Contagious equine metritis

Taylorella equigenitalis is a fastidious, Gram-negative, microaerophilic coccobacillus that serves as the primary agent of Contagious Equine Metritis (CEM). This highly contagious venereal disease specifically affects equines, causing significant reproductive impairment and economic instability within the horse breeding industry. It is not an agricultural plant pathogen, but a strictly animal-focused bacterium.

The host range is limited to horses, donkeys, and mules. In the context of animal husbandry, this bacterium targets the mucosal surfaces of the reproductive tract. While it does not affect any agricultural crops, its impact on horse farms is substantial due to the potential for rapid spread among the breeding population if strict veterinary biosecurity protocols are ignored.

Clinical signs in mares include the development of a profuse, mucopurulent vaginal discharge, typically appearing shortly after breeding, often accompanied by inflammation of the uterus and cervix. Many mares may also become asymptomatic carriers, which makes control efforts difficult. Stallions exhibit no clinical symptoms, serving as silent carriers that harbor the bacteria in their preputial folds and urethral fossae.

Transmission of the disease primarily occurs during natural mating or artificial insemination. The bacterium is highly adapted to survive on the genital mucosa of carriers for extended periods, allowing it to persist in a population even without active disease outbreaks. Environmental survival is generally limited, but the bacterium can survive for short periods on contaminated equipment, such as breeding supplies.

Management and prevention focus on identifying carriers through rigorous microbiological testing of swabs taken from the genital tract before the breeding season begins. Implementing strict quarantine measures for imported horses and using artificial insemination protocols with certified disease-free semen are the most effective strategies for maintaining herd health. Infected horses require targeted antibiotic treatment and thorough cleaning to eliminate the pathogen.