1C19.1

ICD-11 MMS 2026-01

Legionnaires disease

Description

Legionnaires’ disease, the pneumonic form, has an incubation period of 2 to 10 days (but up to 16 days has been recorded in some outbreaks). Initially, symptoms are fever, loss of appetite, headache, malaise and lethargy. Some patients may also have muscle pain, diarrhoea and confusion. There is also usually an initial mild cough, but as many as 50% of patients can present phlegm. Blood-streaked phlegm or hemoptysis occurs in about one-third of the patients. The severity of disease ranges from a mild cough to a rapidly fatal pneumonia. Death occurs through progressive pneumonia with respiratory failure and/or shock and multi-organ failure.

Index terms

  • Legionnaires disease
  • Legionnaires pneumonia
  • legionella pneumonia

Exclusions from above levels

  • NE83.1 – Infection arising from device, implant or graft, not elsewhere classified

Sibling codes

  • 1C19.0 – Nonpneumonic Legionnaires' disease
  • 1C19.Z – Legionellosis, unspecified

Foundation entity

Legionnaires disease – http://id.who.int/icd/entity/424434722

Allowed postcoordination axes

Part of: 1C19: Legionellosis › 01: Certain infectious or parasitic diseases