Strangles is a fairly common but highly contagious equine disease. This bacterial infection is caused by Streptococcus equi subsp. equi and, fortunately, can be prevented, although an outbreak in a herd can cause considerable problems. It most often affects young horses, but older horses can also develop it. Although strangles can be fatal in rare cases, most cases can be treated if you act promptly. How can you recognise the first signs, treat affected animals and prevent it spreading through the herd? This article provides all the essential information about symptoms, treatment and prevention.
What are the symptoms of strangles in horses?
Strangles usually becomes apparent a few days after infection. The first sign to watch for is fever: your horse's temperature may rise to 39-41°C, which, together with weakness and loss of appetite, should cause concern. If your horse has been in contact with new herd members, be particularly vigilant. Another possible sign is a cough and thick, purulent nasal discharge, often yellowish or greenish. As the disease progresses, swelling may develop around the jaw and throat, and the lymph nodes become painful and enlarged. This leads to difficulty swallowing and breathing. In the most advanced cases, abscesses may form in the lymph nodes, eventually bursting and releasing pus. Although this can look alarming, the horse usually begins to recover once the abscesses burst, but still needs ongoing veterinary care for some time.
How soon do strangles symptoms appear?
Symptoms usually appear within 3-14 days of infection. Fever is the first sign to watch for. Nasal discharge and swollen lymph nodes may follow shortly afterwards. Abscesses in the nodes begin to mature within 7-14 days. During this time, appropriate veterinary care and isolation from other animals are important to prevent infection spreading.
Is strangles contagious? How does infection spread?
Strangles is exceptionally contagious because Streptococcus equi bacteria spread easily between horses. Infection can spread quickly through a herd, particularly where horses have frequent contact. It spreads not only through direct contact with an affected horse, such as saliva, nasal discharge or pus from burst abscesses, but also indirectly through equipment used by infected animals, such as headcollars, buckets and brushes. People who do not wash their hands or change clothes after contact with affected horses can also carry the bacteria. Strangles can also cause serious complications, such as pneumonia, lung abscesses and, rarely, sepsis. Although uncommon, these show the importance of prompt treatment and isolation. Sometimes bacteria enter the bloodstream, causing so-called "bastard strangles", with abscesses in internal organs. Even after treatment, bacteria can remain in animals that become chronic carriers despite no longer showing symptoms.
Are all horses at risk of strangles?
Yes, but horses are not all equally at risk. Young horses are most susceptible, particularly those under 5 years old, including foals that have not previously encountered the bacterium. Risk is also high among horses living in large herds or frequently travelling long distances, particularly to competitions. Reduced immunity caused by stress, poor diet or other illnesses also increases the risk of strangles.
How is strangles treated?
Treating strangles requires patience and consistency. Recognising symptoms promptly and immediately isolating the affected horse from the herd is very important to minimise the risk to other animals. Isolation should be in a clean, well-ventilated space, helping your horse focus on fighting infection. Treatment is essentially symptomatic, mainly supporting the horse's body as it fights the disease. In most cases, horses do not need antibiotics because their bodies can tackle the infection themselves. Antibiotics are used only for serious infections or where there is a risk of complications such as pneumonia or sepsis. Remember, however, that giving antibiotics too early can inhibit abscess maturation and slow recovery. If abscesses develop, warm compresses help them mature and burst. Once an abscess bursts, daily wound cleaning and suitable antiseptics are important to prevent secondary infection. Alongside direct treatment, provide suitable conditions for recovery. Maintain hydration and a vitamin-rich diet to support immunity. Supplementing vitamin C and zinc also speeds recovery.
How can you prevent strangles in horses?
Preventing strangles is important to keep the whole herd healthy and minimise infection risk. What steps can reduce that risk? Here are some effective prevention methods. Hygiene and biosecurity are fundamental. Regular disinfection of stables, equipment, drinkers, headcollars, buckets and brushes is essential to prevent bacteria spreading. Each horse should have its own equipment, without sharing with others. Newly arrived horses should undergo compulsory quarantine for at least 3 weeks to avoid transmitting infection to the herd. Isolating affected horses is absolutely essential. Horses showing any symptoms must not travel, compete or train, to avoid endangering other animals. Respond quickly to the first signs and do not expose other horses to infection. Although vaccines against Streptococcus equi are available, they do not provide complete protection. They are nevertheless recommended at studs with a higher infection risk, particularly large groups of horses in frequent contact. Vaccination can considerably reduce the likelihood of infection and help maintain herd health.
Conclusions and practical advice for treating strangles
Strangles can have serious consequences if it is not diagnosed and treated early enough. Early signs should be taken seriously immediately, and the horse isolated from the herd. Remember that young horses and those with weakened immunity face a higher risk of severe illness. Treatment mainly supports the horse in fighting infection, sometimes with antibiotics, particularly for complications. Prevention is equally important and requires consistent hygiene and isolation of newly arrived horses. Following these simple principles considerably reduces disease risk. Remember: responding quickly to the first symptoms can make an enormous difference to your horses' health. Act responsibly and prioritise prevention, as this is key to good health.
