Dam Influences on Liver Fluke Transmission: Fish Infection and Human Fish Consumption Behavior

Infectious diseases associated with dams in many parts of the world suggest a strong possibility of similar occurrence in Southeast Asia, but little is known about the influences of dams on disease occurrences in Southeast Asia, where a wide range of water-related diseases are present. An important public health issue in Southeast Asia is opisthorchiasis, the infection from liver fluke spread by ingesting raw or undercooked freshwater fish. This study investigated the effects of the Ubolratana reservoir in Thailand on Opisthorchis viverrini infection through the analyses of fish species assemblage and fish host infection in the reservoir and rivers, human fish consumption behavior, and their interactions. Multivariate analyses for community ecology and surveys of human practices were used to examine human–environment interactions involved in O. viverrini transmission. The results showed that the reservoir and the rivers harbored different fish species of varied O. viverrini infection densities, with the reservoir having higher overall infection rates than the rivers. Although the preferred species for raw fish dishes was found with low infection, several high-infection species were commonly consumed. The reservoir might have implications for opisthorchiasis risk through the potential change of fish species assemblage and the supply of high O. viverrini–infected fish to most of the villages around it. This study underscored the need to consider human–environment interactions for understanding the risks of disease transmission.