Traditionally considered a West Coast disease, pigeon fever was recently diagnosed in several Florida horses.

Pigeon fever is caused by the bacterium Corynebacterium pseudotuberculosis, which tends to live in the soil in hot, dry environments. It is primarily spread by flies and causes abscesses on the pectoral region that give a horse a "pigeon breast" appearance (hence the name).

Pigeon fever is not unusual in West Coast states like California, which reportedly had severe pigeon fever conditions during the 2009 fly season. While an estimated 2% of the 1,922 mustangs at the Calico Complex in Nevada had signs of pigeon fever from the end of December 2009 until the beginning of February 2010, even this was not widely considered an official "outbreak."

In contrast, it is not typical to see any cases of pigeon fever on the East Coast. Nonetheless, Michelle M. LeBlanc, DVM, Dipl. ACT, a reproduction specialist at Rood & Riddle Equine Hospital in Lexington, Ky., diagnosed pigeon fever in several horses in Florida this past spring