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Canadian Journal of Public Health

, Volume 97, Issue 5, pp 369–373 | Cite as

Seroprevalence of West Nile Virus in Saskatchewan’s Five Hills Health Region, 2003

  • Tara L. Schellenberg
  • Maureen F. Anderson
  • Michael A. Drebot
  • Mark T. R. Vooght
  • A. Ross Findlater
  • Phillip S. Curry
  • C. Alexia Campbell
  • William D. Osei
Article

Abstract

Background

The Five Hills Health Region of Saskatchewan reported the highest West Nile virus (WNV) case rates in the 2003 outbreak. A serologic and telephone survey was undertaken to assess the seroprevalence of the virus and the knowledge, attitudes and behaviours of the residents.

Methods

Respondents had to be at least 18 years of age, and residents of the Five Hills Health Region between July 1st and September 15th, 2003. Blood samples of respondents were tested at the National Microbiology Laboratory for flavivirus immunoglobulin using a WNV IgG ELISA and plaque reduction neutralization test. Descriptive analyses performed related to respondents’ demographics, knowledge, attitudes, behaviours, and seropositivity. WNV infection risk was assessed using odds ratio.

Results

There were 619 questionnaire respondents, of whom 501 donated a blood sample. The seroprevalence of WNV in the Five Hills Health Region was 9.98% (95% CI 7.37–12.59%). Seropositivity of rural areas was 16.8% and urban was 3.2%. Most (97%) of participants thought WNV was an important health issue. Forty-eight percent of the participants used insect repellents containing DEET most of the time. There was good knowledge regarding WNV transmission and prevention of the spread of WNV. Rural compared to urban residents were six times more likely to be positive for WNV (OR=6.13, 95% CI 2.82–13.34).

Interpretation

This is the highest seroprevalence rate of West Nile virus recorded in North America thus far. Many factors could have influenced this outbreak, such as eco-region, early prolonged hot weather, level of mosquito control programs, urban and rural community differences, and personal protective behaviours.

MeSH terms

West Nile virus seroepidemiologic study Saskatchewan knowledge attitude behavior 

Résumé

Contexte

La région sanitaire de Five Hills, en Saskatchewan, est celle qui a déclaré le plus grand nombre de cas de virus du Nil occidental (VNO) durant la flambée épidémique de 2003. Nous avons mené une enquête sérologique et téléphonique pour évaluer la séroprévalence du virus ainsi que les connaissances, les attitudes et les comportements des résidents.

Méthode

Les répondants devaient avoir au moins 18 ans et avoir habité la région sanitaire de Five Hills entre le 1er juillet et le 15 septembre 2003. Le Laboratoire national de microbiologie a examiné les échantillons de sang des répondants à l’aide de l’ELISA IgG et d’un test de séroneutralisation par réduction des plaques pour y détecter les immoglobulines dirigées vers le flavivirus. Nous avons effectué des analyses descriptives des données démographiques des répondants, ainsi que de leurs connaissances, de leurs attitudes, de leurs comportements et de leur séropositivité. Le risque d’infection à VNO a été évalué selon un rapport de cotes.

Résultats

Les répondants du questionnaire étaient au nombre de 619, dont 501 ont produit un échantillon de sang. La séroprévalence du VNO dans la région sanitaire de Five Hills était de 9,98 % (IC de 95 % = 7,37–12,59). La séropositivité était de 16,8 % dans les zones rurales et de 3,2 % dans les zones urbaines. La plupart des participants (97 %) considéraient le VNO comme un problème de santé important. Quarante-huit p. cent utilisaient la plupart du temps des insectifuges contenant du diéthyltoluamide (DEET). On connaissait bien le mode de transmission du VNO et les mesures pour prévenir sa propagation. Les résidents des zones rurales étaient six foix plus susceptibles d’être séropositifs pour le VNO que les résidents des milieux urbains (RC=6,13, IC de 95 % = 2,82–13,34).

Interprétation

Il s’agit du plus fort taux de séroprévalence du virus du Nil occidental enregistré en Amérique du Nord jusqu’à maintenant. De nombreux facteurs pourraient avoir influencé cette flambée, dont l’écorégion, la chaleur précoce et prolongée, l’ampleur des programmes de désinsectisation, les différences entre les communautés urbaines et rurales, et les comportements de protection individuels.

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Copyright information

© The Canadian Public Health Association 2006

Authors and Affiliations

  • Tara L. Schellenberg
    • 1
  • Maureen F. Anderson
    • 2
  • Michael A. Drebot
    • 3
  • Mark T. R. Vooght
    • 1
  • A. Ross Findlater
    • 2
  • Phillip S. Curry
    • 2
  • C. Alexia Campbell
    • 4
  • William D. Osei
    • 2
  1. 1.Department of Public Health ServicesFive Hills Health RegionMoose JawCanada
  2. 2.Population Health BranchSaskatchewan HealthReginaCanada
  3. 3.National Microbiology LaboratoryPublic Health Agency of CanadaWinnipegCanada
  4. 4.Department of Public Health SciencesUniversity of TorontoTorontoCanada

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