Difference between revisions of "Brucella species"

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*Serological testing of milk (Milk Ring Test) and beef cattle (Rose Bengal Plate Test)
 
*Serological testing of milk (Milk Ring Test) and beef cattle (Rose Bengal Plate Test)
 
*Serological tests detect anti-lipopolysaccharide antibodies
 
*Serological tests detect anti-lipopolysaccharide antibodies
 +
*LPS antigen present in virulent as well as some vaccine strains therefore vaccination may confuse serological testing
 +
*False positives due to cross-reaction with LPS in other bacteria
 +
*Vaccination:
 +
**Strain S19, a live vaccine, stimulating a cell-mediated immune response; vaccination of young animals; interferes with serological testing
 +
**Newer RB51 vaccine has no LPS O-antigen therefore not detcted by serological tests
 +
**Live attenuated ''Brucella melitensis'' vaccine to protect sheep and goats against ''B. melitensis''
 +
*Test and slaughter program has eradicated Brucellosis in the UK

Revision as of 17:10, 17 May 2008

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Overview

  • Important zoonoses worldwide
  • Cause chronic granulomatous diseases


Characteristics

  • Small, non-moltile, Gram negative coccobacilli
  • Facultatice intracellular pathogens
  • 6 species

Pathogenesis and pathogenicity

  • Penetrate nasal, oral or pharyngeal mucosa
  • Phagocytosed and carried to regional lymph nodes
  • Survive and multiply in cells of the reticulo-endothelial system
  • Inhibit lysosome-phagosome fusion
  • Lymph nodes enlarge (lymphatic and lymphoreticular hyperplasia) and inflammation is induced
  • Surviving organisms spread to other organs (liver, spleen, placenta) and cause granulomatous reactions
  • Eythritol is a growth stimulant and attracts the bacteria to the bovine placenta
  • Infection of foetus and abortion


Clinical disease

Diagnosis

Control

  • Serological testing of milk (Milk Ring Test) and beef cattle (Rose Bengal Plate Test)
  • Serological tests detect anti-lipopolysaccharide antibodies
  • LPS antigen present in virulent as well as some vaccine strains therefore vaccination may confuse serological testing
  • False positives due to cross-reaction with LPS in other bacteria
  • Vaccination:
    • Strain S19, a live vaccine, stimulating a cell-mediated immune response; vaccination of young animals; interferes with serological testing
    • Newer RB51 vaccine has no LPS O-antigen therefore not detcted by serological tests
    • Live attenuated Brucella melitensis vaccine to protect sheep and goats against B. melitensis
  • Test and slaughter program has eradicated Brucellosis in the UK