(Pseudoglanders)

  • Caused by Pseudomonas (Malleomyces) pseudomallei, Closely related to P. mallei in horses
  • Causes disease in sheep, goats and pigs, occasionally other species
  • Starts as a pyemia and localises in varius tissues, including the lung as abscessation
    • Encapsulated abscesses contain yellow, caseous or creamy pus
  • Pathogenesis:
    • Infection via ingestion, inhalation or skin wounds from environment
    • Exotoxin, dermonecrotic protease and lecithinase implicated in pathogenicity
    • Strain virulence and host immunosuppression important
  • Clinical infections:
    • Opportunistic infection with stress and immunosuppression predisposing to disease
    • Abscesses develop in many organs including lungs, spleen, liver, joints, CNS, upper respiratory tract
    • Chronic, debilitating, progressive disease with long incubation period
    • Many animal species susceptible
    • Referred to as pseudoglanders in horses
  • Diagnosis:
    • Specimens: pus from abscesses, affected tissues, blood
    • Fluorescent antibody technique on tissue smears
    • Blood agar and MacConkey agar plates, incubated aerobically
    • Colonies have musty smell
    • Lactose fermentation on MacConkey
    • Slide agglutination
    • ELISA, complement fixation and indirect haemagglutination tests for serum antibodies
  • Treatment/control: slaughter of infected animals where exotic
  • Pneumonia and arthritis are the most common presentation