Strangles is one of the most common diseases affecting horses worldwide. It also carries a massive amount of stigma with affected yards being locked-down and horses from infected areas being precluded from entering competitions for fear of spreading the disease. But what is strangles and are we right to be so fearful of it?
What is equine strangles?
Simply put, equine strangles is an upper respiratory tract infection caused by the bacterium, Streptococcus equi. Youngsters seem to be prone to more severe attacks of the disease although it can affect any type and age of horse.
Signs and symptoms
Affected animals become depressed, lose their appetite and have a thick, yellow mucous running from the nostrils. A fever is also present and the horse’s temperature will rise to over 38.50. As the disease progresses, large painful abscesses often develop on the sides of the horse’s head and throat. These abscesses eventually burst and discharge pus. Due to the pain in its throat, the horse may have trouble eating or extending its head.
A less severe, atypical strangles is commonly seen these days, particularly in healthy adult horses. Those affected display a mild, brief fever, loss of appetite for a day or so and a clear nasal discharge. Unfortunately, these signs are seen with other diseases too but to be on the safe side affected animals should be isolated immediately and veterinary advice sought.
Despite the immediate panic among the equestrian community at the mention of a horse with strangles, it is rarely fatal. Possible complications include metastatic (bastard) strangles in which abscesses form in other areas of the body, and the immune disorder, purpura haemorrhagia.
The disease can be spread directly to a non-infected horse via bacteria which are shed in the nasal discharge or pus from draining abscesses. Indirect infection is usually the main culprit in the spread of the disease where bacteria are transferred on clothing, people’s hands or tack. It’s therefore vital that biosecurity measures are taken on yards where infected horses are stabled in order to isolate the disease and prevent it from being transferred further afield.
The incubation period of the disease is up to 14 days although the abscesses can take a week after that to manifest themselves and affected animals can still shed bacteria for up to six weeks following recovery.
Antibiotics can be used to treat strangles but this remains controversial. The majority of cases recover simply with good nursing care, rest and anti-inflammatories. Abscesses can be hot compressed to encourage them to rupture or your vet may opt to lance them.
Around 10% of horses that have suffered strangles appear outwardly healthy but continue to carry bacteria within their guttural pouches. These ‘carriers’ can shed bacteria for months, or even years, posing a very real threat to other horses.
A vaccination for strangles was introduced in the UK a number of years ago but was withdrawn after many horses developed severe side effects, including full-blown strangles, following the injection. Vaccination is available again now but many horse owners are reluctant to use it because of the side effects. The vaccine is not 100% effective although it is thought to reduce the severity of the disease should a horse contract it.
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