A genus of the family Picornaviridae. Members of the human rhinovirus group include at least 113 antigenically distinct types. Like the enteroviruses, the rhinoviruses are small (17–30 nanometers), contain ribonucleic acid (RNA), and are not inactivated by ether. Unlike the enteroviruses, they are isolated from the nose and throat rather than from the enteric tract, and are unstable if kept under acid conditions (pH 3–5) for 1–3 h. Most strains can be recovered by culture only in cells of human origin; they grow better when cultures are rolled (rather than held stationary) and are kept at a temperature of 91.5°F (33°C).