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 enzootic in domesticated horses worldwide.

Biology
The disease is spread when the nasal discharge or material from the draining abscess contaminates pastures, barns, feed troughs, etc.

Equines of any age may contract the disease, although younger and elderly equines are more susceptible. Young equines may lack immunity because they have not had prior exposure. Elderly equines may have a weaker immune system.

Signs and symptoms
Clinical signs and symptoms include fever, heavy nasal discharge, and swollen or enlarged lymph nodes in the neck and jaw (mandible). Affected animals may also stop eating and have a dull affect.

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

Complications
Possible complications include the horse 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, abscesses, purpura hemorrhagica, and heart disease. The average length for the course of this disease is 23 days.

Prevention
Both intramuscular and intranasal vaccines are available. 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. As with any contagious disease, handwashing is a simple and effective tool.