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former genus name for the viruses that cause influenza, now found to be two different genera, which were named influenzavirus A and influenzavirus B.
Influenzavirus A/In·flu·en·za·vi·rus A/ (in″floo-en´zah-vi″rus) a genus of viruses of the family Orthomyxoviridae containing the agent of influenza A. See influenza virus, under virus> .
a genus of viruses of the family Orthomyxoviridae containing the agent of influenza A. It is usually the cause of epidemics and pandemics. It is divided into subgroups based on two surface proteins: neuraminidase and haemoglutinin. Vaccination against influenza A is available. See also influenza.