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Home / Equine Research Bank / Can Vet J / Factors associated with West Nile virus disease fatalities i...
The Canadian veterinary journal = La revue veterinaire canadienne2007; 48(11); 1137-1145;

Factors associated with West Nile virus disease fatalities in horses.

Abstract: In 2003, the occurrence and location of horses with clinical signs of West Nile virus infection were identified in the southern portion of Saskatchewan with the help of veterinarians, owners, and the regional laboratory. A total of 133 clinical cases were reported between July 30 and September 19, 2003; however, postseason surveillance suggests that the number of cases was underestimated. The case fatality rate was 43.8% (95% CI 35.2, 52.4). Factors associated with fatality in clinical cases included sex, week of onset of clinical signs, and coat color. Reported clinical cases clustered within regional health authority districts, suggesting regional differences in geographic factors, potentially including climate and mosquito control, that could contribute to the risk of disease. However, most of the variation in the risk of fatality in clinical cases is explained at the individual level rather than the Regional Health Authority level, which suggests the outcome of clinical disease is primarily determined by characteristics of, or management factors affecting, the individual horse. En 2003, l’apparition des signes cliniques d’infection au virus du Nil occidental chez les chevaux et le lieu où ils étaient situés ont été identifiés dans le sud de la Saskatchewan avec l’aide des vétérinaires, des propriétaires et du laboratoire régional. Un total de 133 cas cliniques ont été rapportés entre le 30 juillet et le 19 septembre 2003 et les observations de fin de saison laissent présager que le nombre de cas a été sous-estimé. Le taux de mortalité était de 43,8 % (95 % IC 35,2, 52,4). Les facteurs associés à la mortalité dans les cas cliniques comprenaient le sexe, la semaine du début des signes cliniques et la couleur de la robe. Les cas cliniques rapportés étaient regroupés dans certains districts des autorités régionales de la santé, laissant présager des différences régionales dans les facteurs géographiques, dont le climat et le contrôle des moustiques, qui auraient pu affecter le facteur de risque. Cependant, la majorité de la variation du risque de mortalité dans les cas cliniques semble relié à l’individu plutôt qu’aux autorités régionales de la santé, ce qui laisse présager que l’apparition des cas cliniques est en majeure partie déterminée par des caractéristiques propres à l’animal ou par des facteurs de gestion qui l’influence. (Traduit par Docteur André Blouin)
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Publication Date: 2007-12-07 PubMed ID: 18050794PubMed Central: PMC2034420
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  • Journal Article
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  • Non-U.S. Gov't

Summary

This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.

This research investigates factors associated with fatalities in horses due to West Nile virus in Saskatchewan in 2003. The study found that sex, timing of clinical symptoms onset, and coat color were factors that influenced fatality rates, most of which could be attributed to individual characteristics or management practices affecting each horse.

Study Overview

The study aimed to identify the factors influencing West Nile virus fatalities in horses by evaluating demographics, onset of symptoms, and geographic factors. Key points included:

  • The study took place in the southern part of Saskatchewan in 2003.
  • The information was gathered with the assistance of veterinarians, horse owners, and the regional laboratory.
  • The research was conducted during the WNV infection season, between July 30 and September 19.
  • Surveillance data indicated that the total number of cases reported (133) was likely an underestimate.

Case Fatality and Associated Factors

From the reported cases, a high rate of fatality (43.8%) was observed. The different factors associated with horse fatalities were identified as:

  • The horse’s sex
  • The week when the clinical signs were first noticed
  • The horse’s coat color

Role of Geographic Factors

Reports showed that cases were notably concentrated within certain regional health authority districts. This suggests that geographical factors such as:

  • Regional climate conditions
  • Effective mosquito control

may have influenced the risk and spread of the disease.

Individual Horse Characteristics & Management Practices

The study concluded that most of the variation in the risk of fatality was tied to individual-level factors rather than regional factors. This suggests that the outcome of the disease, in most cases, was primarily determined by:

  • The characteristics of the individual horse – its sex, coat color etc.
  • Management factors affecting the horse – how the horse was taken care of once the symptoms were detected.

Cite This Article

APA
Epp T, Waldner C, West K, Townsend H. (2007). Factors associated with West Nile virus disease fatalities in horses. Can Vet J, 48(11), 1137-1145.

Publication

The Canadian veterinary journal = La revue veterinaire canadienne
ISSN: 0008-5286
NlmUniqueID: 0004653
Country: Canada
Language: English
Volume: 48
Issue: 11
Pages: 1137-1145

Researcher Affiliations

Epp, Tasha
  • Department of Large Animal Clinical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Saskatchewan. tasha.epp@usask.ca
Waldner, Cheryl
    West, Keith
      Townsend, Hugh

        MeSH Terms

        • Animal Husbandry / methods
        • Animals
        • Antibodies, Viral / blood
        • Breeding
        • Cluster Analysis
        • Female
        • Horse Diseases / epidemiology
        • Horse Diseases / mortality
        • Horses
        • Male
        • Mosquito Control
        • Risk Factors
        • Saskatchewan / epidemiology
        • Seasons
        • Seroepidemiologic Studies
        • Sex Factors
        • West Nile Fever / epidemiology
        • West Nile Fever / mortality
        • West Nile Fever / veterinary
        • West Nile virus / immunology
        • West Nile virus / isolation & purification

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