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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: Global Change Biology
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. Global Change Biology. 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: nvironmental changes associated with warming have created new opportunities for transmission of pathogens and parasites in Arctic wildlife, including among threatened species such as 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. We 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. We detected antibodies to six of eight pathogens and identified increases in seroprevalence between 1987–1994 and 2008–2017 for five: Toxoplasma gondii, Neospora caninum, Francisella tularensis, Brucella abortus/suis, and canine distemper virus (CDV). Our results revealed the most pronounced increases in pathogen exposure reported for polar bears to date and demonstrated these changes occurring over a relatively short (20–30 year) time span. However, contrary to prior studies, there was no correlation between summer land use and pathogen exposure among adult females, suggesting other factors are more important in the Chukchi Sea. We identified links between specific prey items and pathogen exposure and detected significant effects of age and sex on seroprevalence. Females had higher seroprevalence of bacterial pathogens F. tularensis, C. burnetii, and B. abortus/suis than males, whereas T. gondii and CDV were more common in adults than subadults; these patterns appear largely explained by a combination of diet, behavior, including cumulative time spent on land, and variable antibody duration among pathogens. We used hematology data to evaluate immune response associated with pathogen exposure. Blood cell counts suggested elevated immune response for specific pathogens, although further work is needed to determine broader health impacts.