Clonorchis sinensis

The life cycle of Clonorchis sinensis involves freshwater snails and fishes as intermediate hosts and humans and piscivorous animals as definite hosts. Humans are infected through ingestion of raw or undercooked freshwater fish containing C. sinensis metacercariae. Around 15 million people are infected in China, South Korea, northern Vietnam, and far east of Russia. A high burden is exerted due to diverse hepatobiliary morbidity (e.g., cholangitis, cholecystitis, cholelithiasis, and cholangiocarcinoma). A vaccine is not currently available. Chemotherapy for morbidity control is the mainstream intervention against clonorchiasis. Mass drug administration is adopted in high endemic areas, while selective chemotherapy is used in moderately endemic areas, targeting those ingesting raw freshwater fish. Environmental modification to block feces contamination and education to promote behavioral change on raw-eating habits are needed to increase the effectiveness and sustainability of control.