SEROLOGICAL AND MOLECULAR EVALUATION OF TISSUE-DWELLING PARASITES (SARCOCYSTIDAE) IN HARVESTED WILDLIFE IN THE CANADIAN ARCTIC
Date
2024-04-25
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
ORCID
0000-0002-9949-4324
Type
Thesis
Degree Level
Doctoral
Abstract
Country foods are integral to Inuit cultural identity and food security. However, the harvest and consumption of wildlife pose risks of transmission of zoonotic parasites, such as Toxoplasma gondii, of concern for Inuit communities in the Canadian Arctic. The main aim of this thesis was to determine seroprevalence and tissue prevalence of Toxoplasma gondii and related tissue-dwelling coccidian parasites in harvested wildlife in the Canadian Arctic. To address these objectives, I used multiple serological techniques to detect antibodies against parasites and molecular approaches to detect DNA in tissue samples. The overall seroprevalence for T. gondii in caribou from Nunavik, Québec was 18% (95% CI: 11.5-28%) and 1% (95% CI: 0.2-4.6%) in belugas from the Eastern Beaufort Sea, Northwest Territories. On magnetic capture DNA extraction and qPCR for T. gondii in heart and brain of caribou and belugas, DNA of T. gondii was detected in only one beluga heart. This suggests that the risk of zoonotic transmission of T. gondii from harvesting and consuming caribou and belugas is low, but not zero. Antibodies to Neospora caninum were detected in 5% (95% CI: 0.6-8%) and DNA was detected in tissues of 1.5% (95% CI: 0.3-7.9%) of caribou harvested in Nunavik. Furthermore, DNA of Sarcocystis spp. was detected in both heart and skeletal muscle from caribou (85%, 95% CI: 76.4-91.2%), and muscle of beluga (59%, 95% CI: 47.9-69.2%). Phylogenetic analysis of Sarcocystis spp. from caribou were linked to terrestrial canids, and were similar to sequences reported in Europe, possibly reflecting translocations of Rangifer sp. In contrast, Sarcocystis sp. from belugas indicated a potential marine life cycle. Finally, I compared in-house ELISAs with a commercial ELISA kit in previously tested polar bear samples for T. gondii to optimize these tests in wildlife, emphasizing the need for improved testing protocols, known controls, and statistical approaches to test comparison when gold standards are lacking. In conclusion, this thesis contributes to our understanding of tissue-dwelling coccidian parasites in wildlife harvested for human consumption, offers insights into arctic trophic dynamics, and highlights the importance of a One Health concept for human and animal health in the Canadian North.
Description
Keywords
Country foods, Toxoplasma, Sarcocystidae, Canadian North,
Citation
Degree
Doctor of Philosophy (Ph.D.)
Department
Veterinary Microbiology
Program
Veterinary Microbiology