ABSTRACT
<p><b>OBJECTIVE</b>The aim of this research was to investigate the third phase Anisakis simplex larvae (Anisakis L₃) infection in marine fish caught in Zhoushan Fishery and to find out its physicochemical and biological characteristics.</p><p><b>METHODS</b>A total of 444 fish belonging to 29 species were dissected to isolate anisakis larvae which were then morphologically identified. The survival tolerance of Anisakis L₃ were observed in various conditions, such as in different temperature and medium.</p><p><b>RESULTS</b>A total of 218 fish from 21 species were infected by Anisakis simplex larvae, yielding an overall infection rate of 49.10% (218/444). Trichiurus haumela, pneumatophorus japonicus, miichthys miiuy, argyrosomus argentatus and anguilliformes had high infection rate and had an average infection intensity of 15.28 per fish. 3332 Anisakis larvae were detected in 218 fish, among which Anisakis L₃ and Pseudoterranova larvae accounted for 99.46% (3314/3332) and 0.54% (18/3332) respectively. Anisakis L₃ was highly resistant to common condiment. We found the liquor with high concentration of alcohol showed better insecticidal effect than that with low concentration of alcohol (t = 4.105, P < 0.05) and low concentration mebendazole composite was not only more effective than high concentration mebendazole composite (F = 45.198, P < 0.01) but also more effective than other drugs, such as albendazole and mebendazole. Anisakis L₃ could live up to 9 h and 12 h at -20°C, -10°C respectively, however they were very sensitive to high temperature. It has been shown that they could only survive for less than 11 s and 1 s at 50°C and 60°C respectively.</p><p><b>CONCLUSION</b>The observed Anisakis L₃ infection rate in the marine fish found in Zhoushan Fishery was very high. Anisakis L₃ showed high resistance to low temperature but not to high temperature.</p>
Subject(s)
Animals , Anisakiasis , Parasitology , Anisakis , Fish Diseases , Parasitology , Fisheries , Fishes , Parasitology , Larva , TemperatureABSTRACT
Objective To study the rates of infection and physicochemical characteristics of the third stage Anisakis simplex larvae among marine fish caught in Zhoushan Fishery. Methods 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. Results 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 miiuy,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 ℃, -10 ℃ 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 ℃ and 60 ℃. Conclusion 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 ℃ 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.