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Intracellular parasites of the genus Glugea Thélohan, 1891 (Microsporidia) comprise about 34 putative species capable of causing high morbidity and mortality in freshwater and marine teleost fishes. In this study, we report on the first mass mortality event associated with Glugea sp. infecting free-ranging round sardinella Sardinella aurita in the southern Tyrrhenian Sea (Italy). Here, we describe the ultrastructure of mature spores of this microsporidian and characterize it molecularly, as well as report its phylogenetic position. Most of the affected fish showed an irregular swelling of its abdomen. At necropsy, a variable number of xenomas, spherical to ellipsoidal in shape, were found in the peritoneal cavity strongly attached to the viscera of all fish. Histological analysis revealed varying severity of chronic inflammation along with occasional necrosis in visceral organs associated with multiple xenoma proliferation. These pathological findings were considered the main cause of this mass mortality event. Morphologically, the present material was closely related to G. sardinellesis and G. thunni. The phylogenetically closest taxa to the newly SSU rDNA sequence were G. thunni and an erroneusly identified  G. plecoglossi, which were very closely related to each other, also suggesting that all these sequences might belong to the same species., (© 2024 John Wiley & Sons Ltd.)

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 20 cm 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.