Equine influenza is a highly contagious respiratory virus causing significant welfare impacts at the individual level and catastrophic consequences when outbreaks occur across competition venues.
Equine influenza causes genuine suffering - the high fever, myalgia, and respiratory difficulty of acute influenza are as unpleasant in horses as equivalent symptoms in humans. Severely affected horses may be unable to eat or drink adequately. The temptation to return horses to work prematurely risks serious cardiac and respiratory complications including myocarditis and secondary bacterial pneumonia. When outbreaks occur at large events, horses are exposed during a period of transport and competition stress, amplifying welfare harm. Appropriate biosecurity and vaccination programs protect individual horses and prevent the welfare catastrophe of large-scale outbreaks.