Investigation of the prevalence of Echinococcus multilocularis, and risk of infection, in wild canids in Ontario, Canada

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Echinococcus multilocularis (the fox tapeworm) is a zoonotic parasite that has a high case fatality rate in people when untreated. In North America, adult E. multilocularis occur in the small intestine of foxes and coyotes. When mature, eggs are shed in the feces; if ingested by the intermediate host (e.g. wild rodents) an alveolar hydatid cyst develops in the liver. The life cycle is completed when the intermediate host is ingested by wild canids. Historically, there are two recognized endemic areas in North America; the Northern Tundra Zone, and the North Central Region that includes three Canadian provinces and 13 contiguous US states. Strangely, despite this broad geographic distribution, very few cases of E. multilocularis have been described in dogs, cats or people. Prior to 2012, E. multilocularis had never been diagnosed in Ontario. However, since then, six cases of alveolar echinococcosis have been reported in southern Ontario; four in dogs, two in non-human primates. Five of the animals had not travelled outside southern Ontario. Since this is a new, emerging threat to canine and human health, the objectives of this study are: (i) to determine the prevalence and geographic distribution of E. multilocularis in coyotes and foxes across southern Ontario, (ii) to identify risk factors associated with E. multilocularis infection in coyotes and foxes, and (iii) to identify high risk areas for infection in dogs and people in this region. These objectives will be accomplished through the collection of fecal samples from 386 coyote and 386 fox carcasses over 2 years. Thereafter, the samples will be analyzed in Sweden using a polymerase chain reaction assay considered the most sensitive diagnostic method for E. multilocularis in feces at the current time. Using spatial analysis techniques, the diagnostic data and information about the geographic place of origin of each carcass will be used to map the risk of infection for dogs and humans across southern Ontario. Risk factors for E. multilocularis infection in coyotes and foxes will also be determined. Such information is needed to determine public and animal health risks across this region.