1.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 a genus of viruses containing the agent of influenza A. See also influenza virus .
Influenzavirus B a genus of viruses containing the agent of influenza B. See also influenza virus .
Influenzavirus C a genus of viruses containing the agent of influenza C. See also influenza virus .