Sciensano is recognised as the Belgian National Reference Laboratory (NRL) for contagious equine metritis.

Contagious Equine Metritis (CEM) is a sexually transmitted disease caused by the Taylorella equigenitalis bacterium that attacks horses. Very contagious, it can have disastrous consequences on equine reproduction. This disease only affects horses, but all breeds are at risk of contracting it.
Contagious Equine Metritis (CEM) is a venereal disease that attacks equines. The bacterium responsible for this disease is Taylorella equigenitalis, which can survive for several months in the genital tract of horses.
The disease spreads in particular directly during natural mating. Infected stallions are usually the main source of infection because they can carry the disease for years without exhibiting clinical signs.
This disease is not transmissible to humans and poses no risk to their health.
Contagious equine metritis is a notifiable disease.
In the mare, the first sign of infection is a shortened estrous cycle accompanied by a copious mucopurulent vaginal discharge occurring 10 to 14 days after mating with an infected stallion. The mare may remain chronically infected for several months, and the stallions may be healthy carriers for years, Taylorella equigenitalis persisting mainly at the level of the urethral fossa. Bacteriological isolation therefore remains the prescribed test for international trade.