Revised:  01/05/2009

Memo for December 31, 2008













New Jersey Department of Agriculture



To: Veterinarians

From: Nancy E. Halpern, DVM State Veterinarian

Date: December 31, 2008

Re: Contagious Equine Metritis (CEM) update II


As of December 31, 2008 seven stallions (four in Kentucky and three in Indiana), have been confirmed infected with the bacterium that causes Contagious Equine Metritis (CEM). Each of these stallions stood the 2008 season at a reproductive facility in Kentucky. Semen was collected and shipped for artificial insemination. The investigations revealed that semen/mares were shipped to 27 states and it is estimated that over 250 mares have been exposed to infected stallions. The numbers are likely to grow as more stallions are confirmed as carriers.


Veterinarians and equine owners who suspect that an animal may have CEM or been exposed to infected semen should immediately contact NJDA Division of Animal Health at (609) 292-3965 or USDA APHIS VS at (609) 259-8387 for assistance. CEM is a reportable disease if suspected or diagnosed and must be reported to the Department of Agriculture without delay, and in any case, within 48 hours (N.J.A.C. § 2:2-1.1 and 1.5).


CEM is a transmissible venereal disease of horses caused by the bacterium Taylorella equigenitalis. This exotic highly contagious disease is not normally found in the US.


CEM is transmitted easily at breeding but also may be transmitted indirectly through artificial insemination or contact with contaminated hands or objects. It usually results in infertility and, on rare occasions, abortion. An acute infection causes active inflammation of the uterus with obvious thick, milky, mucoid vulvar discharge 10 to 14 days after breeding. Chronic infections induce milder uterine inflammation with less obvious vulvar discharge. The carrier mare is asymptomatic, but still infectious and can remain a carrier for several months. Stallions exhibit no clinical signs but can carry the CEM bacteria on their external genitalia for years. Because animals may be asymptomatic, the disease is difficult to detect and control. CEM can be treated with disinfectants and antibiotics. There is no evidence that CEM affects people.


The New Jersey State Animal Health Diagnostic Laboratory is approved by the United States Department of Agriculture to perform CEM culture. Differentiating CEM from Klebsiella and Pseudomonas spp. can only be done reliably by laboratory isolation of T. equigenitalis. T. equigenitalis is a fastidious organism requiring specific growth conditions. For further information about testing please contact Dr. Beatriz Miguel at 609-292-3965.






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