 The WHO estimates that foodborne trematodiases (infection by worms or "flukes", mainly "Clonorchis", "Opisthorchis", "Fasciola" and "Paragonimus" species) affect 56 million people worldwide and 750 million are at risk of infection.Eighty million are at risk of opisthorchiasis, 67 million from infection with "Opisthorchis viverrini" in Southeast Asia and 13 million from "Opisthorchis felineus" in Kazakhstan, Russia including Siberia, and Ukraine.In the lower Mekong River basin, the disease is highly endemic, and more so in lowlands, with a prevalence up to 60% in some areas of northeast Thailand.