General Information for Canada
In late November 1998, 2,389 question-naires were sent to small and mixed animal clinics and to institutions in Canada to assess heartworm (HW) infection primarily in dogs in 1998. On January 15, 1999, the questionnaire was sent again to clinics in Ontario and Manitoba which had not responded.
There were 1,329 questionnaires returned for 1998. But 22 of them were not included in the analysis of the data because they were returned uncompleted with incorrect addresses or were improperly completed with the clinic's name missing and the data in the questionnaire could not be verified. The rate of response was 55.2%.
There were 653 dogs reported with HW in Canada in 1998 (812 in 1997). More dogs were blood tested in 1998 (418,728) than in 1997 (413,351) and the prevalence of HW in dogs in 1998 was 0.16% (0.20% in 1997). The major focus of infection in Canada continues to be in southern Ontario. The three other foci are in southern Manitoba, southern Quebec and in the Okanagan Valley in British Columbia. In 1998, there were 25 dogs with HW in Manitoba, 69 in Quebec and 2 in British Columbia. There were also 3 dogs with HW in Alberta, 4 in Nova Scotia and 1 in New Brunswick.