What Does Pigeon Fever Look Like in a Horse?


Pigeon fever or dryland distemper is a highly contagious condition in horses. It causes massive swelling in the horse’s chest, causing it to bulge. This bulging looks like a pigeon’s breast, hence the reference pigeon fever.


The cause of pigeon fever is the bacteria Corynebacterium pseudotuberculosis. The bacteria live in the ground, hay, and shavings. Moreover, it can survive in the soil for long periods. It makes its way into a horse’s body through wounds in the skin. Insects can deposit it on broken skin or contamination by soil that has the bacteria.

It occurs all year round. However, peak cases occur during summer and may run all the way till early winter.


Pigeon fever manifests in three forms. These are external abscesses, internal abscesses, and ulcerative lymphangitis. The symptoms that show in the horse will depend on which form of the disease is present. One or more swellings will appear on the chest area or mid-abdomen. The swellings may also appear on the hindquarters or legs. These swellings appear like those from kicks by pasture mates.

External Abscesses

External abscesses are the most common form of pigeon fever. The external abscesses develop in the muscles, just under the skin near the surface of the horse’s body. They can appear anywhere, but mostly they will show up in the chest area.

Horses with this form of pigeon fever do not develop symptoms. Diagnosis will require a bacterial culture. Most horses will recover fully when the abscesses drain and the wounds heal. However, some will develop a fever. If there are other symptoms, the probability is that the infection has spread internally.

Internal Abscesses

These develop when the bacteria infect the kidney, liver, lungs, or other internal organs. They are not as common as external abscesses. However, they are harder to identify and treat. The difficulty is from abscesses taking longer to show any symptoms. Due to the difficulty in identification and treatment, they have a high fatality rate.

When the symptoms manifest, they are evasive and non-specific. The symptoms of internal abscesses include fever, coughing, colic, weight loss, loss of appetite, and lethargy. Diagnosis will require a blood test and an ultrasound. The ultrasound will help locate the abscesses. It will also help to know their size and maturity.

Ulcerative Lymphangitis

Ulcerative lymphangitis causes ulcers and swelling on the lower legs. It is the rarest form of pigeon fever. In this form, ulcers appear in the lymph channels, causing significant swelling of the leg. The abscesses progress into cellulitis. The symptoms of ulcerative lymphangitis include loss of appetite, lameness, and lethargy.

The exact environmental conditions that lead to pigeon fever are not clear. However, the bacteria thrive in soils with moist to dry conditions. With climate change, the weather is becoming hotter, and areas are becoming arider. The bacteria may thus continue to thrive more. You will need to be vigilant to ensure your horses are safe.

Closely monitor your animal, and if you notice any abscesses in the chest area, contact the veterinarian. Do not forget to obtain a culture.

For more information on pigeon fever, visit Chapparal Veterinary Medical Center at our office in Cave Creek, Arizona. You can also call (480) 595-8600 to book an appointment today.