Clonorchis sinensis is a fluke that is also known as a trematode. Trematoda is part of the phylum Platyhelminthes. Vertebrates are usually the host of adult trematode parasites. The interesting characteristic of these mostly hermaphroditic flukes is that they require one or more intermediate hosts. The first intermediate hosts are mollusks, without which miradicium (egg) development cannot occur. After a series of generations within the mollusk, large numbers of larvae are released - cercariae. In the case of Clonorchis sinensis the cercaria penetrate the flesh of freshwater fish. When a person consumes the infected fish, the parasite moves to the biliary ducts.
The purpose of this page is to provide useful information about Clonorchiasis. Although the parasite is primarily endemic in Korea, China, Taiwan, and Vietnam cases have been reported in the United States. Also known as the Chinese liver fluke, its clinical occurrence in humans is usually asymptomatic. Large infections, however, do result in fever, diarrhea, and other related ailments. Today, Clonorchiasis remains a major public health challenge in numerous areas of Asia because people living near freshwater often become infected. In some places like Korea, eating raw pond smelt is a major cultural dish. The only problem is that clonorchis sinensis targets freshwater fish. If undercooked there is a significant chance that the fish contains the parasite. Aside from drug treatment, public health strategies emphasize the importance of thoroughly cooking fish. Read on to learn more about this tiny pest.