Strangles in Horses: Symptoms, Treatment, and Prevention


Strangles, a highly contagious equine disease caused by the bacterium Streptococcus equi, predominantly affects the upper respiratory tract of horses. 

Despite its menacing name and severe symptoms, with prompt treatment and proper management, recovery is possible. This article delves into the specifics of strangles, helping horse owners and caregivers recognize, address, and prevent its occurrence.

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What is Strangles?

Strangles is a highly contagious bacterial infection that affects horses. It’s caused by the bacterium Streptococcus equi subspecies equi

The name “strangles” describes the swollen lymph nodes around the throat, which can sometimes become so enlarged that they strangle or suffocate the horse. This disease is particularly concerning for horse communities as it spreads easily and rapidly among equine populations.

Symptoms of Strangles in Horses

Symptoms of Strangles in Horses

The symptoms of strangles can range from mild to severe, and they typically appear 3-14 days after exposure to the bacteria. Some common symptoms include:


Affected horses might present with an unexpected or unexplained fever.

Swollen Lymph Nodes: 

Lymph nodes, especially those around the throat, can become swollen and filled with pus. They might even rupture and drain pus.

Nasal Discharge: 

Initially, a horse with strangles might have a clear nasal discharge, but this can quickly turn into a thick, yellowish or white discharge as the disease progresses.


Persistent cough is another common symptom.

Difficulty Swallowing: 

Due to swollen lymph nodes, the horse might have difficulty swallowing.

Loss of Appetite and Lethargy: 

Affected horses might show reduced interest in food and might appear more tired than usual.

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How is Strangles Transmitted?

Strangles is primarily transmitted through direct or indirect contact:

Transmission Modes of Strangles

Direct Contact: 

This is the most common mode of transmission. If a healthy horse comes into direct contact with an infected horse – through nose-to-nose touch, for instance – the disease can spread.

Indirect Contact: 

The bacteria can live for a while outside the horse’s body. Therefore, any equipment, tools, or even human hands that come into contact with an infected horse can become a source of infection. Items like bridles, buckets, brushes, and even shared water troughs can be contaminated and spread the disease. People can also transmit the bacteria from one horse to another if they do not practice proper hand hygiene.

Airborne Transmission: 

In rare cases, the bacteria can become airborne and infect nearby horses, especially in confined spaces with poor ventilation.

Diagnosis of Strangles

Diagnosing strangles involves a combination of clinical signs and specific tests:

Clinical Examination: 

The veterinarian will begin by examining the horse for common symptoms such as swollen lymph nodes, nasal discharge, fever, and cough.

Bacterial Culture: 

A swab from the nasal discharge or from the pus drained from the lymph nodes can be cultured to identify the presence of Streptococcus equi subspecies equi.

Polymerase Chain Reaction (PCR) Testing: 

This molecular test detects the DNA of the bacteria and can be a quicker way to diagnose strangles. It is especially useful in carriers that don’t show clinical signs.

Blood Tests: 

In some cases, blood tests might be used to determine the horse’s immune response to the bacteria, aiding in diagnosis.

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Treatment Options

Treatment Options

The approach to treating strangles can vary based on the severity of the symptoms and the specific circumstances:


There’s some debate about the use of antibiotics in treating strangles. While they can be effective, using them too early might hinder the natural drainage of abscesses. A veterinarian will decide on the use and type of antibiotic based on the horse’s condition.

Supportive Care: 

This involves managing the symptoms and ensuring the horse remains as comfortable as possible. It might include:

  • Anti-inflammatory medications to reduce fever and discomfort.
  • Warm compresses to promote abscess maturation and drainage.
  • Ensuring hydration and encouraging the horse to eat.

Surgical Intervention: 

In rare cases, especially if the abscesses are not draining on their own, a veterinarian might decide to surgically open and drain them.

Complications of Strangles

While many horses recover from strangles without long-term issues, complications can arise:

Bastard Strangles: 

This is when abscesses form in unexpected parts of the body, such as in the lungs or abdomen. These internal abscesses can be harder to treat.

Purpura Hemorrhagica: 

This is a severe immune-mediated reaction where small blood vessels become inflamed and leaky. It can lead to swelling and hemorrhages in various parts of the body.

Guttural Pouch Infections: 

The guttural pouches can become infected and fill with pus. This condition can become chronic and might be a reservoir for future outbreaks.


Rarely, the swollen lymph nodes can obstruct the airway, leading to suffocation.

Chronic Carriers: 

Some horses might not show symptoms but continue to carry the bacteria, posing a risk of future outbreaks.

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Preventing the Spread

Minimizing the spread of strangles requires vigilance and proactive measures:


Isolate any new or returning horses for 2-4 weeks before introducing them to the herd. Also, immediately isolate any horse showing symptoms of strangles.

Disinfect Equipment: 

Regularly sanitize shared equipment like water troughs, feed buckets, brushes, and tack. Ideally, infected horses should have their own equipment until recovery.

