Infection and physico-chemical characteristics of Anisakis among marine fish caught in Zhoushan Fishery

Abstract

To study the rates of infection and physicochemical characteristics of the third stage Anisakis simplex larvae among marine fish caught in Zhoushan Fishery. Fish were dissected to detect Anisakis larvae and identified morphologically. The survival tolerance of the third stage Anisakis simplex larvae in various medium, anthelmintic drug, temperature were studied in laboratory. The total infection rate of Anisakis simplex larvae in fish was 49.10%. High rates of Anisakis infection were observed in hairtails, Pneumatophorus japonicus, Miichthys milky, Argyrosomus argentatus and Muraenesox cinereus (infection rates > 90 percent). The infection intensity of Anisakis per fish varied from 1 to 114. The mean intensity of Anisakis larvae was 15.20 per fish. 3314 Anisakis were detected in 218 marine fish. The survival tolerance of the third stage Anisakis simplex larvae in various Medium, anthelmintic drug, temperature were observed in laboratory condition. The third stage Anisakis simplex larvae showed a strong endurance to stock condiment. The anisakicidal effects of the high purity wine were more effective than that of the low purity wine. The anisakicidal effects of 6.25 g/L mebendazole composite were more effective than that of 18.75 g/L and also more effective than those of other drugs. The third stage Anisakis simplex larvae could survive with length up to 9 h and 12 h in condition of -20°C, -10°C and very sensitive to high temperature treatment. However, they could barely survive in more than 11 s and 1 s under the temperature of 50°C and 60°C. The percentage of infection was fairly high for Anisakis larvae of marine fish caught in Zhoushan Fishery. The third stage Anisakis simplex larvae was shown to have a fairly good tolerance to the external environments. The marine fish were frozen under -20°C beyond 24 h before they were sold on market and cooked with high temperature seemed to be helpful for preventing and controlling effectively the infection of Anisakis.