5 Things You
Need To
Know About
Equine Flu

21 July 2018

Equine influenza – or flu - is one of those things that you hear about as horse owners, often don’t know about in any depth.

Much like human flu, we assume that it’s nothing more than a bit of a sniffle and tend to brush it aside.


Anyone who has had flu though (not just a cold!) will tell you that it’s actually far more debilitating than most of us realise; and guess what – horses are exactly the same!


In association with FEI Campus, a free e-learning platform full of certified content about horses, we look at 5 things you should know…

Foals, young
horses and
older horses
are most at risk

1. It’s highly contagious

Again, there are a huge amount of similarities between human flu and equine flu. Just as flu spreads around schools and workplaces like wildfire, equine flu can infect a whole stableyard or even area at unbelievable speed.


Because the incubation period is so short (1-3 days) it’s not unheard of for an entire herd to have contracted the disease before you’ve seen clinical signs in the first horse to develop it. It can also be spread indirectly via contaminated equipment such as feed buckets.


2. Some horses are more susceptible than others

Foals, young horses and older horses are most at risk for contracting equine flu. 


Horses who regularly compete or travel are another group who may be more susceptible to contracting flu. This is partly because travelling stresses the immune system (especially when coupled with intense physical exercise as seen when horses compete), but also because they are more likely to encounter the virus by virtue of being exposed to a large number of different horses. 



3. Vaccinations are effective

Vaccinations against equine influenza have been available for many years, and scientific developments over the decades have only made them more effective.


In fact, scientists estimate that if the equine population were totally unvaccinated, equine flu would have a 100% infection rate. 


The recommended vaccination schedule can vary somewhat from country to country, but generally it is recommended that horses are given their initial vaccine followed by a second one 4-6 weeks later; boosters are then given for the remainder of the horse’s life.


These boosters are recommended every 6-12 months, but remember that if you compete, you’ll need to check the rules of your governing body. Some will only allow horses to compete when they receive boosters every six months, others may only require boosters every 12 months. 


4. Clinical signs to look out for

Equine flu is usually undetectable in the first few days of infection, but by carefully monitoring your horse  and being aware of the clinical signs, you will be able to recognise the disease earlier:

  • A very high temperature of more than 39C (103F) 
  • Loss of appetite
  • Lethargy/depression
  • Deep, dry cough
  • A clear discharge from the nose – this can become thickened and may turn yellow or green 
  • Swollen lymph nodes under the jaw

5. Prolonged rest is necessary following flu

Because the flu virus can adversely affect the lungs, heart and general immune system, it’s very important to give horses adequate time to recover after suffering flu.


Some horses can develop secondary infections following flu. However, if your horse is “lucky” and simply contracts flu, clinical should resolve within ten days.


Resuming exercise too soon can cause chronic disease in horses who have suffered from flu. These include sinus inflammation, respiratory disease  as well as heart damage. Always seek advice from your vet before returning your horse to work. 



To learn more about equine influenza, complete the course on feicampus.org. FEI Campus is a free e-learning platform full of certified content about horses, how to take care of them and much more!