Difference between revisions of "Taylorella equigenitalis"

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<big><center>[[Infectious agents and parasites|'''BACK TO INFECTIOUS AGENTS AND PARASITES''']]</center></big>
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Also known as: '''''Contagious Equine Metritis — CEM'''''
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<big><center>[[Bacteria|'''BACK TO BACTERIA''']]</center></big>
  
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==Introduction==
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===Overview===
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''Taylorella equigenitalis'' is the causal agent of contagious equine metritis (CEM). It is found exclusively in the '''genital tracts of stallions, mares and foals''', specifically, in the '''urethral fossa''' of stallions and the '''clitoral fossa''' of mares.
 
  
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The disease '''disrupts breeding programs''' on thouroughbred stud farms. Currently, the UK is '''free from contagious equine metritis'''.
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*Causes contagious equine metritis
 +
*Found in genital tracts of stallions, mares and foals
 +
*Found in urethral fossa of stallions and clitoral fossa of mares
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*Disrupts breeding programs on thouroughbred stud farms
  
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==Characteristics==
 
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The organism is a short, non-motile Gram-negative rod which is catalase, oxidase and phosphatase positive.
 
  
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The bacterium is microaerophilic, grows slowly, and is '''fastidious''' as it requires chocolate agar and 5-10% carbon dioxide for growth.
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===Characteristics===
  
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It does not grow on MacConkey.
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*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
  
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==Pathogenesis and Pathogenicity==
 
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Transmission occurs '''during coitus or via contaminated instruments'''. The seminal fluid of stallions is contaminated with ''T. equigenitalis'' from the urethral fossa, and deposition in the uterus is required for infection to establish. The bacteria replicate in the uterus and cause '''acute endometritis'''. There is initial influx of mononuclear cells and [[Plasma Cells|plasma cells]], followed by [[Neutrophils|neutrophils]], which cause a mucopurulent discharge. The acute endometrial changes only last a few days.
 
  
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==Clinical Infections==
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===Pathogenesis and pathogenicity===
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Contagious equine metritis is a '''highly contagious venereal disease of Thorougbred horses'''.
 
  
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Infected stallions and mares are a '''reservoir of infection''', and stallions and some mares are '''asymptomatic'''.
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*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
  
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Most mares experience '''mucopurulent vulval discharge''' and temporary infertility after service with a carrier stallion. Inflammation of the uterus hinders implantation, the discharge may continue for 2 weeks, and mares may remain '''infertile''' for several weeks.
 
  
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Mares may recover without treatment but 25% become carriers and re-infection can occur.
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===Clinical infections===
  
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Foals become infected ''in utero'' or during parturition and may be source of infection for other horses.
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*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
 +
*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
  
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==Diagnosis==
 
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Specimens required for bacteriology include:
 
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:Mares: swabs from the clitoral fossa and sinuses and endometrium during oestrus
 
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:Fillies: swabs from the clitoral fossa
 
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:Colts: swabs from the penile sheath and tip of penis
 
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:Stallions: swabs from the urethra, urethral fossa, penile sheath and pre-ejaculatory fluid
 
  
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Swabs should be placed in a '''charcoal-containing transport medium'''.
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===Diagnosis===
  
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The organism can be isolated on chocolate agar with amphotericin B, crystal violet and streptomycin.
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*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
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*Slide agglutination test
 +
*Fluorescent antibody test
 +
*Latex agglutination
 +
*PCR
 +
*Serology only detects active infection
  
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The colonies appear as '''small, smooth and yellow-grey'''.
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===Treatment and control===
  
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'''Other diagnostic tests''' include:
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*Wash external genitalia of mares and stallions with 2% chlorhexidine combined with antimicrobials
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:Slide agglutination test
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*Lavage uterus with a penicillin-containing solution daily for 5-7 days in mares
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:[[FAT|Fluorescent antibody test]]
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*Ablation of clitoral sinuses in persistently-infected mares
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:Latex agglutination
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*Notifiable disease
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:[[PCR]]
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*Laboratory detection of carrier animals and clinical infections
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:Serology, but it only detects active infection
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*Hygiene
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*Stop breeding if CEM diagnosed on stud farm
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==Treatment and Control==
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*Sample recovered animals to ensure free from disease
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The external genitalia, including the clitoral fossa of mares and stallions should be '''washed with 2% chlorhexidine combined with antimicrobials''' such as crystalline penicillin. A '''2% nitrofurazone ointment''' can be packed into the clitoral fossa.
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*Test-mating of stallions to 2 maiden mares to detect infection
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The uterus of mares should be '''lavaged''' with a penicillin-containing solution daily for 5-7 days.
 
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Persistently-infected mares may benefit from '''ablation of the clitoral sinuses'''.
 
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CEM is a notifiable disease in the UK. Carrier animals and clinical infections should be detected by laboratory testing, and breeding should be '''stopped''' if the disease is diagnosed on a stud farm. Hygiene rules should be strictly adhered to.
 
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Recovered animals should be '''sampled''' to ensure they are free from disease.
 
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Stallions may be test-mated to 2 maiden mares to detect the spread of infection.
 
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{{Learning
 
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|flashcards = [[Equine Reproduction and Stud Medicine Q&A 14]]
 
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}}
 
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{{review}}
 
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{{OpenPages}}
 
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[[Category:Bacteria miscellaneous]][[Category:Gram_negative_bacteria]][[Category:Rods]][[Category:Horse Bacteria]]
 
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[[Category:Reproductive Diseases - Horse]]
 
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[[Category:Expert Review - Horse]]
 

Revision as of 08:25, 20 July 2008

BACK TO INFECTIOUS AGENTS AND PARASITES
BACK TO BACTERIA

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


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
  • 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
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