Background: Pontiac fever is usually described in epidemic settings. Detection of Pontiac fever is a marker of an environmental contamination by Legionella and should thereby call for prevention measures in order to prevent outbreak of Legionnaire's disease. The objective of this study is to propose an operational definition of Pontiac fever that is amenable to epidemiological surveillance and investigation in a non epidemic setting.

Our results suggest that measurement of Fe(NO), a simple and reproducible test, could be useful in the screening of BHR in workers newly exposed to agents known to cause occupational asthma.

The water and threshold values identified in this research could be used to inform guidance measures aimed at protecting institutionalised older people from Legionnaires' disease. Immunosuppressive therapy in the same population group can significantly enhance susceptibility to Legionella bacteria.