Less than 50% of the UK’s horse population is vaccinated for flu — and even those that are inoculated are susceptible. Vet Ricky Farr MRCVS outlines the risks
Why equine flu is still a big problem
The equine influenza (flu) virus is specific to horses. Like human flu, the virus attacks the upper respiratory tract and causes a multitude of symptoms. Flu is endemic in the UK, which means it is regularly found within the country and it is not unusual for new cases to be reported every few months. Flu occurs in unvaccinated horses or those with a lapsed vaccination status. Flu belongs to the H7N7 and H3N8 subtypes, of which those currently circulating are H3N8. We have data from 1963 that shows how the flu virus has developed. However, equine flu split into two distinctive branches (types) in the 1980s: American and European sublineages. The American branch has since split into two more clades and it’s these strains that are currently circulating.
If you’ve ever had flu, you’ll know how poorly it makes you feel. Common symptoms include: Raised temperature Lethargy Reduced appetite Muscle soreness Increased respiratory effort Coughing Nasal discharge Enlarged glands Sore eyes If you suspect your horse has flu, isolate him, preventing him from coming into contact with other animals. Call your vet. Biosecurity protocols — isolation, yard closure, diagnostic tests on all individuals susceptible and practical advice on keeping equipment and clothing clean — will help prevent the spread.
If your vet suspects flu, a swab is taken from the horse’s nose to look for the flu virus. The process is quick and although it may look a little alarming — your vet will poke a long swab up your horse’s nose — it is quick. Blood samples may also be taken and tested to look for a change in the antibody levels over a period of time. This can be beneficial in helping to make a diagnosis when there is a delay in samples being taken after showing clinical signs. Some horses may show no signs of flu, however they are still able to carry the flu virus around and pass it on to other horses. Vaccination is not a 100% guarantee but all cases of flu reported in the UK have been in unvaccinated individuals. An outbreak of flu will cost you — and possibly your yard or fellow livery owners — a lot more money, time and effort compared to a simple annual vaccination.
Coughing and increased respiratory effort is a clinical sign of flu
Nasal discharge is a common symptom of equine flu
Your vet will take a nasal swab to check for flu