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. 2019 Jun;60(6):605-612.

Heartworm infection in domestic dogs in Canada, 1977-2016: Prevalence, time trend, and efficacy of prophylaxis

Erin McGill  1 , Olaf Berke  1 , J Scott Weese  1 , Andrew Peregrine  1
Affiliations

Heartworm infection in domestic dogs in Canada, 1977-2016: Prevalence, time trend, and efficacy of prophylaxis

Erin McGill et al. Can Vet J. 2019 Jun.

Abstract
in English, French

Dirofilaria immitis (heartworm) is a mosquito-borne parasite that primarily infects domestic and wild canids. The objectives of this study were to i) determine if there has been a temporal change in prevalence of heartworm infection among domestic dogs in Canada from 1977 to 2016; ii) explore the spatial extension of heartworm across Canada using choropleth maps; and iii) assess the efficacy of preventive drugs using the estimated "Attributable Fraction Exposed." Heartworm surveys that collected data from 1977 to 2010 and serological laboratory data from 2007 to 2016 were analyzed. The data depicted a decrease in heartworm prevalence, both nationally and provincially, from 1977 to the early 2000s. However, an increase in prevalence was identified for tested dog populations in Manitoba and Quebec from 2007 to 2016. Chemoprophylaxis was associated with an estimated 93.0% [95% confidence interval (CI): 92.85, 93.3] reduction of heartworm infections in domestic dogs in Canada from 1977 to 2010.

Infection par le ver du coeur chez les chiens domestiques au Canada, 1977–2016 : prévalence, tendance dans le temps et efficacité de la prophylaxie. Dirofilaria immitis (ver du coeur) est un parasite transporté par des moustiques qui infecte principalement les canidés domestiques et sauvages. Les objectifs de cette étude consistaient : i) à déterminer s’il y avait eu un changement temporel de la prévalence de l’infection parmi les chiens domestiques au Canada de 1977 à 2016; ii) à explorer le prolongement spatial du ver du coeur au Canada à l’aide de cartes choroplèthe; et iii) à évaluer l’efficacité des médicaments préventifs en utilisant l’estimation de la «fraction attribuable exposée». Les sondages sur le ver du coeur qui ont recueilli des données de 1977 à 2010 et les données sérologiques de laboratoire de 2007 à 2016 ont été analysés. Les données illustraient une baisse de la prévalence du ver du coeur, tant à l’échelle nationale que provinciale, de 1977 au début des années 2000. Cependant, une hausse de la prévalence a été identifiée pour les populations de chiens testées au Manitoba et au Québec de 2007 à 2016. La chimioprophylaxie était associée à une réduction estimée de 93,0 % [intervalle de confiance (IC) de 95 % : 92,85, 93,3] des infections du ver du coeur chez les chiens domestiques au Canada de 1977 à 2010.(Traduit par Isabelle Vallières).

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Figures

Figure 1
Figure 1
Heartworm prevalence scatterplots weighted by sample size with smoothing lines for Canada (black), Manitoba (green), Ontario (pink), and Quebec (blue). The x-axis depicts years of data collection and the y-axis depicts prevalence of heartworm infection as a percentage. Left panel, survey data; right panel, laboratory data.
Figure 2
Figure 2
Choropleth map of aggregated smoothed heartworm prevalence using heartworm survey data for Canada for all dogs tested from 1981 to 2010.
Figure 3
Figure 3
Choropleth map of aggregated smoothed heartworm prevalence from 2007 to 2016 using laboratory data for Canada for all dogs tested. The distribution of veterinary clinics with submitted samples is overlaid; the size of the point is weighted by the number of submissions.
See this image and copyright information in PMC

References

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