Agriculture and Forestry Commissioner Mike Strain, DVM, said more than 30 cases of pigeon fever in horses have been recently reported to the Louisiana Department of Agriculture and Forestry.

Strain said the Veterinary Teaching Hospital (VTH) at the Louisiana State University School of Veterinary Medicine treated 10 cases of pigeon fever in horses and the Louisiana Animal Disease Diagnostic Laboratory reported 20 positive cases from referring veterinarians. The VTH estimated there were at least 100 cases in Louisiana in 2011 and suspect that the number of cases may be related to drought and heat.

Pigeon fever is the common term for an infection caused by the bacterial organism Corynebacterium pseudotuberculosis which can form abscesses in the pectoral region and ventral abdomen of the horse. The abscesses cause swelling and give the horse a "pigeon-breast" appearance. The illness is also known as dryland strangles or dryland distemper.

Cross-species transmission usually occurs only between horses and cattle because they can carry the same strain of bacterium. The bacterium rarely infects humans.

There are three recognized forms of the disease in horses: external abscesses, internal abscesses, and ulcerative lymphangitis.

There is no vaccination to protect horses against pigeon fever. Horse owners should contact their veterinarians if they suspect pigeon fever so a definitive diagnosis can be made through bacterial culture.

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