Understanding Strangles in horses – the symptoms, testing, and treatment
Strangles is one of the most recognised infectious diseases in horses, ponies, and donkeys — and for good reason. Although it can spread rapidly through a yard, prompt diagnosis, appropriate management, and good biosecurity can dramatically reduce its impact. Here’s what every horse owner should know about this highly contagious disease.
What Is Strangles?
Strangles is a bacterial infection caused by Streptococcus equi subspecies equi. It affects the upper respiratory tract, particularly the lymph nodes around the head and neck. While it’s rarely fatal, it can cause significant illness, yard closures, and disruption to training or competition schedules.
How Strangles spreads
Strangles is extremely contagious and can spread in several ways:
Direct contact with an infected horse (nose-to-nose contact is a common route).
Indirect contact via contaminated equipment, tack, feed or water buckets, clothing, or hands.
Carrier horses, which show no signs of illness but still harbour and shed the bacteria.
Poor biosecurity on yard can lead to cross-contamination and increase the spread
The bacteria can survive in the environment for several weeks, particularly in damp, cool conditions — making thorough cleaning and disinfection vital during an outbreak.
Common symptoms to watch out for
Signs of Strangles can vary in severity, but typical symptoms include:
Fever (often the first sign)
Lethargy and loss of appetite
Nasal discharge — often thick and yellow
Swelling and abscess formation under the jaw or behind the throatlatch
Difficulty swallowing or breathing (in severe cases)
Persistent coughing in some horses
If you notice any of these symptoms, isolate the horse immediately and contact your vet.
When is a Strangles test needed?
Testing is recommended in several situations:
When a horse shows symptoms consistent with Strangles
Before introducing a new horse to a yard or after a period away from home
To confirm recovery in a horse that has been infected
To screen for carriers after an outbreak
Early testing helps to control the spread and identify infected or carrier horses before they reintroduce the disease into a healthy population.
Treatment and management
Most horses recover fully with appropriate care. Treatment focuses on:
Isolation: Infected horses must be kept separate from healthy ones.
Supportive care: Rest, hydration, and soft feed to aid swallowing.
Abscess management: Vets may lance and drain abscesses when mature to relieve discomfort and speed recovery.
Antibiotics: Occasionally prescribed, depending on disease stage and severity.
Monitoring: Temperatures of all horses on the yard should be checked daily.
Once symptoms have resolved, follow-up testing ensures the horse is no longer infectious before rejoining others.
It is important to note that there is a vaccine available. This vaccine not only reduces the spread of Strangles, but also lessens the clinical symptoms should a vaccinated horse become infected - reducing the time that they are unwell, and reducing the level to which they fall ill.
Owner responsibilities and prevention
As a horse owner, you can play a major role in preventing and controlling Strangles:
Vaccinate horses to reduce the spread and symptoms amongst horse populations
Isolate new arrivals for at least 2–3 weeks.
Avoid sharing equipment between horses.
Change clothes between yards for optimum biosecurity.
Disinfect stables, water troughs, and grooming tools regularly.
Screen horses before and after travelling or competing.
Stay informed — work with your vet to create a yard biosecurity plan.
Strangles outbreaks can be stressful, but with prompt veterinary involvement and good management, recovery and return to normal life is entirely achievable.
Need advice, testing or vaccination?
If you’re concerned about Strangles on your yard or want to discuss your options, our equine vet team is here to help. We stock the Stangles vaccine, Strangvac and are able to administer this vaccine on your next visit if you book this with our team - simply get in touch via phone (01473 970 393) or email (office@starlingequinevets.co.uk) to arrange your vaccine. We can also provide tailored advice, carry out testing, and support you through effective management and recovery.
Get in touch with our team to book your Strangles test.