Factors influencing gastrointestinal parasites in a colony of Alpine ibex (Capra ibex) interacting with domestic ruminants

Abstract

Parasitic infections in populations of wild herbivores can affect the individual fitness and population dynamics of their hosts. In this study, the ecology of gastrointestinal (GI) parasites was investigated in anAlpine ibex colony of theMarmoladamassif, eastern Alps. Both individual and environmental factors were studied to reveal their relationship with parasite prevalence and burden. In a four-year period, 414 individual faecal samples of ibex were collected on a monthly basis during summer and autumn and were subjected to quali-quantitative examinations for the identification and quantification of oocysts and eggs. Domestic ungulates grazing in the same area were also sampled to investigate the risk of GI parasite transmission. Negative binomial regression models were developed to study the influence of physiological and environmental factors on parasite burdens. The results of the qualitative examination were in agreement with the few data already present in the literature for Alpine ibex, showing high prevalence values for Coccidia and GI strongyles, low values for Cestoda and sporadic presence of whipworms. Higher burdens in kids were found for Coccidia and Cestoda. Analysis of the GI endoparasite community of cattle and sheep suggested a negligible risk of parasite transmission to the Alpine ibex population. The sanitary risk represented by Coccidia and Cestoda in ibex kids and some peculiarities of the endoparasite distribution patterns in the Marmolada ibex population call for future in-depth ecological studies to investigate their influence on the limited growth rate shown by the ibex colony during the last decade.