Strangles is an infectious respiratory disease that can affect all types of horses and ponies. Caused by a subspecies of the bacterium Streptococcus equi, the disease is extremely contagious and can spread rapidly between animals.
How do I know if my horse has strangles?
Common signs of strangles include depression, lethargy, a purulent yellow nasal discharge and a cough. Often, the infected horse’s appetite will be reduced. This may be due to a combination of the high fever caused by the infection and swollen lymph nodes (glands) in the horse’s throat area. These enlarged lymph nodes can press on the airways causing breathing difficulties and can interfere with swallowing. Abscesses may form within the lymph nodes and these can spontaneously rupture, draining extremely infectious material into the environment. Very young, old or unwell horses can be more severely affected as their immune systems may not be as effective at tackling the disease.
In rare cases, horses can become very ill, with the bacteria spreading to other parts of the body. This is known as “bastard strangles” and can prove fatal.
How can infection be confirmed?
In order to confirm the presence of the bacteria, your vet will need to perform some tests. Commonly, this will involve passing a long swab up the nostril to get a sample from the back of the throat. Other tests include isolating the bacteria from abscess contents or from washes of the guttural pouches, which sit at the back of the throat. Blood samples can also be useful in assessing the likelihood of infection.
Given the extremely contagious nature of the disease, your vet may advise strict isolation while awaiting the results of these tests.
Can the infection be treated?
Although strangles is a bacterial infection, the use of antibiotics to treat it is controversial. It is thought that antibiotic treatment can actually slow the development of abscesses, thereby prolonging the course of the disease. Hence, antibiotics are considered on a case-by-case basis and may only be used in vulnerable or severely affected animals. Anti-inflammatories, however, can be extremely useful, as they can help reduce the fever and hence, improve appetite. Hot packing of abscesses and flushing with dilute antiseptic can also be useful.
How can I minimise the spread of the disease?
Strangles is transmitted by both direct and indirect contact. This means that contaminated equipment and people who have handled the infected horse can be responsible for the spread of disease. While nasal discharge and draining abscesses are obvious sources of bacteria, horses can also shed bacteria before they show any signs of disease.
If a horse is thought to be suffering from strangles, he should be isolated immediately, even if the infection is yet to be confirmed. Ideally, he should be kept in a separate stable block, far away other horses. Buckets, grooming kits and any equipment used to muck out the affected horse’s stable should be used only for this horse and kept away from other horses on the yard. A disinfectant foot dip should be placed outside the stable and should be replenished and refreshed daily. Protective clothing, such as clean overalls, gloves and separate boots should be worn when handling the horse, and must be removed and washed immediately after leaving the stable. Hands should be washed thoroughly before attending to any other animals.
Horses that have previously been in contact with the infected animal should be monitored closely for signs of infection. A high temperature is usually the first sign of strangles and so, if possible, these horses should have their temperatures taken twice daily. Contact your vet if a sudden rise in temperature is noted in any of the horses on the yard.
Ideally, horses should not be moved on or off the yard while the infection is ongoing due to the extremely contagious nature of the disease.
How do I know when my horse has recovered?
While most horses will clear the infection over a period of weeks, approximately 10% of horses who have suffered from strangles become carriers, harbouring the bacteria in their guttural pouches. While these horses may appear perfectly healthy, and may no longer be showing any signs of disease, they can still prove a source of infection for other horses. In order to be sure that your horse has fully recovered, your vet will need to perform further tests. Either a series of swabs can be taken from up the nose, with three clear swabs each taken one week apart needed to provide a clean bill of health. Alternatively, your vet can pass an endoscope up your horse’s nose in order to obtain a sample from the guttural pouches. Only one clear guttural pouch wash is required to rule out carrier status.
Can I vaccinate my horse against strangles?
A vaccination for strangles is available. However, the vaccine only provides immunity for up to three months and does not guarantee that a horse will not become infected. The vaccine is instead aimed at reducing clinical signs of disease and reducing the occurrence of abscesses in the lymph nodes.
If you have any queries about strangles, or are concerned that your horse may be infected, contact your vet for advice.
If you have any questions about any aspects of your horses’s health, or indeed your pet, farm or smallholding animals, please do not hesitate to contact us on 01892 835456. Putlands Veterinary Surgery is based in Paddock Wood in Kent, and offers a friendly, proffessional and personal service for all species of animal. We have four dedicated large animal vets with a wealth of equine experience between us, and are always happy to help