Disease factsheet: Contagious Equine Metritis (CEM) - Swabbing
Swabbing requirements are different for the stallion/teaser and mare. For the
mare they vary, depending on whether she has been previously infected
or exposed to risk of infection. Where this is the case, mares are classified
'high risk'. Otherwise, they are classified 'low risk' - see Section 8
below. Swabs should be taken by veterinary surgeons using standard techniques
(see Equine Veterinary Education 1996 Volume 8 (3) 166-170).
For mares there are 2 types of swab:
'Endometrial swab': a swab taken during early oestrus from the lining of the uterus via the cervix.
'Clitoral swab': swabs taken to demonstrate whether the clitoral
fossa and sinuses are free from infection.
For stallions and teasers 'a set of swabs' includes samples from the urethra,
urethral fossa and penile sheath, plus pre-ejaculatory fluid when possible.
Swabs from mares, stallions and teasers should be taken each year after
1st January. The swabs should be dated and timed, marked with the horse's
name and the site from where the swab was taken and sent to an Approved
Laboratory to arrive within 48 hours of being taken. Swabs should be fully
submerged in Amies Charcoal Transport Medium. Veterinary surgeons submitting
samples by routine postal services are advised not to swab mares on Fridays,
Saturdays or Sundays as this usually leads to transit delays.
The Approved Laboratory will culture all swabs aerobically and microaerophilically to screen for CEMO, Klebsiella pneumoniae (pathogenic capsule types) and Pseudomonas aeruginosa. The results will be returned on an official Laboratory Certificate. The immunofluorescence test may be used in addition to culture, but is only available in France at the moment.
For information on Approved Laboratories, please click on "The Advancement of Veterinary Science and Education" at the top of this web page, then click on "Laboratory Approval Scheme" in the navigation panel to the left.
Results of swabs: for 'low risk' mares, the stallion stud manager may, on veterinary advice, allow mating to proceed on the basis of satisfactory results from aerobic culture of endometrial swabs if adequate clitoral swabbing has already been carried out and clinical disease is not suspected. Positive microaerophilic endometrial swab results must be reported to the stallion stud as soon as they are confirmed so that disease transmission may be limited. When a positive result is confirmed, the results of all previous swab tests conduced at the stud farms concerned must be made available for epidemiological tracking. For 'high risk' mares, all results must be confirmed as negative before mating commences, and negative CEMO results will not be available until swabs have been cultured for at least 6 days.
Clitoral swabs: in the case of pregnant mares, these swabs may be taken before or after foaling.
Endometrial swabs: a negative result remains valid during the oestrous period in which the mare is mated and subsequently if she is not mated. If she does not conceive on first mating, a repeat endometrial swab should be taken during all subsequent oestrous periods prior to further mating.
Abnormal return to service (all mares): If mares come back into season at unusual (especially shorter) times, a repeat clitoral swab and a repeat endometrial swab must be taken and cultured under aerobic and microaerophilic conditions.
'Low Risk' and 'high risk' mares
'High risk' mares are:
a. mares from which CEMO has been isolated within the
last 2 years. The 'high' risk status will be removed after this period
only if the mare has been mated since being treated and has had a foal
which has swabbed negative for CEM.
b. mares mated/teased by any stallions/teasers which
transmitted CEM during the last breeding season
c. mares arriving from countries other than Canada, France,
Germany, Ireland, Italy, the UK and the USA, if mated with stallions resident
outside these countries during the last breeding season
d. barren and maiden mares arriving from countries other
than Canada, France, Germany, Ireland, Italy, the UK and the USA
'Low risk' mares are any mares not defined as 'high risk'.NB: Mares which have been mated in Canada, France, Germany, Ireland, Italy, the UK or the USA, which have then gone to other countries and which subsequently return to one of these countries are 'low risk' providing they have not been mated again in a high risk country. However, additional swabbing may be carried out as an extra precaution.
