Prevalence of Clonorchis sinensis infection in market-sold freshwater fishes in Jinzhou city, Northeastern China

Clonorchis sinensis is an important human parasite in parts of the world, in particular in southeastern Asia, including China. In China’s northeastern Liaoning province, the high prevalence of C. sinensis infection in humans has been reported. However, limited information is available for the prevalence of C. sinensis in its second intermediate host (freshwater fishes). Hence, the prevalence of C. sinensis infection in market-sold freshwater fishes was investigated in Jinzhou city, Liaoning Province, China between July and August 2011. A total of 607 fish representing 22 species were collected from Jinzhou city, Liaoning Province, and were examined for the presence of C. sinensis metacercariae by digestion technique. The average prevalence of C. sinensis infection in freshwater fishes was 36.1%. While the prevalences of C. sinensis metacercariae in some fish were very high, such as 100% in Pseudorasbora parva and Mastacembelus aculeatus, no C. sinensis metacercariae was found in Macropodus ocellatus, Opsariichthys bidens,Monopterus albus, Misgurnus anguillicaudatus and Parabramis pekinensis. The present investigation revealed a high prevalence of C. sinensis in its second intermediate host (freshwater fishes) in Jinzhou city, Liaoning province, northeastern China, which provides relevant “base-line” data for conducting control strategies and measures against clonorchiasis in this city. Key words: Clonorchiasis, Clonorchis sinensis, metacercariae, intermediate host, freshwater fish, prevalence, Northeastern China