CEM Investigation Appears to be Wrapping Up

Barring any big surprises, the investigation into contagious equine metritis (CEM) in the United States might be winding down, with testing and treatment completed for 91.2% of the 715 exposed mares and 77.7% of the 274 exposed stallions as of Sept. 24.

In total there were five positive mares and 22 positive stallions identified during the course of the investigation. All positive horses, and all exposed horses that have not yet completed testing and treatment protocols, remained under quarantine or hold order. 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.

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.

Investigators have yet to determine the source of the outbreak.

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 might be transmitted indirectly through artificial insemination or contact with contaminated hands or objects. It can be treated with disinfectants and antibiotics.

About the Author

Erin Ryder

Erin Ryder is a former news editor of The Horse: Your Guide To Equine Health Care.

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