Strangles in Horses: Welfare and Biosecurity

Equine strangles, caused by Streptococcus equi, is one of the most common and welfare-significant infectious diseases in horses, causing painful abscess formation and potential life-threatening complications.

Key Facts

Strangles affects horses, ponies, and donkeys; it is the most frequently diagnosed infectious equine disease globally
S. equi causes abscess formation in the lymph nodes of the head and neck, which rupture to drain pus
Atypical strangles with internal abscesses (bastard strangles) carries a much more serious prognosis
Some horses become persistent carriers and shed bacteria without clinical signs for years
Vaccination can reduce severity of disease but does not prevent infection in all individuals

Welfare Considerations

Clinical strangles causes painful swelling, difficulty swallowing, and systemic fever that impairs normal eating and drinking. The formation and rupture of abscesses causes acute pain. Horses with bastard strangles face internal abscess formation with potential involvement of any lymph node in the body, causing chronic, progressive illness. Outbreaks at livery yards cause significant welfare harm across multiple animals and create management challenges. Prompt isolation, veterinary diagnosis, and biosecurity implementation are the foundations of welfare-centred strangles outbreak management.

What You Can Do

Isolate any horse showing signs of upper respiratory disease or lymph node swelling immediately
Test horses returning from shows or contact with unfamiliar horses before reintroduction to the yard
Discuss vaccination strategies with your vet for horses at high risk through frequent movement and contact
Follow veterinary advice precisely on isolation periods to prevent transmission to susceptible yard mates