Contagious Equine Metritis Pathology

The nature, cause, origin, and progress of Contagious Equine Metritis.

Contagious Equine Metritis is a venereally transmitted bacterial disease of horses. The organism causing CEM is a bacterium (microaerophilic gram-negative coccobacillus) and is highly contagious

The disease usually does not become evident until 10 to 14 days post breeding when the mare short-cyles and shows signs of estrus. The first exposure to the CEM organism often causes severe metritis (inflammation of the lining of the uterus), which may result in temporary infertility. However, subsequent exposure to the organism is less severe and may not prevent conception.

There are essentially three states - acute, chronic, and carrier:

• Acute: there is active inflammation and obvious discharge, seen 1-6 days after infection at mating.
• Chronic: the signs and symptoms may be less obvious and discharge may not be seen for up to 80 days after infection.
• Carrier: the animal is infected with the bacteria and is infectious to other animals, but shows no signs of infection.