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1. Detection of SARS-CoV-2 RNA in commercial passenger aircraft and cruise ship wastewater: a surveillance tool for assessing the presence of COVID-19 infected travellers

   https://doi.org/10.1093/jtm/taaa116  

   Ahmed, Warish; Bertsch, Paul M; Angel, Nicola; Bibby, Kyle; Bivins, Aaron; Dierens, Leanne; Edson, Janette; Ehret, John; Gyawali, Pradip; Hamilton, Kerry A; et al (July 2020, Journal of Travel Medicine)

   null (Ed.)

   Abstract Background Wastewater-based epidemiology (WBE) for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can be an important source of information for coronavirus disease 2019 (COVID-19) management during and after the pandemic. Currently, governments and transportation industries around the world are developing strategies to minimize SARS-CoV-2 transmission associated with resuming activity. This study investigated the possible use of SARS-CoV-2 RNA wastewater surveillance from airline and cruise ship sanitation systems and its potential use as a COVID-19 public health management tool. Methods Aircraft and cruise ship wastewater samples (n = 21) were tested for SARS-CoV-2 using two virus concentration methods, adsorption–extraction by electronegative membrane (n = 13) and ultrafiltration by Amicon (n = 8), and five assays using reverse-transcription quantitative polymerase chain reaction (RT-qPCR) and RT-droplet digital PCR (RT-ddPCR). Representative qPCR amplicons from positive samples were sequenced to confirm assay specificity. Results SARS-CoV-2 RNA was detected in samples from both aircraft and cruise ship wastewater; however concentrations were near the assay limit of detection. The analysis of multiple replicate samples and use of multiple RT-qPCR and/or RT-ddPCR assays increased detection sensitivity and minimized false-negative results. Representative qPCR amplicons were confirmed for the correct PCR product by sequencing. However, differences in sensitivity were observed among molecular assays and concentration methods. Conclusions The study indicates that surveillance of wastewater from large transport vessels with their own sanitation systems has potential as a complementary data source to prioritize clinical testing and contact tracing among disembarking passengers. Importantly, sampling methods and molecular assays must be further optimized to maximize detection sensitivity. The potential for false negatives by both wastewater testing and clinical swab testing suggests that the two strategies could be employed together to maximize the probability of detecting SARS-CoV-2 infections amongst passengers. 

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2. Wastewater surveillance for bacterial targets: current challenges and future goals

   https://doi.org/10.1128/aem.01428-23  

   Philo, Sarah E; De_León, Kara B; Noble, Rachel T; Zhou, Nicolette A; Alghafri, Rashed; Bar-Or, Itay; Darling, Amanda; D'Souza, Nishita; Hachimi, Oumaima; Kaya, Devrim; et al (January 2024, Applied and Environmental Microbiology)

   Elkins, Christopher A (Ed.)

   ABSTRACT Wastewater-based epidemiology (WBE) expanded rapidly in response to the COVID-19 pandemic. As the public health emergency has ended, researchers and practitioners are looking to shift the focus of existing wastewater surveillance programs to other targets, including bacteria. Bacterial targets may pose some unique challenges for WBE applications. To explore the current state of the field, the National Science Foundation-funded Research Coordination Network (RCN) on Wastewater Based Epidemiology for SARS-CoV-2 and Emerging Public Health Threats held a workshop in April 2023 to discuss the challenges and needs for wastewater bacterial surveillance. The targets and methods used in existing programs were diverse, with twelve different targets and nine different methods listed. Discussions during the workshop highlighted the challenges in adapting existing programs and identified research gaps in four key areas: choosing new targets, relating bacterial wastewater data to human disease incidence and prevalence, developing methods, and normalizing results. To help with these challenges and research gaps, the authors identified steps the larger community can take to improve bacteria wastewater surveillance. This includes developing data reporting standards and method optimization and validation for bacterial programs. Additionally, more work is needed to understand shedding patterns for potential bacterial targets to better relate wastewater data to human infections. Wastewater surveillance for bacteria can help provide insight into the underlying prevalence in communities, but much work is needed to establish these methods. IMPORTANCEWastewater surveillance was a useful tool to elucidate the burden and spread of SARS-CoV-2 during the pandemic. Public health officials and researchers are interested in expanding these surveillance programs to include bacterial targets, but many questions remain. The NSF-funded Research Coordination Network for Wastewater Surveillance of SARS-CoV-2 and Emerging Public Health Threats held a workshop to identify barriers and research gaps to implementing bacterial wastewater surveillance programs. 

