Safeguarding public and animal health
Contagious equine metritis
What is CEM?
Contagious equine metritis is a highly contagious venereal disease of horses. Infected stallions do not show clinical signs but can spread the infection to mares. Infected mares show variable clinical signs ranging from none to a severe and purulent inflammation of the uterus lining.
CEM is caused by a bacterium called Taylorella equigenitalis, often referred to as CEMO (contagious equine metritis organism).
There are two strains of T. equigenitalis. One is sensitive to streptomycin while the other is not.
Both strains are capable of producing epidemic venereal disease in susceptible mares. The second taylorella, T. asinigenitalis, was isolated from donkeys in the USA in the late 1990s.
CEM in the UK
CEM was first reported in England in 1977. Since then the disease has occurred in many countries. Suspicion of CEMO infection must be reported to Defra. The last recorded incident confirmed in Great Britain was in 2005. In recent years confirmed cases in Britain have been confined to non-thoroughbred horses, mainly involving or resulting from imported warmbloods.
VLA's role
The VLA has a number of roles in relation to Contagious Equine Metritis (CEM) and CEMO.
- to advise the Food and Farming Group of Defra (FFG) on the control of CEM, and
- to isolate and identify CEMO.
VLA Bury St Edmunds is an OIE Reference Laboratory for CEMO.
This involves identifying suspect CEMO isolates notified to Animal Health and FFG, and carrying out bacteriological examinations in support of Animal Health/FFG investigations into CEMO infections.
In addition, VLA Bury St Edmunds provides bacteriological examinations for CEMO on samples submitted as part of international trade requirements. The majority of these samples relate to the pre-export licence requirements of other countries.