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Home / Equine Research Bank / Virology / Western Equine Encephalitis submergence: lack of evidence fo...
Virology2008; 380(2); 170-172; doi: 10.1016/j.virol.2008.08.012

Western Equine Encephalitis submergence: lack of evidence for a decline in virus virulence.

Abstract: The incidence of Western Equine Encephalitis (WEE) in humans and equids peaked during the mid-20th century and has declined to fewer than 1-2 human cases annually during the past 20 years. Using the mouse model, changes in WEE virus (WEEV) virulence were investigated as a potential explanation for the decline in the number of cases. Evaluation of 10 WEEV strains representing a variety of isolation locations, hosts, and all decades from the 1940's to the 1990's yielded no evidence of a decline in virulence. These results suggest that ecological factors affecting human and equine exposure should be investigated to explain the decline in WEE.
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Publication Date: 2008-09-17 PubMed ID: 18801549PubMed Central: PMC2574696DOI: 10.1016/j.virol.2008.08.012Google Scholar: Lookup
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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 the decrease in Western Equine Encephalitis (WEE) cases over years and refutes the possibility of a decline in the virulence of the WEE virus as a reason for this decline. Instead, it proposes that changes in ecological factors impacting exposure to the virus should be examined.

Understanding Western Equine Encephalitis virus (WEEV) and Its Trend

  • The first part of the study focuses on the Western Equine Encephalitis virus (WEEV), an infectious virus primarily affecting horses and humans. This disease was prevalent during the mid-20th century but has been declining for the past 20 years to only 1-2 human cases per year.

The WEEV Experiment in a Mouse Model

  • In an effort to understand why the number of WEE cases has been decreasing, researchers questioned whether the virus had become less virulent, or less harmful.
  • Using a mouse model for testing, ten different WEEV strains were evaluated. These strains represented a wide range of isolation locations, hosts, and time periods (from the 1940s to the 1990s). This variety was essential to ensure a comprehensive study.

Results and Conclusion

  • The research results contradict the hypothesis that the virus has become less virulent over time. The findings did not exhibit any evidence of a decline in the virus’ virulence across the decades studied.
  • These results led to the conclusion that the reduction in WEE cases over recent decades is unlikely to be due to the virus losing its harmful power.
  • Instead, the study suggests considering other factors that may have changed over time, such as the ecological factors affecting how humans and horses are exposed to the virus.

Cite This Article

APA
Forrester NL, Kenney JL, Deardorff E, Wang E, Weaver SC. (2008). Western Equine Encephalitis submergence: lack of evidence for a decline in virus virulence. Virology, 380(2), 170-172. https://doi.org/10.1016/j.virol.2008.08.012

Publication

Virology
ISSN: 1096-0341
NlmUniqueID: 0110674
Country: United States
Language: English
Volume: 380
Issue: 2
Pages: 170-172

Researcher Affiliations

Forrester, Naomi L
  • Center for Biodefense and Emerging Infectious Diseases, Sealy Center for Vaccine Development and Department of Pathology, University of Texas Medical Branch, TX 77555-0609, USA.
Kenney, Joan L
    Deardorff, Eleanor
      Wang, Eryu
        Weaver, Scott C

          MeSH Terms

          • Animals
          • Body Weight
          • Encephalitis Virus, Western Equine / pathogenicity
          • Encephalomyelitis, Western Equine / epidemiology
          • Encephalomyelitis, Western Equine / virology
          • Humans
          • Incidence
          • Mice
          • Survival Analysis
          • Virulence

          Grant Funding

          • U54 AI057156 / NIAID NIH HHS
          • U54 AI057156-010003 / NIAID NIH HHS
          • U54 AI057156-05S18269 / NIAID NIH HHS
          • T32 AI060549-05 / NIAID NIH HHS
          • T32 AI007526 / NIAID NIH HHS
          • T32 AI060549 / NIAID NIH HHS
          • T32 AI060549-04 / NIAID NIH HHS

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