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Also Known As

Lymph gland infection


The name "strangles" was coined due to the strangled breathing sounds made by horses with enlarged lymph glands that are characteristic of the disease.

A horse that is exposed to Streptococcus equi will begin to show symptoms within two to six days and the characteristic abscessed lymph nodes will develop within one to two weeks after exposure. The lymph nodes rupture and drain and the drainage is highly contagious.


  • Lack of appetite
  • Fever
  • Listlessness
  • Swelling of lymph nodes in throat area
  • Nasal discharge that turns thick and yellow
  • Difficulty breathing


Strangles is caused by the bacterium Streptococcus equi that is specific to horses.


Separating or quarantining a horse at the earliest signs of the disease is important because the disease is highly contagious and may be passed from one horse to another via nasal secretions and pus from ruptured abscesses in the lymph nodes. Horses remain contagious for approximately a month after having the disease.

Good horse management techniques are necessary to prevent the spread of the disease through contaminated water buckets, brushes, stalls, fences, or any other surface in the stable or pasture area. Bleach or other disinfectant should be used to wash down stalls including walls and floors, all equipment and tack, and any other surfaces that may have become contaminated by a horse with the disease. Fortunately, the bacteria die fairly quickly in the environment.


Treatment of strangles depends on the general health of the horse and the severity and stage of the particular horse's case. Penicillin has been effective, but should be administered during the initial stages of the disease or after any abscesses have ruptured. Once abscesses form, penicillin has been reported to delay the opening and draining of the abscesses, which can lead to complications.

In mild cases, some veterinarians prefer to let the disease work its course because the disease is self-limiting and can be fought off by the immune system of most healthy horses without medication. Many veterinarians claim that antibiotics may do more harm than good by killing off beneficial bacteria the horse needs to fight the strangles infection.

The main complications that can occur include extreme swelling of lymph nodes to the point that airways are compressed and the horse's ability to breathe becomes restricted. In this case, a tracheotomy will be necessary to create an open airway. .

Another complication occurs when pus from the ruptured lymph nodes drains into the horse's lungs, causing a secondary infection of pneumonia. Treatment of the secondary infection becomes necessary and may include a round of antibiotics.

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EquiMed staff writers team up to provide articles that require periodic updates based on evolving methods of equine healthcare. Compendia articles, core healthcare topics and more are written and updated as a group effort. Our review process includes an important veterinarian review, helping to assure the content is consistent with the latest understanding from a medical professional.