Quarter Horse in KY Positive for CEM

Edited report from the Kentucky Department of Agriculture

Kentucky and federal agriculture officials are investigating a case of contagious equine metritis in a Quarter Horse in central Kentucky.

The 16-year-old stallion tested positive for CEM during routine testing Dec. 10. The test was performed by the University of Kentucky Livestock Disease Diagnostic Center as a preliminary step to shipping frozen semen to the European Union. Samples were sent to the National Veterinary Services Laboratories in Ames, Iowa, which confirmed the diagnosis on Monday.

The index horse and all exposed horses are under quarantine and undergoing testing protocols. The index horse is being treated, and exposed horses have been tested to see if they are infected.

The index horse was moved to Kentucky in February from Texas, where he had been located for his entire breeding career. All breeding was done artificially with no history of natural service. During the 2008 breeding season, 22 stallions from various states were bred on the farm. Thirteen of the stallions were relocated to other states, and one was relocated to another facility in Kentucky. The index stallion was bred to 44 mares both on the farm and by shipped semen.

Contagious equine metritis is a transmissible, exotic venereal disease in horses. It usually results in infertility in mares and, on rare occasions, can cause mares to spontaneously abort. Infected stallions exhibit no clinical signs but can carry the CEM bacteria for years. CEM is commonly transmitted during sexual intercourse but also may be transmitted indirectly through artificial insemination or contact with contaminated hands or objects.

There is no evidence that CEM affects people.

CEM can be treated with disinfectants and antibiotics. CEM-positive mares and mares from CEM-positive countries in Kentucky are required by state regulations to go through a treatment protocol and remain in quarantine for no less than 21 days. Stallions in Kentucky that have CEM or come from a CEM-positive country also are required to remain quarantined until a treatment protocol is completed and they test negative for the disease.