CEM in a Kentucky Stallion; Quarantine Begins

The following press release is from the Commonwealth of Kentucky Department of Agriculture. Anyone working with horses in the state should be aware of this situation as it may affect how the horse business is conducted and might stop horses from being shipped inot and out of the state of Kentucky. With breeding season upon us, this is NEWS….and not good news.

An important point in this article that is not clearly stated in the press release is that stallions generally show no signs of being infected with CEM. The danger is the effect that the disease has on the mares bred to an infected stallion, and the ongoing transmission of the disease.

FRANKFORT, Ky. ? State and federal agriculture officials are investigating a case of contagious equine metritis (CEM) in a quarter horse in central Kentucky.

The 16-year-old stallion tested positive for CEM during routine testing on 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 counties 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.

The first cases of CEM in the United States were diagnosed in central Kentucky in 1978. Another outbreak occurred in Missouri in 1979. The disease was eradicated rapidly in both outbreaks.

TO LEARN MORE: This blog covered CEM in detail in 2007 when stallions at the Spanish Riding School in Vienna, Austria tested positive for CEM. What is missing from the Kentucky press release is where the other horses are who came into contact with this stallion. Finding them will not be easy, but it is certainly important.

The United States has very strict restrictions against the import of horses from CEM-positive countries, and a very complex testing regimen is required to ascertain that a stallion is negative before it can be imported.

Identifying CEM in the USA, a country believed to be free of the disease, could have far-reaching effects, including stopping the export of horses from the US to some other countries, or even the interstate transport of horses into and out of Kentucky on the cusp of the Thoroughbred breeding season.

In the bigger picture, consider this: in the past six weeks, two very serious equine diseases believed to have been eradicated from US soil–piroplasmosis and CEM–have shown up in our horses, bringing us back to square one in prevention and endangering the livelihood of horse owners, trainers, breeders, and competitors. If Americans don’t know much about CEM, it is because they weren’t around back in 1978 when it stopped the Thoroughbred industry in its tracks. Thirty years later, reading the history of that year–ironically the last year a horse won the Triple Crown–will send a chill down your spine.

Here are some links to past stories:

CEM: Equine Reproductive Nightmare (2007) This blog post describes the disease and why it is taken so seriously.

When Bad Things Happen to Nice Horses: Equine Venereal Disease at Austria’s Spanish Riding School (2007)Good News from Vienna: Spanish Riding School Stables Are Open Again (2007)

USDA Ease of Import Restrictions Against CEM-Infected Countries (June 2008)




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