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ARS Home » Northeast Area » Beltsville, Maryland (BARC) » Beltsville Agricultural Research Center » Animal Parasitic Diseases Laboratory » Research » Publications at this Location » Publication #408465
Research Project: Foodborne Parasites and their Impact on Food Safety

Location: Animal Parasitic Diseases Laboratory

Title: Increased pathogen exposure of a marine apex predator over three decades

Author
item RODE, KARYN - Us Geological Survey (USGS)
item VAN HEMERT, CAROLINE - Us Geological Survey (USGS)
item WILSON, RYAN - Us Fish And Wildlife Service
item WOODRUFF, SUSANNAH - Us Fish And Wildlife Service
item PABILONI, KRISTY - Colorado State University
item BALLWEBER, LORA - Colorado State University
item Kwok, Oliver
item Dubey, Jitender

Submitted to: PLOS ONE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/10/2024
Publication Date: 10/23/2024
Citation: Rode, K., Van Hemert, C., Wilson, R., Woodruff, S., Pabiloni, K., Ballweber, L., Kwok, O.C., Dubey, J.P. 2024. Increased pathogen exposure of a marine apex predator over three decades. PLOS ONE. 19(10). Article e0310973. https://doi.org/10.1371/journal.pone.0310973.
DOI: https://doi.org/10.1371/journal.pone.0310973

Interpretive Summary: Climate change can affect the transmission of infectious agents. Neospora caninum and Toxoplasma gondii are 2 single celled parasites with a very wide host range and they have a worldwide distribution. Toxoplasma gondii infections are prevalent even in Arctic wildlife, including polar bears. The Chukchi Sea, situated between the northwest coast of Alaska and eastern Russia, is home to one of the most southerly ranging polar bear populations and is undergoing rapid sea ice loss making it an important area for disease surveillance. The authors conducted a study of wildlife and zoonotic pathogens in Chukchi Sea polar bears to determine whether prevalence in adult females has increased over time, and to identify potential risk factors for exposure among all sex and age classes. Results revealed the most pronounced increases in pathogen exposure, Including Toxoplasma, reported for polar bears to date and demonstrated these changes occurring over a relatively short (20–30 year) time span. These results will be of interest to parasitologists and biologists. This research was completed before redirection of Toxoplasma research at ARS.

Technical Abstract: Environmental changes associated with global warming create new opportunities for pathogen and parasite transmission in Arctic wildlife. As an apex predator ranging over large, remote areas, changes in pathogens and parasites in polar bears are a useful indicator of changing transmission dynamics in Arctic ecosystems. We examined prevalence and risk factors associated with exposure to parasites and viral and bacterial pathogens in Chukchi Sea polar bears. Serum antibodies to six pathogens were detected and prevalence increased between 1987–1994 and 2008–2017 for five: Toxoplasma gondii, Neospora caninum, Francisella tularensis, Brucella abortus/suis, and canine distemper virus. Although bears have increased summer land use, this behavior was not associated with increased exposure. Higher prevalence of F. tularensis, Coxiella burnetii, and B. abortus/suis antibodies in females compared to males, however, could be associated with terrestrial denning. Exposure was related to diet for several pathogens indicating increased exposure in the food web. Elevated white blood cell counts suggest a possible immune response to some pathogens. Given that polar bears face multiple stressors in association with climate change and are a subsistence food, further work is warranted to screen for signs of disease.