Strangles in Horses 2025: Vet‑Approved Detection, Treatment & Prevention

By Dr Duncan Houston BVSc 🩺

Strangles is a highly contagious respiratory disease in horses, caused by Streptococcus equi equi. Despite its alarming symptoms, it is usually non‑fatal with proper veterinary care. This article explores clinical signs, diagnostics, treatment, biosecurity, vaccination, and long‑term herd management—fully vet‑informed and optimized for 2025 care standards.

1. What Is Strangles?

Strangles is caused by the bacterium S. equi equi, which infects the lymph nodes in the head and throat, leading to abscess formation and respiratory distress :contentReference[oaicite:3]{index=3}. The name “strangles” comes from the way enlarged lymph nodes may compress the airway, causing labored breathing and difficulty swallowing :contentReference[oaicite:4]{index=4}.

2. How Horses Get It & Who's at Risk

• Transmission: Through nose-to-nose contact, sharing feed/water buckets, and contaminated equipment or people :contentReference[oaicite:5]{index=5}.
• High-risk populations: Young horses (1–5 years) and naïve horses, with morbidity up to 100% in unexposed groups :contentReference[oaicite:6]{index=6}.
• Carrier animals: Up to 40% of horses can become silent carriers, shedding bacteria long after recovery :contentReference[oaicite:7]{index=7}.

3. Recognizing Clinical Signs

Early detection is vital:

• Fever (103–106°F) is the first sign, appearing 3–14 days post‑exposure :contentReference[oaicite:8]{index=8}.
• Nasal discharge starts clear and becomes thick and purulent :contentReference[oaicite:9]{index=9}.
• Swollen, painful lymph nodes under jaw and throatlatch, often forming abscesses :contentReference[oaicite:10]{index=10}.
• Respiratory distress or noisy breathing, difficulty swallowing, extended neck posture :contentReference[oaicite:11]{index=11}.
• Complications:
  • Bastard strangles: Abscesses beyond head & neck (e.g. abdomen, chest) :contentReference[oaicite:12]{index=12}.
  • Purpura hemorrhagica: Severe immune response causing swelling of limbs/head and mucosal bleeding :contentReference[oaicite:13]{index=13}.
  • Neurological signs: Rare brain abscesses—circling, head pressing, ataxia :contentReference[oaicite:14]{index=14}.

4. Veterinary Diagnosis

Ensure diagnosis and herd safety:

• Culture or PCR from nasal/ guttural pouch wash or abscess aspirate :contentReference[oaicite:15]{index=15}.
• PCR is more sensitive and rapid, though cannot distinguish live from dead bacteria :contentReference[oaicite:16]{index=16}.
• Endoscopy can confirm guttural pouch involvement and identify carriers :contentReference[oaicite:17]{index=17}.
• Serology helps screen exposed horses and manage vaccination risk :contentReference[oaicite:18]{index=18}.

5. Supportive Treatment

Most uncomplicated cases recover with:

• Isolation and rest in a clean, warm stall :contentReference[oaicite:19]{index=19}.
• NSAIDs (e.g., flunixin, phenylbutazone) to reduce fever, pain, and encourage appetite :contentReference[oaicite:20]{index=20}.
• Compresses for lymph node abscesses; light lancing post-ripening with vet guidance :contentReference[oaicite:21]{index=21}.
• Maintain hydration and soft, palatable food :contentReference[oaicite:22]{index=22}.
• In severe airway compression, tracheostomy may be necessary :contentReference[oaicite:23]{index=23}.

6. Antibiotic Use – When to Choose Caution

Antibiotics are debated:

• Often not needed as most horses develop immunity; antibiotics may delay abscess maturation and affect immune response :contentReference[oaicite:24]{index=24}.
• Indicated for severe cases like airway distress, systemic complications, or purpura hemorrhagica :contentReference[oaicite:25]{index=25}.
• Typical choices: penicillin, ceftiofur, ampicillin—with vet guidance :contentReference[oaicite:26]{index=26}.

