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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