Waterborne Disease Outbreaks Associated With Environmental and Undetermined Exposures to Water — United States, 2013–2014

McClung, R. Paul; Roth, David M.; Vigar, Marissa; Roberts, Virginia A.; Kahler, Amy M.; Cooley, Laura A.; Hilborn, Elizabeth D.; Wade, Timothy J.; Fullerton, Kathleen E.; Yoder, Jonathan S.; Hill, Vincent R.

doi:10.15585/mmwr.mm6644a4

Cited by 45 publications

(22 citation statements)

References 5 publications

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“…These concerns are driven by the potential for water quality to deteriorate in building plumbing systems due to chemical and biological reactions in the bulk water and interactions with pipe surfaces [1]. One manner in which water quality may deteriorate in buildings is through the growth of opportunistic premise plumbing pathogens (OPPPs) (i.e., Legionella pneumophila [2,3], non-tuberculous mycobacteria, Pseudomonas aeruginosa, etc. ), which can be enabled by the loss of residual disinfectant over extended residence times.…”

Section: Introductionmentioning

confidence: 99%

Managing Water Quality in Premise Plumbing: Subject Matter Experts’ Perspectives and a Systematic Review of Guidance Documents

Singh

Hamilton

Rasheduzzaman

et al. 2020

Water

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Although many guidance documents have been developed to inform the design and operation of building water systems to ensure safe water quality, there is a lack of consensus on some topics. This study interviewed 22 subject matter experts (SMEs) to identify topics of concern for managing water quality in buildings and compared SME views with information available on these topics in 15 systematically screened important guidance documents. The study found 18 design and 11 operational topics as critical for managing water quality in buildings. No one guidance document addressed all these topics, suggesting that a compendium of available guidance is needed. SMEs most frequently recommended temperature and residual disinfectant measurements as good parameters for monitoring overall building water quality. Both SME and guidance document recommendations for temperature for controlling opportunistic pathogen growth were reasonably consistent with water heater setpoint >60 °C. However, hot water temperature recommendations varied between 50 and 55 °C for other locations (i.e., the water temperature at the tap or end of the return loop). On the contrary, recommendations for disinfectant residual levels (0.2–2.0 mg/L), flushing frequency (1–14 days), and allowable time for hot water to reach the tap (10–60 s) were not consistent. While this study was able to reconcile diverging views on some of the water quality topics, such as identifying common guidance for water heater set point to at least 60 °C, it also highlights lack of definitive guidance on other critical topics, such as residual level, flushing frequency, hot water time to tap, and the use of thermostatic mixing valves, indicating that these are significant knowledge gaps that need further investigation. The study concludes that there is a need for developing evidence-based guidance, particularly on the topics where expert opinions diverged.

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Section: Introductionmentioning

confidence: 99%

Managing Water Quality in Premise Plumbing: Subject Matter Experts’ Perspectives and a Systematic Review of Guidance Documents

Singh

Hamilton

Rasheduzzaman

et al. 2020

Water

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“…Although most LD cases are sporadic (CDC 2011), our understanding of the sources of LD comes almost entirely from outbreaks. L. pneumophila is now responsible for the majority (57%-63%) of waterborne disease outbreaks in the United States and for all of the outbreak-associated deaths (Benedict et al 2017;McClung et al 2017). Most outbreaks of LD have been associated with exposure to aerosols from warm water systems in large buildings that house vulnerable populations, such as hospitals and long-term care facilities (Garrison et al 2016).…”

Section: Introductionmentioning

confidence: 99%

Multiple Sources of the Outbreak of Legionnaires’ Disease in Genesee County, Michigan, in 2014 and 2015

