1. Prof. Dr. Ivaylo Chenchev, PhD, DVSc
Legislative background of horse infectious disease surveillance principles in EU with particular reference to infectious metritis
Prof. Dr. Ivaylo Chenchev, PhD, DVSc
National Diagnostic and Research Veterinary Medical Institute, Bulgaria

2. CONTAGIOUS EQUINE METRITIS
Contagious equine metritis is an inflammation of the endometrium of mares caused by Taylorella equigenitalis, which usually results in temporary infertility.
It is a nonsystemic infection, the effects of which are restricted to the reproductive tract of the mare.

3. CONTAGIOUS EQUINE METRITIS
In general the clinical signs are a slight to copious mucopurulent vaginal discharge and a variable cervicitis and vaginitis.
Recovery is uneventful, but prolonged asymptomatic carriage is established in a proportion of infected mares.

4. CONTAGIOUS EQUINE METRITIS
Taylorella equigenitalis is most frequently transmitted by sexual contact with carrier stallions, which are always asymptomatic and in which the principal sites of T. equigenitalis colonisation are the urogenital membranes (urethral fossa, urethral sinus, urethra and penile sheath).
The sites of persistence of T. equigenitalis in the mare are urogenital membranes, principally in the clitoral sinuses and fossa and very infrequently in the uterus.
Foals born of carrier mares may also become carriers.
The organism can infect equid species other than horses, e.g. donkeys.

5. CONTAGIOUS EQUINE METRITIS
Contagious equine metritis was first described in the United Kingdom in 1977, after which it was diagnosed in a number of countries world-wide.
It first presented as disease outbreaks characterised by a mucopurulent vaginal discharge originating from inflammation of the endometrium and cervix, resulting in temporary infertility.

6. CONTAGIOUS EQUINE METRITIS
Serum antibody persists for 3–7 weeks after infection, but often it is not detectable for up to 15–21 days after recovery from acute infection in the mares.
Most mares recover uneventfully, but some may become carriers of T. equigenitalis for many months.
Many primary cases of infection with T. equigenitalis in the mare are subclinical, and a frequent indicator of infection is a mare returning in oestrus prematurely after being bred to a putative carrier stallion.

7. CONTAGIOUS EQUINE METRITIS
Carrier mares and stallions act as reservoirs of T. equigenitalis, but stallions, because they mate with numerous mares, play a much more important role in transmission of the bacterium.
The urogenital membranes of stallions become contaminated at coitus, leading to a carrier state that may persist for many months or years.
Other sites of the horse’s body are not known to harbour T. equigenitalis. Most carrier mares are clitoral carriers of T. equigenitalis.
Taylorella equigenitalis can cause abortion in the mare but this is a rare occurrence.

8. CONTAGIOUS EQUINE METRITIS
Prior infection and vaccination are not fully protective, and failure of antibody to persist has meant that control of infection has relied entirely on prevention of transmission through the detection of T. equigenitalis on swabs of urogenital membranes.
In spite of difficulties in culturing T. equigenitalis, screening mares and stallions prior to and while on the stud farm has successfully eliminated the disease from thoroughbred horses in countries using a voluntary code of practice.

9. Proposed minimum standards
Housed in individual stalls
One empty stall between CEM quarantine horses and other horses – prevent direct contact
Groups of horses (Gypsies) can be kept in same paddock together (housed together before shipped)
Test mares separated after breeding

10. Helpful farm policies Individual water and feed buckets cleaned daily
Isolation barn for sick horses
Monitor for feed intake and manure
Temperature daily
Concerns: EHV1, Strangles, Influenza
Facilities should not harm horses

11. Mares and Stallions One person to hold mare One person to hold tail
One person to handle stallion
One person to handle test mares
One person to assist breeding

12. Import mare procedures
3 sets of clitoral sinus and fossa cultures
Interval – 3 days between cultures
Current regulations - 1, 4, and 7 days of a 7 day period
Complete cultures by 12 days after 1st culture

13. How to get the swab from mare

14. Stallions – swab sample – urethral sinus

15. Stallions – swab sample – urethral sinus

16. Stallions – swab sample - Fossa

17. Stallions – swab sample - prepuce

18. Stallions – swab sample - prepuce

19. Stallion – swab sample – terminal urethral

20. Swab (Culture) sample handling
Special media – Amies charcoal media
Refrigerate right away (4º C)
Needs to arrive to lab within 48 hours
Approved lab
Cultures read at 7 days after plating
Proposed clarification – read by hours -168 hrs vs 7 days

21. Test breeding of stallions
After negative cultures – at least 7 days
Breed stallion to two qualified test mares
Clean vulva and place tail bandage on test mare
Tease stallion before breeding to see if test mare is in heat

22. Test mare qualification
3 negative sets of sinus and fossa cultures with at least 3 days between cultures
Negative CF test for CEM
Vaccinate test mares for EVA
Negative Coggins test (EIA)

23. Positive stallions
Positive – Either initial culture, culture in test mares or positive CF in test mares
Same procedures as described for stallions after breeding
Treatment
Wait 21 days after last treatment
Repeat initial culture protocol and procedures

24. Positive mares Positive culture or CF test in test mares
Same as previously described for import mares after 3rd culture
Treatment
Wait at least 21 days
Repeat qualification protocols
Proposed – Identify and don’t use positive test mares

25. Positive test mares - discharge

26. Example Treatment protocols – for positive mares
Sulfamethoxazole Trimethoprim (TMS) – Systemic (30mg/kg PO) 5 days
1500 mg Gentamicin + 20 cc 8.4% Sodium Bicarbonate + 25 cc saline – IU for 3 days
Flush beans (Cerumene®) & sinuses (4% Chlorhexidine) day 1
Scrub area for 2-5 days – 4% Chlorhexidine
Pack area with 1% Silver Sulfadiazine 5 days

27. After Treatment protocols
Wait 21 days
Repeat initial protocols – include intra-uterine in one set of the 3 cultures
Test mares – negative CF

28. Example treatment protocol for positive stallion
TMS – 30mg/kg PO for 7 days
Scrub penis for 10 days with 4% Chlorhexidine scrub
Pack penis for 10 days with 1% Silver Sulfadiazine Cream
Wait 21 days before culturing
Culture at 21, 28 and 35 days after treatment
Breed two test mares and follow previously stated protocols – starting over

29. CONTAGIOUS EQUINE METRITIS IDENTIFICATION OF THE AGENT
Taylorella equigenitalis is a Gram-negative, nonmotile, bacillus or cocco-bacillus that is often pleomorphic (up to 6 μm long) and may exhibit bipolar staining. It is catalase positive, phosphatase positive, and strongly oxidase positive.
If a slow-growing organism is isolated that fits the description for cellular morphology and that is strongly oxidase positive, it should be tested for reactivity with T.-equigenitalis-specific

30. Agglutination method
A latex agglutination kit is available commercially for the antigenic identification of T. equigenitalis.
It is based on polyclonal antibodies.
This is widely used by routine testing laboratories for the confirmation of the identity of colonies growing on selective medium that give a biochemical reaction consistent with T. equigenitalis.
It should be emphasised that it will not necessarily distinguish strains of T. equigenitalis from T. asinigenitalis.

31. PCR method
A PCR method has been used for detecting T. equigenitalis and was compared with culture methods.
It was highly specific and was able to detect very small numbers of T. equigenitalis
PCR is more sensitive than culture for the detection of T. equigenitalis from genital swabs of horses in the field.
Real-time PCR is more useful and it uses directly on genital swabs and compared with culture.
This PCR has advantage of speed of result and also differents T. equigenitalis from T. asinigenitalis.