RESUMO
Wastewater-based epidemiology (WBE) is an environmental approach to monitor community health through the analysis of sewage. The COVID-19 pandemic catalyzed scientists and public health professionals to revisit WBE as a tool to optimize resource allocation to mitigate disease spread and prevent outbreaks. Some studies have highlighted the value of WBE programs that coordinate with public health professionals; however, the details necessary for implementation are not well-characterized. To respond to this knowledge gap, this article documents the framework of a successful WBE program in Arizona, titled Wastewater Analysis for Tactical Epidemiological Response Systems (WATERS), detailing the developed structure and methods of communication that enabled public health preparedness and response actions. This communication illustrates how program operations were employed to reduce outbreak severity. The structure outlined here is customizable and may guide other programs in the implementation of WBE as a public health tool.
Assuntos
COVID-19 , Saúde Pública , Águas Residuárias , Humanos , COVID-19/epidemiologia , COVID-19/prevenção & controle , Arizona/epidemiologia , Vigilância Epidemiológica Baseada em Águas Residuárias , SARS-CoV-2RESUMO
Water age in drinking water systems is often used as a proxy for water quality but is rarely used as a direct input in assessing microbial risk. This study directly linked water ages in a premise plumbing system to concentrations of Legionella pneumophila via a growth model. In turn, the L. pneumophila concentrations were used for a quantitative microbial risk assessment to calculate the associated probabilities of infection (Pinf) and clinically severe illness (Pcsi) due to showering. Risk reductions achieved by purging devices, which reduce water age, were also quantified. The median annual Pinf exceeded the commonly used 1 in 10,000 (10-4) risk benchmark in all scenarios, but the median annual Pcsi was always 1-3 orders of magnitude below 10-4. The median annual Pcsi was lower in homes with two occupants (4.7 × 10-7) than with one occupant (7.5 × 10-7) due to more frequent use of water fixtures, which reduced water ages. The median annual Pcsi for homes with one occupant was reduced by 39-43% with scheduled purging 1-2 times per day. Smart purging devices, which purge only after a certain period of nonuse, maintained these lower annual Pcsi values while reducing additional water consumption by 45-62%.
Assuntos
Água Potável , Legionella pneumophila , Legionella , Abastecimento de Água , Microbiologia da Água , Engenharia Sanitária , Medição de RiscoRESUMO
Candida auris is an opportunistic fungal pathogen and an emerging global public health threat, given its high mortality among infected individuals, antifungal resistance, and persistence in healthcare environments. This study explored the applicability of wastewater surveillance for C. auris in a metropolitan area with reported outbreaks across multiple healthcare facilities. Influent or primary effluent samples were collected over 10 weeks from seven sewersheds in Southern Nevada. Pelleted solids were analyzed using an adapted quantitative polymerase chain reaction (qPCR) assay targeting the ITS2 region of the C. auris genome. Positive detection was observed in 72 of 91 samples (79%), with higher detection frequencies in sewersheds serving healthcare facilities involved in the outbreak (94 vs 20% sample positivity). Influent wastewater concentrations ranged from 2.8 to 5.7 log10 gene copies per liter (gc/L), and primary clarification achieved an average log reduction value (LRV) of 1.24 ± 0.34. Presumptive negative surface water and wastewater controls were non-detect. These results demonstrate that wastewater surveillance may assist in tracking the spread of C. auris and serve as an early warning tool for public health action. These findings provide the foundation for future application of wastewater-based epidemiology (WBE) to community- or facility-level surveillance of C. auris and other high consequence, healthcare-associated infectious agents.
