Nonhuman primate models of encephalitic alphavirus infection: historical review and future perspectives.

Venezuelan, western, and eastern equine encephalitis viruses are New World alphaviruses that are recognized as potential agents of biowarfare and bioterrorism owing to their morbidity and mortality in humans, ease of production, considerable stability, and high infectivity in aerosols. As a result, these encephalitic alphaviruses are defined as category B select agents. Studies involving infection of nonhuman primates have been instrumental in gaining an understanding of the in vivo pathogenesis of these viruses and have provided relevant models to evaluate the efficacy of candidate human vaccines. Recent advances have led to refinement and further characterization of these models toward the goal of utility in the licensure of next-generation alphavirus vaccines and therapeutics for use in humans by the Animal Rule.