Orthomyxoviridae

Or·tho·myx·o·vir·i·dae (ôrth-mks-vîr-d)

n.

A family of myxoviruses that includes the various types of influenza viruses.

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Orthomyxoviridae

a family of viruses containing influenza viruses A, B and C of which only influenza A viruses cause disease in domestic animals. Virions are 100 nm diameter, enveloped and contain a single-stranded negative sense RNA genome in eight segments. The envelope carries two glycoprotein spikes, hemagglutination (H) and neuraminidase (N), each of which is coded for by a different genome segment and undergo continuous antigenic variation, either because of mutation (antigenic drift) or genetic recombination (antigenic shift).