[Venezuelan equine encephalitis].

Abstract

Venezuelan equine encephalomyelitis (VEE) viruses are taxonomically classified within the genus Alphavirus of the family Togaviridae (formerly the Group A arboviruses). The VEE complex of viruses includes six antigenic subtypes (I–VI) divided by antigenic variants. Within subtype I there are five antigenic variants (variants AB–F). Originally, subtypes I-A and I-B were considered to be distinct variants, but they are now considered to be identical (I-AB). Antigenic variants I-AB and I-C are associated with epizootic/epidemic activity in equids and humans. The other three variants of subtype I (I-D, I-E, and I-F) and the other five subtypes of VEE (II–VI) circulate in natural enzootic cycles.