Contagious Equine Metritis (CEM) is a venereal disease affecting horses, causing infertility in mares and serving as a carrier state in stallions. While not currently widespread in the United States, the disease poses a risk through imported horses, necessitating careful monitoring and preventative measures.
Understanding Contagious Equine Metritis
CEM is caused by the bacterium Taylorella equigenitalis, a fastidious, microaerophilic, Gram-negative coccobacillus. The disease is primarily spread through live breeding or artificial insemination using contaminated equipment or infected semen. It’s considered a non-systemic disease, meaning it doesn’t affect the horse’s overall health beyond the reproductive system, but its impact on breeding potential is significant.
Clinical Signs in Horses
Interestingly, stallions typically exhibit no outward signs of CEM, making them asymptomatic carriers. This allows them to unknowingly spread the infection. Mares, however, will usually show clinical signs approximately 10 to 14 days after exposure. These signs include:
- Vaginal discharge
- Infertility
- Abortion (though rare)
Mares can also become carriers of the organism, and critically, foals born to infected or carrier mares may also become long-term carriers themselves. This highlights the importance of identifying and managing CEM to prevent its perpetuation within a horse population.
Diagnosis and Testing
Diagnosing CEM involves evaluating horses exhibiting genital discharge or those experiencing difficulties conceiving after breeding with an untested or imported stallion. Prophylactic annual testing of stallions used for breeding is recommended by the USDA as a proactive measure to reduce the risk of transmission. This is particularly important given the stallion’s ability to carry and spread the disease without showing symptoms.
Treatment Protocols
Treatment for CEM focuses on eliminating the bacteria from the affected areas. The standard protocol involves a thorough washing of the external genitalia in both stallions and mares using a disinfectant soap, such as 2% Chlorhexidine, followed by a thorough rinse and application of a topical antibiotic like nitrofurazone or silver sulfadiazine. This process is repeated for five consecutive days. While most horses respond well to a single course of treatment, some may require retreatment to fully eradicate the infection.
Prevention and Control Measures
Because CEM is not endemic to the United States, preventing its introduction and spread is paramount. The USDA requires negative tests for all imported horses to minimize the risk of importing the disease. Biosecurity measures are also crucial in controlling potential outbreaks. These include:
- Strict hygiene protocols during breeding
- Use of single-use or thoroughly disinfected breeding equipment
- Careful monitoring of imported horses
- Regular testing of breeding stallions
The recent strengthening of disease management systems, as noted in reports from , underscores the ongoing commitment to maintaining CEM-free status in the US. This includes a focus on safe stud practices based on comprehensive testing and accurate estrus cycle diagnosis.
Zoonotic Concerns
Currently, there are no known zoonotic concerns associated with Contagious Equine Metritis. This means the disease is not known to be transmissible from horses to humans.
Impact on the Equine Industry
CEM can have significant economic consequences for the equine industry. The disease can disrupt breeding programs, reduce fertility rates, and necessitate costly testing and treatment protocols. Maintaining a vigilant approach to prevention and control is therefore essential for protecting the health and economic viability of the horse population.
Looking Ahead
Continued research and surveillance are vital for understanding the evolving dynamics of CEM and developing more effective prevention and treatment strategies. The USDA’s ongoing monitoring of imported horses and the recommendation for annual stallion testing remain key components of the national strategy to safeguard against this potentially disruptive equine disease. The emphasis on biosecurity, as highlighted in recent reports, further reinforces the importance of proactive measures in protecting horse health and maintaining the integrity of the breeding industry.
