Metacercaria Infection Status of Fishborne Zoonotic Trematodes, Except for Clonorchis sinensisin Fish from the Heilongjiang Province, China

AbstractTo investigate the metacercarial infections of fishborne zoonotic trematodes (FZT), a total of 6815 freshwater fish (in representing 13 species of 5 families) were collected from Songhua river (n= 2636), Nenjiang river (n= 1935), Mudanjiang river (n= 301), and other lakes or ponds (n= 1943) in 36 representative regions in Heilongjiang Province, China, from August 2012 to December 2015. Metacercariae of four FZT species, that is, Clonorchis sinensis, Metorchis orientalis, Isthmiophora hortensis,and Metagonimus yokogawai, metacercariae were detected in the examination by the artificial digestion method. As the partial data for C. sinensiswere previously reported, the remaining three FZT species are to be treated in this study. The overall prevalence of M. orientalis, I. hortensis, and M. yokogawai, metacercariae was 10.54%, 0.28%, and 1.35%, respectively. Metacercariae of M. orientaliswere detected in seven fish species, that is, Pseudorasbora parva, Hemiculter leucisculus, Saurogobio dabryi, Rhynchocypris lagowskii, Carassius auratus, Rhodeus ocellatusand Perccottus glehnii. Their prevalences were the highest in false dace, P. parva(26.81%), and in fish from Songhua river (17.94%). Metacercariae of I. hortensiswere detected in only one fish species, Misgurnus anguillicaudatus, from Nenjiang river only. Metacercariae of M. yokogawaiwere detected in three fish species, that is, P. parva, H. leucisculusand S. dabryi. Their prevalences were the highest in sharpbelly, H. leucisculus(6.05%), and in fish from Mudanjiang river (5.65%). This study first demonstrated the existence of M. orientalis, I. hortensis, and M. yokogawaiin freshwater fish from Heilongjiang Province, posing a major public health concern. Eight fish species, namely M. anguillicaudatus, P. parva, H. leucisculus, S. dabryi, R. lagowskii, C. auratus, R. ocellatus, and P. glehnii, cannot be eaten raw. Moreover, the findings of this study not only extended the second intermediate host range of FZT, but also improve the information of the distribution of FZT in China.