Strangles in Horses: Contagious Upper Respiratory Infection
Strangles is a highly contagious bacterial infection causing abscessed lymph nodes. Quarantine and vaccination prevent outbreaks.
Strangles is a bacterial infection of the upper respiratory tract in horses, caused by Streptococcus equi subspecies equi. It's one of the most common and concerning infectious diseases of horses worldwide, known for its highly contagious nature and characteristic abscess formation in the lymph nodes.
Key Points
- Strangles is caused by Streptococcus equi and spreads via direct contact or contaminated equipment
- Signs include fever, nasal discharge, cough, and abscessed lymph nodes under the jaw
- Bastard strangles — spread to internal organs — is a rare but fatal complication
- Quarantine of new horses for 2-3 weeks prevents introduction
- Vaccination reduces severity but doesn't fully prevent infection
- Carriers with guttural pouch infections perpetuate outbreaks
Understanding Strangles
The bacterium Streptococcus equi infects the tonsils and pharyngeal lymphoid tissue. From there, it travels to the submandibular and retropharyngeal lymph nodes, causing abscess formation. The abscesses mature, rupture, and drain thick, creamy pus. Infected horses shed bacteria in nasal discharge and draining pus for weeks. Some horses become carriers with persistent guttural pouch infection.
Treatment and Prevention
Most cases resolve with supportive care — rest, soft palatable food, and NSAIDs for fever and pain. Antibiotics are controversial — they may delay abscess maturation. Vaccination with live attenuated intranasal or killed injectable vaccines reduces severity. Isolate new horses for 2-3 weeks and test before introduction. Disinfect stalls, equipment, and water sources. Screen recovered horses for carrier status.
When to See a Vet Immediately
- Your horse has fever, nasal discharge, and swollen lymph nodes under the jaw
- There's thick yellow nasal discharge and difficulty swallowing
- Abscesses are draining pus from the throat area
- Multiple horses on the property show similar signs
- A new horse was recently introduced without quarantine
How RVC Can Help
This article is for educational purposes only and does not replace professional veterinary advice. If your pet is showing any symptoms, please contact Royal Veterinary Center immediately at +853 6677 6611.