Equine owners should be extra vigilant for signs of pigeon fever in their horses, according to Colorado State University veterinarians at the Veterinary Teaching Hospital. A spike in reported cases of this infectious disease has been reported in the northern Front Range of Colorado.
This highly contagious disease is also called pigeon breast, breastbone fever, false strangles, dryland strangles or dryland distemper. Signs of pigeon fever can initially resemble those of other diseases such as strangles. Sometimes the only initial signs are lameness and a reluctance to move. Other signs include lameness, fever, lethargy and weight loss. There may also be very deep abscesses and multiple sores along the horses’ chest, midline and groin area. Abscesses in other areas such as the back, flank or ears have been seen but internal abscesses are rare. Horses can be infected for several weeks before developing signs of the disease, especially abscesses.
The disease, which can be fatal, is caused by bacteria called Corynebacterium pseudotuberculosis. The bacteria live in the soil and can enter the animal’s body through wounds, broken skin or mucous membranes. Research also indicates that the disease may be spread through flies, especially cattle horn flies. These are biting flies that tend to feed under the belly of the horse. The flies transmit the bacteria from horse to horse when they have been in contact with pus draining from abscesses. Bacteria in drained puss can survive up to 55 days in the environment.
Pigeon fever can affect a horse of any age, sex or breed, but it usually attacks young adult animals. Humans cannot catch pigeon fever, but they can spread it from horse to horse because the bacteria can be carried on shoes, clothing, hands or barn tools. Any horse showing signs of pigeon fever should be isolated to prevent spread to other animals. Areas where infected horses are held must be properly cleaned and completely disinfected.
The disease is treated with hot packs or poultices that are applied to abscesses. Open abscesses are drained and regularly flushed with saline. Veterinarians may need to lance deep abscesses. Veterinarians will also prescribe anti-inflammatory drugs to control swelling and pain and sometimes an antibiotic will be prescribed. Antibiotic usage before the abscesses have been drained may prolong the course of the disease.
Horses with the disease usually recover within a few weeks with proper treatment. If caught early and treated properly, horses usually make a complete recovery, although the disease may reoccur in some horses.