What is Strangles in Horses

Strangles is a form of distemper that occurs in horses and related equines. It is an infection that occurs in the upper respiratory tract and is contagious. As the infection builds a foothold, it begins to cause the lymph nodes of the horse to swell. That causes the larynx, pharynx, and trachea of the horse to start closing from compression. Without treatment, strangles can be life-threatening to a horse.

Strangles can also cause numerous abscesses to form in and around the head and neck area. Some horses may have these abscesses form in other places on their body as well. These abscesses can burst, creating a painful wound. 

How to Tell if a Horse Has Strangles

The first symptoms of strangles that can be seen tend to be the swelling of the lymph nodes. Many horses will develop abscesses on their lymph nodes around the neck and head area. As the swelling worsens, the horse will begin to hack and cough more often. They may have difficulty swallowing as well, which puts them off their feed.

The swelling may be localized when a horse has strangles or it may affect their entire head and neck region.

A horse with strangles will also develop a fever, often as high as 106F. There is usually discharge that comes from the eyes and nose as strangles develops as well. It is this discharge that spreads the disease to other horses. The discharge comes from the lymph nodes draining pus or mucus being discharged from the nose and will contaminate everything from the feed trough to the pasture to the tack of the horse.

What Is Bastard Strangles?

Bastard strangles is a severe form of the disease that causes abscesses to appear in other parts of the horse’s body. When bastard strangles is presence, the lungs, abdomen, and even the brain may experience growths. These abscesses can rupture and that can cause serious life-threatening conditions for the horse that goes beyond airway swelling.

Horses of any age can contract either form of strangles. Horses that are younger and elderly horses tend to be at the highest levels of risk. Horses that have a compromised immune system can also struggle with this disease.

When both forms of strangles are evaluated, the mortality rate of this disease is about 8%. Horses that can avoid the problems of bastard strangles typically have a higher rate of recovery. Morbidity is very high with this disease and horses must be isolated to protect the rest of the herd. The isolation period for strangles, in most instances, can be up to 6 weeks to ensure the bacteria which cause the disease are not continuing to incubate.

How to Treat Strangles in Horses

Because strangles is a bacterial infection, it can be treated with common antibiotics. If the horse is diagnosed with strangles before abscesses begin to form, then the condition is treated like a streptococcal infection in humans. Penicillin or derivative antibiotics are used, unless there is an allergy to the medicine. Alternative antibiotics can be prescribed to avoid the health issues of an allergy.

Once abscesses have begun to form, however, some veterinarians may recommend against using antibiotics as there is the possibility that it can spread through the lymphatic system to other parts of the body.

Should an exterior abscess burst, it is important to keep the wound clean and disinfected. Iodine and povidone solutions are used to clean out the wound. A syringe is often necessary to reach all areas and scrubbing around the wound to remove bacteria is helpful as well.

Some horses may also benefit from having a warm pack placed on their abscesses to help them mature with less pain.

The best way to treat strangles, however, is to vaccinate the horse as soon as possible. There are intramuscular and intranasal vaccines that are available through local veterinarians. Proactive disinfection of all equipment, stalls, tack, and buckets is necessary, especially if strangles is suspected.

It is also a best practice to have a designated quarantine area so that new horses can be placed in isolation for 3 weeks to observe the status of their health. Quarantined areas should have dedicated equipment to prevent transmissions to the rest of the herd. Veterinarians can screen new arrivals for strangles as well. 

Good handwashing techniques by owners and handlers is a must as well. Humans that come into contact with the bacteria which causes strangles can pass it along to other horses through basic contact. 

Flies can also pass strangles onto other horses. Place any gauze and materials used to clean the wounds or nasal discharge from the horse in sealed containers to prevent an unintended outbreak. 

What Are the Complications of Strangles in Horses?

A majority of horses will come through a strangles infection without suffering any long-lasting effects and will fully recover. Horses that fully recover from strangles usually have full immunity from the disease for several years afterward.

Some horses can become a chronic carrier of strangles and must be kept away from other horses to avoid having the bacteria spread. In this instance, they should remain in isolation except for coming into contact with other horses who are carriers. About 1 in 10 horses that recover from strangles will become a chronic carrier of the bacteria.

With bastard strangles, several different health conditions can develop because of the presence of the abscesses or complications from them bursting. Pneumonia is the most common health issue that develops with bastard strangles. Some horses may experience heart health issues. The guttural pouch may also begin filling with pus and become very painful for the horse.

It usually takes about 3 weeks for a horse to fully recover from strangles.

Can Humans Catch Strangles?

Because strangles is caused by a streptococcus bacterium, it is possible for humans to contract an infection when working closely with an infected horse. Avoiding any contact with nasal or abscess discharge will prevent the infection from spreading. Handlers who do come into contact with infectious discharge should avoid having it come around the areas of their eyes, mouth, or nose.

The best way to prevent horse-to-human transmission is to wear disposable gloves while working with an infected horse. Avoid touching the face of an infected horse at all times, even with gloves and other personal protective equipment on. Once finished, always wash hands thoroughly.

Most outbreaks of strangles are required to be reported because of its infectious nature. It is a serious disease and should be treated as such. Although 92% of horses that develop strangles will recover from the disease, the risks go down with early intervention and proactive monitoring. That is why it is so important to know what strangles is in horses.