Strangles is a very contagious disease of the upper respiratory tract caused by bacteria called Streptococcus equi. It is highly contagious and the infection can be spread by horse-to-horse contact or by humans, tack, drinking trough and other environmental factors. It can spread rapidly however sensible measures can minimise the risk of infecting with strangles and an early prompt treatment can lessen the impact in the event of an outbreak.
The typical signs of strangles include:
Sudden high temperature and loss of appetite.
Slight yellowy nasal discharge.
Swollen lymph nodes (glands) under the jaw and in the throat: never present in the early stages of the disease.
Rupture of the abscesses in the affected lymph nodes.
Horses usually recovered fully and naturally after the rupture of the abscesses. Once the horse has recovered from strangles it usually develops a strong immunity and it is rare for an animal to be affected more than once.
If your horse shows any of these symptoms it is important that you contact your vet to help confirm the diagnosis as soon as possible. He will help you with the treatment and management of your horse for their quicker recovery and also so prevent an outbreak of the disease.
The time between infection and development of clinical signs varies but it is usually 1 to 2 weeks.
Strangles is diagnosed primarily on the clinical signs which may be strongly suggestive of its involvement. Nasal swabs samples can be taken for laboratory investigation. Recently a blood test has been developed which is able to tell us whether the horse has had contact with strangles in the recent past. A negative result for strangles in the swab or the blood do not guarantee that the horse does not have strangles, but these laboratory results together with the symptoms can be very helpful in determining if the horse is affected and which horses may be involved when an outbreak occurs in the yard.
Some horses can become carriers, where they do not suffer the disease but they can spread it to other horses.