Strangles

Strangles may also refer to strangling

Strangles (also equine distemper) is a contagious, upper respiratory tract infection of horses and other equines caused by a bacterium, Streptococcus equi. Strangles is endemic in domesticated horse populations worldwide.

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Clinical symptoms are characterised by fever, nasal discharge or pus, and swollen or enlarged mandibular lymph nodes - around the neck and face. Affected animals may also stop eating and have a dull affect.

Possible complications include the horse possibly becoming a chronic carrier of the disease, asphyxia due to enlarged lymph nodes compressing the larynx or windpipe, bastard strangles (spreading to other areas of the body), pneumonia, guttural pouches filled with pus, purpura hemorrhagica, and heart disease. The average length for the course of this disease is 23 days.

The disease is spread when the nasal discharge or material from the draining abscess contaminates pastures, barns, feed troughs, etc. Isolation of new horses for 4 to 6 weeks, immediate isolation of infected horses, and disinfection of stalls, water buckets, feed troughs, and other equipment will help prevent the spread of strangles.

Equines of any age may contract the disease, although younger and elderly equines are more susceptible, owing to a weaker immune system.

Vaccinations are available. The initial vaccination is followed by a booster in three weeks and a third booster in six weeks from the initial vaccine. Annual re-vaccination is given thereafter.

Mortality may be up to 1 in 10 horses affected with strangles, especially bastard strangles. For cases without complications, mortality is usually lower. The disease is very contagious and morbidity is high. Precautions to limit the spread of the illness are necessary and those affected are normally isolated. An isolation period of 6 weeks is usually necessary to ensure that the disease is not still incubating before ending the isolation.

Treatment

As with many streptococcal infections, penicillin or penicillin-derivative antibiotics are the most effective treatments. However, some authorities are of the opinion that use of antibiotics are contra-indicated once abscesses have begun to form, as they pre-dispose to lymphatic spread of the infection (so-called bastard strangles) which has a much higher mortality rate.

After the abscess has burst, it is very important to keep the wound clean. A diluted betadine solution has been used with good results to disinfect the open hole, flushing the inside with a syringe tipped with a teat canula, followed by gentle scrubbing to keep the surrounding area clean.