Rhinovirus. Molecular artwork showing the surface structure of a single rhinovirus, cause of the common cold as well as other respiratory diseases. Rhinoviruses belong to the Picornaviridae family. This icosahedral form is very small and sub-grouped according to its acid sensitivity. It is adapted to low temperatures but cannot invade the gut since it is inactivated by moderately acid conditions. Rhinoviruses are spread readily in the air by droplets produced by talking, coughing and sneezing. The virus may infect mucous membranes of the nose, and also the lungs causing bronchitis. Magnification: unknown.