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Taylorella equigenitalis (view source)
Revision as of 11:20, 7 September 2011
, 11:20, 7 September 2011no edit summary
Also known as: '''''Contagious Equine Metritis — CEM'''''
==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''', specifically, in the '''urethral fossa''' of stallions and the '''clitoral fossa''' of mares.
The disease '''disrupts breeding programs''' on thouroughbred stud farms
Currently, the UK is '''free from contagious equine metritis'''.
==Characteristics==
==Characteristics==
The organism is a short, non-motile Gram-negative rod which is catalase, oxidase and phosphatase postitive.
The bacteria is microaerophilic, grows slowly, and is '''fastidious''' as it requires chocolate agar and 5-10% carbon dioxide for growth.
It does not grow on MacConkey.
==Pathogenesis and pathogenicity==
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, followed by [[Neutrophils|neutrophils]], which cause a mucopurulent discharge.
The acute endometrial changes only last a few days.
==Clinical infections==
Contagious equine metritis is a '''highly contagious venereal disease of Thorougbred horses'''.
Infected stallions and mares are a '''reservoir of infection''', and stallions and some mares are '''asymptomatic'''.
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.
Mares may recover without treatment but 25% become carriers and re-infection can occur.
Foals become infected ''in utero'' or during parturition and may be source of infection for other horses.
==Diagnosis==
Specimens required for bacteriology include:
:Mares: swabs from the clitoral fossa and sinuses and endometrium during oestrus
:Fillies: swabs from the clitoral fossa
:Colts: swabs from the penile sheath and tip of penis
:Stallions: swabs from the urethra, urethral fossa, penile sheath and pre-ejaculatory fluid
Swabs should be placed in a '''charcoal-containing transport medium'''.
The organism can be isolated on chocolate agar with amphotericin B, crystal violet and streptomycin.
The colonies appear as '''small, smooth and yellow-grey'''.
'''Other diagnostic tests''' include:
:Slide agglutination test
:Fluorescent antibody test
:Latex agglutination
:PCR
:Serology, but it only detects active infection
==Treatment and control==
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
The uterus of mares should be '''lavaged''' with a penicillin-containing solution daily for 5-7 days.
Persistently-infected mares may benefit from '''ablation of the clitoral sinuses'''.
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.
Recovered animals should be '''sampled''' to ensure they are free from disease.
Stallions may be test-mated to 2 maiden mares to detect the spread of infection.
===Treatment and control===
{{Learning
|flashcards = [[Equine Reproduction and Stud Medicine Q&A 14]]
}}
[[Category:Bacteria miscellaneous]][[Category:Gram_negative_bacteria]][[Category:Rods]][[Category:Horse Bacteria]]
[[Category:Bacteria miscellaneous]][[Category:Gram_negative_bacteria]][[Category:Rods]][[Category:Horse Bacteria]]
[[Category:To_Do_-_Bacteria]]
[[Category:To_Do_-_Bacteria]]