Environmental and behavioral changes may influence the exposure of an Arctic apex predator to pathogens and contaminants

Authors: ATWOOD, TODD - Us Geological Survey (USGS); DUNCAN, COLLEEN - Colorado State University; PATYK, KELLY - Animal And Plant Health Inspection Service (APHIS); NOL, PAULINE - Animal And Plant Health Inspection Service (APHIS); RHYAN, JACK - Animal And Plant Health Inspection Service (APHIS); MCCOLLUM, MATTHEW - Animal And Plant Health Inspection Service (APHIS); MCKENNEY, MELISSA - University Of Connecticut; RAMEY, ANDREW - Us Geological Survey (USGS); CEZAR, CAMILIA - Non ARS Employee; Kwok, Oliver; Dubey, Jitender; HENNAGER, STEVEN - Animal And Plant Health Inspection Service (APHIS)

Submitted to: Nature Scientific Reports
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/25/2017
Publication Date: 10/16/2017
Citation: Atwood, T., Duncan, C., Patyk, K., Nol, P., Rhyan, J., Mccollum, M., Mckenney, M., Ramey, A., Cezar, C., Kwok, O.C., Dubey, J.P., Hennager, S. 2017. Environmental and behavioral changes may influence the exposure of an Arctic apex predator to pathogens and contaminants. Nature Scientific Reports. 7:13193. https://doi.org/10.1038/s41598-017-13496-9
DOI: https://doi.org/10.1038/s41598-017-13496-9

Interpretive Summary: Toxoplasma gondii is a single-celled parasite of all warm-blooded hosts worldwide. It causes mental retardation and loss of vision in children and abortion in livestock. Cats are the main reservoir of T. gondii because they are the only hosts that can excrete the resistant stage (oocyst) of the parasite in the feces. Humans become infected by eating under cooked meat from infected animals and food and water contaminated with oocyst. Of all animals only cats can excrete oocysts. In the present study, authors survey polar bears for T. gondii infection. Antibodies to T. gondii were found in 33 of 105 (31.4%) and N. caninum in 5 of 133 (4.7%). The authors found that seroprevalence of Brucella spp. and T. gondii antibodies likely increased through time, and provide the first evidence of exposure of polar bears to a related parasite, Neospora caninum. Additionally, the odds of exposure to T. gondii were greater for bears that used land than for bears that remained on the sea ice during summer and fall. Changes in polar bear behavior brought about by climate-induced modifications to the Arctic marine ecosystem may increase exposure risk to certain pathogens and alter contaminant exposure pathways. This is the first report of Neospora exposure of polar bears. The results will be useful for parasitologists, biologists, and epidemiologists.

Technical Abstract: Polar bears (Ursus maritimus) may serve as sentinels for pathogens and contaminants, providing insight into changing Arctic ecosystems and health risks to wildlife and humans. Recent changes in the availability of sea ice habitat have coincided with increased use of land by polar bears from the southern Beaufort Sea (SB), which may alter exposure risks. We assayed blood samples from SB polar bears to assess prior exposure to the pathogens Brucella spp., Toxoplasma gondii, Coxiella burnetii, Francisella tularensis, and Neospora caninum, estimate concentrations of persistent organic pollutants (POPs), and evaluate risk factors associated with exposure to pathogens and POPs. We found that seroprevalence of Brucella spp. and T. gondii antibodies likely increased through time, and provide the first evidence of exposure of polar bears to C. burnetii, N. caninum, and F. tularensis. Additionally, the odds of exposure to T. gondii were greater for bears that used land than for bears that remained on the sea ice during summer and fall, while mean concentrations of the chlordane (_CHL) were lower for land-based bears. Changes in polar bear behavior brought about by climate-induced modifications to the Arctic marine ecosystem may increase exposure risk to certain pathogens and alter contaminant exposure pathways.