Emergence of a new epidemic/epizootic Venezuelan equine encephalitis virus in South America

Rebeca Rico-Hesse, Scott Weaver, Julieta De Siger, Gladys Medina, Rosa Alba Salas

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One of the most important questions in arbovirology concerns the origin of epidemic Venezuelan equine encephalitis (VEE) viruses; these viruses caused periodic, extensive epidemics/epizootics in the Americas from 1938-1973 (reaching the United States in 1971) but had recently been presumed extinct. We have documented the 1992 emergence of a new epidemic/epizootic VEE virus in Venezuela. Phylogenetic analysis of strains isolated during two outbreaks indicated that the new epidemic/epizootic virus(es) evolved recently from an enzootic VEE virus in northern South America. These results suggest continued emergence of epizootic VEE viruses; surveillance of enzootic viruses and routine vaccination of equines should therefore be resumed.

Original languageEnglish (US)
Pages (from-to)5278-5281
Number of pages4
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number12
StatePublished - Jun 6 1995



  • emerging virus
  • epidemiology
  • molecular evolution

ASJC Scopus subject areas

  • Genetics
  • General

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