Characterization of incidental lesions and common causes of morbidity and mortality among free-ranging Leporidae in Canada.
Date
2023-09-18
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Abstract
Wildlife disease surveillance is an important tool for the discovery and mitigation of disease outbreaks. Research into wildlife disease often focuses on charismatic megafauna, but many small and common species play a vital role in their ecosystem and have regular contact with humans. Leporids are common throughout Canada, are an important prey species, and frequently interact with humans through lawns, gardens, domestic animals, and harvesting activities. However, little is known about their diseases, risks to humans and overall health, particularly in an urban setting. The objectives of this thesis were to investigate major causes of morbidity and mortality as well as common incidental lesions and pathogens amongst leporids in Canada. I conducted a retrospective analysis of 569 cases of deceased leporids submitted to the Canadian Wildlife Health Cooperative between 1990 and 2019. Trauma (215/467; 46.0%), specifically vehicle collisions (51/215; 23.7%), was the most common cause of mortality. Moderate to good body condition, male sex, and no incidental findings were associated with an increased odds of trauma related mortality. Incidental lesions were common amongst all categories of mortality. Zoonotic pathogens observed included Francisella tularensis, Pasteurella spp. and Toxoplasma gondii. I also completed autopsies on 140 presumed road-killed urban leporids collected from within Calgary, Alberta, Canada. There were 29 (20.7%) cases of non-trauma related mortalities, which included one case of Tularemia. The majority of non- trauma related mortalities were classified as open diagnosis (21/140; 15%). Incidental lesions were observed in 37.9% of cases and included nephroblastoma (11/140; 6%), Taenia spp. cysts (20/140; 14%), idiopathic splenomegaly (7/140; 5%), and idiopathic interstitial nephritis (11/140; 8%). Again, moderate to good body condition and a lack of incidental lesions or pathogens were associated with an increased odds of trauma related mortality. Overall, this thesis illustrates that Canadian leporids are competent hosts for a variety of zoonotic pathogens but are themselves vulnerable to human related mortality, particularly if they are in apparent good health. The results from this thesis can be used by the public, human health care professionals, veterinarians, and wildlife biologists to make informed decisions on interacting with and conserving free-ranging leporid populations in Canada.
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Keywords
Wildlife, Pathology, Leporids, Rabbit, Hare, Zoonotic, Disease, Disease surveillance, Urban
Citation
Hunter, S. T. (2023). Characterization of incidental lesions and common causes of morbidity and mortality among free-ranging Leporidae in Canada (Master's thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca.