Beavers are not alone: parasitic assessment of released Eurasian beavers in Central Italy

The Eurasian beaver Castor fiber L., 1758, absent in Italy for over 500 years, has established reproductive populations in Central Italy since 2019, most likely following unauthorized releases. Besides positive effects on local biodiversity, beavers may host a plethora of infective agents, including parasites. Therefore, an assessment of parasitic load of released beavers is pivotal to predict potential risks for other species and human health, following beaver releases. Microscopical and molecular analyses on collected beaver feces confirmed the presence of Giardia duodenalis, Trichuris spp., and Travassosius rufus, a species of nematode recorded in Italy for the first time. The necropsy carried out on a road-killed adult female beaver provided us the first records for Italy of the beaver beetle Platypsyllus castoris, and of the ectoparasite "fur mites," belonging to the genus Schizocarpus. The bacterium Bordetella bronchiseptica was isolated for the first time from the bronchi of C. fiber, and it may represent a threat to wild and domestic animals and human health. The dipteran species Chrysomya albiceps was also recorded for the first time on a beaver; this blowfly can cause myiasis in livestock and humans. Although the acquired data represent a first assessment for Italy, the high number of pathogens found in these few samples should be evaluated in terms of disease risk analysis.