Epidemiology of Sulcascaris sulcata (Nematoda: Anisakidae) ulcerous gastritis in the Mediterranean loggerhead sea turtle (Caretta caretta)

Sulcascaris sulcata Rudolphi 1819 is a gastric nematode parasite of sea turtles. Here, we report the occurrence and describe for the first time the pathological changes caused by S. sulcata in the Mediterranean loggerhead sea turtle (Caretta caretta) stranded along the Tyrrhenian coast and northern Adriatic coast of Italy. Prevalence of infection was significantly higher in loggerhead sea turtles from the Adriatic Sea. Both prevalence and abundance of infection showed an increasing trend along with host age classes from both geographical localities. Nevertheless, while many small loggerhead sea turtles were found infected from the Adriatic Sea, only bigger individuals were infected from the Tyrrhenian Sea. The most common gross pathological change was a mucous gastritis with focal to multifocal raised ulcerous lesions roundish to irregular in shape ranging from 1 to over 20cm in length, and cream-yellowish to greenish in color. The severity grade of gastritis increased with higher number of S. sulcata individuals. Microscopic pathological changes ranged from atrophic gastritis with heterophilic infiltration in the lamina propria to the destruction of the mucosal and sub-mucosal surfaces and necrosis. Results here obtained demonstrate that S. sulcata may cause ulcerous gastritis in both samples of loggerhead sea turtles studied from the Mediterranean Sea. Observed differences in S. sulcata infection among the different host age classes and between the two studied basins are likely linked to the differences of regional habitat and intermediate prey host availability.