Taylorella equigenitalis in Horses

Contagious equine metritis (CEM) is an extremely contagious venereal disease that is acquired through genital contact with an infected partner, or through the birth canal of an infected mare. While this disease can be can be carried by either mares or stallions, it is the mare that suffers the ill effects of the infection. Stallions do not show any symptoms of CEM, but mares often will have a thick discharge from the vagina, and will be unable to conceive during the point at which the infection is active.

This is generally a non-lethal disease, and even if left untreated, the mare's system will typically clear the infection on its own over a few weeks time. Blood tests can identify the infection, but it may only indicate that the mare has had the infection, and not whether the infection is still active.

CEM is a bacterial disease, Taylorella equigenitalis, and can be treated with antibacterial washes, which is recommended. Antibiotics are usually not indicated, since the bacteria does not have a good history of being eliminated by antibacterial drugs.

Symptoms and Types

Symptoms, if they appear at all, will typically become apparent between 1-2 weeks after mating with infected stallions. (Note: stallions do not exhibit symptoms.) The mare will exhibit abnormal vaginal discharge. The discharge may be grey in color and is often of a thick consistency. Other symptoms include:

• Inflammation of the endometrium (endometritis)
• Inflammation of the cervix
• Failure to conceive

Causes

CEM is caused by the bacteria T. equigenitalis. It is contracted during sexual contact with an infected horse, typically from stallion to mare.

Diagnosis

The only way to verifiably diagnose contagious equine metritis is to conduct laboratory tests in a clinical setting. As it is highly contagious, the horse must remain in complete isolation until your veterinarian has had an opportunity to examine your horse.

Your veterinarian will perform a thorough physical exam on your horse, with a complete blood profile, chemical blood profile, a complete blood count, and a urinalysis. Your doctor will also need to take a sample of the vulval discharge and tissue cells of the genital tract in the mare, and a sample of ejaculate or pre-ejaculate from the stallion for laboratory testing.