Contagious Equine Metritis

What is it?
Contagious equine metritis is a venereally transmitted bacterial disease of horses. Thoroughbred horses appear to be more severely affected by the disease than other breeds.

What are the symptoms?
Horses may not show symptoms so the disease is difficult to detect and control. Initial exposure usually results in infertility. The main symptom is a discharge from the vulva, resulting from inflammation of the uterus, usually 1 to 6 days after infection at mating.

Where does it come from?
Three species of bacteria are known to cause CEM. Infection spreads through direct transmission of bacteria from mare to stallion during mating. It is also transmitted to mares if semen used in artificial insemination (AI) comes from infected stallions.

How is it diagnosed?
Swabs for bacteriologic cultures from mares are taken from the cervix or endometrium of the uterus. In mares, various blood tests may also be used to detect antibodies to the CEM bacteria.

How is it treated?
The mare cannot be successfully treated until the CEM bacteria clear from the uterus, a process that may take several months. The external genitalia should be washed with disinfectants such as chlorhexidine. In addition, the external genitalia should be coated with an antibiotic ointment such as Nitrofurazone.

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