Equine Strangles

Strangles is a highly infectious respiratory tract disease. It is caused by the bacterium Streptococccus equi equi and affects only horses, donkeys and mules. Early cases are often confused with viral infections (these are usually self limiting and cause low morbidity)



Strangles is usually seen in young horses but can also affect older, naive horses. Symptoms occur 3-14 days after exposure:

  • Depression
  • Reduced appetite
  • Fever
  • Nasal discharge (may initially be clear but rapidly becomes thick pus)
  • Pain (horses may stand with neck extended downwards)
  • Cough
  • Swollen glands in the throat region - generally will rupture and drain within 7-14 days after the onset of symptoms
  • Other (19-42% of cases have complications including asphyxiation, inflammation of blood vessels throughout the body and severe infection of lymph nodes in the gastrointestina l tract)



Strangles is highly infectious. It is spread via direct nose or mouth contact, and / or indirect through contaminated drinking buckets, tack, rugs, feed, pasture, wall, floors or people (boots, clothing, hands etc.). Asymptomatic horses are often responsible for initiation of disease outbreaks.



Illness due to stranlges infection requires prompt veterinary treatment (antibiotics therapy, supportive care, anti-inflammatory medication etc). This is to control the infection, alleviate symptoms and prevent secondary complications.



Vaccination: Unvaccinated horses require 3 vaccinations two weeks apart. Vaccination can be started as early as 12 weeks of age. Vaccinations of dams 2-6 weeks prior to foaling is also recommended. Booster vaccinations are required every 6-12 months. There are complications associated with vaccination which should be discussed with your veterinarian.


  • When introducing a new animal onto a property they should be isolated for 2 weeks.
  • Restricted movements of sick / affected animals.
  • Monitoring rectal temperatures of animals in contact with affected animals.
  • Thorough disinfection.
  • Restricted human access to sick / affected animals.
  • Double fencing or windbreaks along boundary fences.