Legionnaires’ disease is an uncommon form of pneumonia. The disease has no particular clinical features that clearly distinguish it from other types of pneumonia, and laboratory investigations must therefore be carried out in order to obtain a diagnosis.
Probable case: Any person meeting the clinical criterion AND at least one laboratory criterion for a probable case
Confirmed case: Any person meeting the clinical criterion AND at least one laboratory criterion for a confirmed case
Any person with pneumonia
Laboratory criteria for case confirmation
At least one of the following three:
- Isolation of Legionella spp. from respiratory secretions or any normally sterile site
- Detection of Legionella pneumophila antigen in urine
- Significant rise in specific antibody level to Legionella pneumophila serogroup 1 in paired serum samples
Laboratory criteria for a probable case
At least one of the following four:
- Detection of Legionella pneumophila antigen in respiratory secretions or lung tissue e.g. by DFA staining using monoclonal-antibody derived reagents
- Detection of Legionella spp. nucleic acid in respiratory secretions, lung tissue or any normally sterile site
- Significant rise in specific antibody level to Legionella pneumophila other than serogroup 1 or other Legionella spp. in paired serum samples
- Single high level of specific antibody to Legionella pneumophila serogroup 1 in serum
Commission Implementing Decision 2012/506/EU of 8 August 2012, amending Decision 2002/253/EC laying down case definitions for reporting communicable diseases to the Community network under Decision No 2119/98/EC of the European Parliament and of the Council.