7. Recovery & Carrier Risk

Plan for recovery:

• Abscesses open and drain in 1–4 weeks—clean, flush, and monitor healing :contentReference[oaicite:27]{index=27}.
• Shedding continues up to 6 weeks post-recovery; carriers may persist much longer :contentReference[oaicite:28]{index=28}.
• Clearance testing via PCR and culture from guttural pouches; three negative tests over intervals recommended :contentReference[oaicite:29]{index=29}.
• Herd management must consider carriers to prevent reinfection :contentReference[oaicite:30]{index=30}.

8. Vaccination Strategies

Vaccination helps reduce severity:

• Two types: intramuscular (inactivated) and intranasal (live attenuated) :contentReference[oaicite:31]{index=31}.
• Benefits: Reduces fever and abscess formation; does not prevent infection completely :contentReference[oaicite:32]{index=32}.
• Risks: Intramuscular vax may cause abscess; intranasal may cause minor nasal symptoms :contentReference[oaicite:33]{index=33}.
• Best used in low-risk situations—not during active outbreak :contentReference[oaicite:34]{index=34}.
• Titers and serology mapping help guide timing and assess risk :contentReference[oaicite:35]{index=35}.

9. Biosecurity & Outbreak Control

• Immediately isolate suspected cases; monitor temperatures twice daily—>=101.5°F is a warning sign :contentReference[oaicite:36]{index=36}.
• Restrict barn movements and separate into clean/exposed/infected groups with dedicated staff and equipment :contentReference[oaicite:37]{index=37}.
• Disinfect tack, buckets, stalls; remove organic matter before disinfecting with chlorhexidine or bleach solutions :contentReference[oaicite:38]{index=38}.
• Simple behaviors matter: feed healthy horses first, change clothing or shower after handling sick horses :contentReference[oaicite:39]{index=39}.
• Control flies and environmental reservoirs; isolate new horses for at least 3–4 weeks before introduction :contentReference[oaicite:40]{index=40}.

10. Complications & Specialized Care

• Bastard strangles: Metastatic abscesses—require antibiotics and often surgery :contentReference[oaicite:41]{index=41}.
• Purpura hemorrhagica: Treated with corticosteroids, antibiotics, and supportive care :contentReference[oaicite:42]{index=42}.
• Guttural pouch empyema/chondroids: Treated with guttural pouch flushing or surgical removal, then follow-up testing :contentReference[oaicite:43]{index=43}.
• Neurologic signs & colic: Evaluate for brain or abdominal abscesses with imaging and tailored care :contentReference[oaicite:44]{index=44}.

11. Prognosis & Herd Health Impact

Uncomplicated strangles typically resolve in 3–6 weeks, with most horses developing 5+ years of immunity :contentReference[oaicite:45]{index=45}. Mortality is low (~1–2%), but young horses and those with complications have higher risk :contentReference[oaicite:46]{index=46}.

12. Ask A Vet Guidance & Owner Support

Ask A Vet offers:

• 📲 Live consults on fever, abscess care, quarantine planning.
• 🧪 Diagnostic support including PCR guidance and herd testing protocols.
• ⚙️ Treatment protocols—NSAIDs, antibiotic judicious use, tracheostomy care.
• 🛡 Vaccine scheduling and risk assessment tools.
• 🧹 Biosecurity training and stall management guidance.

Final Thoughts

Strangles remains one of the most contagious equine diseases—but with vigilant detection, smart treatment, and unwavering biosecurity, it is manageable and usually non-fatal. In 2025, integrating evidence-based veterinary care, herd health strategies, and trusted veterinarians ensures your horses stay safe, healthy, and thriving.

Have concerns or need personalized protocols? Download the Ask A Vet app or visit AskAVet.com today to connect with expert veterinary guidance and tools for comprehensive herd care. 🐴❤️

Disclaimer: This article provides general guidance. Always consult your veterinarian for individual horse care decisions.