Parasite populations of river otter and mink in Western Canada and first report of the zoonotic trematode Alaria mustelae in river otter in

Kyle M Shanebeck^1*Melissa Todd²Philippe J Thomas³Stephen Raverty⁴Stephanie Green¹Clement Lagrue^1,5

• ¹Department of Biological Sciences, Faculty of Science, University of Alberta, Edmonton, Alberta, Canada
• ²Coast Area Research Section, British Columbia Ministry of Forests, Nanaimo, BC, Canada
• ³National Wildlife Researh Centre, Environment and Climate Change Canada, Carleton UniversityC, Ottawa, ON, Canada
• ⁴Animal Health Centre, British Columbia Ministry of Agriculture, Abbotsford, British Columbia, Canada
• ⁵Department of Conservation, Wellington, Wellington, New Zealand

At the top of aquatic ecosystems, the north American river otter (Lontra canadensis) and mink (Neogale vison) are definitive hosts to a range of parasite species. We surveyed the helminth parasites of otter and mink in Alberta and British Columbia, comparing our data against historical reports of parasites from across North America. Results showed a lower diversity of species in Western Canada than previously reported, especially in comparison to the southern United States. Parasite communities in sampled animals were characterized by four main species (Alaria mustelae, Filaroides martis, Isthmiophora inermis, and Versteria rafei). As mesocarnivores that connect aquatic and terrestrial food webs, otter and mink are definitive as well as potential intermediate or paratenic hosts for parasitic species that use aquatic hosts. We observed adult and larval infections of V. rafei and A. mustelae in our animals, which are both of concern for zoonotic transmission. Larval infections by mesocercariae of A. mustelae were highly prevalent, and larval migrans was associated with inflammation and fibrosis in various tissues. Increasing intensities of infection were related to decreasing nutritional condition. As these associations have not been previously reported in otter or mink, it may represent an emergent disease of concern for these important sentinel species. This research highlights a serious gap in knowledge of helminth communities in Western Canada and the threat of zoonotic infection for vulnerable communities. Research to assess the risk of exposure and infection for First Nation communities and fur trappers who handle these mammals is warranted. Furthermore, research into the distribution of these parasites in other intermediate and definitive hosts is required to understand the range of this threat to wildlife and human communities and its potential link to warming waters due to global climate change.