Investigation on the commercial freshwater fish infection with encysted Metacercaria of Clonorchis sinensis in Nanning

Objective To investigate the infection of commercial freshwater fish with the encysted metacercaria of Clonorchis sinensis in Nanning, analyse the related prevalent factors and provide scientific basis for making effective control. Methods Samples were collected from of the commercial freshwater fishes in Nanning. The direct compression and artificial digestion method were used to examine the encysted metacercaria of Clonorchis Sinensis in freshwater fishes. The encysted metacercaria of Clonorchis Sinensis were classified, counted and analyzed as well. Results By the direct compression method, the totle positive rate was 9.41% . The highest positive rate was observed in Cypfinus carpio 23.3% (7/30), while Pseudolaubuca sinensis Bleeker in second 13.3% (4/30)and Carassius auratus the third 10% (3/30).While detected by the artificial digestion method, the overall infection density was 9.89/case,0.14/g, of which the infection density of Cypfinus carpio was the highest(17.56/case、 0.65/g),compared with the lower infection density in Pseudolaubuca sinensis Bleeker (16.93/case、 0.24/g) and Carassius auratus(14.40/case、 0.21/g),and even lower in other kinds of fish. Conclusion The commercial freshwater fish in Nanning were partly infected by the encysted metacercaria of Clonorchis sinensis, of which Cypfinus carpio was infected badly. People may be infected by eating omophagia.