Difference between revisions of "Moraxella bovis"

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#redirect[[Infectious Bovine Keratoconjunctivitis]]
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<big><center>[[Infectious agents and parasites|'''BACK TO INFECTIOUS AGENTS AND PARASITES''']]</center></big>
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<big><center>[[Bacteria|'''BACK TO BACTERIA''']]</center></big>
  
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===Overview===
  
[[Category:Bacteria miscellaneous]] [[Category:Rods]] [[Category:Cocci]] [[Category:Cattle Bacteria]]
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*''Moraxella bovis'' causes infectious bovine keratoconjunctivitis
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*Found on mucous membranes of carrier cattle
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*Susceptible to desiccation therefore short survival in environment
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*Flies act as vectors, in which the bacteria can survive 72 hours
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*Other species non-pathogenic
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===Characteristics===
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*Short, plump Gram negative rods or cocci occuring in pairs
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*Non-motile
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*Aerobic
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*Catalase positive, oxidase postitive
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*Unable to utilise sugars
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*No growth on MacConkey agar
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*Growth enhanced by addition of blood or serum to media
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===Pathogenesis and pathogenicity===
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*Virulent strains have fimbriae, are haemolytic and grow into agar
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*Fimbriae allow adherence to the cornea
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*Q fimbriae are specific for colonisation; I fimbriae allow local persistence of infection
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*Fimbrial antigens stimulate immunity
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*Haemolysin, fibrinolysin, phosphatase, hyaluronidase and aminopeptidase as well as LPS contribute to virulence
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*Haemolysin damages neutrophil membranes; release of hydrolytic enzymes from these neutrophils damages the corneal surface
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*Isolates from carrier animals often avirulent, and are non-haemolytic and have no fimbriae; reversion to virulence can occur
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===Clnical infections===
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*Infectious bovine keratoconjunctivitis, or pink-eye/New Forest disease is an ocular disease of cattle
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*Highly contagious infection of superficial tissues of eye
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*Affects animals under 2 years old
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*Decreased weight gain in beef cattle, decreased milk production in dairy herds
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*Age-related immunity due to previous exposure
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*Asymptomatic carrier animals harbour the bacteria in the nasolacrimal ducts, nasopharynx and vagina
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*Transmission by direct contact, aerosol and via flies
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*Clinical signs: blepharospasm, conjunctivitis, lacrimation
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*Keratitis and corneal ulceration, opacity and abscessation may lead to panophthalmitis and permanent blindness
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===Diagnosis===
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===Treatment and control===

Revision as of 17:28, 26 May 2008

BACK TO INFECTIOUS AGENTS AND PARASITES
BACK TO BACTERIA

Overview

  • Moraxella bovis causes infectious bovine keratoconjunctivitis
  • Found on mucous membranes of carrier cattle
  • Susceptible to desiccation therefore short survival in environment
  • Flies act as vectors, in which the bacteria can survive 72 hours
  • Other species non-pathogenic


Characteristics

  • Short, plump Gram negative rods or cocci occuring in pairs
  • Non-motile
  • Aerobic
  • Catalase positive, oxidase postitive
  • Unable to utilise sugars
  • No growth on MacConkey agar
  • Growth enhanced by addition of blood or serum to media

Pathogenesis and pathogenicity

  • Virulent strains have fimbriae, are haemolytic and grow into agar
  • Fimbriae allow adherence to the cornea
  • Q fimbriae are specific for colonisation; I fimbriae allow local persistence of infection
  • Fimbrial antigens stimulate immunity
  • Haemolysin, fibrinolysin, phosphatase, hyaluronidase and aminopeptidase as well as LPS contribute to virulence
  • Haemolysin damages neutrophil membranes; release of hydrolytic enzymes from these neutrophils damages the corneal surface
  • Isolates from carrier animals often avirulent, and are non-haemolytic and have no fimbriae; reversion to virulence can occur

Clnical infections

  • Infectious bovine keratoconjunctivitis, or pink-eye/New Forest disease is an ocular disease of cattle
  • Highly contagious infection of superficial tissues of eye
  • Affects animals under 2 years old
  • Decreased weight gain in beef cattle, decreased milk production in dairy herds
  • Age-related immunity due to previous exposure
  • Asymptomatic carrier animals harbour the bacteria in the nasolacrimal ducts, nasopharynx and vagina
  • Transmission by direct contact, aerosol and via flies
  • Clinical signs: blepharospasm, conjunctivitis, lacrimation
  • Keratitis and corneal ulceration, opacity and abscessation may lead to panophthalmitis and permanent blindness



Diagnosis

Treatment and control