First Occurrence of Eustrongylides spp. (Nematoda: Dioctophymatidae) in a Subalpine Lake in Northwest Italy: New Data on Distribution and Host Range

摘要

The genus includes nematodes that infect fish species and fish-eating birds inhabiting freshwater ecosystems. Nematodes belonging to the genus are potentially pathogenic for humans; infection occurs after the consumption of raw or undercooked fish. In the two-year period 2019–2020, a total of 292 fish belonging to eight species were examined for the occurrence of spp. from Lake San Michele, a small subalpine lake in northwest Italy. The prevalence of infestation was 18.3% in , 16.7% in , and 10% in . The other five fish species ( , , , , and ) were all negative for parasite presence. There were no significant differences in prevalence between the three fish species (Fisher’s exact test; = 0.744). The mean intensity of infestation ranged from 1 ( and ) to 1.15 ( , and the mean abundance ranged from 0.1 ( ) to 0.28 ( ). There were significant differences in the infestation site between the four muscle quadrants (anterior ventral, anterior dorsal, posterior ventral, and posterior dorsal) and the visceral cavity (Kruskal–Wallis test; = 0.0008). The study findings advance our knowledge about the distribution and host range of this parasite in Italy.