Equine Influenza cases on the rise

MANY of us know that autumn and winter is a time when colds and flu start to spread, and horses are no different. Equine Influenza, commonly known as Equine ‘Flu, is similar to human ‘flu, but not exactly the same – horses cannot catch human ‘flu or vice versa.

Autumn 2022 has seen an increase in the number of horses diagnosed with Equine ‘Flu, so it is more important than ever to be vigilant for the symptoms. Symptoms include coughing, fever of 38.5°C or higher, nasal discharge, loss of appetite, lethargy, poor performance, gagging when eating and enlarged lymph nodes. Additionally, the disease can weaken the horse, leaving it vulnerable to secondary infection and complications. This is a particular concern in young foals, elderly animals and those with pre-existing conditions. In severe cases, this can be fatal.

Equine ‘flu is airborne and therefore can spread very quickly through a group of horses. When a horse coughs, respiratory droplets can spread up to 2km on the wind. Furthermore, direct horse to horse contact, shared equipment, and even clothing can contribute to the spread. For this reason, it is advised that, as soon as you suspect a case of ‘flu on your yard, immediately isolate the infected horse and seek further veterinary advice as soon as possible.

Both Rossdales Laboratories in Newmarket (funded by the Horserace Betting Levy Board Scheme) and the Irish Equine Centre in Kildare (funded by the Irish Department of Agriculture, Food and Marine), provide free Polymerase Chain Reaction (PCR) testing for Equine ‘Flu of nasopharyngeal swabs from horses in Northern Ireland. The sooner a diagnosis is made, treatment can commence and the sooner the horse can return to full health. Infected horses can shed for up to 10 days and must be isolated until your vet confirms the horse is no longer infected. All horse movement on and off the yard should be stopped, as even horses showing no symptoms can spread the virus.

Vaccination is available and is the best way to decrease risk of infection. Vaccination is compulsory when competing under rules and when attending activities run by various organisations nationally and internationally, e.g. British Horse Racing Authority, Irish Horse Racing Regulatory Board, Show Jumping Ireland, Federation Equestre Internationale (FEI) and The Pony Club. Rules relating to vaccination protocols (primary course and boosters) vary and it is important that all those with responsibility for horses check these and implement them appropriately on a regular basis, e.g. some organisations require six monthly boosters once the primary course has been completed.

Equine ‘flu is an adaptive virus and therefore it is changing all the time. Whilst vaccine manufacturers strive to ensure currently available vaccines reflect the strains that are currently circulating, this may not always be the case. This means that even if your horse is vaccinated, it may not have full immunity if the horse catches a different strain of the virus than they were vaccinated against. Despite this, it is still worth vaccinating your horse, as vaccinated horses will have less severe symptoms and will shed the virus less than unvaccinated horses.

If your horse is vaccinated and another horse at the barn has a confirmed case of ‘flu, a booster shot is available to boost your horse’s immunity. Your veterinarian will be able to advise you on the best vaccination for your horse.

As always, prevention is better than cure, so to reduce the risk of infection, follow good biosecurity practices. Don’t allow your horse to have nose to nose contact with other horses at events/ shows and never share equipment, including water and water buckets, between horses. Disinfect equipment and transport when returning to the yard.

Confirm all resident horses and any new arrivals are vaccinated against Equine Influenza. Even if the new horse is vaccinated, new arrivals should be quarantined, ideally for three weeks, at least 25 metres from other horses before allowing mixing. Handlers should wash their hands between horses and all horses should have dedicated equipment, feed buckets and water buckets, which are regularly cleaned and disinfected.

By familiarising yourself with the symptoms of Equine ‘Flu, getting horses vaccinated, implementing good biosecurity protocols and promptly reporting cases, we can all do our bit to control the spread and reduce horse suffering. If you are even in doubt, contact your veterinarian for advice.