What signs may suggest Strangles?
• Fever (>38.3oC)
• Nasal discharge (serous to purulent) with or without an ocular discharge
• Lack of appetite
• Cough
• Enlarged lymph glands

How is Strangles treated?
Although caused by a bacterium, use of antibiotics is not always beneficial. The vet will decide on their use depending on the stage and severity of the disease. Placing hot compresses over the lymph glands will hasten development of the abscess, and encourage them to burst or allow them to be lanced. The opened cavity can them be flushed and allowed to heal naturally. Anti inflammatories will often be used to bring the temperature down and relieve the pain associated with these abscesses.

Are there any possible complications?

Following infection most horses will return to normal health relatively quickly, however in as many as 20% complications may occur. Some of these may be fatal. Empyema occurs when a lymph gland ruptures through the floor of the guttural pouch releasing pus and bacteria into the cavity. The consistency of this material will often prevent it from draining easily through the valve into the throat (the slit in the middle of the picture on the left is the opening to the right guttural pouch) The infectious material dries out resulting in hard nuggets of pus containing bacteria known as chondroids. Removal of chondroids can be a difficult and expensive job. The organism can continue living within the pouch. Effected horses (silent carriers) carry the infection undetected and can be responsible for maintaining a Strangles outbreak within a yard for many months. The only way of identifying such a persistent infection involves examining the inside of the guttural pouch with an endoscope as seen in this picture on the right.

Bastard strangles occurs when the Strangles bacterium travels to another part of the horse’s body via the blood stream and develops a separate site of infection. This may occur in any part of the body but is most commonly recognised in the heart muscle, the liver, the lymph nodes within the abdomen, and the lungs. Aggressive veterinary treatment is required to treat these animals successfully.

Purpura haemorrhagica is an unusual immune reaction to the Strangles bacterium and causes extensive damage to blood vessels. This results in painful swelling of the head and limbs, and variable areas of apparently spontaneous bruising. Severe circulatory problems may subsequently develop.

How do I prevent the disease occurring on my yard?
Prevention of the disease or its spread primarily depends upon good management. New horses should be isolated for 2-3 weeks and their temperatures checked regularly. Any horse which shows suspicious signs of illness (high temperature, nasal discharge, difficulty in swallowing, swollen throat or glands) should be isolated until strangles is confirmed or ruled out by veterinary examinations and laboratory investigations. Any horse which has strangles should be immediately isolated from all other horses. It should have its own water and feed mangers, grooming kit and tack and no equipment used for the affected horse should be allowed near other horses. One person should look after the affected horse(s) and avoid contact with all other horses. All equipment, stables, fences, trailers, etc. should be thoroughly disinfected using an approved disinfectant (eg. Virkon).

Unfortunately, some horses become symptom-less persistent carriers of Streptococcus equi, most commonly in their guttural pouches (see above), and can infect horses intermittently although showing no signs of infection themselves. This is probably the most important cause of infection recurring at intervals of several months, after apparent clearance. Part of the clearance process for recovered cases should therefore be the collection of deep nasopharyngeal swab and guttural pouch wash samples for laboratory investigations.

Can I vaccinate against Strangles?

A new vaccine has now become licensed for use in UK and, although not 100% protective, does offer significant defence against strangles infection. Do please phone the practice to discuss your particular situation. Click here to read more about Vaccinations

Code of Practice - Control of Strangles Infections
Since 1978, the Horserace Betting Levy Board has annually updated and produced its highly successful Code of Practice for the control of equine venereal diseases and now includes guidelines on strangles. This contains detailed advice and recommendations on the disease and its effects, diagnosis, control and prevention. Your veterinary surgeon will have a copy of the Code and copies may be obtained via the Thoroughbred Breeders Association or the British Horse Society. Although a voluntary Code it has become the industry standard for the benefit of all and all horse breeders should read it and follow its advice.

n.b. acknowledgement of pictures from the internet, and disclaimers

DISCLAIMER: This advice is intended for use by registered clients of Priors Farm only. The advice offered is general advice only. Priors Farm clients who wish to discuss the individual circumstances of their horse should contact the office. To speak to a vet please phone between 8.30 - 10.00 am on weekday mornings.