Strangles, Educate Yourself

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Strangles, Educate Yourself

Strangles is a very common but unpleasant bacterial disease that can affect horses, ponies and even donkeys. Signs vary between individuals and can range from very mild to dramatic in appearance. The disease is caused by bacteria called Streptococcus equi subspecies equi (Strep. equi) and is highly contagious being spread by direct contact with infected discharges or with contaminated clothing or equipment. Horses can be silent carriers of the bacteria displaying no outward signs but being capable of infecting others.

Clinical Signs

> Classical signs of fever, loss of appetite, depression, cough, thick nasal discharge and pain, swelling and abscess formation in the lymph nodes under the jaw and in the throat region are most commonly seen in younger horses;

> Milder signs of short term fever, dullness, loss of appetite and mild nasal discharge are increasingly common and may be evidence of a previous or ongoing infection;

Some cases can have serious complications:

> “bastard” strangles is caused by the spread of bacteria and abscess formation in different areas of body;

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>  Purpura haemorrhagica is inflammation of the blood vessels with fluid swelling (oedema) of the limbs,
sheath and under the belly and small areas of bleeding or bruising on the mucous membranes of the gums
and eyes.

> Up to 10% of horses may recover and appear normal but remain infected. These horses are ‘silent carriers’ harbouring the bacteria in the guttural pouches of the throat; they can infect other horses.


Diagnosis can be difficult and may require multiple tests:

> bacterial detection on nasopharyngeal (nose and throat) swabs, guttural pouch washes and fluid collected from an abscess

> blood test for raised or rising antibodies

> carriers can be detected using a screening blood test and guttural pouch wash (flushing and collecting fluid from the pouches in the throat).


Key Points

> highly infectious;

> very debilitating;

> affects all equines of all ages;

> takes a long time to treat;

> some horses can become silent carriers of the bacteria after infection.


Nursing care is the mainstay of treatment involving:

> damp/sloppy foods to aid swallowing;

> warm packs/poultices to help the abscess mature and cleaning and flushing to speed their resolution;

> anti-inflammatories to make the patient feel more comfortable.

> Antibiotic use is controversial and may delay abscess bursting and increase the risk of complications (cases should be individually assessed).

> Following recovery, a guttural pouch wash should be performed to confirm resolution of disease.


Strict biosecurity policies including:

> quarantine new horses for three weeks prior to entry to the yard;

> new horses should have a clear blood test in the week preceding entry onto the main yard;

> routine screening blood tests of horses to identify carriers. When an outbreak is confirmed or strongly suspected:

> close the yard to prevent horses leaving and alert all visitors to the yard;

> institute the protocol for dealing with an outbreak of infectious disease;

> isolate infected animals and all that have been in contact;

> clean and disinfect all equipment;

> unless the source is clear, investigation should be carried out to identify and treat carriers of the disease.


A vaccine is available in the UK that reduces the severity of signs use may be recommended in some yards following a specific risk assessment.

In Association with XLEquine – Picture of Health, where prevention is better than cure


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