Geographic distribution of Venezuelan equine encephalitis virus subtype IEgenotypes in Central America and Mexico

Phylogenetic analysis of 20 strains of Venezuelan equine encephalitis (VEE) virus subtype IE isolated from 1961 to 1996 in Mexico and throughout Centr al America showed that VEE virus subtype IE was monophyletic with respect t o other VEE virus subtypes. Nonetheless, there were at least three distinct geographically separated VEE virus LE genotypes: northwestern Panama, Paci fic coast (Mexico/Guatemala), and Gulf/Caribbean coast (Mexico/Belize). Str ains from the Caribbean coast of Guatemala, Honduras, and Nicaragua may clu ster with the Gulf/Caribbean genotype, but additional isolates from the reg ion between Guatemala and Panama will be required to firmly establish their phylogenetic position. Viruses associated with two separate equine epizoot ics in Mexico in the 1990s were phylogenetically related to nonepizootic vi ruses from neighboring Guatemala and may represent the emergence or re-emer gence of equine-virulent VEE virus subtype IE in Middle America.