Occurrence of ascaridoid nematodes in Illex coindetii, a commercially relevant cephalopod species from the Ligurian Sea (Northwest Mediterranean Sea)

In this study we investigated the occurrence of larval ascaridoid nematodes in Illex coindetii, a commercially relevant cephalopod, via a cross-sectional prevalence study (January 2015 to February 2018) in two fishing areas (Savona and Piombino) in the Ligurian Sea (northwest Mediterranean Sea). A total of 745 specimens of I. coindetii were caught by local fisherman through bottom trawling. Parasitological examination revealed ascaridoid nematodes (L3) larvae (n = 9): Hysterothylacium sp. (n = 6) and Anisakis spp. (n = 3). All larvae morphologically referred to the genus Anisakis were identified by PCR-RFLP as A. pegreffii. The prevalence of Hysterothylacium sp. infestation was 0.88% for the Savona and 0.56% for the Piombino sampling site; the prevalence of A. pegreffii was 0.18% for Savona and 1.11% for Piombino and did not differ between the two sampling sites (chi-square test; p = 0.0848). Better knowledge of the distribution of ascaridoid nematodes, especially of Anisakis species is essential for defining their epidemiological role and the potential risk for consumer health.