equigenitalis (Contagious Equine Metritis Organism)
Taylorella equigenitalis is the bacterium responsible for
Contagious Equine Metritis (CEM), a uterine infection of mares
which results in temporary infertility. CEM can cause widespread
reduced fertility and serious disruption to breeding operations
particularly amongst the Thoroughbred population in which
the permitted covering season is short.
Infection spreads mainly through direct transmission of the
bacteria from stallion to mare or mare to stallion, at mating.
It may also be spread by artifical insemination (AI) if the
semen used is from an infected stallion.
Infected stallions do not show signs of disease. Mares may
develop varying degrees of vaginal discharge within 2 - 10
days of mating, or may also appear unaffected. Although recovery
is usually uneventful, a large proportion of mares will remain
carriers of the infection.
Bacterial culture is essential for diagnosis, as similar
signs may be caused by other bacteria such as Klebsiella and
Pseudomonas species and Streptococcus zooepidemicus.
Swabs should be taken from the clitoral sinuses and fossa
of the mare and from the urethra, urethral fossa, penile sheath
and pre-ejaculatory fluid (where possible) of stallions. All
swabs should be submerged in Amies Charcoal Transport Medium
and sent immediately to an approved laboratory.
Mares and stallions require 5-7 days of careful washing with
2% chlorhexidine, combined with local and systemic antibiotics.
Mares with signs of uterine infection require daily intrauterine
antibiotic irrigations. Follow-up swabs are taken to assess
the success of treatment. Occasionally treatment needs to
be repeated. In some mares with intractable clitoral infections,
surgery to remove the affected tissue is indicated.
The principal means of control is by the identification of
infected animals before breeding commences. These animals
should not be used for breeding until the infection has been
successfully treated. All stallions and mares should be thoroughly
screened for T. equigenitalis (and Equine Viral Arteritis)
at the beginning of each breeding season.
In the UK, isolation of Taylorella equigenitalia is notifiable
by law to the Ministry of Agriculture, Fisheries and Food
The Horserace Betting Levy Board produces Codes of Practice
for the prevention and control of CEM, Klebsiella and Pseudomonas,
along with other important equine infectious diseases.
These codes outline the minimum measures which should be
implemented by horse owners, in conjunction with their veterinary
surgeons, as a means of limiting and resolving disease outbreaks.
Copies of the Codes of Practice are available from:
Horserace Betting Levy Board
52 Grosvenor Gardens
Tel: 020 7333 0043
Fax: 020 7333 0041
Strict adherence to the Codes of Practice along with good
stud management and hygiene should prevent introduction and
spread of disease onto and within farms.
To find out more about the AHT why not visit their website