Horse Equine Influenza Outbreak Response: Vaccination and Biosecurity

Equine influenza outbreaks cause significant welfare impact and economic disruption; vaccination and biosecurity are the primary responses.

Key Facts

Equine influenza (EIV) is caused by influenza A H3N8 and spreads rapidly by aerosol between horses.
Clinical signs include fever, nasal discharge, dry cough, and lethargy lasting 2-3 weeks.
Secondary bacterial pneumonia is the most serious complication, particularly in unvaccinated horses.
The 2019 outbreak in the UK affected over 3,000 horses and caused widespread competition cancellations.
FEI and British Equestrian require vaccination with documented evidence of up-to-date status.
Vaccines must include strains representative of currently circulating virus clades — Florida clade 1 and 2.

Welfare Considerations

EIV causes significant welfare impact through fever, respiratory distress, and exercise intolerance. Secondary pneumonia in unvaccinated horses can be life-threatening. During outbreaks, strict movement restrictions and biosecurity measures impose management challenges but are essential to prevent spread. All horses in regular contact with others should be vaccinated and boosted according to current guidelines.

What You Can Do

Vaccinate all horses at least annually with an EIV vaccine containing Florida clade 1 and 2 strains.
Maintain vaccination records and ensure they comply with any competition or livery yard requirements.
Isolate any horse with respiratory signs and notify your vet promptly during outbreak periods.
Implement robust biosecurity when attending competitions — avoid communal water troughs and nose-to-nose contact.