Seroprevalence of Borrelia burgdorferi, Anaplasma phagocytophilum, Ehrlichia canis, and Dirofilaria immitis among dogs in Canada.

The seropositivity of dogs to Borrelia burgdorferi, Anaplasma phagocytophilum, and Ehrlichia canis antibodies, and Dirofilaria immitis antigen was assessed in Canada. Borrelia burgdorferi had the highest seroprevalence, while that of Dirofilaria immitis has not changed significantly in the past 20 y. The risk for these vector-borne infectious agents in Canadian dogs is low but widespread with foci of higher prevalence.