Contagious Equine Metritis

Contagious Equine Metritis (CEM) is a sexually transmitted disease among horses caused by the bacteria Taylorella equigenitalis. Clinical signs may include a mucopurulent vaginal discharge in up to 40% of affected mares, abortion, and infertility. Stallions typically show no clinical signs. Stallions and mares can become chronic carriers of CEM and be sources of infection for future outbreaks. The transmission rate is high and naturally occurs by mating, but contaminated instruments and equipment may and indirect source of infecting mares and stallions. The bacteria can also be spread via semen collected for artificial insemination.

CEM Requirements for Imported Horses

To import horses from other countries into Colorado under quarantine for CEM, please contact the State CEM Coordinator, Dr. Carl Heckendorf at (303)869-9142. To apply for a CEM import permit, please complete the CEM Import Permit Application; email the completed form to animalhealth@state.co.us.

Imported horses must meet all import requirements outlined in VS Guidance 13406.1: Contagious Equine Metritis (CEM) Testing for Imported Horses at Approved Quarantine Facilities.


The Merck Veterinary Manual: Contagious Equine Metritis

USDA Contagious Equine Metritis Information

USDA Equine Import and Export Information

Equine Disease Communication Center: Disease Outbreak Alerts