Intestinal helminth communities of the red fox ( Vulpes vulpes L.) in the Italian Alps

The study analyses the intestinal helminth communities found in 645 red foxes of alpine populations from five areas of Northern Italy. In particular, the aim was to evaluate the contribution of both environmental variability and the structure of fox population (extrinsic and intrinsic factors, respectively) in shaping the structure and composition of the intestinal helminth communities. To identify the influence of the characteristics of the host (i.e. age and sex) together with extrinsic factors (year, site, season, and altitude of collection) on number of species, total load per fox, prevalence and abundance of each parasite species, general linear models were performed. Fifteen helminth species have been detected in the intestine of 545 infected animals (84.5%) with a total of 17,144 parasites collected. The analysis of factors influencing both prevalence and abundance of infection of the parasite species revealed the preponderance of extrinsic factors on intrinsic ones. In particular, geographical areas influenced prevalence and abundance of every parasite species, showing high spatial variability. The lower influence of host factors may suggest that, in this case, host dynamics play a trivial role with respect to spatial variability in determining parasite abundance. These results pointed out high prevalence of intestinal helminth infections in the Italian Alpine fox, confirmed the typical composition of parasite fauna within fox populations, underlined local differences in the structure and composition of the helminth communities. Moreover, this study highlights the major role of extrinsic factors vs intrinsic ones.