any of a group of viruses constituting the family Rhabdoviridae, responsible for rabies and vesicular stomatitis of cattle and horses. The virus particle is enveloped in a fatty membrane; is bullet-shaped, 70 by 180 nanometres (nm; 1 nm = 10^-9 metre); and contains a single helical strand of ribonucleic acid (RNA). See also rabies; vesicular stomatitis.