Survey for Selected Parasites in Alaska Brown Bears (Ursus arctos)

To assess infection with or exposure to endo- and ectoparasites in Alaska brown bears (Ursus arctos), blood and fecal samples were collected during 2013-17 from five locations: Gates of the Arctic National Park and Preserve; Katmai National Park; Lake Clark National Park and Preserve; Yakutat Forelands; and Kodiak Island. Standard fecal centrifugal flotation was used to screen for gastrointestinal parasites, molecular techniques were used to test blood for the presence of Bartonella and Babesia spp., and an ELISA was used to detect antibodies reactive to Sarcoptes scabiei, a species of mite recently associated with mange in American black bears (Ursus americanus). From fecal flotations (n=160), we identified the following helminth eggs: Uncinaria sp. (n=16, 10.0%), Baylisascaris sp. (n=5, 3.1%), Dibothriocephalus sp. (n=2, 1.2%), and taeniid-type eggs (n=1, 0.6%). Molecular screening for intraerythrocytic parasites (Babesia spp.) and intracellular bacteria (Bartonella spp.) was negative for all bears tested. We detected antibodies to S. scabiei in six of 59 (10.2%) individuals. The relatively low level of parasite detection in this study meets expectations for brown bear populations living in large, relatively undisturbed habitats near the northern edge of the range. These results provide a contemporary understanding of parasites in Alaska brown bears and establish baseline levels of parasite presence to monitor for changes over time and relative to ecologic alterations.

Automated summary

To assess infection with or exposure to parasites, blood and fecal samples were collected from Alaska brown bears at five locations. Gastrointestinal parasites were screened using fecal centrifugal flotation, blood was tested for Bartonella and Babesia spp., and an ELISA was used to detect antibodies to Sarcoptes scabiei. The results showed low levels of parasite detection, which is expected for brown bear populations in undisturbed habitats near the northern edge of their range. These findings provide important baseline data for monitoring changes in parasite presence over time and in response to ecological alterations.