Contagious equine metritis (CEM) is a highly contagious venereal disease affecting horses, primarily mares, causing vaginal discharge, temporary infertility, and long-term carrier states. Stallions can be asymptomatic carriers, spreading the disease through breeding or artificial insemination. CEM can spread between mares and stallions during breeding, through contaminated semen, or shared breeding equipment.
In the U.S., there have been multiple CEM outbreaks since the mid-1980s, with the most significant occurring from 2008 to 2010 involving 23 stallions and five mares. In a recent outbreak in Florida, 52 cases were confirmed, with at least another 140 potentially exposed. This outbreak was the first to show extensive spread of the disease from gelding to gelding through inadequate biosecurity during sheath-cleaning practices.
To prevent CEM outbreaks, veterinarians recommend following biosecurity guidelines, testing breeding stallions before the season, and taking precautions to reduce the risk of spread to geldings. Compliance with testing and biosecurity measures is crucial to protect breeding programs, prevent outbreaks, and maintain the country’s CEM-free status. By taking proactive steps, the equine industry can continue to thrive while minimizing the risks associated with this preventable disease.
