Taylorella equigenitalis

Overview

• Causes contagious equine metritis
• Found in 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

• Short, non-motile Gram-negative rod
• 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