Assuntos
Candida , Candidíase , Humanos , Candida/genética , Candidíase/diagnóstico , Candidíase/epidemiologia , Candidíase/microbiologia , Candida auris , Águas Residuárias , Vigilância Epidemiológica Baseada em Águas Residuárias , Nevada/epidemiologia , Surtos de DoençasRESUMO
An increasing body of literature suggests that aerosol inhalation plays a primary role in COVID-19 transmission, particularly in indoor settings. Mechanistic stochastic models can help public health professionals, engineers, and space planners understand the risk of aerosol transmission of COVID-19 to mitigate it. We developed such model and a user-friendly web application to meet the need of accessible risk assessment tools during the COVID-19 pandemic. We built our model based on the Wells-Riley model of respiratory disease transmission, using quanta emission rates obtained from COVID-19 outbreak investigations. In this report, three modelled scenarios were evaluated and compared to epidemiological studies looking at similar settings: classrooms, weddings, and heavy exercise sessions. We found that the risk of long-range aerosol transmission increased 309-332% when people were not wearing masks, and 424-488% when the room was poorly ventilated in addition to no masks being worn across the scenarios. Also, the risk of transmission could be reduced by â¼40-60% with ventilation rates of 5 ACH for 1-4â h exposure events, and â¼70% with ventilation rates of 10 ACH for 4â h exposure events. Relative humidity reduced the risk of infection (inducing viral inactivation) by a maximum of â¼40% in a 4â h exposure event at 70% RH compared to a dryer indoor environment with 25% RH. Our web application has been used by more than 1000 people in 52 countries as of September 1st, 2021. Future work is needed to obtain SARS-CoV-2 dose-response functions for more accurate risk estimates.
Assuntos
COVID-19 , Humanos , COVID-19/epidemiologia , SARS-CoV-2 , Pandemias , Aerossóis e Gotículas Respiratórios , Medição de RiscoRESUMO
The aeromicrobiological transmission pathway of enteric pathogens in places with unsafe sanitation services is poorly understood. In an attempt to partly fill this knowledge gap, we assessed the potential public health impact of bioaerosols near open waste canals (OWCs) using Quantitative Microbial Risk Assessment (QMRA). We used data acquired in La Paz, Bolivia to characterize the risk of disease that aerosolized enteric pathogens may pose through food, fomites and inhalation (all followed by ingestion). Three reference pathogens were selected to conduct the assessment: enterotoxigenic Escherichia coli (ETEC), Shigella flexneri, and Campylobacter jejuni. Inhalation followed by ingestion had the highest median infection risk per event i.e. 3 × 10-5 (3 infections for every 100,000 exposures), compared to contaminated food e.g. 5 × 10-6 and fomites e.g. 2 × 10-7, all for C. jejuni infections. Our sensitivity analysis showed that bacterial fluxes from the air were the most influential factor on risk. Our results suggest that fecal bacterial aerosols from OWCs present non-negligible risks of infection in La Paz, with median annual infection risks by C. jejuni being 18 (food), and 100 (inhalation) times greater than the EPA's standard for drinking water (1 × 10-4). We included two of the QMRA models presented here in a novel web application we developed for user-specified application in different contexts.
Assuntos
Escherichia coli , Saneamento , Aerossóis , Cidades , Medição de RiscoRESUMO
Current fecal indicators for environmental health monitoring are primarily based on fecal indicator bacteria (FIB) which do not accurately represent viral pathogens. There is a need for highly abundant, human-associated viral fecal indicators to represent viral pathogens in sewage-contaminated water. In the present study, we evaluate the abundance of the emerging viral fecal indicator crAssphage in 156 Italian wastewater samples collected between 2014 and 2018. Samples were collected using two separate viral concentration methods, glycine-CF and PEG-dextran and qPCR assays were run for crAssphage (CPQ56) and Human Polyomavirus (HPyV) and endpoint PCR assays were run for Human Bocavirus (HBoc) and Hepatitis E Virus (HepE). CrAssphage was detected in 96% of samples and no statistically significant difference was observed in crAssphage abundance between concentration methods (p = 0.39). CrAssphage concentrations also did not correlate with location (latitude) or size (load and capacity) of the wastewater treatment plant. HPyV detection rates with the glycine-CF and PEG-dextran methods were 64% and 100%, respectively, and the concentrations of HPyV were statistically significantly influenced by the concentration method (p < 0.0001). CrAssphage was measured at significantly higher concentrations than HPyV for both concentration methods (p < 0.0001). The observed concentration ranges were 3.84-7.29 log10GC/100 mL for crAssphage and 3.45-5.17 log10GC/100 mL for HPyV. There was a strong positive correlation between crAssphage and HPyV abundance for both concentration methods; however, the slope of the correlation depended on the concentration method. CrAssphage presence correlated with the presence of HBoc in samples concentrated with glycine-CF, but did not correlate with the presence of HBoc concentrated with the PEG-dextran method or with the presence of HepE. Overall, these results demonstrate that crAssphage is an abundant viral fecal indicator in wastewater with statistically significant correlation with human viral pathogens (e.g., HPyV) and viral concentration methods influence the interpretation of fecal viral indicator detection.