Epidemiology & Risk Factors
Clonorchis species are liver fluke parasites (trematodes or worms).
Liver fluke infections occur mostly in people living in some areas where the parasites are found. Clonorchis is found mainly in Korea, China, Taiwan, Northern Vietnam, Japan, and Asian Russia. Travelers to Asia who consume raw or undercooked fish are at risk for liver fluke infection.
People become infected by eating raw or undercooked freshwater fish containing the larvae. Lightly salted, smoked, or pickled fish may contain infectious parasites. Drinking river water or other nonpotable water will not lead to infection with Clonorchis.