viruses of the family Orthomyxoviridae that cause influenza and influenzalike infections of humans and other animals. These viruses contain single-stranded RNA that is segmented, accounting in part, for their epidemic spread. Viruses included are influenza virus types A and B of the genus Influenzavirus, causing, respectively, influenza A and B, and Influenzavirus C, which belongs to a separate genus and causes influenza C.
