Horse Equine Influenza: Welfare During Respiratory Disease

Equine influenza is a highly contagious respiratory virus causing significant welfare harm in affected horses and requiring vaccination and biosecurity to prevent outbreaks.

Key Facts

Equine influenza is one of the most important infectious respiratory diseases of horses worldwide causing outbreaks affecting thousands of animals
The 2007 Australian outbreak infected approximately 76,000 horses causing the first equine influenza incursion in a country previously free of the virus
Affected horses experience fever, nasal discharge, coughing, and severe lethargy causing welfare harm over 1-3 weeks
Competition horses are at highest risk due to frequent mixing with horses from different premises at events
Annual vaccination is essential for horses at risk as vaccine-induced immunity wanes and the virus evolves requiring updated vaccines

Welfare Considerations

Equine influenza causes welfare harms through fever, respiratory distress, and the secondary complications of bacterial pneumonia in incompletely recovered horses returned to work too soon. The temptation to return horses to work before full recovery from influenza is a welfare concern particularly in competitive contexts. Appropriate rest periods following influenza infection — typically 1 week per day of fever — prevent secondary complications and welfare harms from exercise-induced pneumonia. Vaccination is highly effective and vaccination compliance across the equine community provides herd immunity protection for vulnerable horses.

What You Can Do

Maintain current equine influenza vaccination for all horses particularly those competing or mixing at events
Implement strict rest protocols following equine influenza infection to prevent secondary bacterial complications
Practice biosecurity including isolation of new arrivals and horses returning from events to prevent influenza transmission
Notify neighboring horse owners promptly about influenza cases to enable protective measures