Anisakis simplex Larvae: Infection Status in Marine Fish and Cephalopods Purchased from the Cooperative Fish Market in Busan, Korea

The infection status of marine fish and cephalopods with Anisakis simplex third stage larva (L3) was studied over a period of 1 year. A total of 2,537 specimens, which consisted of 40 species of fish and 3 species of cephalopods, were purchased from the Cooperative Fish Market in Busan, Korea, from August 2006 to July 2007. They were examined for A. simplex L3 from the whole body cavity, viscera, and muscles. A. simplex L3 were confirmed by light microscopy. The overall infection rate reached 34.3%, and average 17.1 larvae were parasitized per infected fish. Fish that recorded the highest infection rate was Lophiomus setigerus (100%), followed by Liparis tessellates (90%), Pleurogrammus azonus (90%), and Scomber japonicus (88.7%). The intensity of infection was the highest in Gadus macrocephalus (117.7 larvae per fish), followed by S. japonicus (103.9 larvae) and L. setigerus (54.2 larvae). Although abundance of A. simplex L3 was not seasonal in most of the fish species, 10 of the 16 selected species showed the highest abundance in February and April. A positive correlation between the intensity of L3 infection and the fish length was obvious in S. japonicus and G. macrocephalus. It was likely that A. simplex L3 are more frequently infected during the spring season in some species of fish. Our study revealed that eating raw or undercooked fish or cephalopods could still be a source of human infection with A. simplex L3 in Korea.

Survival of the Third Stage Larvae of Anisakis simplex in Various Conditions and Experimental Infection in Rats / 中国寄生虫学与寄生虫病杂志

Objective To observe the characteristics of biology and pathogenicity of the third stage Anisakis simplex larvae ( L3). Methods The survival time of the L3 in various conditions was observed and the pathological change after experimental infection in rats was examined. Results The results showed that the L3 frozen at -20℃ for 10 - 12 h can be killed. In the temperature range of 4 - 10 ℃ , the L3 can survive for over 8 months. The L3 was very active at 37℃ , and was killed at the high temperature over 40℃ in a very short time. The ingredients for sashimi cannot kill the L3. The experiment of rats infected by the L, showed that about 15% -25% of the L3 penetrated into the gastrointestinal wall or migrated into the peritoneal cavity in 2 days. After 3d the L4 was not infectious, and died automatically in 7 - 10 days and could not develop into adults. The animals can be easily infected when the stomach was empty. The pathological study showed that the primary infection was a kind of reaction to foreign body, while that of the re - infection was allergic. Conclusion The L3 has a strong resistance to low temperature and to ingredients , it can be killed by freezing at -20℃ in 24 hours. The L3 can not mature in the body of terrestrial mammals but causes pathological change in the stomach and allergy.[