Barbara Paoletti, University of Teramo

Bears harbour a wide variety of endoparasites, including nematodes (roundworms, hookworms, capillariids), cestodes, trematodes and protozoa. Many of these parasites have significant veterinary and zoonotic importance. The roundworm Baylisascaris transfuga is considered the most important bear parasite, believed to be responsible of both disease in bears and life-threatening larva migrans syndrome in humans. There is no evidence of patent natural infections by B.transfuga in non-ursid or humans, although experimental studies have shown that migrating larvae may invade the central nervous system in some animal species. In Italy, little information is available on the occurrence of parasites in free-ranging bears, therefore the present study aimed to update the information currently available in brown bears from the Abruzzo, Lazio e Molise National Park (PNALM). In 2024, fecal samples from Marsican brown bears (n = 102) were collected in the PNALM. The samples were stored at -20°C and thawed 24h prior to copromicroscopic examination. All the samples were examined by floatation and McMaster techniques. Parasite elements were identified according to their morphological and morphometrical features. Sixteen samples were positive for parasites (15.68%). This result should be carefully interpreted, as it cannot be excluded that multiple samples from the same animal have been collected, causing an overestimation of the infection rate. The most prevalent parasite was B.transfuga (7%) followed by Ancylostomatidae (6%), coccida (5%), Capillaria aerophila (2%) and cestodes (1%). All parasites found showed a low level of parasitism. The results of this study confirm that brown bears are infected with different parasite species, some of them with a zoonotic potential, such as B.transfuga, Ancylostomatidae and C.aerophila. A constant parasitological surveillance is pivotal for monitoring the health status of bears and for the availability of updated epidemiological information.