- an acute, commonly epidemic disease, occurring in several forms, caused by numerous rapidly mutating viral strains and characterized by respiratory symptoms and general prostration.
- an acute, contagious disease occurring in horses and swine, characterized by fever, depression, and catarrhal inflammations of the eyes, nasal passages, and bronchi, and caused by a virus.
- a highly contagious and often epidemic viral disease characterized by fever, prostration, muscular aches and pains, and inflammation of the respiratory passages
