title: Confirmed and Potential Sources of Legionella Reviewed.
abstract: Legionella bacteria are ubiquitous in natural matrices and man-made systems. However, it is not always clear if these reservoirs can act as source of infection resulting in cases of Legionnaires' disease. This review provides an overview of reservoirs of Legionella reported in the literature, other than drinking water distribution systems. Levels of evidence were developed to discriminate between potential and confirmed sources of Legionella. A total of 17 systems and matrices could be classified as confirmed sources of Legionella. Many other man-made systems or natural matrices were not classified as a confirmed source, since either no patients were linked to these reservoirs or the supporting evidence was weak. However, these systems or matrices could play an important role in the transmission of infectious Legionella bacteria; they might not yet be considered in source investigations, resulting in an underestimation of their importance. To optimize source investigations it is important to have knowledge about all the (potential) sources of Legionella. Further research is needed to unravel what the contribution is of each confirmed source, and possibly also potential sources, to the LD disease burden.
authors.affiliation: †National Institute for Public Health and the Environment, A. van Leeuwenhoeklaan 9, 3721 MA Bilthoven, The Netherlands.
authors.forename: Eri
authors.initials: E
authors.lastname: van Heijnsbergen
authors.affiliation: †National Institute for Public Health and the Environment, A. van Leeuwenhoeklaan 9, 3721 MA Bilthoven, The Netherlands.
authors.forename: Johanna A C
authors.initials: JA
authors.lastname: Schalk
authors.affiliation: ‡Regional Public Health Laboratory Kennemerland, Haarlem, Boerhaavelaan 26, 2035 RC Haarlem, The Netherlands.
authors.forename: Sjoerd M
authors.initials: SM
authors.lastname: Euser
authors.affiliation: †National Institute for Public Health and the Environment, A. van Leeuwenhoeklaan 9, 3721 MA Bilthoven, The Netherlands.
authors.forename: Petra S
authors.initials: PS
authors.lastname: Brandsema
authors.affiliation: ‡Regional Public Health Laboratory Kennemerland, Haarlem, Boerhaavelaan 26, 2035 RC Haarlem, The Netherlands.
authors.forename: Jeroen W
authors.initials: JW
authors.lastname: den Boer
authors.affiliation: †National Institute for Public Health and the Environment, A. van Leeuwenhoeklaan 9, 3721 MA Bilthoven, The Netherlands.|§Institute for Risk Assessment Sciences, Utrecht University, Yalelaan 2, 3584 CM Utrecht, The Netherlands.
authors.forename: Ana Maria
authors.initials: AM
authors.lastname: de Roda Husman
mesh_terms: D004197:Disease Reservoirs; D006801:Humans; D007875:Legionella / Q000302:isolation & purification*; D007876:Legionellosis / Q000453:epidemiology* / Q000382:microbiology; D007877:Legionnaires' Disease / Q000453:epidemiology / Q000382:microbiology; D014871:Water Microbiology