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Equine Influenza

Equine influenza (flu) is caused by a highly contagious virus, widespread throughout the UK

What is equine influenza?

Equine influenza (flu) is caused by a highly contagious virus and while it does not usually cause a long term or fatal illness, your horse will be unwell and require time off work sometimes for an extended period. The disease is widespread throughout the UK horse population. It can lead to serious complications in very young or old horses and due to its infectious nature can spread rapidly through groups of unprotected animals.

How is influenza spread?

Influenza is an airborne virus and can spread quickly and easily through a yard. Under favourable weather conditions it can spread up to 5km.  It can be transmitted by direct horse-to-horse contact and also via people, tack, feed and equipment.

What are the signs of equine influenza?

Signs are caused by infection of the respiratory tract and typically include;

  • Dry, hacking cough

  • Nasal discharge

  • Fever

  • Lack of appetite

  • Lethargy

More severe signs such as pneumonia can occur in some individuals particularly foals.

Do all horses show the same signs?

The severity of symptoms depends on numerous horse related factors such as age, stress, exercise level, vaccination status but also on how potent the infecting virus is. Naïve unvaccinated horses experiencing infection for the first time are likely to show marked signs whereas other horses may only show mild signs which can be easy to mistake for something else.

Can my horse die of influenza?

The disease carries a low rate of mortality so it is unlikely that your horse will die from infection. However, the virus can cause a form of pneumonia which may prove to be fatal in foals or yearlings.

Are there any long term consequences of influenza?

Most horses recover within 2 weeks however in some horses a post-viral cough can persist for a much longer time. In some individuals it can take up to 6 months to regain full health. Horses can develop permanent lung damage following a bout of influenza which will cause performance related issues. There is also the potential that horses can develop sore muscles and myocarditis (heart muscle inflammation), which can subsequently cause an irregular heartbeat.

How is equine influenza treated?

There is no specific treatment for equine influenza and although antibiotics may be useful to control a secondary bacterial infection they will not treat the virus itself. Your horse will need a minimum of six weeks rest to recover or longer in more severe cases and your vet will advise you on this.

Can I exercise my horse as soon as he has stopped coughing?

Following a bout of flu it is important to give a horse complete rest for at least 6 weeks. Without rest the potential for long term consequences increases.

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