Occurrence of Sulcascaris sulcata (Rudolphi, 1819) in Stranded Mediterranean Loggerhead Sea Turtles (Caretta caretta) Along the Coasts of North-West Adriatic and Ionian Sea (Italy)

The anisakid nematode Sulcascaris (S.) sulcata is one of the most frequently reported pathogenic parasite of gastrointestinal tract of sea turtles, with wide diffusion in warm marine ecosystems of Pacific, Atlantic, and Mediterranean basin. Sea turtles, including the Mediterranean loggerhead turtle (Caretta caretta), act as definitive hosts by ingesting infected bivalve and gastropod molluscs with fourth- larval stage. Infected sea turtles typically develop ulcerative gastritis and chronic mucosal inflammation. We molecularly characterized 19 anisakid nematodes collected from the gastric tract of stranded C. caretta (n = 19) along the Adriatic and Ionian coasts and examined at local Zooprophylactic Institutes. Stomach samples from 5 severely infested turtles were also submitted to histological analysis. Species identification was performed through two conventional PCRs targeting MT-CO1 and MT-CO2; sequencing of 35 amplicons confirmed their identity as S. sulcata species revealing high genetic homogeneity. Phylogenetic analyses showed no clustering by geographic origin or host. The pathological examination revealed mucocatarrhal gastritis with ulcerative lesions, while histological analysis showed chronic gastritis characterized by lymphocytic infiltration. These findings refine current knowledge on S. sulcata distribution and host–parasite dynamics, with implications for marine turtle health and intermediatehost ecology.