<i>Naegleria fowleri:</i> An emerging drinking water pathogen

Bartrand, Timothy A.; Causey, Jonathan Jake; Clancy, Jennifer L.

doi:10.5942/jawwa.2014.106.0140

Cited by 42 publications

(38 citation statements)

References 90 publications

(127 reference statements)

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“…Given that the end response is death with a 100% percent mortality rate, it may be wise to pick a lower range of critical concentration (0.29 CFU/L) for developing standards, and the same can be applied for developing standards for other scenarios related to N. fowleri. Previous studies found the detection limit of N. fowleri to be 1-50 cells per reaction using both the nested and real-time PCR assays [19]. Considering 50 cells of N. fowleri and 200 L as a volume of water sample to be filtered, the detection limit of N. fowleri would be 0.25 N. fowleri/L which is also aligned with our calculated boundary concentration of N. fowleri using the annual risk metric.…”

Section: Discussionsupporting

confidence: 87%

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Reverse QMRA as a Decision Support Tool: Setting Acceptable Concentration Limits for Pseudomonas aeruginosa and Naegleria fowleri

Rasheduzzaman

Singh

Haas

et al. 2019

Water

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Opportunistic premise plumbing pathogens such as Pseudomonas aeruginosa and Naegleria fowleri are a growing concern in building water systems because of their potential risks to human health. The aim of this study was to determine the critical concentrations of P. aeruginosa and N. fowleri in water that are associated with meaningful public health risks. To determine these concentrations, a reverse quantitative microbial risk assessment (QMRA) was conducted. Environmental concentrations of P. aeruginosa and N. fowleri corresponding to the risk target of one micro-disability-adjusted life year (DALY) per person per year and 10−4 annual risks of illness were calculated for several applicable exposure scenarios. To calculate the concentration of P. aeruginosa, cleaning contact lenses with potentially contaminated tap water in the absence of an appropriate cleaning solution was considered. For N. fowleri, two exposure scenarios, recreational exposure (swimming) and nasal cleansing (via the use of a neti pot™ or similar device) were considered. The highest critical concentration for P. aeruginosa was found to be 33 CFU/L with a 95% confidence interval of (2.0, 118) for the drop exposure scenario using the 10−4 annual risk target. For N. fowleri, based on the DALY approach, critical concentrations were 0.000030 N. fowleri/L for swimming and 0.00000060 N. fowleri/L for neti pot™ use scenario. Considering heat inactivation, the critical concentration limits for P. aeruginosa using the DALY approach and the 10−4 annual risk target approach were found to be 0.55 CFU/L and 55 CFU/L, respectively. For N. fowleri, the 10−4 annual risk target approach resulted in 0.022 N. fowleri/L and the DALY approach resulted in 0.00000064 N. fowleri/L for the neti pot™ scenario. For P. aeruginosa, N50 (the median infective dose) and alpha (α) contributed the most and contact rates the least to the variability and uncertainty of the estimates for all the scenarios. For N. fowleri, N50 and contact rates contributed the most and α the least to the variability and uncertainty to calculate the concentrations for all the scenarios. The QMRA framework implemented in this research can be used to incorporate more information regarding opportunistic pathogens to inform management decisions, and to prioritize the best interventions regarding estimated reduction in infections caused by opportunistic pathogens.

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Section: Discussionsupporting

confidence: 87%

“…N. fowleri infections can only occur when contaminated water enters a person's body through the nose [18]. PAM has an high fatality rate, up to 98% [19,20]. Infection occurs when N. fowleri travels through the nose into the brain through the cribriform plate and begins consuming brain cells (i.e., astrocytes and neurons) [21,22].…”

Section: Introductionmentioning

confidence: 99%

Reverse QMRA as a Decision Support Tool: Setting Acceptable Concentration Limits for Pseudomonas aeruginosa and Naegleria fowleri

