Giving Horses the BEST Protection From Strangles

We all know strangles is something to avoid, but many horse owners facing an outbreak say that they simply didn’t think it would happen to them. Unfortunately, the disease can happen to any horse or yard, usually bringing stress, disruption and expense for everyone involved, and often lasting for weeks or even months.

Strangles is one of the conditions covered in the final chapter of the Bare Bones of the Matter series. Veterans and Veterinary Care is the final chapter of the Bare Bones of the Matter series and premieres on Wednesday 26 November 2025.

In this article, Nic de Brauwere, MRCVS, Head of Welfare and Behaviour at Redwings explains how every owner can take steps to protect their horse from strangles - a debilitating but often avoidable infection.

Strangles is endemic in the UK and cases appear to be on the rise. Although many yards only take precautions when there is an outbreak in their area, constant horse movements mean strangles is never that far away.

A Unique Disease

Strangles is caused by the bacteria Streptococcus equi, - infecting the horse’s upper respiratory tract. It’s highly infectious and can be transmitted through direct contact between horses or indirectly on equipment, surfaces, hands, clothes and in water.

The earliest sign of infection is usually fever, often progressing to a snotty nose, swollen glands and abscessation of lymph nodes around the head and neck. Horses may also have a cough and difficulty swallowing and are likely to feel very unwell, appearing dull and off their food.

However, not all infected horses present with the obvious signs and may only develop a raised temperature and be a little off colour.

Thanks to the sensitivity and accuracy of modern tests like PCR, many cases of mild respiratory illness have been shown to be strangles. Testing less obvious cases has become an important part of identifying strangles and preventing the onward spread of infection.

Although it’s a bacterial infection, antibiotics are often ineffective and may even slow the horse’s recovery or weaken their post-infection immunity. An equine vet will be able to ensure that targeted medication is prescribed as needed and provide anti-inflammatory drugs to offer comfort during the acute stages of the disease.

Strangles targets the lymph system and ends up in the lymph nodes between the mandibles or those that sit at the back of the horse’s throat, adjacent to the guttural pouches. Infected pus from the lymph nodes in the throat mostly collects in the pouches and can only drain whilst soft enough to run out of the narrow exit into the pharynx, where it gets swallowed or runs onward and appears at the nose (from where it can infect the next horse).

Before the lymph nodes burst, they are extremely painful and horses who are reluctant to eat can benefit from raised bowls to make this more comfortable. Once abscesses are draining, horses tend to be much more comfortable and providing food and water at ground level will support drainage from the guttural pouches.

Pus that doesn’t drain from the guttural pouches is at risk of becoming thicker and eventually solidifying and becoming stuck in the chamber. Balls of dried pus, known as ‘chondroids, can support live bacteria for months or years after the horse has recovered in all other respects. These horses are strangles carriers and can intermittently shed bacteria via their nasal passage, potentially triggering new outbreaks, until they are diagnosed and treated.

Screening all horses as they recover from strangles is the best way to prevent them becoming carriers and also helps find those horses that are still highly infectious despite having no more outward signs. Recent studies suggest most new outbreaks are linked to recently recovered but not yet infection free horses.

Making the BEST of things

The good news is that continued research has fuelled significant advances in our ability to diagnose, treat and – even better – prevent the disease.

Straightforward, practical measures can drastically reduce horses’ risk of infection and by making a habit of good biosecurity, we can challenge the relentless circulation of strangles around the UK.

As part of the Strangles Awareness Week campaign, Redwings promotes the four BEST steps to protect horses (see image right).

Boost Immunity

In the UK and Europe strangles vaccination is intramuscular (usually the neck) and isn’t a ‘live’ vaccine, meaning it cannot trigger infection. The vaccine also won’t affect blood test results. After two primary injections, data shows that boosting vaccination at 12-month intervals can maintain adequate immunity. Six-monthly boosters are currently recommended for horses at increased risk.

Vaccinated horses may still become infected but experience much milder symptoms that resolve more quickly than in an unvaccinated horse. As with any vaccine, side effects are possible, such as a raised temperature, some swelling at the injection site or stiffness in the horse’s neck. These likely resolve within a few days at most.

Engage with Trusted Information

Perceptions of strangles can be affected by misinformation and uncertainty. Accurate, up-to-date advice is more widely available now and using trustworthy sources of information around both preventing and managing strangles plays a vital role in reducing the number and severity of cases.

Horse owners can also contribute to tackling misinformation by being open about their own outbreaks, supportive when others are affected by strangles; and by sharing evidence-based messages about the disease such as those provided by Strangles Awareness Week.

Separate Unfamiliar Horses

A mobile horse population facilitates the spread of infectious disease. Having routine separation of new horses to a yard for at least two weeks, ideally three, addresses one of the biggest strangles risk factors, that of infected, but symptom-free, horses mixing with the rest of the yard.

It isn’t only carriers with chondroids that pose a threat. Horses who have recently recovered from strangles (and are therefore free from signs) can remain infectious for many weeks afterwards and research indicates that these horses may be the most common source of new infections.

Precautionary quarantine is increasingly common on yards and can be achieved without dedicated facilities.

As strangles isn’t airborne, paddock quarantine is effective when incorporating a safety zone to prevent contact with neighbouring horses or potential transmission through mucus that is coughed or snorted into the environment.

Temperature-check Routinely

Temperature is an important health indicator for any horse. Fever is usually the first sign of infectious disease. In the case of strangles, fever develops one to two days before the horse becomes fully contagious, offering an opportunity to take action and prevent further transmission.

Many horse owners only check their horse’s temperature if they look unwell, but in the case of an infectious disease, this may be too late to prevent other horses becoming infected.

Routine temperature-checking, ideally daily, helps both horse and handler to be familiar and comfortable with the procedure and the owner to know what their own horse’s normal resting temperature is. Fever (a temperature above 38.5^o)or a rise of more than 0.5 degrees above a horse’s normal range is a cause for concern and allows steps to be taken to minimise the spread of possible infectious disease until more is known.

Do Your BEST!

Prevention is always better than cure when it comes to infectious disease. By adopting a practical, proactive approach, horse owners and yard managers can significantly reduce the risk of a strangles outbreak and help protect their own horses and others from the threat of a debilitating, potentially life-threatening disease.

For more information and to join the Strangles Awareness Week mailing list, please visit www.redwings.org.uk/strangles

Caring for Older Horses

In Chapter 7 of the Bare Bones of the Matter Gillian is joined by vet Matthew Barlow to discuss caring for older horses, covering common conditions such as Cushing’s, choke, strangles, melanomas, and more. Also, in this deeply emotional chapter Gillian shares the final stage of Freddie’s journey. While a difficult topic, it’s an important one that every horse owner will face at some point.

Independent equine nutritionist, Clare MacLeod discusses the nutritional demands of veterans and the practical challenges of feeding older horses. Plus, Diane Gilby explores the ways in which ageing and weakened immunity reduce a horse’s resistance to worms.

The chapter also features a thoughtful interview with Nic de Brauwere, offering valuable insights into end-of-life care.

Honest and heartfelt, this is essential viewing for every responsible horse owner.

Bare Bones of the Matter - Chapter 7 Veterans and Veterinary Care

£25.00

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