any of three genera of arthropod-borne viruses (arboviruses) of the family Togaviridae. Flaviviruses, once considered to be of the Togaviridae, are now designated as members of a separate family, Flaviviridae.

The togavirus genera are Alphavirus, which is carried by mosquitoes; Rubivirus, also called rubella, or German measles, virus; and Pestivirus, which infects only animals (hog cholera virus and bovine diarrhea virus). Some Alphavirus species produce severe encephalitis in humans. Horses also may be severely or fatally infected by equine encephalitis. Rubivirus is immunologically distinct from the other togaviruses.