Strangles, also known as Equine distemper, is one of the most common and highly contagious diseases affecting horses throughout the United States. The disease is caused by the bacterium Streptococcus equi and primarily affects the upper respiratory tract and lymph nodes. Because of its contagious nature, strangles can spread rapidly through barns, boarding facilities, shows, and training centers if proper precautions are not taken.
What Causes Strangles?
The disease spreads through direct horse-to-horse contact through contaminated equipment, water buckets, feed tubs, tack, clothing, and human hands. The bacteria are commonly found in nasal discharge and the drainage from ruptured abscesses.
One of the challenges of controlling strangles is that some horses can become carriers. These horses may appear healthy and show no signs of illness while continuing to harbor and spread the bacteria to other horses.
Common Signs and Symptoms
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Fever: Usually, one of the earliest signs
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Loss of appetite: Reluctance to eat or drink
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Depression or lethargy: Low energy
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Nasal discharge: Thick mucus from the nose
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Swollen lymph nodes: Particularly under the jaw and around the throat
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Coughing: Caused by throat irritation
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Difficulty swallowing: The horse may drop or hold its head oddly
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Respiratory distress: Severe swelling that restricts the airway
As the disease progresses, the lymph nodes often become enlarged and may develop abscesses. These abscesses can eventually rupture and drain, which is where the disease gets its name – the swelling around the throat can make it appear as though the horse is being “strangled.”
How Contagious Is Strangles?
Strangles is extremely contagious and can spread quickly throughout an entire barn. Horses can become infected by:
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Direct contact with an infected horse
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Shared water sources
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Contaminated feed buckets and equipment
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Grooming tools
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Human hands and clothing that have come in contact with infected horses.
Because of this, early detection measures are essential to preventing an outbreak.
What To Do If You Suspect Strangles
1. Quarantine the barn
Separate the affected horse from all other horses as soon as possible. Avoid sharing equipment, water buckets, feed tubs, or grooming supplies with healthy horses.
2. Contact your veterinarian
A vet can confirm the diagnosis through laboratory testing and recommend an appropriate treatment plan. Early diagnosis can help limit the spread of the disease.
3. Monitor other horses
Take temperatures daily and watch for signs of illness in all other horses that may have been exposed. Fever is often the first sign.
4. Follow strict disease protocols
Disinfect stalls, buckets, grooming equipment, and any surfaces the infected horse may have touched. Caretakers should wash their hands well and change clothing between handling infected horses.
Treatment Options
Treatment depends on the severity and stage of the disease. Your veterinarian will determine whether antibiotics are appropriate. In some cases, penicillin may be recommended, while other horses may be managed primarily with supportive care.
Supportive care is also important and may include:
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Always providing fresh water
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Offering soft, easy-to-eat foods
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Monitoring temperature and overall condition
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Keeping the horse comfortable and stress-free
Caring for Abscesses
When lymph node abscesses mature and rupture, proper wound care becomes essential. Because the drainage contains large amounts of bacteria, careful cleaning helps reduce the risk of spreading the infection. If the abscess bursts:
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Wear gloves when handling drainage
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Keep the area clean and free of debris
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Flush the wound with diluted povidone-iodine solution as directed by your veterinarian.
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Gently clean the surrounding skin to remove discharge and prevent irritation.
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Properly dispose of contaminated materials and disinfect equipment after use.
Prevention and Vaccination
While no prevention method is 100% effective, horse owners can significantly reduce the risk of strangles by:
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Quarantining new arrivals for at least 12-21 days
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Avoiding shared water sources at events and shows
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Practicing good barn hygiene
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Disinfecting equipment daily
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Monitoring horses for fever and respiratory symptoms
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Discussing vaccination options with a vet
Strangles remains one of the most common infectious diseases in horses, but with prompt recognition, appropriate veterinary care, and strict biosecurity measures, most horses recover fully. Horse owners who understand the signs of strangles and respond quickly can help protect not only their own horses but also the broader equine community from a potentially serious outbreak.
If you suspect your horse may have strangles, contact your veterinarian immediately and implement quarantine procedures to help prevent further spread of the disease.
