Strangles is a highly contagious bacterial disease that affects horses, donkeys, and mules. It causes fever, swollen lymph nodes around the jaw and throat, and thick nasal discharge. The disease spreads easily through direct contact, shared water buckets, grooming tools, tack, and even handlers’ clothing, and the bacteria can survive in the environment for weeks. While most horses recover in 3-4 weeks, some may continue to carry and shed the bacteria, posing a risk to other animals. Good biosecurity and early detection are essential for preventing outbreaks.
Clinical Signs
Clinical signs of equine strangles can develop 3 to 14 days after exposure to
Streptococcus equi subspecies
equi. Horses commonly develop:
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Fever is often the first noticeable sign, appearing 1 to 2 days before other signs
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Enlarged lymph nodes under the jaw and throatlatch area, which may form abscesses
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Thick, mucopurulent nasal discharge, progressing from white to yellow pus
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Difficulty swallowing, wheezing, cough, and throat inflammation that may lead to noisy breathing
Severe or complicated cases may develop abscesses in other body regions like the chest or abdomen (called “bastard strangles”) or other immune-mediated issues.
Prevention & Biosecurity
The following actions are important for disease prevention and control:
- Reduce direct horse‑to‑horse contact and avoid sharing tack, equipment, water sources, or grooming tools.
- Prevent indirect spread by cleaning hands, clothing, and footwear after handling different horses.
- Regularly clean shared spaces at barns/stables. Following any cases, thoroughly clean and disinfect barns, stalls, fencing, buckets, tack, grooming items, and any shared surfaces with effective disinfectants.
- Isolate new arrivals, horses that may have been exposed during travel, and sick horses for 14 to 21 days.
- Vaccines are available for horses at higher risk but may be associated with some complications, decisions about vaccination should be made with a veterinarian.
- Remember that recovered horses may still carry and shed the bacteria, so monitor them closely and manage contact with others.
If you suspect Strangles
Contact your veterinarian.
Recommendations & Treatment
Your veterinarian can help diagnose equine strangles, usually through physical exam and laboratory testing of nasal swabs or lymph node samples as appropriate. Your veterinarian also will be able to provide guidance on treatment, potential vaccination, and proper biosecurity. Most affected horses recover within a few weeks with supportive care, including rest, hydration, warm compresses on abscesses, and management of fever or discomfort. Continued monitoring and good biosecurity remain important to prevent further spread. Animal health officials may work with your veterinarian to quarantine affected and exposed animals.
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