Medical Definition of alphavirus
1 capitalized : a genus of single-stranded RNA viruses of the family Togaviridae that are transmitted by arthropods and especially mosquitoes and that include the Mayaro virus, Semliki Forest virus, Sindbis virus, and the causative agents of chikungunya and equine encephalitis
2plural alphaviruses : any virus of the genus Alphavirus <Although naturally transmitted by mosquitoes, the encephalitic alphaviruses are also highly infectious by aerosol.—David R. Franz et al., The Journal of the American Medical Association, 6 Aug. 1997>
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