Strangles

Streptococcus equi

Shetland pony with strangles

Shetland pony with strangles (side view)

Strangles is a highly contagious bacterial infection that affects the upper respiratory tract of horses and other equids. The disease is caused by the bacterium Streptococcus equi subspecies equi. Strangles is characterized by the formation of abscesses in the lymph nodes of the head and neck, which can lead to severe swelling and respiratory distress.

Symptoms

The symptoms of strangles typically appear within 3 to 14 days after exposure to the bacterium. Common symptoms include:

• Fever
• Nasal discharge, which may start as clear and become purulent
• Swelling of the lymph nodes around the throat
• Difficulty swallowing
• Coughing
• Loss of appetite
• Lethargy

Transmission

Strangles is highly contagious and can be spread through direct contact with infected horses or through indirect contact with contaminated equipment, water, feed, or human handlers. The bacterium can survive in the environment for several weeks, making it important to implement strict biosecurity measures to prevent the spread of the disease.

Diagnosis

Diagnosis of strangles is typically based on clinical signs and can be confirmed through laboratory tests such as:

• Bacterial culture of nasal swabs or abscess material
• Polymerase chain reaction (PCR) testing to detect bacterial DNA
• Serology to detect antibodies against Streptococcus equi

Treatment

Treatment of strangles may include:

• Isolation of affected horses to prevent the spread of the disease
• Supportive care, such as providing soft, palatable feed and ensuring adequate hydration
• Administration of antibiotics in severe cases or to prevent complications
• Surgical drainage of abscesses if they do not rupture on their own

Prevention

Preventive measures to control the spread of strangles include:

• Quarantine of new horses for at least 2 weeks before introducing them to the herd
• Regular cleaning and disinfection of equipment and facilities
• Vaccination, although it may not provide complete protection and is typically used in high-risk populations

Complications

Complications of strangles can include:

• Bastard strangles, where abscesses form in other parts of the body
• Purpura hemorrhagica, an immune-mediated condition causing widespread inflammation and bleeding
• Chronic carrier state, where horses continue to shed the bacterium without showing symptoms

Related Pages

• Equine infectious diseases
• Upper respiratory tract infection
• Bacterial infection
• Lymph node

See Also

• Streptococcus equi
• Equine health
• Veterinary medicine