• Notifiable, Severe pneumonia (10% fatality rate) caused by Legionella bacteria (L pneumophila.)
  • Transmission via water aerosol
  • Incubation 2 - 14 days
  • Not transmitted from person-to-person


Risk factors:

  • Age, male, smoking
  • Chronic lung disease
  • Immunodeficiencies (incl.diabetes)

Differential Dx

  • Any severe community acquired or nosocomial pneumonia


  • Sputum C&S
  • Urine: Ag detection
  • Dx confirmed by culture or x4 rise in serum antibodies or detection of legionella DNA by PCR


  • Supportive care incl. early ventilation as required
  • Beware occult dehydration and hypoperfusion
  • Contact ID/respiratory team for advice about azothromycin, fluoroquinolones or macrolids
  • Inform microbiology and public health of your working Dx

Content by Dr Íomhar O' Sullivan . Last review Dr ÍOS 10/06/21.