Equine influenza is a highly contagious respiratory virus that causes significant welfare impacts in affected horses. Vaccination and biosecurity are key to prevention and outbreak control.
Equine influenza causes acute suffering through high fever, severe respiratory distress, and profound lethargy. Affected horses are visibly unwell — the illness is debilitating for 1-3 weeks even in uncomplicated cases. Horses forced to continue working during infection — something that occurs when owners fail to recognize illness or are reluctant to withdraw from competition — experience compounded suffering and risk severe complications. Outbreaks in large facilities expose many horses simultaneously and can cause significant mortality from secondary complications. The welfare case for vaccination is strong: prevention through regular vaccination and biosecurity eliminates this suffering for protected horses and reduces outbreak amplification in the broader horse population.