Historical Background and Discovery
CEM was first identified in the early 1970s in the United Kingdom and the United States. The disease gained attention due to its impact on breeding operations, particularly thoroughbred racing and other high-value equine industries where successful reproduction is paramount. The causative bacterium, *Taylorella equigenitalis*, primarily colonizes the genital tract of horses, causing inflammation and mucopurulent discharge in mares and occasional stallions.
Transmission and Spread
Transmission of CEM occurs through direct contact during mating or through contaminated fomites (objects or materials capable of carrying infectious organisms). Stallions are asymptomatic carriers and can spread the disease during breeding, while mares typically exhibit clinical signs such as vaginal discharge, inflammation of the reproductive tract, and infertility. The ability of the bacterium to survive in the genital tract for extended periods contributes to its persistence in affected populations.
Clinical Signs and Diagnosis
Clinical signs of CEM in mares usually appear within 10 days to 2 weeks after exposure and include:
- Vaginal discharge (often mucopurulent)
- Endometritis (inflammation of the uterine lining)
- Infertility or difficulty conceiving
Diagnosis of CEM involves:
- Culture and Isolation: Culturing Taylorella equigenitalis* from swabs taken from the clitoral fossa or urethral sinus.
- **PCR Testing:** Polymerase Chain Reaction (PCR) tests can detect the presence of the bacterium more quickly than traditional culture methods.
Treatment and Management
Treatment of CEM involves the use of antibiotics effective against *Taylorella equigenitalis*. Commonly used antibiotics include penicillin and streptomycin. Infected animals should be isolated and treated promptly to prevent further spread. Additionally, strict biosecurity measures should be implemented to limit transmission within and between facilities.
Prevention and Control Measures
Prevention of CEM relies heavily on biosecurity protocols:
- **Quarantine:Importation of horses should be accompanied by stringent quarantine measures to detect and isolate carriers.
- **Testing: Regular screening and testing of breeding animals, especially stallions and mares intended for breeding.
- **Hygiene:Cleaning and disinfection of equipment, including reproductive instruments and facilities.
Economic and Regulatory Impact
The economic impact of CEM can be substantial, particularly in industries reliant on equine breeding and international movement of horses. Outbreaks can disrupt breeding seasons, affect the marketability of affected animals, and result in trade restrictions between countries until eradication measures are confirmed.Global Eradication Efforts
Many countries have established eradication programs to control and eliminate CEM. These programs typically involve:
- **Surveillance:** Monitoring and reporting cases to regulatory authorities.
- **Eradication Protocols:** Implementing strict control measures, including testing and treatment of infected animals.