Black Bear Population Health Monitoring in the Southeast

Author

Kathleen Elizabeth RieseFollow

Date of Award

8-2023

Degree Type

Thesis

Degree Name

Master of Science

Major

Comparative and Experimental Medicine

Major Professor

Richard Gerhold

Committee Members

Richard Gerhold, Michelle Dennis, Julie Sheldon

Abstract

Recent growth of the American black bear (Ursus americanus) population in the southeast raises concerns about the potential spread of density-dependent diseases among bears, particularly sarcoptic mange. However, research on the health of bears in this area is limited. We analyzed samples from 169 bears in the region. We performed Knotts tests, skin scrapes, fecal floats; Canine adenovirus (CAV), canine parvovirus (CPV), canine distemper virus (CDV), and Toxoplasma gondii serology, Trypanosoma, Rickettsia rickettsii, and apicomplexan PCR, and identified ecto- and endoparasites found grossly or histologically. We found that 69% (63 of 91) had microfilaria; genetic analysis identified the microfilaria as a novel Mansonella ozzardi-like nematode. We performed 122 fecal floats and found 35 (28.7%) had Baylisascaris transfuga, 16 (13%) had Capillarid spp., 11 (9%) had nematode larva, 2 (1.7%) had Ancylostoma spp., and 4 (3.3%) had Coccidia spp. No Sarcoptes scabiei mites were identified on skin scrapes; however, Ursicoptes americanus mites were identified on six (6.4%). T. gondii antibodies were detected in 49.7% (78 of 157) of bears. CPV, CAV, and CDV antibodies were detected in 2.1%, 2.1%, and 18.8% of bears, respectively. Of the 113 bears tested, 10 were PCR-positive for Babesia (8.9%). All bears were PCR-negative for Rickettsia rickettsii and Trypanasoma spp. Collected ticks were morphologically identified; 64.5% of bears (69 of 107) were infested with Dermacentor variabilis, and 4.7% (5 of 107) were infested with Ambylomma maculatum, 0.9% (1 of 107) were infested with Ambylomma americnaum and 0.9% (1 of 107) were infested with Ixodes scapularis. Additionally, endoparasites identified on autopsy or histology include Macracanthorhynchus ingens, Gongylonema spp., Physaloptera spp., Dirofilaria immitis, Trichinella spp., Angiostrongylus vasorum, Pelodera spp., and Sarcocystis spp. This research will lay the foundation for future research on bear diseases in the southeast and aid wildlife managers with management decisions on free-ranging black bear populations.

Recommended Citation

Riese, Kathleen Elizabeth, "Black Bear Population Health Monitoring in the Southeast. " Master's Thesis, University of Tennessee, 2023.
https://trace.tennessee.edu/utk_gradthes/9964