Smith

Huss

Dorevitch

et al. 2019

Environ Health Perspect

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BACKGROUND: A community-wide outbreak of Legionnaires' disease (LD) occurred in Genesee County, Michigan, in 2014 and 2015. Previous reports about the outbreak are conflicting and have associated the outbreak with a change of water source in the city of Flint and, alternatively, to a Flint hospital. OBJECTIVE: The objective of this investigation was to independently identify relevant sources of Legionella pneumophila that likely resulted in the outbreak. METHODS: An independent, retrospective investigation of the outbreak was conducted, making use of public health, health care, and environmental data and whole-genome multilocus sequence typing (wgMLST) of clinical and environmental isolates. RESULTS: Strong evidence was found for a hospital-associated outbreak in both 2014 and 2015: a) 49% of cases had prior exposure to Flint hospital A, significantly higher than expected from Medicare admissions; b) hospital plumbing contained high levels of L. pneumophila; c) Legionella control measures in hospital plumbing aligned with subsidence of hospital A-associated cases; and d) wgMLST showed Legionella isolates from cases exposed to hospital A and from hospital plumbing to be highly similar. Multivariate analysis showed an increased risk of LD in 2014 for people residing in a home that received Flint water or was located in proximity to several Flint cooling towers. DISCUSSION: This is the first LD outbreak in the United States with evidence for three sources (in 2014): a) exposure to hospital A, b) receiving Flint water at home, and c) residential proximity to cooling towers; however, for 2015, evidence points to hospital A only. Each source could be associated with only a proportion of cases. A focus on a single source may have delayed recognition and remediation of other significant sources of L. pneumophila.

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“…L. pneumophila is the main causative agent of legionellosis—pulmonary morbid forms normally are acquired by inhalation of aerosols containing the bacterium—which occurs in various pathologies among which pneumonia is the most severe form [1]. Legionellosis is considered a water-borne disease [2] and Legionella is among the main emerging pathogenic bacteria of the last fifty years [3]. As part of the normal aquatic microflora, Legionella can be found both in natural and man-made aquatic environments, surviving free, in biofilms or as a parasite of protozoa [4–6].…”

Section: Introductionmentioning

confidence: 99%

Environmental surveillance and spatio-temporal analysis of Legionella spp. in a region of northeastern Italy (2002–2017)

et al. 2019

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Legionella spp . are considered an important cause of potentially preventable morbidity and mortality, making environmental surveillance a crucial component of risk assessment plans. In this work, 20,319 water samples were collected in 3,983 environmental surveys during a 16-year period by ARPA, the Regional Agency for Environmental Protection, Friuli Venezia Giulia, and the results were studied to better understand the diffusion mechanisms of Legionella . The data showed a strong seasonal signal, a prevalence of L. pneumophila serogroup 2–15 in most environments (63% of positive samples), a prevalence of L. pneumophila serogroup 1 in swimming pool-associated environments (82% of positive samples), a persistent presence of Legionella in hospitals and a recurrent presence of Legionella in other facilities such as hotels, possibly years after interventions, highlighting the difficulty of eradicating the bacteria. Retrospective spatio-temporal analyses on geocoded historical data were carried out with SaTScan using an ordinal model with risk as a covariate to identify potential clusters with an excess of cases in the higher-risk categories. Although no outbreaks occurred during the period of study, such analyses identified spatially restricted zones with unusual contamination, which sometimes were also areas in which several surveys triggered by notifications of clinical cases were performed. Simulations of periodic prospective analyses permitted the assessment of the efficacy of the method in early detection of such clusters. The proposed method may be a useful tool in environmental surveillance, prevention and control of Legionella .

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Waterborne Disease Outbreaks Associated With Environmental and Undetermined Exposures to Water — United States, 2013–2014

Cited by 45 publications

References 5 publications

Managing Water Quality in Premise Plumbing: Subject Matter Experts’ Perspectives and a Systematic Review of Guidance Documents

Managing Water Quality in Premise Plumbing: Subject Matter Experts’ Perspectives and a Systematic Review of Guidance Documents

Multiple Sources of the Outbreak of Legionnaires’ Disease in Genesee County, Michigan, in 2014 and 2015

Environmental surveillance and spatio-temporal analysis of Legionella spp. in a region of northeastern Italy (2002–2017)

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