New Jersey Department of Agriculture

Memo

To: Veterinarians

From: Nancy E. Halpern, DVM, New Jersey State Veterinarian

Date: December 17, 2008

Re: Case of Contagious Equine Metritis (CEM) in Kentucky

State and federal agriculture officials are investigating a case of contagious equine metritis (CEM) in a quarter horse in central Kentucky. CEM is a transmissible, exotic, venereal disease of horses caused by the bacterium Taylorella equigenitalis.

The 16-year-old stallion tested positive for CEM during routine semen export testing on December 10. Samples were sent to the National Veterinary Services Laboratories which confirmed the diagnosis on Monday December 15. The index horse was moved to Kentucky from Texas in February of this year, where he had been located for his entire breeding career. All breeding was done artificially with no history of natural service. The index horse and all exposed horses are under quarantine and undergoing testing. The index horse is being treated and exposed horses are being tested. There were twenty-two stallions from various states on the farm during the 2008 breeding season. Thirteen stallions were relocated to other states and one was relocated to another facility in Kentucky. Forty-four mares were artificially inseminated using semen from this stallion. As of today no exposed horses have been traced to New Jersey. 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.

Veterinarians and equine owners who suspect that an animal may have CEM 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).

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. Beatrice Miguel at 609-292-3965.