Eslami et al.: Infection of Anisakids Larvae in Long Tail Tuna… Chai et al. study (11), (3.67 and 35.6 respec- tively) may indicate that Anisakis is dis- persed within the hosts. Anisakis larvae can infect several tissues of fish, a phenomenon which was observed in the present study. In contrast to our findings the migration of the larvae to the skin with- out encysting in fish flesh has been reported by Abollo et al. (18). Apparently anisakiasis does not harm the health of the fish, because no histhopathological lesions were found associated with the presence of encapsulated nematodes in the stomach wall and infected tissues (19). However, the pathological ef- fects depend on the number of larvae present and the size (age) of the fish (20). Juvenile fish nematode infections may lead to some mortality(21).Apart from mortalities, the presence of encapsulated larvae in fish tis- sues, may lead to devaluation of the quality of the fish and significantly lower the aes- thetical quality of products or pose a con- sumer health risk (16, 19). No larvae were found in the flesh of fish in the present study, whereas Anisakis larvae were previously found in the muscles around the body cavity of 20% of other species of Tuna fish (Eu- thynnus sp.) from north Persian Gulf and 15% of pikeperch (Lucioperca lucioperca) from Caspian Sea (5). At the end of 1999, “the Food Sanitation Law Enforcement Regulation "was amended and anisakid larvae were newly added to the causative agents of food poisoning (22). The absence of anisakiasis in human in Iran may be mainly due to cooking habitat of fish in studied areas as well as other parts of the country. Smoking has little detritus effects on the larvae, although smoking of salted fish at high temperature (50 °C) may prove lethal to some larvae (23). Meanwhile it was shown that insufficient fried fish, if infected, could cause visceral larva migrans in man (10). Van thiel et al. (7) showed that heating at 50 °C will kill easily the larvae, but this temperature could not destroy encysted lar- 99 vae and those protected by fish musculature. Raphidascaris sp. another anisakids larvae collected from the intestines of 2 fish (2%) with mean intensity of 1.5 has been reported from Pike (Esox lucius) of Caspian Sea (1). There are some reports on its zoonotic im- portance (16), but according to Cheng (24) since the adults of Raphidascaris group are intestinal parasite of fish, it is doubtful whether they can cause human infection. Acknowledgements This work has not been supported by any foundation. The authors declare that they have no conflict of interest. References 1. Eslami A, Anwar M, Khatibi Sh. Inci- dence and intensity of helminthose in pike (Esox lucius) of Caspian Sea (north- ern Iran). Riv It Piscic Ittiop.1972; 7(1): 1-14. 2. Eslam A, Kohnehshahri M. Study on the helminthiasis of Rutilus frisii katum from the south Caspian Sea. Acta Zool Patho Antverpienia. 1978;70: 153-155. 3. Mokhayer B. A list of parasites of eus- turgeon (Acipenseridae) in Iran. J Vet Fac Univ Tehran. 1973; 29 (1): 11– 12. 4. Farahnak A, Mobedi I, Tabibi R. Fish anisakid helminthes in Khuzestan prov- ince, south west of Iran. Iranian J Publ Health. 2002; 31(3,4):129 – 132. 5. Eslami A, Mokhayer B. Nematode lar- vae of medical importance found in mar- ket fish in Iran. Pahlavi Med J. 1977; 345-348. 6. Mokhayer B. Pseudotangue in snapper fish of Persian Gulf. Proc. 3rd Int Cong Parasitol. Monchen. 345-8. 7. Van Thiel PH, Kuipers FC, Roskam RT. A nematode parasitic to herring causing