Assessment of relative potential for Legionella species or surrogates inhalation exposure from common water uses

Hines, Stephanie A.; Chappie, Daniel J.; Lordo, Robert A.; Miller, Brian D.; Janke, Robert; Lindquist, H. Alan; Fox, Kim R.; Ernst, Hiba; Taft, Sarah C.

doi:10.1016/j.watres.2014.02.013

Cited by 48 publications

(28 citation statements)

References 36 publications

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“…Hines et al 95 reviews in detail water sources that have been identified to contain Legionella and concentrations or emission factors from those sources. Major sources in the built environment include plumbing sources (e.g., showers, faucets, and toilets), cooling towers, respiratory devices (e.g., humidifiers, vaporizers, and nebulizers), swimming pools (including spas/hot tubs and whirlpools), steam-producing appliances, and ornamental fountains.…”

Section: Introductionmentioning

confidence: 99%

Ten questions concerning the aerosolization and transmission of Legionella in the built environment

Prussin

Schwake

Marr

2017

Building and Environment

101

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Legionella is a genus of pathogenic Gram-negative bacteria responsible for a serious disease known as legionellosis, which is transmitted via inhalation of this pathogen in aerosol form. There are two forms of legionellosis: Legionnaires' disease, which causes pneumonia-like symptoms, and Pontiac fever, which causes influenza-like symptoms. Legionella can be aerosolized from various water sources in the built environment including showers, faucets, hot tubs/swimming pools, cooling towers, and fountains. Incidence of the disease is higher in the summertime, possibly because of increased use of cooling towers for air conditioning systems and differences in water chemistry when outdoor temperatures are higher. Although there have been decades of research related to Legionella transmission, many knowledge gaps remain. While conventional wisdom suggests that showering is an important source of exposure in buildings, existing measurements do not provide strong support for this idea. There has been limited research on the potential for Legionella transmission through heating, ventilation, and air conditioning (HVAC) systems. Epidemiological data suggest a large proportion of legionellosis cases go unreported, as most people who are infected do not seek medical attention. Additionally, controlled laboratory studies examining water-to-air transfer and source tracking are still needed. Herein, we discuss ten questions that spotlight current knowledge about Legionella transmission in the built environment, engineering controls that might prevent future disease outbreaks, and future research that is needed to advance understanding of transmission and control of legionellosis.

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Section: Introductionmentioning

confidence: 99%

Ten questions concerning the aerosolization and transmission of Legionella in the built environment

Prussin

Schwake

Marr

2017

Building and Environment

101

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“…Transmission of Legionella to humans occurs through the inhalation of contaminated aerosols or aspiration of contaminated water (Blatt et al, 1993; Bartram et al, 2007; Cassier et al, 2013; Hines et al, 2014). Worldwide, incidences of Legionnaires’ disease are often linked to manufactured water systems (Beer et al, 2015) and in the United States, Legionella is the primary cause of all drinking water related outbreaks (Centers for Disease Control and Prevention, 2013).…”

Section: Introductionmentioning

confidence: 99%

Legionella Persistence in Manufactured Water Systems: Pasteurization Potentially Selecting for Thermal Tolerance

2017

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Legionella is an opportunistic waterborne pathogen of increasing public health significance. Pasteurization, otherwise known as super-heat and flush (increasing water temperature to above 70°C and flushing all outlets), has been identified as an important mechanism for the disinfection of Legionella in manufactured water systems. However, several studies have reported that this procedure was ineffective at remediating water distribution systems as Legionella was able to maintain long term persistent contamination. Up to 25% of L. pneumophila cells survived heat treatment of 70°C, but all of these were in a viable but non-culturable state. This demonstrates the limitations of the culture method of Legionella detection currently used to evaluate disinfection protocols. In addition, it has been demonstrated that pasteurization and nutrient starvation can select for thermal tolerant strains, where L. pneumophila was consistently identified as having greater thermal tolerance compared to other Legionella species. This review demonstrates that further research is needed to investigate the effectiveness of pasteurization as a disinfection method. In particular, it focuses on the potential for pasteurization to select for thermal tolerant L. pneumophila strains which, as the primary causative agent of Legionnaires disease, have greater public health significance compared to other Legionella species.

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“…Recent studies focus on the survival of Legionella bacteria and amoeba in biofilms (Konishi et al, 2006, Buse et al, 2014. Other research projects look at the exposure mechanics once a system is contaminated (Schoen et al, 2011, Hines et al, 2014 or focus on the influence of tubing material (Van Der Kooij et al, 2005) etc. The literature about decontamination strategies for contaminated systems is similarly scattered as that on the proliferation of Legionella, usually focusing on a single decontamination technique and tested in limited lab configurations or in case studies (Lehtola et al, 2005).…”

Section: State Of the Artmentioning

confidence: 99%

Simulation of Legionella concentration in domestic hot water: comparison of pipe and boiler models

Kenhove

Backer

Janssens

et al. 2019

Journal of Building Performance Simulation

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The energy needed for the production of domestic hot water represents an important share in the total energy demand of well-insulated and airtight buildings. Domestic hot water is produced, stored and distributed above 60°C to kill Legionella pneumophila. This elevated temperature is not necessary for domestic hot water applications and has a negative effect on the efficiency of hot water production units. In this paper, system component models are developed/updated with L. pneumophila growth equations. For that purpose different existing Modelica pipe and boiler models are investigated to select useful models that could be extended with equations for simulation of bacterial growth. In future research, HVAC designers will be able to investigate the contamination risk for L. pneumophila in the design phase of a hot water system, by implementing the customized pipe and boiler model in a hot water system model. Additionally it will be possible, with simulations, to optimise temperature regimes and estimate the energy saving potential without increasing contamination risk. Keywords: domestic hot water (DHW), Legionella pneumophila, pipe model, boiler model, contamination risk, energy use Attachment Annex 1-Approach 1 to determine multiplication time (y and yb) Annex 2-Approach 2 to determine multiplication time (y and yb) Annex 3-Explanation of conservation equations Annex 4-Pipe and boiler models: reasons for non-retention Annex 5-Simulation model components used in pipe and boiler component Annex 6-Understanding the simulation log basics

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Assessment of relative potential for Legionella species or surrogates inhalation exposure from common water uses

Cited by 48 publications

References 36 publications

Ten questions concerning the aerosolization and transmission of Legionella in the built environment

Ten questions concerning the aerosolization and transmission of Legionella in the built environment

Legionella Persistence in Manufactured Water Systems: Pasteurization Potentially Selecting for Thermal Tolerance

Simulation of Legionella concentration in domestic hot water: comparison of pipe and boiler models

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