Rasheduzzaman

Singh

Haas

et al. 2019

Water

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“…Over the last decade, the interest in premise plumbing from the water industry has increased. Numerous studies have investigated different issues surrounding premise plumbing, such as corrosion [78][79][80][81] and the growth of opportunistic pathogens [82][83][84][85][86][87][88]. Premise plumbing systems are an area of the distribution system that can be overlooked by water utilities, since most premise plumbing systems are not owned or maintained by the utility and most drinking water regulations do not address premise plumbing, with the exception of the Lead and Copper Rule (LCR).…”

Section: Nitrification In Premise Plumbingmentioning

confidence: 99%

Nitrification in Premise Plumbing: A Review

Bradley

Haas

Sales

2020

Water

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Nitrification is a major issue that utilities must address if they utilize chloramines as a secondary disinfectant. Nitrification is the oxidation of free ammonia to nitrite which is then further oxidized to nitrate. Free ammonia is found in drinking water systems as a result of overfeeding at the water treatment plant (WTP) or as a result of the decomposition of monochloramine. Premise plumbing systems (i.e., the plumbing systems within buildings and homes) are characterized by irregular usage patterns, high water age, high temperature, and high surface-to-volume ratios. These characteristics create ideal conditions for increased chloramine decay, bacterial growth, and nitrification. This review discusses factors within premise plumbing that are likely to influence nitrification, and vice versa. Factors influencing, or influenced by, nitrification include the rate at which chloramine residual decays, microbial regrowth, corrosion of pipe materials, and water conservation practices. From a regulatory standpoint, the greatest impact of nitrification within premise plumbing is likely to be a result of increased lead levels during Lead and Copper Rule (LCR) sampling. Other drinking water regulations related to nitrifying parameters are monitored in a manner to reduce premise plumbing impacts. One way to potentially control nitrification in premise plumbing systems is through the development of building management plans.

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“…This free-living amoebae (FLA) has been detected in drinking water systems [26,88,90], with domestic water supply systems being implicated in a South Australian outbreak of the disease in children exposed to bathing water [91]. N. fowleri has also been detected in recreational waters [92], premise plumbing [93], irrigation systems [94] and rain water tanks in Queensland [95]. This pathogen is resistant to standard chlorine disinfection concentrations [96][97][98].…”

Section: N Fowlerimentioning

confidence: 99%

Health Risks Associated with the Use of Water Mist Systems as a Cooling Intervention in Public Places in the Pilbara Region of Western Australia

Masaka¹,

Reed²,

Ooosthuizen³

et al. 2019

Preprint

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The exposure of people to opportunistic premise plumbing pathogens (OPPPs) such as Legionella, Mycobacterium and Pseudomonas in aerosolised water has been linked to opportunistic infections. Water mist systems (WMS) that are used to cool public places by flash evaporation of tiny water aerosols are gaining prominence in hot climatic regions of Australia. Their potential to be colonised by OPPPs has not been adequately studied. The public health impact of OPPPs is significant, as Legionella caused 63% of waterborne disease case hospitalisations in the United States associated with drinking water systems during 2013–2014, and the incidence of Mycobacterium avium over the same period was 647 cases per 100,000. As WMS are part of premise plumbing, they have structural characteristics that can promote biofilm formation, as well as the presence of free-living amoebae (FLA), low residual disinfection levels, elevated water temperatures and oligotrophic conditions, all of which can promote OPPP inhabitancy. This review highlights the potential public health risks of using WMS as a cooling intervention in public places and advocates for their regulation in places of public assembly and entertainment.

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Naegleria fowleri: An emerging drinking water pathogen

Cited by 42 publications

References 90 publications

Reverse QMRA as a Decision Support Tool: Setting Acceptable Concentration Limits for Pseudomonas aeruginosa and Naegleria fowleri

Reverse QMRA as a Decision Support Tool: Setting Acceptable Concentration Limits for Pseudomonas aeruginosa and Naegleria fowleri

Nitrification in Premise Plumbing: A Review

Health Risks Associated with the Use of Water Mist Systems as a Cooling Intervention in Public Places in the Pilbara Region of Western Australia

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