myxovirus (miks-oh-vy-rŭs) n. one of a group of RNA-containing viruses that are associated with various diseases in animals and humans. The orthomyxoviruses cause diseases of the respiratory tract, most notably influenza. The related paramyxoviruses include the respiratory syncytial virus (RSV) and the agents causing measles, mumps, and parainfluenza.

myxovirus One of a group of RNA-containing viruses associated with various diseases of humans and other vertebrates. Orthomyxoviruses produce diseases of the respiratory tract, e.g. influenza; paramyxoviruses include the causal agents of mumps, measles, and fowl pest.