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Updated: Jul 23, 2026
07:23
Detection of Infectious Virus from Field-collected Mosquitoes by Vero Cell Culture Assay
Published on: June 9, 2011
Equine West Nile encephalitis, United States
E N Ostlund1, R L Crom, D D Pedersen
1Animal and Plant Health Inspection Service, U.S. Department of Agriculture, 1800 Dayton Ave., Ames, IA 50010-0844, USA. eileen.n.ostlund@aphis.usda.gov
Emerging Infectious Diseases
|October 9, 2001
Summary
Following the 1999 West Nile (WN) encephalitis outbreak in horses, a case definition was established. This definition, combining clinical signs and lab results, confirmed 60 equine cases in 2000, aiding future diagnostic refinement.
Area of Science:
- Veterinary Medicine
- Epidemiology
- Infectious Diseases
Background:
- The 1999 West Nile (WN) encephalitis outbreak in New York horses necessitated a standardized case definition.
- Early diagnostic criteria were based on clinical signs and initial laboratory findings.
Purpose of the Study:
- To establish and refine diagnostic criteria for West Nile encephalitis in equines.
- To classify cases of WN encephalitis in horses as probable or confirmed based on specific criteria.
Main Methods:
- Development of a case definition incorporating clinical observations and laboratory test results.
- Application of the case definition to classify equine cases during the 1999 and 2000 outbreaks.
Main Results:
- A case definition was successfully developed after the 1999 outbreak.
- Sixty horses across seven states met the criteria for confirmed West Nile encephalitis in 2000.
Conclusions:
- The developed case definition effectively classified equine West Nile encephalitis cases.
- Ongoing clinical and diagnostic data from outbreaks will further refine diagnostic criteria for WN encephalitis in horses.
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