Equine Influenza - what Aberdeenshire horse owners should know in Spring 2026

By Mairi Sinclair, BVM&S MRCVS

Bennachie Equine Vets

EQUINE Influenza remains one of the most contagious respiratory diseases affecting horses in the UK, and as many of you will be aware, there have been recent outbreaks across the UK, which have highlighted just how important vaccination, good biosecurity and prompt testing are.

For horse owners, livery yards, competition centres and riding schools it is a timely reminder that staying informed and prepared really does make a difference.

What is Equine Influenza?

Equine Influenza, often referred to as equine flu, is a highly contagious viral respiratory disease that affects horses, ponies, donkeys, and other equids. The disease is caused by Influenza A viruses, primarily the H3N8 strain, which has circulated globally for many years.

The virus spreads via:

• Direct horse-to-horse contact

• Airborne droplets from an infected horse coughing, which under favourable conditions (such as high winds) can travel over 1km

• Contaminated clothing, tack, buckets and equipment

• Human movement between infected and healthy horses

  
  

One of the biggest challenges with Equine Influenza is that compared to other contagious respiratory conditions such as Strangles, the virus can spread by airborne transmission. This means that even with very careful biosecurity, it can spread through a yard very quickly.

Horses can also begin shedding the virus before obvious symptoms appear, meaning they can be spreading the virus before appearing unwell.

Although Equine Flu is rarely fatal in healthy adult horses, it can cause disruption, cancelled events, unexpected veterinary bills and long recovery periods for affected horses.

Recent UK outbreaks - What We Know So Far

Veterinary surveillance teams across the UK have reported a significant increase in Equine Influenza activity during Spring 2026. In the most recent update from the Equine Infectious Disease Surveillance (EIDS) network on the 28^th May, they reported the following:

• Since the beginning of April 2026, a total of 74 laboratory-confirmed EI outbreaks have been identified across 38 counties

• 8/74 cases were vaccinated and 46/74 were unvaccinated. The remainder had unknown or overdue vaccinations

• 59% of the cases had recently moved premises

While there have currently been no reported outbreaks in the North-east of Scotland, cases have been diagnosed in North and South Lanarkshire, East Lothian and in the Scottish Borders. (https://equinesurveillance.org).

Symptoms of Equine Influenza

Spotting the signs early is one of the most important ways to limit the spread of the virus as clinical signs can appear as soon as 1-5 days after exposure and include:

• Sudden high temperature, often above 38.5°C

• Dry, harsh coughing

• Nasal discharge

• Lethargy or dullness

• Reduced appetite

• Swollen lymph nodes

• Poor performance or reluctance to exercise

Some horses recover relatively quickly, while others can take several weeks or even months to return to full fitness. Secondary bacterial infections may also develop, particularly in younger, older or immunocompromised horses.

Why Vaccination Matters

Vaccination remains the best protection against Equine Influenza. While vaccinated horses can still occasionally become infected, symptoms are usually milder and recovery tends to be faster. Vaccination significantly reduces the severity of the disease and lowers viral shedding, meaning there is far less chance of vaccinated horses infecting others.

Most competition bodies in the UK require horses to be vaccinated before attending affiliated events. In response to the increasing number of cases of Equine Flu, many competition centres have implemented passport check - and some have recommended boosters for any horses who have not been vaccinated in the last six months.

While antibody protection lasts for 12 months following annual vaccination, levels slowly begin to reduce from six months post vaccination. Therefore a six monthly booster will raise antibody levels, increasing protection for both the vaccinated horse and the horses they mix with.

However, vaccination is not only important for competition horses. Leisure horses, retired horses, breeding stock and youngsters all benefit from protection.

As we mentioned above, recent outbreak investigations have shown that many infected horses were either unvaccinated or overdue boosters - and even if your horse does not leave the premises, they can become infected by aerosol transmission from nearby yards.

If you have any questions about flu vaccination, your vet will be able to advise you and answer any questions you may have.

However, if you are competing, it remains the owner's responsibility to ensure that your horse meets the requirements of the governing body or competition centre you are attending.

It is important to remember that many state your horse should not have had a vaccination in the seven days prior to competition.

Biosecurity Measures to Consider

Good biosecurity can dramatically reduce the risk of an outbreak on your yard. Simple but effective precautions include:

• Isolating new arrivals

  
  

Any new horse entering a yard should ideally be isolated for at least 14 days.

During this time, owners should monitor temperatures daily and watch for coughing or nasal discharge.

• Monitoring temperatures

  
  

Taking temperatures routinely during high-risk periods can help identify illness before more severe clinical signs develop.

If your horse has been attending clinics or shows, you should monitor their temperature daily for two weeks.

• Avoiding shared equipment

  
  

Buckets, water troughs, tack, grooming kits and feed utensils should not be shared between horses where possible.

If you are stabling at an event, take some disinfectant to use on the walls and doors before unloading your horse.

• Limiting horse movement

  
  

During periods of active outbreaks, owners should carefully assess whether travel to competitions or gatherings is necessary.

• Hygiene for visitors

  
  

Hand washing, disinfectant footbaths and clean clothing can all to help reduce transmission risks.

Yard managers should also ensure clear communication between liveries and staff if any horse develops respiratory symptoms.

• The Economic and Emotional cost of Outbreaks

Equine Influenza outbreaks can have a significant financial impact on equestrian businesses and horse owners alike.

A single infected horse may force a yard into temporary lockdown, disrupting:

• Lessons and clinics

• Competition schedules

• Horse sales

• Breeding programmes

• Livery arrangements

• Riding school income

In severe outbreaks, entire competition calendars may be affected. The 2019 Equine Influenza outbreak in the UK demonstrated how quickly national movement restrictions and event cancellations can occur when disease spreads extensively.

For many owners, there is also a considerable emotional toll. Watching horses become ill, managing prolonged isolation and coping with uncertainty can be stressful for everyone involved.

• What To Do If You Suspect Equine Influenza

  
  

If your horse develops a fever, cough or respiratory symptoms, you should:

1. Isolate the horse immediately

2. Contact your veterinary surgeon

3. Stop all horse movement on and off the premises until test results are back

4. Avoid sharing equipment

5. Inform anyone who may have had recent contact with the horse

   
   

Prompt veterinary diagnosis can help limit spread and protect neighbouring horses.

• Final thoughts ...

  
  

Equine Influenza remains a serious and highly contagious disease that requires ongoing vigilance from horse owners throughout Aberdeenshire and beyond.

The recent increase in outbreaks across the country is a reminder that vaccination programmes and sensible biosecurity measures remain essential for every type of horse owner, not just those competing regularly.

By recognising symptoms early, maintaining up-to-date vaccinations and adopting sensible disease prevention measures, the equestrian community can help reduce the risk of widespread outbreaks and keep horses healthy.

As always, if you have any concerns about vaccination schedules, disease prevention or respiratory symptoms in your horse, it’s best to contact your veterinary practice for advice as early as possible.

Steffi Wood and Mairi Sinclair with Betty and Piglet.

Bennachie Equine Vets was established by Mairi Sinclair BVM&S MRCVS and Steffi Wood MA VetMB CVLM MRCVS in 2025. Between them, they have over 25 years of equine veterinary experience.

To contact Bennachie Equine Vets, email info@bev.scot or phone 01467 450121. Or visit https://www.bev.scot