Prevalence of parasitic infections in fish from markets in Zhenjiang City from 2017 to 2020

Abstract

To investigate the prevalence of parasitic infections in freshwater fish and marine fish from markets in Zhenjiang City, so as to provide the evidene for formulating targeted control measures. Freshwater fish and marine fish were collected from farmers' markets and supermarkets in Zhenjiang City using a random sampling method. The metacercaria and larvae of parasites were detected using microscopy and the direct dissection method. The prevalence of parasitic infections was analyzed in freshwater fish and marine fish. The overall prevalence of parasite infections was 11.21% (208/1 856) in the 1 856 fish (34 species) detected from 2017 to 2020, and the prevalence was 9.81% (117/1 193) in freshwater fish and 13.73% (91/663) in marine fish. Among the 1 193 freshwater fish (23 species), high prevalence of parasitic infections was detected in Gambusia affinis (43.33%), coarse fish (32.93%) and Hemiculter leucisclus (20.20%), and there was no significant difference in the prevalence of parasitic infections among different species of freshwater fish (χ2 = 105.66, P < 0.05). Clonorchis sinensis, Metorchis orientalis and other parasite species were detected in freshwater fish, with detection rates of 0.59% (7/1 193), 1.93% (23/1 193) and 7.29% (87/1 193), respectively, and there was a significant difference in the detection of C. sinensis and M. orientalis in freshwater fish (χ2 = 8.64, P < 0.05). The prevalence and intensity of larval Anisakis infections were 13.73% (91/663) in marine fish and 3.43 parasites per fish. High prevalence of Anisakis infections was seen in little yellow croaker fish (30.28%) and hairtail (27.50%), and there was a significant difference in the prevalence of parasitic infections in different species of marine fish (χ2 = 12.93, P < 0.05). Parasitic infections are prevalent in freshwater fish and marine fish from markets of Zhenjiang City, and there is a risk of parasitic infections following consumption of raw or under-cooked freshwater fish and marine fish.