Contagious Equine Metritis (CEM), qPCR

Screening of 3 pathogens responsible Contagious Equine Metritis (CEM): 

• Taylorella equigenitalis, qPCR
• Pseudomonas aeruginosa, qPCR
• Klebsiela pneumonia, qPCR

Sample requirements

• 2 or 3 genital swabs in swab Amies transport medium with charcoal.

• Clitoral fossa – use standard swab with Amies culture and transport system

• Clitoral sinuses swabbed – use Minitip Amies culture and transport system. Openings to the sinuses are on the dorsum of the clitoris - the central one is usually always present whereas the lateral sinuses may be multiple or not be present. Swab all that are present.

• Either cervical (closed cervix if pregnant or mid-cycle) or endometrial (while in estrus or true anestrus) swab – use guarded 25” swab.

Turnaround time

• 2 to 5  working days

What is Contagious Equine Metritis?

• Contagious equine metritis is an inflammatory disease of the proximal and distal reproductive tract of the mare 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.

Clinical signs

• When present, general clinical signs include endometritis, cervicitis and vaginitis of variable severity and a slight to copious mucopurulent vaginal discharge.

In mares there are two states of infection:

• The active state in which the main outward sign is a vulval discharge, which may range from very mild to extremely profuse.
• The carrier state in which there are no outward signs of infection. However, the mare remains capable of transmitting infection because the bacteria are established on the surface of the clitoris, the clitoral fossa and sinuses and, in the case of pneumoniae and P. aeruginosa, sometimes in the urethra and bladder.

In stallions: (‘stallion’ means mating stallions, teasers and stallions used for AI)

• Infected stallions do not usually show clinical signs of infection but the bacteria are present on their penis, sheath and. These stallions can infect mares during mating, teasing or AI.
• Occasionally, the bacteria may invade the stallion’s sex glands, causing pus and bacteria to contaminate the semen.

Transmission

• Direct venereal contact during natural mating presents the highest risk for the transmission of equigenitalis from a contaminated stallion or an infected mare.
• Direct venereal transmission can also take place by artificial insemination using infective raw, chilled and possibly frozen semen.
• Indirectly, infection may be acquired through fomite transmission, manual contamination, inadequate observance of appropriate biosecurity measures at the time of breeding and at semen- collection centres. Stallions can become asymptomatic carriers of equigenitalis.
• The principal sites of colonisation by the bacterium are the urogenital membranes (urethral fossa, urethral sinus, terminal urethra and penile sheath).

The sites of persistence of equigenitalis in the majority of carrier mares are the clitoral sinuses and fossa and infrequently the uterus.

• Foals born of carrier mares may also become carriers.
• The organism can infect equid species other than horses, e.g. donkeys.

Prevention

• If infection with equigenitalis is suspected in any mare, stallion or teaser on the basis of clinical signs, all breeding activities must cease immediately.
• The affected horse(s) should be isolated and swabbed by the attending veterinary surgeon.
• Arrange swabbing of any at risk horse.
• Disinfect all equipment used for breeding procedures.
• Inform all owners of mares booked to the stallion, including any which have already left the premises;
• Inform people to whom semen from the stallion has been sent;
• Arrange for one straw from every ejaculate of stored semen from infected and at risk stallions to be tested by a laboratory. If a straw from any ejaculate is infected, all straws from that ejaculate should be destroyed;
• Any at risk pregnant mare must be foaled in isolation. The placenta must be incinerated. Foals born to these mares should be swabbed three times, at intervals of not less than seven days, before three months of age.
• Any mares with an abnormal vaginal exudate, or returning to oestrus prematurely, should be investigated and managed as though infected with equigenitalis until results of laboratory testing prove otherwise.
• If carriers of equigenitalis are detected, the organism can be eliminated by treatment with systemic and/or local antibiotics combined with antiseptic washing of the sites of persistence in the mare and the stallion.