The U.S. Department of Agriculture's Animal and Plant Health Inspection Service (APHIS) has published an emerging disease notice on Mycoplasma bovis (M. bovis), a bacterial pathogen that recently became a major concern in the North American commercial bison industry. APHIS's Center for Epidemiology and Animal Health (CEAH) produced the 6-page report, Mycoplasma Bovis - An Emerging Pathogen in Ranched Bison, in October 2013.

In bison, M. bovis seems to be a primary pathogen, causing disease in feedlots and in breeding-age cows on pasture. Mortality rates in adult bison have been as high as 25 percent, causing significant economic losses to producers. Because Mycoplasmas do not produce toxins like other pneumonia-causing pathogens, affected animals remain alert early in the disease but often trail behind the herd due to exercise intolerance. The chronic nature of Mycoplasma bovis disease in bison eventually leads to emaciation and weakness. Affected bison are often euthanized.

This 6-page emerging disease notice describes the clinical presentation of Mycoplasma bovis in bison; gives examples of diagnostic procedures and tests to detect M. bovis; provides a clinical case definition; hypothesizes reservoirs and transmission pathways; suggests treatment and prevention options; discusses economic and animal welfare consequences; and explores future directions for research and effective treatment and prevention strategies.

For additional information on this topic, contact Lyndsay Cole at 970-494-7410 (email: or Dr. Steven Sweeney, CEAH Project Manager, at 970-494-7276 (email: