||||||
| Clonorchis sinensis | ||||||||||||
| ( McConnell , 1875) |
The Chinese liver fluke ( Clonorchis sinensis ) is a parasite belonging to the class of flukes . Definitive hosts are fish-eating mammals ( cats ) and humans. It is estimated that 20 to 30 million people are infected worldwide.
distribution
The Chinese liver fluke occurs in East Asia ( People's Republic of China , Taiwan , Vietnam , Japan , Korea ). The life cycle is tied to fresh water .
features
The adult leech is flattened, 10 to 25 mm long and 3 to 5 mm wide. It has two suction cups (oral and ventral). Clonorchis means “twig-shaped testicle” and describes the structure of the male sexual organs of the parasite that is visible through the transparent parenchyma. The worms are hermaphrodites .
Life cycle
The life cycle begins when the eggs are deposited in the host's faeces . The first intermediate host is a freshwater snail ( Bithynia siamensis ), in which the miracidium (ciliated larva) hatches after ingestion. Within the screw, the Miracidium converts into a sporocyst to (breeding hose), which internally by budding rediae produced (bar larvae). The redia themselves continue to develop - still within the snail - and release cercariae (tail larvae) through further asexual reproduction . These escape into the water and pierce the skin of a fish. They form metacercarial cysts in its muscles . Humans can become infected by eating uncooked fish. The metacercariae penetrate the small intestine and migrate to the liver . There they stay in the biliary tract and mature into adult leeches. After three to four weeks, the worm begins to lay eggs, which enter the stool through the bile .
illness
The infestation of humans with Clonorchis sinensis is called clonorchiosis . Despite its low level of awareness, it is the third most common worm disease in the world . It is a risk factor for the development of cholangiocarcinoma .
See also
Web links
Individual evidence
- ↑ Shin H, Lee C, Park H, Seol S, Chung J, Choi H, Ahn Y, Shigemastu T: Hepatitis B and C virus, Clonorchis sinensis for the risk of liver cancer: a case-control study in Pusan, Korea . In: Int J Epidemiol . 25, No. 5, 1996, pp. 933-940. doi : 10.1093 / ije / 25.5.933 . PMID 8921477 .