Venezuelan equine encephalitis

Annu Rev Entomol. 2004:49:141-74. doi: 10.1146/annurev.ento.49.061802.123422.


Venezuelan equine encephalitis virus (VEEV) remains a naturally emerging disease threat as well as a highly developed biological weapon. Recently, progress has been made in understanding the complex ecological and viral genetic mechanisms that coincide in time and space to generate outbreaks. Enzootic, equine avirulent, serotype ID VEEV strains appear to alter their serotype to IAB or IC, and their vertebrate and mosquito host range, to mediate repeated VEE emergence via mutations in the E2 envelope glycoprotein that represent convergent evolution. Adaptation to equines results in highly efficient amplification, which results in human disease. Although epizootic VEEV strains are opportunistic in their use of mosquito vectors, the most widespread outbreaks appear to involve specific adaptation to Ochlerotatus taeniorhynchus, the most common vector in many coastal areas. In contrast, enzootic VEEV strains are highly specialized and appear to utilize vectors exclusively in the Spissipes section of the Culex (Melanoconion) subgenus.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.
  • Review

MeSH terms

  • Aedes / virology
  • Animals
  • Disease Outbreaks
  • Encephalitis Virus, Venezuelan Equine / genetics
  • Encephalitis Virus, Venezuelan Equine / pathogenicity*
  • Encephalomyelitis, Venezuelan Equine / epidemiology
  • Encephalomyelitis, Venezuelan Equine / transmission*
  • Equidae
  • Horse Diseases / epidemiology
  • Horse Diseases / transmission
  • Horses
  • Host-Parasite Interactions
  • Humans
  • Insect Vectors / virology*
  • Mutation
  • Viral Envelope Proteins / genetics*
  • Viral Vaccines
  • Virulence / genetics


  • Viral Envelope Proteins
  • Viral Vaccines
  • glycoprotein E2, equine encephalitis virus