Introduced and Native Haplotypes of Echinococcus multilocularis in Wildlife in Saskatchewan, Canada.

Recent detection of a European-type haplotype of the cestode Echinococcus multilocularis in a newly enzootic region in British Columbia prompted efforts to determine if this haplotype was present elsewhere in wildlife in western Canada. In coyote (Canis latrans) definitive hosts in an urban region in central Saskatchewan (SK), we found a single haplotype of E. multilocularis that was most similar to a haplotype currently established in the core of this parasite's distribution in Europe and to the European-type haplotype found in coyotes and a dog (Canis lupus familiaris) in British Columbia. We found six haplotypes of E. multilocularis from deer mouse (Peromyscus maniculatus) intermediate hosts in southwestern SK that were closely related to, and one haplotype indistinguishable from, a haplotype previously reported in the adjacent north-central US. This is a higher level of diversity than has previously been recognized for this parasite, which suggests that the population native to central North America is well established, rather than a recent introduction from the Arctic. These findings, in combination with recent cases of alveolar hydatid cysts in dogs in Canada, raise concerns that European haplotypes of E. multilocularis may be increasing in distribution within wildlife in Canada. European haplotypes may pose greater risks to veterinary and human health than native haplotypes long established in central North America.