Distribution System Operational Deficiencies Coincide with Reported Legionnaires’ Disease Clusters in Flint, Michigan

Rhoads, William J.; Garner, Emily; Ji, Peng; Zhu, Ni; Parks, Jeffrey; Schwake, David Otto; Pruden, Amy; Edwards, Marc

doi:10.1021/acs.est.7b01589

Cited by 60 publications

(84 citation statements)

References 32 publications

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“…No L. pneumophila was detected in small buildings, including single-family residences, in Flint in August 2015. Therefore, if the Flint water switch created more favorable conditions for L. pneumophila to grow in connected water systems (Schwake et al 2016;Rhoads et al 2017), the local conditions of the building water system and water use probably determined whether it could lead to an outbreak. Hence, key to LD outbreak prevention is proper design, operation, and maintenance of specific water systems in buildings.…”

Section: Aerosolmentioning

confidence: 99%

“…The Michigan Department of Health and Human Services (MDHHS) reported an outbreak of LD in Genesee County in 2014 and 2015 and associated the majority of cases with one hospital in Genesee County (MDHHS 2018). Tap water surveys conducted by academic researchers showed L. pneumophila DNA markers were detectable in Flint hospital plumbing in October 2015 but not in Flint homes and small buildings in August 2015 (Schwake et al 2016;Rhoads et al 2017). However, a modeling study (Zahran et al 2018) suggested the outbreak was caused by system-wide proliferation of L. pneumophila in the potable water supply of the City of Flint, enabled by low chlorine levels in the distribution network after the switch to Flint River water as the source.…”

Section: Introductionmentioning

confidence: 99%

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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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Section: Aerosolmentioning

confidence: 99%

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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“…In large buildings and residential drinking water supplied by municipal water systems, detection of Legionella spp. and Legionella pneumophila has been positively associated with warm water temperatures (Borella et al 2004;Lasheras et al 2006;Raki c et al 2012;Rhoads et al 2017), water hardness (Lasheras et al 2006), inorganic contaminants (Borella et al 2004;Raki c et al 2012;Rhoads et al 2017) and water heater type (Alary and Joly 1991;Borella et al 2004) and negatively associated with disinfectant residuals (Borella et al 2004;Rhoads et al 2017). The extent to which these factors are also associated with Legionella proliferation in home plumbing served by private wells is unclear.…”

Section: Introductionmentioning

confidence: 99%

Legionella pneumophila occurrence in drinking water supplied by private wells

Mapili

Pieper

Dai

et al. 2020

Letters in Applied Microbiology

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Unregulated private wells are understudied potential sources of community‐acquired Legionnaires’ disease. Here we conducted a comprehensive survey of 44 homes supplied by private wells in Wake County, North Carolina, quantifying Legionella spp. DNA, Legionella pneumophila DNA, and total bacterial 16S rRNA genes via real‐time polymerase chain reaction in hot and cold drinking water samples, along with culturable L. pneumophila via IDEXX Legiolert in cold drinking water samples. Legionella spp. DNA, L. pneumophila DNA and culturable L. pneumophila were detected in 100, 65·5 and 15·9% of the 44 homes, respectively, and culturable levels were comparable to some municipal surveys applying the same methods. Total coliforms and Escherichia coli were monitored as representative faecal indicators and were found in 20·4 and 0·0% of homes. Within certain sample types, Legionella spp. and L. pneumophila gene copy numbers were positively associated with total bacteria (i.e. total 16S rRNA genes) and water softener use, but were not associated with faecal indicator bacteria, inorganic water parameters or other well characteristics. These findings confirm that occurrence of Legionella and L. pneumophila is highly variable in private wells. Significance and Impact of the Study Legionella is the leading identified cause of waterborne disease outbreaks associated with US municipal water systems. While Legionella is known to occur naturally in groundwater, prior efforts to characterize its occurrence in unregulated private wells are limited to sampling at the wellhead and not in the home plumbing where Legionella can thrive. This work documents much higher levels of Legionella in home plumbing versus water directly from private wells and examines factors associated with higher Legionella occurrence.

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“…The water also disrupted the biofilm that forms on the inner surface of pipes, liberating the bacteria that grow there. Combined with persistently low chlorine levels in parts of the water system and the abundance of iron rust offering a ready microbial food supply, this created a situation conducive to bacterial growth (Byrne et al, ; Rhoads et al, ; Schwake, Garner, Strom, Pruden, & Edwards, ; Zahran et al, ). Efforts to counteract bacterial threats led in some instances to overchlorination, resulting in elevated levels of carcinogenic trihalomethanes (THMs) created through the interaction of chlorine and organic matter.…”

Section: Causes Of the Flint Water Crisismentioning

confidence: 99%

The Flint water crisis

Pauli

2020

WIREs Water

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The Flint water crisis is one of the most significant environmental contamination events in recent American history. In April 2014, the city of Flint, Michigan, while under the control of an emergency manager appointed by the governor, switched its drinking water supply from Lake Huron water treated and distributed by the Detroit Water and Sewerage Department to the Flint River. Failure to treat the water properly at the Flint Water Treatment Plant led to a variety of problems with water quality and public health. Low chlorine in parts of the water system fostered bacterial growth and contributed to an historic outbreak of Legionnaires' disease in 2014-2015. High levels of trihalomethanes brought the city into violation of the Safe Drinking Water Act in late 2014. Finally, systemic lead contamination-revealed through a collaborative sampling effort by local activists and engineers in the summer of 2015resulted from corrosive water eating into lead pipes and other lead-bearing components of Flint's water infrastructure. In October 2015, after considerable public pressure, the city switched back to Lake Huron water. Efforts by federal, state, and local officials to respond to the crisis have focused on restoring water quality, repairing and replacing dangerous and damaged pipes, and addressing public health needs. At the popular level, residents and activists have continued to fight for accountability, reparations, and restoration. A variety of causal explanations for the crisis have been put forward, some focusing on water treatment, regulation, and infrastructure, others on the political context created by state takeover of the city, and others on historical factors like structural racism, deindustrialization, and depopulation.

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Distribution System Operational Deficiencies Coincide with Reported Legionnaires’ Disease Clusters in Flint, Michigan

Cited by 60 publications

References 32 publications

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

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

Legionella pneumophila occurrence in drinking water supplied by private wells

The Flint water crisis

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