Indagine sulla presenza di larve di nematodi Anisakidae in alici e sardine del Mar Adriatico settentrionale: una possibile mappatura del rischio per il consumatore.

Anisakis spp. larvae (L3) are parasitic and potentially zoonotic nematodes transmitted by marine fish and cephalopods, which are the main paratenic hosts of the third larval stage. The accidental consumption of infected raw or undercooked fish may cause gastroenteric diseases and allergies in humans. The aim of the present study was to map the "Anisakis risk" in populations of anchovies (Engraulis encrasicolus) and sardines (Sardina pilchardus) caught in the northern Adriatic Sea. For this purpose, periodic samples were carried out in three different fishing areas (Cesenatico, Caorle and Rimini) collecting data on geographic coordinates, distance from the coast and bathymetric depth for each sample. From November 2010 to February 2012 a total of 3287 fish were sampled and subjected to parasitological exams aimed at detect and identify Anisakidae larvae. Prevalence, mean intensity and mean abundance were determined. An overall prevalence of 23.4% for Hysterothylacium sp. and of 0.2% for Anisakis sp. was detected in anchovies, while 30.2% of sardines resulted positive for Hysterothylacium sp. and 0.2% for Anisakis sp. respectively. The anisakid larvae were always found viable in the body cavity. All the isolated Anisakis larvae were identified as “type I” on the basis of morphological features. Molecular analyses allowed to identify them as A. pegreffii, with the exception of a specimen identified as a hybrid A. pegreffii/A. simplex, and to ascribe all the Hysterothylacium larvae to the species H. aduncum. The results of this survey showed very low values of prevalence and mean intensity of Anisakis larvae both in anchovies and sardines from north-western Adriatic Sea fishing grounds. Considerations on different environmental, ecological and hydrogeographical factors influencing anisakid infections in anchovies and sardines caught in different marine areas are given