Taylorella equigenitalis
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Description
Taylorella equigenitalis is the causal agent of contagious equine metritis (CEM). It is found exclusively in the genital tracts of stallions, mares and foals. *Found in urethral fossa of stallions and clitoral fossa of mares
- Disrupts breeding programs on thouroughbred stud farms
- UK free from contagious equine metritis
Characteristics
T. equigenitalis is a short, non-motile Gram-negative rod. It is catalase, oxidase and phosphatase postitive.
- Microaerophilic
- Grows slowly
- Fastidious growth - requires chocolate agar and 5-10% carbon dioxide for growth
- No growth on MacConkey
Pathogenesis and pathogenicity
- Transmission during coitus or via contaminated instruments
- Semenal fluid contaminated with T. equigenitalis from the urethral fossa
- Deposition in uterus required for infection to establish
- Bacteria replicate in uterus and cause acute endometritis
- Initial influx of mononuclear cells and plasma cells, followed by neutrophils, which cause a mucopurulent discharge
- Acute endometrial changes only last a few days
Clinical infections
- Contagious equine metritis
- Highly contagious venereal disease of thorougbred horses
- Infected stallions and mares are a reservoir of infection
- Stallions and some mares asymptomatic
- Mucopurulent vulval discharge and temporary infertility in mares after service with a carrier stallion
- Inflammation of uterus hinders implanation
- Discharge may continue for 2 weeks, and mares may remain infertile for several weeks
- Mares may recover without treatment; 25% become carriers
- Re-infection can occur
- Foals become infected in utero or during parturition
- Infected foals and mares that recover clinically may be a source of infection
Diagnosis
- Specimens for bacteriology:
- Mares: swabs from clitoral fossa and sinuses and endometrium during oestrus
- Fillies: swabs from clitoral fossa
- Colts: penile sheath and tip of penis
- Stallions: swabs from urethra, urethral fossa, penile sheath and pre-ejaculatory fluid
- Place swabs in charcoal transport medium
- Isolation on chocolate agar with amphotericin B, crystal violet and streptomycin
- Small, smooth, yello-grey colonies
- Slide agglutination test
- Fluorescent antibody test
- Latex agglutination
- PCR
- Serology only detects active infection
Treatment and control
- Wash external genitalia of mares and stallions with 2% chlorhexidine combined with antimicrobials
- Lavage uterus with a penicillin-containing solution daily for 5-7 days in mares
- Ablation of clitoral sinuses in persistently-infected mares
- Notifiable disease
- Laboratory detection of carrier animals and clinical infections
- Hygiene
- Stop breeding if CEM diagnosed on stud farm
- Sample recovered animals to ensure free from disease
- Test-mating of stallions to 2 maiden mares to detect infection