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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orthokeratinized, (ôr´thōker´tinī´zd),

adj of a specific type of epithelium; its four layers include a keratin component whose cells are nuclei-free. Most oral mucosa consists of parakeratinized epithelium, which contains nucleated keratinocytes.

Orthomyxoviridae

n.pl one of the major RNA virus families, to which the influenza virus belongs. Viruses in this family have a single-stranded, eight-segmented, linear molecular structure with helical symmetry.

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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).