Wastewater surveillance offers a rapid evaluation of SARS-CoV-2 transmission in a community. We describe how a community group, the Yarmouth Wastewater Testing Team (YWTT), in Yarmouth, Maine, (population 8,990) utilized an asset-based community design framework to organize and manage a program to monitor SARS-CoV-2 RNA concentrations. From September 22, 2020 through June 8, 2021, the YWTT disseminated weekly reports of the wastewater results and reported COVID-19 cases within the Yarmouth postal code. After high and increasing SARS-CoV-2 RNA concentrations, the YWTT issued two community advisories to encourage extra care to reduce exposure. Correlations between SARS-CoV-2 RNA concentrations and COVID-19 cases were stronger the week after sampling, and the average of the COVID-19 cases during the week of sampling and the following week, indicating that surveillance provided advance notice of cases. A 10% increase in SARS-CoV-2 RNA concentrations was associated with a 13.29% increase in the average number of weekly reported cases of COVID-19 during the week of sampling and the following week (R2 = 0.42; p < 0.001). Adjusting for viral recovery (December 21, 2020 through June 8, 2021), improved R2 from 0.60 to 0.68. Wastewater surveillance was an effective tool for the YWTT to quickly respond to viral transmission.

Water quality models use log-linear decay to estimate the inactivation of fecal indicator bacteria (FIB). The decay of molecular measurements of FIB does not follow a log-linear pattern. This study examined the factors associated with the persistence of Escherichia coli uidA, enterococci 23S rDNA, and Bacteroides thetataiotaomicron 1,6 alpha mannanase in microcosms containing 10% (vol/vol) sewage spiked river water stored at 4°C for up to 337 days. The study estimated the markers' persistence with log-linear models (LLMs) to the best-fit models, biphasic exponential decay (BI3) and log-logistic (JM2) and compared the estimates from the models. Concentrations of B. thetataiotaomicon decreased to levels below detection after 31 days in storage and were not fit to models. BI3 and JM2 were fit to E. coli and enterococci, respectively. LLMs had larger Bayesian information criterion values than best-fit models, indicating poor fit. LLMs over-estimated the time required for 90% reduction of the indicators (T₉₀) and did not consider dynamic rates of decay. Time in storage and indicator species were associated with the persistence of the markers (p < 0.001). Using the T₉₀ values of the best-fit models, enterococci was the most persistent indicator. Our data supports the use of best fit models with dynamic decay rates in water quality models to evaluate the decay of enteric markers.

Figure outlines the flow of wastewater from the community where a norovirus GII outbreak occurred to two wastewater treatment facilities (Wastewater Treatment Facilities A and B). Plots are shown to demonstrate that norovirus GII was measured at these wastewater treatment facilities over time. Norovirus is a leading cause of acute gastrointestinal illness (AGI). Norovirus is not notifiable in the United States; therefore, health departments typically only receive reports of norovirus outbreaks. While wastewater surveillance has been demonstrated to be useful for tracking community norovirus case reports, its value during outbreak investigations is less understood. This study evaluates the impact of a single norovirus outbreak on wastewater measurements in a community. Norovirus genogroup 2 (GII) concentrations were measured at two wastewater treatment facilities (WWTFs) near a restaurant experiencing a norovirus GII outbreak (Restaurant A). The largest increase in norovirus GII RNA concentrations (increase of 13,111.8 gc/mL) at the WWTF serving Restaurant A (WWTF A) occurred on the same day most (44%) outbreak case patients reported symptom onset. This increase occurred 1 day before the outbreak was reported to public health, 2 days before norovirus was identified in clinical specimens, and 3 days before clinical specimens were genotyped at the public health laboratory. At a second local WWTF, WWTF B, norovirus GII RNA concentrations also increased at the same time but peaked 2 days after WWTF A. These findings suggest wastewater measurements can serve as a leading indicator of norovirus outbreaks and inform outbreak response efforts.

Opportunistic pathogens such as Legionella spp. (including Legionella pneumophila) and Mycobacterium avium complex (MAC) are common within building plumbing systems. These opportunistic pathogens can be amplified by conditions of premise plumbing, including diminished disinfectant residual, high surface area to volume ratios resulting from smaller-diameter pipes, and elevated water temperatures compared to distribution mains. Understanding the risk of infection from these pathogens through common exposure pathways is critical to addressing and mitigating human health risks. This study presents a quantitative microbial risk assessment (QMRA) framework for inhalation exposures to aerosolized Legionella spp. and MAC during three common residential water uses, showering, toilet flushing, and handwashing. Inhalation risks were quantified by Monte Carlo simulation of bulk water pathogen concentrations, size-specific aerosol generation, respiratory deposition, and dose–response assessment. Because co-located paired measurements for Legionella spp. and MAC were limited, organism-specific results reflect modeled concentration distributions and dose–response assumptions rather than direct field co-occurrence comparisons. Across modeled scenarios, Legionella spp. presents a higher risk of infection than MAC. Risks were greatest for shower exposures and lowest for handwashing. Correlation analysis shows that risks are most sensitive to exposure dose (ρ > 0.99) and the concentration of pathogen in bulk water (ρ > 0.96).