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United Kingdom


Horse in stable looking out


Streptococcus sp. infections play an important role in equine medicine all over the world, with the ability to cause severe disease of varying and sometimes fatal symptoms in horses.

Strangles results from an infection of Streptococcus equi, causing upper respiratory tract inflammation, a muco-purulent nasal discharge, and inflammation of the regional lymph nodes. This infection results very quickly in the formation of an abscess (usually in the sub-mandibular area), which may be small and resolve over time, or may become a very large and open abscess, requiring appropriate treatment. Strangles is highly contagious, and horses can be carriers and shed the infection, although they themselves may show no outward clinical signs. This means that without proper biosecurity and isolation, an infection could result in large outbreaks of this disease in horse populations.

Symptoms can be highly suggestive of strangles although not all horses develop the characteristic swollen lymph nodes of the head and neck. Definitive diagnosis is usually achieved through a combination of blood testing and nasopharyngeal swabs for bacterial culture and DNA isolation.



1. Waller A (2014) New Perspectives for the Diagnosis, Control , Treatment, and Prevention of Strangles in Horses. Vet Clin Equine 30,591–607