Contagious Equine Metritis confirmed in Gloucestershire


We have been made aware that Defra yesterday (28 March 2012) confirmed a case of Contagious Equine Metritis (CEM) in a thoroughbred mare in Berkley, Gloucestershire.

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 The disease was spotted during pre-breeding testing. Initial results for a second mare, the only other horse on the premises, are also positive.  The last occurrence of CEM in the UK was in 2010. 

No action need to be taken regarding your horses in Britain as the infection is treatable and easily controlled, but we wanted to make you aware. 

About the disease

CEM is a notifiable venereal infection that causes a discharge from the vulva, resulting from inflammation of the uterus.  It is a sexually transmitted equine disease. There are no human health implications and infected horses can be treated with antibiotics and recover.

Infection spreads through direct transmission of bacteria from mare to stallion or teaser stallion, or from stallion or teaser to mare at the time of mating or teasing. It is also transmitted to mares if semen used in artificial insemination (AI) comes from infected stallions.

Indirect infection can also occur through contaminated water, utensils and instruments; on the hands of staff and veterinary surgeons who handle the tail and genital area of the mare, or the penis of the stallion or teaser; or genital to genital or nose to genital contact between stallions/teasers and mares.

Control and treatment

The spread of infection is easily controlled by preventing the mating of infected horses, treating the infection, re-testing several times to check the infection has cleared up before resuming mating, and applying strict hygiene measures when handling the horses involved. In this case, movement restrictions on the mare and in-contacts have been put in place.

A full epidemiological investigation is now underway.  The investigation is focusing initially on the infected premises and recent contact premises.


There are no CEM related certification requirements for the movement of horses from the UK to other EU Member States. Most third country destinations do not insist on CEM country freedom as a prerequisite for export and rely on pre and post export testing. However, the fact disease has been confirmed in a thoroughbred could also have trade implications with some third countries (such as India, a priority market for the UK's thoroughbred industry, where it took more than 20 years to agree certification due to CEM) potentially changing their current import conditions. 

Further details about Contagious Equine Metritis can be found on the Defra website.

The Horse Racing Betting Levy Board has also produced a Codes of Practice with Defra on preventing disease, which you can access here.