West Nile encephalitis

Vet Clin North Am Equine Pract. 2000 Dec;16(3):427-41. doi: 10.1016/s0749-0739(17)30087-1.


WNV encephalitis in horses, previously reported in Africa, Asia, and Europe, occurred for the first time in the Western Hemisphere in 1999. The causative agent, WNV, is a flavivirus maintained in nature by a bird-mosquito cycle. The disease in horses is manifested primarily by ataxia of variable severity. Outbreaks of encephalitis may have a case fatality rate in excess of 40%, although this virus infection is inapparent in some horses. Early evidence indicates that WNV has overwintered in the northeastern United States and poses a threat for future disease occurrences in horses. No vaccine is available to protect against WNV infection in horses; disease control is predicated on mosquito abatement.

Publication types

  • Review

MeSH terms

  • Animals
  • Antibodies, Viral / analysis
  • Brain / virology
  • Disease Outbreaks / veterinary*
  • Horse Diseases / diagnosis
  • Horse Diseases / epidemiology*
  • Horse Diseases / therapy
  • Horses
  • Mosquito Control
  • United States / epidemiology
  • West Nile Fever / diagnosis
  • West Nile Fever / epidemiology
  • West Nile Fever / therapy
  • West Nile Fever / veterinary*


  • Antibodies, Viral