The selectivity for the second intermediate host (fish) of Clonorchis sinensis in the Jialing River basin, China-from the perspective of fish ecological viewpoint

Clonorchiasis poses a great threat to human public health. Clonorchis sinensis (Opisthorchiidae: Digenea) is the most representative fish-borne parasitic zoonotic agent. As the second intermediate host of C. sinensis, fish are necessary for C. sinensis to complete its life cycle and infect humans. This study was the first to explore the selectivity for the second intermediate host of C. sinensis from the fish ecological viewpoint. A total of 162 fish species were found in the Jialing River basin, and 46 fish species were confirmed to be the host of C. sinensis. Cyprinidae fish, which are frequently infected by C. sinensis, are distributed worldwide; thus, this selection strategy may play an important role in the wide spread of C. sinensis. Correlation analysis demonstrated that fish distributed downstream or those that inhabit the middle water layer were more likely to be the host species of C. sinensis. Additionally, we inferred that a fish species with broad activity space has a high possibility of becoming a host of C. sinensis. No direct relationship was found between host percentage and the average trophic levels of each trophic guild. However, host percentage may be correlated with feeding behavior. In general, these results can help humans in reducing the prevalence and infection range of clonorchiasis.