Preventing Infection-recommendations
Stallions and Teasers
After 1st January and before the start of the breeding season, stallion and boarding studs should, for all stallions and teasers:
- Take 2 sets of swabs, at intervals of no less than 7 days.
- Do not mate or tease, or collect or inseminate semen, until ALL the swab results are available.
First season stallions and any other stallion standing on the stud for the first time warrant additional precautions. The first mares mated with them should be screened thoroughly for bacterial reproductive infections by post-mating clitoral and endometrial swabbing under veterinary direction.
It should be noted that, in stallions, bacterial growth of the CEMO is generally more easily recoverable after mating. Swabbing of all stallions after their first few matings in any season should therefore be considered in consultation with the attending veterinary surgeon. In addition, mid-season swabbing should be considered for all stallions and teasers. These swabs may be examined for the presence of the CEMO only.
Stallion and boarding studs should receive, for each mare booked in, a Mare Certificate and, where appropriate, Laboratory Certificate(s) before the mare arrives. Advance Laboratory Certificate requirements are detailed in Section B below.
Mares
Mares for AI: Semen should not be accepted unless the donor stallion has an up-to-date negative Laboratory Certificate.
Mares for Mating: Before mares are moved to the stallion or boarding stud, owners should classify them as 'high risk' or 'low risk', then:
- Complete a Mare Certificate (available from the Thoroughbred Breeders' Association).
- Carry out any swabbing to be done at the home premises and await the Laboratory Certificate.
- Send the Mare Certificate and any Laboratory Certificate to the stallion and/or boarding stud. Ensure that certification is received there before the mare arrives.
Swabbing requirements are as follows:
'Low risk' mares - Resident at stallion stud
Before first mating:
- Clitoral swab on arrival at stallion stud*
- Endometrial swab during oestrus at stallion stud
Mating in subsequent oestrous periods:
· Repeat endometrial swab as above
*This swab may be taken at the home premises by agreement with the stallion stud. The Laboratory Certificate must be sent to the stallion stud before the mare arrives.
'High risk' mares - Resident at stallion stud
Before first mating:
- Clitoral swab before arrival at stallion stud*
- Clitoral swab on arrival at stallion stud
- Endometrial swab during oestrus at stallion stud
Mating in subsequent oestrous periods:
· Repeat endometrial swab as above
* The Laboratory Certificate must be sent to the stallion stud before the mare arrives. NB: Do not mate until all the swab results are available.
'Low risk' mares - Walking in
Before the mare is first walked in:
- Clitoral swab*
- Endometrial swab during oestrus*
Walkings in during subsequent oestrous periods:
· Repeat endometrial swab as above
* The Laboratory Certificates for the clitoral swab and aerobic culture of the endometrial swab must be sent to the stallion stud before the mare is walked in.
'High risk' mares - Walking in
Before the mare is first walked in:
- Clitoral swab before arrival at boarding stud*
- Clitoral swab on arrival at boarding stud*
- Endometrial swab during oestrus at boarding stud*
Walkings in during subsequent oestrous periods:
Repeat endometrial swab as above
*Laboratory Certificate from first clitoral swab - send to the boarding
stud before the mare arrives. Laboratory Certificates from all swabs -
send to the stallion stud before the mare is walked in. NB: Do not mate
until all the swab results are available.
'High risk' mares - Extra precautions
High risk walking in mares should be boarded at a farm which is under control by or meets full approval of the stallion stud. The veterinary practices involved should liaise closely to ensure adherence to the Code of Practice and to arrange any additional precautions.
If CEM is confirmed on a boarding farm where a 'high risk' mare resides or at a stallion stud she has visited, no mares should be moved from the boarding farm until all have been swabbed with negative results.
High risk mares infected with CEM during pregnancy must be foaled in isolation. The placenta must be disposed of hygienically.
Foals born to known infected mares should be swabbed 3 times, at intervals of not less than 7 days, before 3 months of age: · Filly foals: swab the clitoral fossa · Colt foals: swab inside the penile sheath and around the tip of the penis
Page last modified:
August 28, 2008