Overview

Coronaviruses (CoVs) are a large family of related RNA viruses that cause illness in mammals and birds. CoVs are enveloped viruses containing long RNA polymers packed into the center of the virus particle and surrounded by a protective capsid (nucleocapsid), which is a lattice of repeated protein molecules referred to as coat or capsid proteins. The nucleocapsid protein is termed the "N" protein. The nucleocapsid gives the virus a helical symmetry. In the outer membrane of coronaviruses, the key set of proteins that project out from the particle are known as spike (S) proteins. These S proteins are recognized by receptor proteins on host cells that will be infected. The genome size of CoVs ranges from 26–32 kilobases, one of the largest among RNA viruses.

CoVs have characteristic club-shaped spikes that project out from their surface and create a microscopically appearing image similar to the “solar corona” from which the name “coronavirus” is derived. The actual name "coronavirus" is derived from the Latin “corona,” which means "crown" or "wreath.” The word was first used in print in 1968 by a group of virologists in the journal Nature to designate the new family of viruses.