Contagious equine metritis is a bacterial mating infection of horses that causes temporary infertility in mares. Humans are not infected.

There are reports of the occurrence of the infectious equine metritis worldwide. The pathogen has also been regularly detected in many EU countries in recent years.

Horses and other equidae

Transmission mainly occurs through mating or artificial insemination. Indirect transmission via contaminated equipment or persons is possible.

2-12 days

In mares, vaginitis, cervicitis and endometritis with mucopurulent discharge and temporary infertility occur. However, striking clinical manifestations are often absent, and umrusis is often the only symptom. Abortions are extremely rare. Infected stallions show no clinical symptoms.

A combination of systemic antibiotic therapy with local antiseptic washing is used in both the mare and the stallion. Especially in mares, freedom from pathogens is not always achieved.

Regular testing of all breeding animals before mating or semen collection and exclusion of positive animals from breeding. Hygiene management to prevent indirect transmission.

According to European animal health legislation, contagious equine metritis is a disease whose entry and spread within the EU must be prevented and which must be monitored. Positive test results must therefore be reported to the official veterinarians. There is currently no special surveillance programme in Austria.

Contagious equine metritis is a non-systemic disease of the reproductive organs unique to equids, caused by Taylorella equigenitalis, an immobile, Gram-negative, microaerophilic rod. Taylorella are very fastidious and reproduce very slowly. Therefore, cultures are incubated for at least 7 days, and some countries require a longer incubation period as part of import controls.

Symptomatology

Infected stallions are asymptomatic carriers and show no symptoms. In mares, symptoms vary widely from clear clinical signs of vaginitis, cervicitis, and endometritis with mucopurulent vaginal discharge to subclinical infections. Temporary infertility lasting several weeks develops regardless of the degree of other symptoms. The general condition is usually not affected. After recovery, mares may remain carriers of the germ for months to years and act as a source of infection. The pathogen can also be transmitted to the foal at birth.

The detection methods recommended by the WOAH are direct pathogen detection by cultivation and PCR. Direct pathogen detection by cultivation is necessary to confirm the disease in an asymptomatic carrier animal. 

Sampling, transport

Swab samples for cultivation must be sent to the laboratory cooled in transport medium with activated charcoal. Swab samples for PCR can be sent with or without transport medium. No more than 48 hours may elapse between sampling and analysis. Uncooled samples must be analysed within 24 hours. Samples for both culture and PCR may only be taken at least 7 days after parenteral and 21 days after local antibiotic therapy.

Sample collection mare

• Fossa clitoridis
• Clitoral sinus
• Uterus or cervix

Sample collection stallion

• Glandular fossa
• Urethra
• Penis shaft (envelope site)
• For insemination stallions, a swab of pre-secretion or semen