What You Need to Know About Equine Influenza in 2025

Equine Influenza is a highly contagious viral respiratory disease affecting horses in the UK. Recent outbreaks have highlighted its significance, especially following the British Horseracing Authority's suspension of UK horse racing due to flu cases. This guide provides essential knowledge on symptoms, prevention, vaccination schedules, and competition rules to help horse owners protect their animals.

What is Equine Influenza?

Equine Influenza (EI) is caused by Type A influenza viruses and spreads rapidly among horses through airborne respiratory droplets and contaminated objects like tack and clothing. It has a short incubation period of 1 to 3 days and can cause explosive outbreaks in susceptible populations, particularly in environments with frequent horse movement such as racing yards, stud farms, competitions, and livery yards.

EI is not contagious to humans, but it can seriously impact horse health and equine activities.

Symptoms of Equine Influenza

• High temperature (fever) and lethargy
• Harsh dry cough often occurring in epidemics
• Watery nasal discharge
• Loss of appetite and fatigue
• Muscle weakness and occasional muscular pain
• Swollen lymph nodes in some cases

Prompt veterinary attention is essential if your horse shows any signs of flu to prevent complications like secondary bacterial infections.

Vaccination and Immunity

Vaccination is the cornerstone of Equine Influenza control in the UK. Although vaccination is not mandatory, it is strongly recommended by veterinary experts and governing bodies.

• Annual vaccinations are advised for general leisure horses.
• Competition horses must follow strict vaccination regimens, typically requiring a flu booster every six months under British Eventing, British Showjumping, British Dressage, the FEI, and the British Horseracing Authority rules.
• The primary vaccination course includes three injections: an initial dose, a second between 21 and 92 days later, and a third six months after the second, followed by annual boosters.
• Vaccines are usually administered in the neck, although some vets may use alternative sites to reduce reaction risks.
• Immunity tends to wane from six to twelve months post-vaccination, so timely boosters are essential.

Even vaccinated horses can contract EI but often display milder symptoms and recover more rapidly.

Equine Influenza and Competitions

• Unaffiliated competitions may not formally require vaccination, but many organisers adopt rules from British Showjumping, British Eventing, and British Dressage which require unbroken vaccination history.
• Horses late even by one day on vaccination schedules are considered to have lapsed and must restart the vaccination course.
• Horses should not be present within seven days after vaccination and must have immunity established after the second injection before attending events.
• FEI rules require boosters every six months for competing horses.
• Show organisers reserve the right to inspect passports and may refuse entry to unvaccinated or lapsed horses.
• Current outbreak concerns lead some regional competitions to reject horses without recent vaccination boosters.

Preventive Measures and Biosecurity

• Vaccinate your horses and consult your vet about boosters, especially if your horse’s last vaccination was over six months ago.
• Quarantine new arrivals for 21 days with strict isolation, including separate equipment and clothing to avoid cross-contamination.
• Recognise flu symptoms early and seek veterinary advice immediately.
• Avoid sharing equipment at events and restrict nose-to-nose contact between horses.
• Limit movement both on yards and when competing to reduce transmission risk.
• Yards with confirmed cases should close temporarily to prevent outbreaks.

Current equine influenza outbreaks have affected Europe, Ireland, USA, and West Africa. While the British Equestrian Federation currently advises no event cancellations, individual organisers may impose stricter rules or checks depending on circumstances.

Key Takeaways for Horse Owners

1. Ensure your horse's vaccinations are up to date following your competition discipline's guidelines.
2. Maintain high biosecurity by isolating new horses and practising strict hygiene.
3. Observe your horses closely for any signs of illness and contact your vet promptly.
4. Carry and maintain an accurate horse passport including vaccination history at all times, especially when travelling.
5. Follow event organisers' rules for vaccination and be prepared for spot checks, particularly during outbreaks.

For detailed guidance, always check updates from the British Equestrian Federation, FEI, British Horseracing Authority and consult your veterinary surgeon.

Responsible vaccination and sensible biosecurity remain the best defence against this highly infectious disease, protecting the horse community and supporting safe equine activities.