Statewide Quantitative Microbial Risk Assessment for Waterborne Viruses, Bacteria, and Protozoa in Public Water Supply Wells in Minnesota

Abstract

Infection risk from waterborne pathogens can be estimated via quantitative microbial risk assessment (QMRA) and forms an important consideration in the management of public groundwater systems. However, few groundwater QMRAs use site-specific hazard identification and exposure assessment, so prevailing risks in these systems remain poorly defined. We estimated the infection risk for 9 waterborne pathogens based on a 2-year pathogen occurrence study in which 964 water samples were collected from 145 public wells throughout Minnesota, USA. Annual risk across all nine pathogens combined was 3.3 × 10 –1 (95% CI: 2.3 × 10 –1 to 4.2 × 10 –1 ), 3.9 × 10 –2 (2.3 × 10 –2 to 5.4 × 10 –2 ), and 1.2 × 10 –1 (2.6 × 10 –2 to 2.7 × 10 –1 ) infections person –1 year –1 for noncommunity, nondisinfecting community, and disinfecting community wells, respectively. Risk estimates exceeded the U.S. benchmark of 10 –4 infections person –1 year –1 in 59% of well-years, indicating that the risk was widespread. While the annual risk for all pathogens combined was relatively high, the average daily doses for individual pathogens were low, indicating that significant risk results from sporadic pathogen exposure. Cryptosporidium dominated annual risk, so improved identification of wells susceptible to Cryptosporidium contamination may be important for risk mitigation.

Study design and methods of the Wells and Enteric disease Transmission (WET) Trial: a randomised controlled trial

“…If the burden estimates from the QMRA and RCT are similar, the results of this study would provide support for the use of QMRA for estimating the burden of disease attributed to private well water contamination 45. Moreover, most groundwater QMRAs use assumed pathogen values rather than measurements,46 51 and few studies that use pathogen measurements consider more than one pathogen 45 47 52. Our QMRA is based on 270 measurements of each pathogen, so risk estimated by QMRA represents many of the viral, bacterial and protozoan pathogens that can cause the GI recorded by our epidemiological observations, allowing a robust comparison.…”

“…Use QMRA to quantify the risk of GI associated with consuming untreated private well water and compare to Aim 1. Using approaches similar to other QMRA models of risk from well water consumption,45–47 a multi-pathogen QMRA model will be developed using the untreated well water quality data collected from the subcohort of 180 households (270 samples). The following pathogens will be included in the QMRA: adenovirus, enterovirus, norovirus, diarrheagenic E. coli , Campylobacter , Salmonella , Shigella , Cryptosporidium , Giardia.…”

Prevalence and whole‐genome sequencing characterization of Salmonella in urban karst groundwater and predominantly groundwater‐fed surface waters for serotypes and antimicrobial resistance

“…The groundwater system is an important contributor to drinking water sources via outlet springs feeding into surface streams. The detection of Salmonella in the groundwater features that mainly feed into a surface river used as a source of drinking water for the local community will have public health consequences if the water is not properly treated before distribution (Burch et al, 2022(Burch et al, , 2021Hynds et al, 2014;Levantesi et al, 2012;Murphy et al, 2017;Owens et al, 2020).…”

Quantitative Risk Assessment of Five Foodborne Viruses in Shellfish Based on Multiplex qPCR

“…The use of a comprehensive risk assessment and risk management can be effective in improving the safety of food [ 13 ]. Quantitative Microbial Risk Assessments (QMRAs) generate an understanding of the risks associated with edible shellfish by characterizing the pathogen occurrence in shellfish and evaluating how well these pathogens are controlled by short cooking [ 12 ].…”