Number of U.S. Horses Exposed to CEM Hits 920

The ongoing investigation into contagious equine metritis (CEM) now includes more than 920 exposed or positive horses, according to the USDA.

The investigation began in mid-December 2008, when a Quarter Horse stallion on a Kentucky farm tested positive during routine screening for international semen shipment.

According to the USDA's Animal and Plant Health Inspection Service (APHIS), as of May 20 the positive horses include 18 stallions and five mares. In addition to these horses, they have confirmed the locations of 897 horses exposed to Taylorella equigenitalis. The 920 horses are located in 48 states (only Hawaii and Rhode Island did not have at least one exposed or positive horse). There are 262 exposed or positive stallions in 29 states and 658 exposed or positive mares in 46 states.

An exposed horse is one that was bred to a positive horse, either naturally or via artificial insemination, or one that is otherwise epidemiologically linked to a positive horse, as determined by animal health officials.

Of the 262 stallions involved, a total of 71 had completed their entire testing and treatment protocol and were negative for T. equigenitalis. Of the 658 mares, a total of 415 had completed testing and treatment.

APHIS spokesman Jim Barrett said the USDA will cover some costs associated with testing these horses, which includes assisting the veterinarian taking samples, mailing test samples, and laboratory testing. The estimated cost of veterinary services for testing ranges from $1,500 to $5,000 per animal tested, depending on the state.

About the Author

Erin Ryder

Erin Ryder is a former news editor of The Horse: Your Guide To Equine Health Care. She owns a portly gray gelding named Duncan and dabbles in several equestrian disciplines, with an emphasis on dressage.

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