Second Wisconsin Stallion Is CEM-Positive; Found In Trace From Previous Case

A second stallion quarantined in Outagamie County, Wisc., has tested positive for contagious equine metritis (CEM), a treatable reproductive disease of horses.

The National Veterinary Services Laboratories in Ames, Iowa, reported the positive test result Thursday afternoon, Jan. 22. The stallion, a 4-year-old Paint, has been quarantined since Jan. 16, when state animal health authorities learned he had been at a Wisconsin artificial insemination center at the same time as another infected stallion from Outagamie County.

He was one of 18 stallions quarantined because they had been exposed to that earlier reported CEM-positive stallion in Outagamie County. All are located in Wisconsin. In addition, 29 exposed mares are quarantined in Wisconsin because they have been exposed to CEM-positive stallions.

State and federal animal health personnel will examine the newly identified stallion's breeding records and movement history to trace what mares may have been exposed via natural breeding or artificial insemination, and what stallions may have been exposed via shared artificial insemination equipment.

Any exposed animals, in Wisconsin or other states, will be quarantined for testing. Wisconsin owners of exposed animals will be contacted by the Department of Agriculture, Trade and Consumer Protection. For those in other states, the department will notify those states' animal health authorities, who will contact owners.

There is no human health risk and no risk to horses in the general population.

Nationwide, the CEM investigation now involves at least 383 horses in 42 states, according to the U.S. Department of Agriculture. The outbreak began in mid-December, when a quarter horse stallion on a Kentucky farm tested positive during routine testing for international semen shipment.

CEM is a contagious bacterial infection that passes between mares and stallions during mating. It can also be transmitted on contaminated insemination equipment. Stallions do not suffer any symptoms, but the infection causes inflammation in the mare's uterine lining. This may prevent pregnancy or cause the mare to abort if she becomes pregnant. The disease is treatable with disinfectants and antibiotics.

CEM is considered a foreign animal disease in the United States. It was first discovered in Europe in 1977, and has appeared in the United States only twice outside quarantine stations where stallions are required to be tested and treated before being released into the country. In 1979, there was an outbreak. In 2006, three Lipizzaner stallions imported into Wisconsin from Eastern Europe tested positive after their arrival, but before they had been used for breeding.

More information about CEM is available on the USDA Web site.

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