Hand Hygiene: 

Handlers should wash their hands thoroughly after touching each horse, especially if handling an infected horse.

Biosecurity Measures: 

Limit horse-to-horse contact during an outbreak. Restrict the movement of horses in and out of an affected area.

Environmental Cleaning: 

Disinfect stalls, trailers, and common areas where infected horses have been.

Regular Monitoring: 

Keep an eye on horses for symptoms, especially after attending events with other horses or introducing new horses.

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Vaccination against Strangles

Available Vaccines: 

There are vaccines available to help protect horses from strangles. The two main types are intramuscular and intranasal vaccines.


While the vaccine reduces the risk of infection and severity of the disease, no vaccine offers 100% protection. However, vaccinated horses typically have milder symptoms if they do get infected.


Vaccination decisions should be made in consultation with a veterinarian, considering factors like the horse’s age, health, exposure risk, and the prevalence of strangles in the area.

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Recovery and Aftercare


While most horses start showing improvement within a few weeks, full recovery can take longer, especially if there were complications.

Post-Infection Monitoring: 

Even after symptoms subside, keep the horse isolated until a veterinarian confirms that the horse is no longer infectious.

Diet and Nutrition: 

Ensure that the horse receives a balanced diet to support recovery. Soft or wet feed might be preferable if the horse has difficulty swallowing.

Regular Check-ups: 

Schedule follow-up visits with the veterinarian to monitor recovery and catch any potential complications early.


Gradually reintroduce exercise, ensuring the horse is not pushed too hard too soon.

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Myths and Misconceptions

Only Young Horses Get Strangles: 

While younger horses are more susceptible, horses of any age can get strangles.

Once a Horse Gets Strangles, It’s Immune for Life: 

While some horses might develop immunity after an infection, it’s not lifelong. Horses can get infected more than once.

All Swollen Glands Are Due to Strangles: 

Other conditions can cause lymph node swelling. It’s essential to get a proper diagnosis.

Vaccinated Horses Cannot Spread Strangles: 

While vaccination reduces the risk, it’s still possible for a vaccinated horse to contract and spread the disease, especially if they become carriers.

Long-Term Management and Care for Horses Recovering from Strangles.

Managing the Long-Term Health and Care of Horses Post-Strangles Recovery is a vital element in equine care. It deals with the continuous care and attention needed for horses after they have overcome the initial stage of Strangles, a highly contagious disease affecting equines. The primary goal in this phase is to ensure that these horses not only return to their full health but also avoid any further complications or a reoccurrence of the illness. Key aspects of this process involve:

Health Monitoring: 

Regular veterinary check-ups are vital to monitor the horse’s recovery and catch any signs of potential complications early. This may include periodic blood tests, physical examinations, and monitoring for any recurrent symptoms of Strangles.

Nutritional Support: 

A balanced diet plays a key role in recovery. Depending on the horse’s condition, the diet might need to be adjusted to ensure it is receiving all necessary nutrients. In some cases, horses recovering from Strangles may require a softer or more easily digestible diet, especially if they had difficulty swallowing during their illness.

Exercise and Rehabilitation: 

Gradual reintroduction to exercise is important. Overexertion should be avoided, and exercise plans should be tailored to the horse’s recovery stage and overall health.

Environmental Management: 

Keeping the horse’s environment clean and hygienic is crucial. This includes regular cleaning and disinfecting of stalls, ensuring good ventilation, and maintaining cleanliness in feeding and drinking areas.

Managing Stress: 

Stress can impact a horse’s immune system and overall recovery. Effective stress management involves ensuring a calm environment, maintaining a routine, and providing adequate socialization, as appropriate.

Quarantine Procedures: 

Even after recovery, it’s important to follow quarantine procedures to ensure the horse is not a carrier of the bacteria. This might involve isolation until a veterinarian confirms the horse is no longer infectious.

Reintegration into the Herd: 

When reintegrating a horse into a herd, it’s essential to do so carefully to ensure it does not pose a risk to others and to monitor its interactions and health closely.

Future Prevention: 

Owners should discuss future prevention strategies with their vet, including potential re-vaccination and ongoing biosecurity measures to minimize the risk of reinfection.


Strangles in horses is undeniably concerning, but with a comprehensive understanding of the disease, its transmission, and the right preventive measures, the risk can be minimized. 

It’s crucial for horse owners, trainers, and caregivers to be well-informed and proactive in ensuring the well-being of their equine companions.


Can strangles in horses be transmitted to humans? 

While rare, there have been reported cases of Streptococcus equi infection in humans. It’s always advisable to maintain proper hygiene when dealing with infected horses.

How long should an infected horse be quarantined? 

A general recommendation is at least three weeks after symptoms subside. However, it’s crucial to consult with a veterinarian and conduct tests to ensure the horse is no longer infectious.

How can I protect my horse if there’s an outbreak nearby? 

Maintain strict biosecurity measures, avoid mingling with unknown horses, sanitize equipment, and consider vaccination if advised by a veterinarian.

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