Abstract

Campylobacteriosis is a zoonotic emerging disease with a broad range of asymptomatic animal hosts. In humans, Campylobacter species is the most commonly reported bacterial cause of gastroenteritis. The role of different wildlife species as reservoirs of Campylobacter spp. remains to be determined. The population of brown bears (Ursus arctos) in Sweden is approximately 3,500 individuals. During the legal bear hunt up to 300 bears are shot in the fall, and the meat is consumed by humans. The aim of this study was to investigate if free-ranging brown bears host Campylobacter spp. in feces. Samples were collected by directly swabbing the rectum of anesthetized brown bears (n=69), or by collecting feces from the colon of hunted brown bears (n=52). Bacteriological analyses were performed by culture in selective media for Campylobacter spp. Six samples (5%) were culture positive. All isolates were C. jejuni, which is the species that causes most cases of human campylobacteriosis. The prevalence of Campylobacter spp. in free-ranging brown bears in this study was low, but brown bears may play a role in the epidemiology of pathogenic Campylobacter spp. Feces from wild bears could potentially contaminate surface water as well as bear meat which may be consumed by humans. In conclusion, the study results indicate that brown bears are probably not an important reservoir, but their feces can be a potential source of infection for humans.

Acknowledgments

We thank the rangers from Länsstyrelsen for sample collection from hunted brown bears, and Dr Andrea Miller and fieldworkers within the Scandinavian Brown Bear Research Project for sample collection from anesthetized brown bears. The study was performed in collaboration with the Scandinavian Brown Bear Research Project, which was supported by the Swedish Environmental Protection Agency, the Norwegian Directorate for Nature Management, the Research Council of Norway, and the World Wide Fund for Nature in Sweden.