Echinococcus multilocularis Infections in Domestic Dogs

Date
2021-06-03
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Abstract
Echinococcus multilocularis, a parasitic helminth of the northern hemisphere, normally cycles through definitive (coyotes, foxes, wolves, raccoon dogs) and intermediate hosts (rodents and some lagomorphs). In urban areas, domestic dogs can also become hosts for this parasite, maintaining the E. multilocularis population in areas with less wild canids. Occasionally, this zoonotic parasite infects humans, resulting in alveolar echinococcosis, which is often lethal. Echinococcus multilocularis has been well-studied in wild definitive hosts throughout its known global distribution, but further investigation into the prevalence of this parasite in dogs is needed. I conducted a literature review and meta-analysis estimating the true prevalence and risk factors associated with E. multilocularis infections in dogs globally. Then, I attempted to fill gaps in the literature by investigating E. multilocularis in dogs living near several parks in Calgary, Alberta. Using qPCR on fecal samples collected in 2012, I determined the true prevalence of E. multilocularis in Calgary dogs. Associated risk factors were assessed using dog behaviour questionnaires submitted by owners. While intestinal E. multilocularis has not previously been found in dog population studies in Canada, I found the prevalence in Calgary in 2012 to be similar to Europe and Asia. Some risk factors for infection were confirmed but more work is warranted. Therefore, I also conducted a pilot study directed at Calgary vet clinics to provide an updated estimate of intestinal E. multilocularis presence and also, for the first time, alveolar echinococcosis prevalence in dogs. This study design and dog behaviour questionnaire are suitable for assessing risk factors for both types of infections and is intended to be applied to a larger future study. Understanding the role of dogs in both the maintenance of the E. multilocularis lifecycle and the transmission of the infection to humans is paramount as urbanization drives humans and their pets closer to wildlife populations.
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Keywords
parasitology, zoonoses, domestic dog, echinococcus, urbanization, PCR, echinococcus multilocularis
Citation
Toews, E. A. W. (2021). Echinococcus multilocularis Infections in Domestic Dogs (Master's thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca.