Molecular characterization of anisakis larvae from fish caught off Sardinia

Anisakis spp. larvae are parasitic nematodes known to cause zoonoses. Fish and cephalopods are the main intermediate hosts of the third larval stage, and the accidental consumption of infected raw or poorly cooked fish dishes may cause gastroenteric diseases and allergies in humans. The aim of the present study was to use PCR-RFLP to define the occurrence, species variability, and host preferences of Anisakis spp. larvae in fish caught off the coast of Sardinia. Necropsy was used on 285 samples, and 552 Anisakis spp. L3 larvae were isolated in the 87 fish that tested positive for this type of nematode. Anisakis pegreffii was most frequently encountered (90.6%), with a primary preference for Scomber scombrus, Zeus faber, and Trachurus mediterraneus. By contrast, the prevalence of Anisakis physeteris was only 1.3%. A hybrid genotype of Anisakis simplex sensu stricto and Anisakis pegreffii was also observed, which confirms the results of previous studies carried out in the western Mediterranean. Interestingly, no Anisakis simplex s.s. larvae were recovered. These results indicate that the diversity of Anisakis species is low in Sardinia waters, because of its geographic position.