Virus

Rhinoviruses (from the Latin word meaning "nose") cause the common cold. They come from the same family as the enteroviruses, described above, and thus contain a single strand of RNA enclosed within an enveloped, 20-sided capsid. Interestingly, 113 types of rhinoviruses have been classified. These 113 types differ slightly in the composition of their capsids, so antibodies that are made against one type of rhinovirus are often ineffective against other types of viruses. For this reason, most people are susceptible to colds from season to season.