equine encephalitis

:  any of three virus diseases chiefly of equines and humans in various parts of North and South America that are transmitted especially by mosquitoes, are characterized in humans by flulike symptoms which often progress to encephalitis and sometimes to coma and death, and are caused by three togaviruses of the genus Alphavirus (species Eastern equine encephalitis virus, Western equine encephalitis virus, and Venezuelan equine encephalitis virus):a:  one that occurs in the eastern U.S. and Canada—called also eastern equine encephalitis, eastern equine encephalomyelitisb:  one that occurs in the western U.S. and Canada—called also western equine encephalitis, western equine encephalomyelitisc:  one that occurs from northern South America to Mexico—called also Venezuelan equine encephalitis, Venezuelan equine encephalomyelitis