July 26 2011 - A 4 year old Arabian stallion in Maricopa County, Arizona tested positive for contagious equine metritis (CEM) today during routine health testing required when qualifying frozen semen for international export. Five horses at the facility have been placed in quarantine and the state is working with federal partners to locate mares that have been bred to this stallion during the current breeding season.
CEM is a venereal disease of horses caused by the bacterium Taylorella equigenitalis. It is commonly transmitted directly during sexual intercourse between CEM-positive mares and stallions but can also occur indirectly by artificial insemination or contact with other objects such as hands, instruments or breeding phantoms contaminated with the disease causing bacterium. It usually results in infertility in mares and, on rare occasions, can cause mares to spontaneously abort. Infected stallions exhibit no clinical signs and can potentially carry and transmit the bacteria for many years.
Aug 8th - info added to USDA website
Stay tuned to this news thread for further updates.