First Results on the Presence and the Molecular Characterization of Anisakid Nematodes in Marine Fish Caught Off Northern Sardinia

Abstract

Anisakidosis is a parasitic zoonosis caused by nematodes of the family Anisakidae, belonging to the genera Anisakis, Contracaecum and Pseudoterranova. Molecular studies have shown that Anisakis larvae comprise a number of sibling species, which have different genetic structures, hosts and geographical distribution. A great variety of fish species can harbour infectious third stage larvae of this nematode. The preliminary results of a study carried out to evaluate the occurrence of this parasite in commercial fish caught off northern Sardinia are herein reported. From October 2008 to November 2009, 599 specimens of 8 commercial fish species were examined for anisakid larvae through visual inspection of body cavity and peptic digestion of the muscle. Isolated Anisakis sp. larvae were observed at light microscope and identified as Type I or Type II (sensu Berland, 1961). Out of 599 fish examined, 239 (40%) were infected by 1187 anisakid larvae, belonging to the genera Anisakis (1169 Type I and 18 Type II) and Hysterothylacium (692). The molecular identification of Anisakis spp. was carried out on a subsample of 30% of Type I larvae and all Type II larvae. Specimens were firstly examined using a species-specific PCR, with primers designed for Anisakis pegreffii (APEF) and Anisakis physeteris (APHF), and ITS-2 of nuclear rDNA. The results were confirmed by the analysis of the ITS region of nuclear rDNA (ITS-1, 5.8S and ITS-2) using the restriction enzymes HinfI and HhaI in PCR-RFLP. Type I larvae examined were all identified as A. pegreffii, and Type II were all A. physeteris. This is the first contribution to the epidemiology and molecular characterization of Anisakis spp. in commercial fish caught off Sardinia

Occurrence of nematodes of the genus Anisakis in Mediterranean and Atlantic fish marketed in Sardinia

“…However, as stated by the European Food Safety Authority report (EFSA, 2010 ), conditions necessary for intra-vitam and post-mortem migration of larvae from the viscera into the muscle is still controversial. Few studies have been conducted to assess the level of infection and the species of Anisakis larvae in fish species commercialized in Sardinian market (Meloni et al , 2011 ; Tedde et al , 2011 ; Piras et al , 2014 ). The objective of the present study was to gain epidemiological information for the risk of anisakiasis associated with the consumption of fish marketed in Sardinia (Italy).…”

Food safety considerations in relation to Anisakis pegreffii in anchovies (Engraulis encrasicolus) and sardines (Sardina pilchardus) fished off the Ligurian Coast (Cinque Terre National Park, NW Mediterranean)

“…whereas infections were found in sardines from other areas along the Adriatic coast of Italy (prevalence 3.3 %) (Mladineo and Poljak, 2013) and the Tyrrhenian around northern Sardinia (prevalence 13.1-20%) (Angelucci et al, 2011;Tedde et al, 2011). The prevalence of Anisakis infection in sardines from the Aegean Sea (Chaligiannis et al, 2011) is reportedly far lower than in sardines from the West coast of Portugal (5.5% vs. 28.1%) (Silva and Eiras, 2003).…”