Strangles in horses

Something every equestrian wants to avoid is the spread of strangles.

Each May, Strangles Awareness Week highlights the importance of protecting horses from this highly contagious infection, while reminding horse owners and riders that all horses are at risk of strangles. 

Thankfully, everyone who owns and/or rides horses (as well as those who operate livery yards) can make a difference by taking action to prevent the spread of this horrible infection. 

Read on, to discover what strangles is, the symptoms and treatment options for strangles, and the preventative measures to put in place to protect horses…

Interesting fact: A record of strangles in horses first appeared in 1251.

What is strangles?

Strangles is an infection caused by bacteria, Streptococcus equi (S.equi), which impacts a horse’s lymph nodes and upper respiratory tract.  

Although strangles isn’t airborne (spread through the air), it can be spread whenever a horse coughs or snorts. For this reason, unfortunately, it’s easy for strangles to be transferred both directly (e.g. horse-to-horse contact) or indirectly (e.g. via contaminated clothing).

The incubation period for strangles (i.e. time frame between a horse being infected by strangles and when they start to show symptoms) ranges from three days to three weeks. In addition, strangles bacteria can survive for up to:

• Three days on fencing or within the soil.
• Seven days on surfaces not exposed to sunlight.
• Six weeks in water and moist areas (e.g. water buckets).

Plus, the S.equi bacteria has been found to survive for at least 24 hours on clothing, too.

So, strangles is known to be challenging to contain once it starts to spread.

Symptoms of strangles in horses

Symptoms of strangles often differ from one horse to another and may include:

• A high temperature (above 38.5°C).
• A cough.
• Thick, discoloured nasal discharge.
• Lethargy (very low energy).
• Depressed body language (e.g. lowered head and neck).
• Loss of appetite or difficulty swallowing.
• Swelling of glands (lymph nodes) under their jaw and around their head/neck that could contain abscesses. 

Please isolate your horse from others and contact an equine vet immediately if you suspect strangles.

To find out how to check your horse’s temperature, pulse, and respiration rate (TPR), you can visit our first aid guide for horse owners.

It’s possible for horses to develop ‘atypical strangles’ as well, meaning they could spread the infection despite not showing the usual symptoms. So, if you suspect atypical strangles, your horse should be isolated as a precaution while awaiting a vet visit. If a horse has atypical strangles, they might show signs like:

• Mild fever.
• Slightly less interest in food.
• Nasal discharge that isn’t thick or discoloured.

Diagnosing strangles in horses

Vets are able to diagnose strangles in horses by:

• Performing a visual examination.
• Checking a horse’s temperature.
• Taking samples to be tested, e.g. nostril swabs.
• Running blood tests to check for strangles antibodies.
• Guttural pouch endoscopy – to take samples from air sacs at the top of each nasal passage.

Treating strangles in horses

Currently, there is no cure for strangles. Also, due to the different ways in which strangles can affect individuals, the treatments for strangles can vary from one case to another. 

Initially, your vet is likely to help your horse feel as comfortable as possible by using anti-inflammatory medication to control body temperature, alongside treating any abscesses. 

If your horse has abscesses, supportive care will be essential – which could include soft feeding to reduce pain while they eat (e.g. warm fibre mashes). You’ll also have to monitor your horse’s condition closely while keeping them isolated from others until they’ve fully recovered, and vets have confirmed your horse’s test results are clear. 

It’s vital to put vet-approved biosecurity precautions in place to protect your horse and others, including:

• Washing your hands regularly, especially after handling a horse who is suffering from strangles.
• Wearing protective clothing while caring for horses with strangles (like gloves and overalls), then removing it before dealing with other horses.
• Cleaning boots in disinfectant foot dips when moving around the stable yard, particularly after leaving the isolation zones for horses with strangles.
• Disinfecting all tools (shavings fork, sweeping brush, wheelbarrow, etc.) after every use.
• Limiting the number of visitors to the yard and making sure they follow the same biosecurity measures as everyone else, whether or not they intend to visit other stable yards.
• Stopping horses from being travelled to and from the stable yard until your vet recommends otherwise. 
• Preventing your horse from interacting with others until vets have confirmed that all horses on the yard are free from strangles.

Preventing strangles in horses

When preventing strangles on a day-to-day basis, you should:

• Consider speaking to a vet about giving your horse the strangles vaccine (which can reduce the severity of strangles but can’t prevent infection).
• Follow good hygiene practices, e.g. regularly disinfect mucking-out tools.
• Keep an eye on your horse and act quickly if they show signs of strangles.

To help you protect horses from strangles in other situations, here are some steps you can take:

Be aware of how to care for new arrivals to your livery yard

Ensure that new horses being moved to your livery yard are tested for strangles before they arrive. 

Quarantine all new horses who arrive at your livery yard for around three weeks before turning them out with a herd or letting them interact directly with other horses.

You could also consider implementing a ‘Strangles-free’ surveillance programme in partnership with your vet, involving periodic testing and clear biosecurity protocols for all horses on the yard. 

Be mindful of strangles when travelling to events or new locations

Stay up to date with events in your local equestrian community (e.g. via social media groups), so you’ll know if there’s a strangles outbreak in your area.

Don’t forget to take precautions to avoid strangles if you and your horse are travelling to an event or new location. For example, since strangles can survive for up to six weeks in water, it’s essential to take your own source of water for your horse when travelling.

Be active in preventing the spread of strangles at your stable yard

Alongside having a strangles strategy in place to contain any potential outbreaks, a couple of steps you could take to prevent the spread of strangles at your yard might include:

• Discouraging horse owners from sharing equipment like mucking-out tools, grooming brushes, and tack.
• Thoroughly disinfecting stables each time a horse leaves before housing another horse in the same stable.
• Preventing other animals from wandering around near infected horses – including dogs, cats, and chickens – because they’re able to pick up the strangles bacteria and spread it.

Remember: Speak to an equine vet for advice about the best ways to prevent strangles, or deal with strangles outbreaks safely, on your stable yard.