Wildlife reservoirs and sentinels for vector-borne zoonoses in northern Canada

• Main Author: Buhler, Kayla Joy
• Other Authors: Jenkins, Emily, Leighton, Patrick, Fenton, Heather, Chilton, Neil, Voordouw, Maarten, Rubin, Joe, Jardine, Claire
• Format: Thesis
• Language: English
• Published: University of Saskatchewan 2022
• Subjects: Wildlife; Vector-borne disease; Bartonella; California serogroup viruses; Francisella tularensis; tularemia; arboviruses; climate change; Arctic; zoonoses; Canada; Fairbanks; Northwest Territories; Nunavut; Antarc*; Antarctica; Arctic Fox; Climate change; polar bear; Rangifer tarandus; Sea ice; Alaska
• Online Access: https://hdl.handle.net/10388/14382

Warming temperatures continue to impact arthropod diversity, density, and distribution in the Canadian Arctic. Consequently, arboviruses and other pathogens that rely on vector transmission have become a growing wildlife and public health concern. As the western Arctic is the most rapidly warming region of Canada and indeed the globe (along with Antarctica), it is imperative to obtain baselines and detect changes in the distribution of vector-borne pathogens, potential reservoirs, and pathogenesis in wildlife hosts. In this thesis, we characterize the prevalence of three groups of vector-borne pathogens in northern Canadian wildlife (California serogroup viruses (CSV), Bartonella spp. and Francisella tularensis bacteria). We also reveal aspects of the disease ecology for these viruses and bacteria, including potential reservoirs and transmission mechanisms. First, we completed a large-scale survey of wildlife in northern Canada for exposure to CSV. Antibodies were detected in all large mammals, including caribou (63%), arctic fox (4%), red fox (12%), and polar bear (28%), and associations with climate and biological factors were identified for polar bears. Both summer air temperatures and sex were significantly correlated with CSV exposure, indicating that climate warming and movement from sea ice onto land increased exposure to CSV in polar bears. Seroprevalence identified in caribou herds from Nunavut (80%) and Northwest Territories (83%) raised questions about their role as a potential reservoir species for Jamestown Canyon virus (JCV), the CSV that is established in cervids in temperate regions of North America. This led to work with captive reindeer (Rangifer tarandus) at the University of Alaska Fairbanks. We determined that reindeer in this herd (housed outdoors) are exposed to CSV under natural conditions, with almost all animals naturally exposed after 2 summers of life. Experimental exposure of naïve and low titre reindeer to JCV demonstrated that they become viremic for up to five days with no ...