Legionellosis is associated with two clinically and epidemiologically distinct illnesses: Legionnaires’ disease, which is characterized by fever, myalgia, cough, and clinical or radiographic pneumonia; and Pontiac fever, a milder illness without pneumonia.
A clinically compatible case that meets at least one of the presumptive (suspected) laboratory criteria.
A clinically compatible case that meets at least one of the confirmatory laboratory criteria.
The 2005 case definition appearing on this page was first published in the 2005 Council of State and Territorial Epidemiologists (CSTE) position statement 05-ID-011 and then re-published in the 2009 CSTE position statement 09-ID-452. The case definitions in the 2005 and 2009 CSTE position statements are identical.