Horse Illustrated Magazine

Swelling, abscesses, and inflammation are signs of a rare equine condition known as pigeon fever. The University of Missouri College of Veterinary Medicine has alerted owners that dry weather conditions this year have led to an increase in the disease.

Pigeon fever is also known as dryland distemper and officially is an infection of the bacterium Corynebacterium pseudotuberculosis. The name “pigeon fever” came about because the swelling that sometimes occurs in an afflicted horse’s chest gives a pigeon breasted appearance. Swelling can also occur in the legs and abdominal area.

The bacterium lives in dry soil and is most common in arid locations in the western U.S.

“Under normal conditions, this disease is uncommon in Missouri,” says Philip Johnson, professor of equine medicine and surgery at the MU College of Veterinary Medicine. “Likely because of the extremely dry weather Missouri has experienced in the last six months, we have seen an abnormally large number of cases pop up throughout the state.”

Aside from visible swelling and abscesses, afflicted horses sometimes have sores on their legs and may appear lethargic and lose their appetite. The disease is contracted through scratches and scrapes in the skin and can also be spread by flea and tick bites. It can also be spread to other horses when the abscesses drain. For this reason, quarantine is usually recommended.

There is no vaccine for Pigeon Fever, but it is treatable by a veterinarian. The greatest risk from the disease is if the infection spreads internally, so it is imperative to treat as early as possible. Horse owners in drought-affected areas are encouraged to keep watch for signs of infection and contact a vet immediately if symptoms appear.