Epizootiologic Investigations of Selected Abortive Agents in Free-Ranging Alpine Ibex (Capra Ibex Ibex ) in Switzerland

Abstract

In the early 2000s, several colonies of Alpine ibex (Capra ibex ibex) in Switzerland ceased growing or began to decrease. Reproductive problems due to infections with abortive agents might have negatively affected recruitment. We assessed the presence of selected agents of abortion in Alpine ibex by serologic, molecular, and culture techniques and evaluated whether infection with these agents might have affected population densities. Blood and fecal samples were collected from 651 ibex in 14 colonies throughout the Swiss Alps between 2006 and 2008. All samples were negative for Salmonella spp., Neospora caninum, and Bovine Herpesvirus-1. Antibodies to Coxiella burnetii, Leptospira spp., Chlamydophila abortus, Toxoplasma gondii, and Bovine Viral Diarrhea virus were detected in at least one ibex. Positive serologic results for Brucella spp. likely were false. Overall, 73 samples (11.2%) were antibody-positive for at least one abortive agent. Prevalence was highest for Leptospira spp. (7.9%, 95% CI=5.0-11.7). The low prevalences and the absence of significant differences between colonies with opposite population trends suggest these pathogens do not play a significant role in the population dynamics of Swiss ibex. Alpine ibex do not seem to be a reservoir for these abortive agents or an important source of infection for domestic livestock in Switzerland. Finally, although interactions on summer pastures occur frequently, spillover from infected livestock to free-ranging ibex apparently is uncommon.

Infectious keratoconjunctivitis in wild Caprinae: merging field observations and molecular analyses sheds light on factors shaping outbreak dynamics

“…Our definition of an “epidemiological unit” was already supported by genetic data on Alpine ibex in Switzerland [53] and by telemetry studies in the Vanoise [46]. Here, our cluster analysis demonstrated that this definition is appropriate for the study of disease dynamics in mountain ungulates.…”

Wildlife health investigations: needs, challenges and recommendations

“…Among other things, it is necessary to assess the real status of livestock to determine the epidemiological role of a wild species in domestic animal disease [11,46]. For example, investigations on bluetongue, bovine viral diarrhea virus and other abortive agents in wild ruminants from Switzerland suggest that wildlife is not a reservoir but rather an occasional spillover host for these pathogens, as infections of wild ruminants is only sporadic while domestic ruminants display significantly higher prevalences of infection [37,47,66]. Interspecific interactions can also influence disease dynamics in other ways.…”

“…Also, soil composition, vegetation and stagnating water can influence the occurrence of pathogens and their vectors or the presence of toxic compounds [18]. Overall, natural and anthropogenic barriers and spatial distribution of wild and domestic hosts need to be taken into consideration when defining epidemiological or sampling units [37,50,66,81]. …”

“…For example, in Switzerland in the winter of 2011/2012, six months of “capture duty” with three different capture systems [102] and the contributions of numerous biologists, veterinarians, hunters and professional game wardens, resulted in the capture of four Eurasian lynx. Similarly, three capture seasons of 2–3 months each involving full-time presence of a capture team in the fields on a single study site resulted in samples from 39 ibex [29], while blood samples from 520 hunted ibex were obtained during the corresponding hunting seasons [66]. Additionally, legal constraints may prevent systematic sampling of a wild animal population [94].…”

“…This problem can be partly overcome by using geographical units for analyses, but data on different hosts are rarely available at the same spatial resolution and at a high enough resolution to allow meaningful inferences to be made [46]. Furthermore, there is often a lack of data concerning species interactions as well as the infection status in other species [11,37,46,66], and it is rarely possible to follow up on individual animals [37,51,69]. …”