Pigeon Fever in Horses by a Vet – 2025 Diagnosis & Treatment Guide 🐴🦠

By Dr Duncan Houston, BVSc

Introduction

Pigeon fever—named for the pigeon-like swelling it causes in a horse’s chest—is a bacterial disease that’s spreading far beyond its historical home in the western U.S. In 2025, this disease is endemic in many states, including Texas, and requires careful management. Caused by Corynebacterium pseudotuberculosis, pigeon fever presents in various forms, from simple external abscesses to life-threatening internal infections. This guide explains the causes, signs, treatments, and biosecurity steps horse owners need to know.

What Causes Pigeon Fever? 🧬

• Caused by the bacterium Corynebacterium pseudotuberculosis
• Infects horses, and different strains affect sheep and goats (caseous lymphadenitis)
• Transmitted primarily through flies (house flies, horn flies, stable flies)
• Environmental contamination (manure, soil) can harbor the bacteria for extended periods

Where Is It Found? 🌎

• Originally recognized in California over 100 years ago
• Now seen in all U.S. regions, with the highest number of cases in Texas
• Increased cases linked to hot, dry weather and high fly populations

Three Forms of Pigeon Fever 🦠

1. External Abscesses (Most Common)

• Typically develop in the pectoral region or ventral abdomen
• Soft swelling resembling a pigeon’s chest
• Eventually rupture or are lanced and drained by your vet

2. Internal Abscesses (Less Common, More Serious)

• Infection travels internally, forming abscesses in organs such as the liver or lungs
• Symptoms: persistent fever, weight loss, colic signs, lab abnormalities
• Requires long-term antibiotic therapy
• Diagnosed via ultrasound and blood tests (e.g. high fibrinogen, serum amyloid A)

3. Ulcerative Lymphangitis

• Affects lower limbs, especially hind legs
• Characterized by swelling, ulceration, and draining tracts
• Requires systemic antibiotics and anti-inflammatory care

How It Spreads 🚫🦟

• Insect vectors: Flies spread the bacteria from wounds, abscesses, or contaminated material
• Contaminated soil: Especially in dry, dusty areas with fecal debris
• Shared tack or equipment if used on infected horses

Prevention Tips for 2025 🛡️

• Implement fly control: sprays, masks, fans, fly predators
• Disinfect abscess drainage areas and equipment
• Quarantine infected horses for at least 30 days
• Do not share water troughs, grooming tools, or halters

When to Call Your Vet 📞

• Swelling in the chest, lower legs, or abdomen
• Fever, loss of appetite, weight loss
• Any abscess with thick pus or foul smell
• Non-healing wounds or recurring swelling

Treatment Strategies 💊

External Abscesses

• Do NOT use antibiotics unless infection spreads—antibiotics can delay abscess maturation
• Allow abscess to “ripen,” then have your vet lance and drain under sterile conditions
• Flush with antiseptic solution and monitor for recurrence

Internal Abscesses

• Require long-term antibiotics (often 4–6 weeks or more)
• May include rifampin and trimethoprim-sulfa or penicillin combinations
• Regular vet follow-up is essential

Ulcerative Lymphangitis

• Systemic antibiotics and anti-inflammatory treatment
• Bandaging and hydrotherapy for wounds

Case Example: Classic Pigeon Fever

1. A 12-year-old gelding in Central Texas developed pectoral swelling in late summer
2. Fever was mild, appetite remained normal
3. Swelling matured over 7 days—abscess was lanced and drained by vet
4. No antibiotics were needed; wound healed over 2 weeks with daily flushing

FAQs About Pigeon Fever

Q: Is there a vaccine for pigeon fever?

A: No commercial vaccine exists as of 2025, though research is ongoing.

Q: Can humans get pigeon fever?

A: Very rarely. The strain affecting horses is different from that affecting people or goats.

Q: Can I use antibiotics right away?

A: Not for external abscesses—antibiotics delay drainage and can cause complications. Always consult your vet first.

Conclusion

Pigeon fever is an increasingly common infection, especially in dry climates with high insect activity. While external abscesses are manageable, internal abscesses or limb infections can be serious. Early recognition, vet-guided drainage, and proper biosecurity measures can prevent the disease from spreading through your barn. In 2025, prevention through fly control and environmental hygiene remains the best protection.

Concerned about a swelling or abscess on your horse? Reach out to AskAVet.com or use our app 📱 to consult Dr Duncan Houston for diagnosis and care planning. 🩺🐴