1. An acute contagious viral infection of humans, characterized by inflammation of the respiratory tract and by fever, chills, muscular pain, and prostration. Also called grippe.
2. Any of various viral infections of domestic or wild animals, generally characterized by fever and respiratory involvement.
[Italian, from Medieval Latin īnfluentia, influence (so called apparently from the belief that epidemics were due to the influence of the stars); see INFLUENCE.]
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