Corynebacterium pseudotuberculosis is a gram-positive, aerobic bacteria. C. pseudotuberculosis is known for causing pigeon fever in horses, manifesting as ulcerative lymphangitis, external subcutaneous abscesses, and internal infections in horses. In a recent survey of veterinary diagnostic laboratories in the United States, it showed a significant increase in the occurrence of C. pseudotuberculosis infections in horses during a 10-year period (2003 to 2012), found in horses living throughout the country. Most cases have been in Texas. C. pseudotuberculosis can survive for up to 2 months in hay and shavings and up to 8 months in soil.