Horse Strangles: Welfare, Prevention and Biosecurity for an Ancient Disease

Strangles is one of the most common infectious diseases of horses worldwide, causing painful abscess formation and posing serious welfare and biosecurity challenges for equine facilities.

Key Facts

Strangles is caused by Streptococcus equi subspecies equi and typically affects lymph nodes around the head and throat
Classic signs include fever, nasal discharge, difficulty swallowing, and formation of painful abscesses in lymph nodes
Abscesses can compress the airway in severe cases, causing the respiratory distress that gives the disease its name
Bastard strangles involves abscess formation in internal organs and has a much more serious prognosis
Recovered horses can become long-term guttural pouch carriers shedding bacteria without clinical signs
A vaccine is available and recommended for horses at high risk of exposure through competition or movement
Strict biosecurity including isolation of new arrivals for 3 weeks prevents most introductions to naive yards

Welfare Considerations

Strangles causes significant acute suffering through fever, painful swollen lymph nodes, and difficulty eating and swallowing. Abscesses cause prolonged discomfort as they develop and mature before rupturing, a process that typically takes 1 to 3 weeks. Affected horses may be unable to eat normally due to pain and need supportive feeding. The welfare of horses in affected yards is broadly impacted through movement restrictions and the stress of isolation protocols. Bastard strangles, where internal abscesses form, causes prolonged chronic illness with much more serious welfare consequences and often fatal outcomes. Carrier horses identified through guttural pouch lavage and culture should be treated to eliminate the carrier state and prevent transmission to naive horses.

What You Can Do

Vaccinate horses against strangles if they frequently attend competitions, clinics, or mixed-yard situations
Implement a 3-week isolation protocol for any new horse arriving at your property
Test all horses for guttural pouch carriage before mixing with naive populations after outbreak exposure
Seek veterinary guidance on appropriate management of abscess maturation rather than premature lancing
Report strangles outbreaks to local equine disease surveillance networks to enable regional monitoring