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3. Building-level wastewater surveillance using tampon swabs and RT-LAMP for rapid SARS-CoV-2 RNA detection

   https://doi.org/10.1039/D1EW00496D  

   Bivins, Aaron; Lott, Megan; Shaffer, Marlee; Wu, Zhenyu; North, Devin; Lipp, Erin K.; Bibby, Kyle (December 2021, Environmental Science: Water Research & Technology)

   Wastewater surveillance for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA has demonstrated useful correlation with both coronavirus disease 2019 (COVID-19) cases and clinical testing positivity at the community level. Wastewater surveillance on college campuses has also demonstrated promising predictive capacity for the presence and absence of COVID-19 cases. However, to date, such monitoring has most frequently relied upon composite samplers and reverse transcription quantitative PCR (RT-qPCR) techniques, which limits the accessibility and scalability of wastewater surveillance, particularly in low-resource settings. In this study, we trialed the use of tampons as passive swabs for sample collection and reverse transcription loop-mediated isothermal amplification (RT-LAMP), which does not require sophisticated thermal cycling equipment, to detect SARS-CoV-2 RNA in wastewater. Results for the workflow were available within three hours of sample collection. The RT-LAMP assay is approximately 20 times less analytically sensitive than RT-droplet digital PCR. Nonetheless, during a building-level wastewater surveillance campaign concurrent with independent weekly clinical testing of all students, the method demonstrated a three-day positive predictive value (PPV) of 75% (excluding convalescent cases) and same-day negative predictive value (NPV) of 80% for incident COVID-19 cases. These predictive values are comparable to that reported by wastewater monitoring using RT-qPCR. These observations suggest that even with lower analytical sensitivity the tampon swab and RT-LAMP workflow offers a cost-effective and rapid approach that could be leveraged for scalable building-level wastewater surveillance for COVID-19 potentially even in low-resource settings. 

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4. Recovering wastewater RNA for virome sequencing by systematically optimized tangential-flow ultrafiltration and Nanotrap microbiome particles

   https://doi.org/10.1128/aem.00777-25  

   Segelhurst, Emily; Bard, Jonathan E; Gallo, Sydney; Huang, Vicky; Pohlman, Alyssa; Yergeau, Donald A; Surtees, Jennifer A; Bradley, Ian M; Ye, Yinyin (August 2025, Applied and Environmental Microbiology)

   Elkins, Christopher A (Ed.)

   ABSTRACT Municipal wastewater harbors diverse RNA viruses, which are responsible for many emerging and reemerging diseases in humans, animals, and plants. Although genomic sequencing can be a high-throughput approach for profiling the RNA virome in wastewater, wastewater processing methods often influence sequencing outcomes. Here, we systematically evaluated two wastewater processing methods, tangential-flow ultrafiltration (TFF) and Nanotrap Microbiome A Particles, for detecting the target RNA virus severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) via amplicon sequencing and characterizing the RNA virome using whole-transcriptome shotgun sequencing. Our results from paired comparison tests showed that the TFF and Nanotrap methods recovered similar SARS-CoV-2 variants at the lineage level (analysis of similarity [ANOSIM]R= −0.012,P= 0.874). Optimizing automated procedures for the Nanotrap method and concentration factors for the TFF method was critical for achieving high-depth and high-breadth coverage of the target virus genome. Notably, the two methods enriched distinct RNA viromes from the same wastewater samples (ANOSIMR= 0.260,P= 0.002), with TFF samples showing 22-fold and 7-fold higher relative abundances ofReoviridaeandCoronaviridae, respectively. These differences are likely due to the distinct virus concentration mechanisms employed by each method, which are influenced by liquid-solid partitioning of virus particles and interactions of viral surface proteins with ligands. Our findings underscore the importance of optimizing wastewater processing methods for genomic monitoring and have implications for broader environmental applications.IMPORTANCEWastewater genomic sequencing is an emerging technology for tracking viral infections within communities. However, different methods for concentrating viruses and extracting nucleic acids can influence the recoveries of RNA virome from wastewater. An in-depth understanding of virus concentration mechanisms and their impact on sequencing data quality and bioinformatic output would be critical to guide method selection and optimization. Specifically, this study systematically evaluated tangential-flow ultrafiltration and Nanotrap microbiome particles for their application to sequence SARS-CoV-2 and whole RNA virome from wastewater. Both methods yielded high-quality sequencing data for amplicon sequencing of SARS-CoV-2, but their outcomes diverged in the recovered RNA virome. We identified RNA viruses that are preferentially recovered by each of these two methods and proposed considerations of method selection for future studies of wastewater RNA virome. 

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5. Effect of SARS-CoV-2 digital droplet RT-PCR assay sensitivity on COVID-19 wastewater based epidemiology

   https://doi.org/10.1371/journal.pwat.0000066  

   Kim, Sooyeol; Wolfe, Marlene K.; Criddle, Craig S.; Duong, Dorothea H.; Chan-Herur, Vikram; White, Bradley J.; Boehm, Alexandria B. (November 2022, PLOS Water)

   Santos, Ricardo (Ed.)

   We developed and implemented a framework for examining how molecular assay sensitivity for a viral RNA genome target affects its utility for wastewater-based epidemiology. We applied this framework to digital droplet RT-PCR measurements of SARS-CoV-2 and Pepper Mild Mottle Virus genes in wastewater. Measurements were made using 10 replicate wells which allowed for high assay sensitivity, and therefore enabled detection of SARS-CoV-2 RNA even when COVID-19 incidence rates were relatively low (~10 −5 ). We then used a computational downsampling approach to determine how using fewer replicate wells to measure the wastewater concentration reduced assay sensitivity and how the resultant reduction affected the ability to detect SARS-CoV-2 RNA at various COVID-19 incidence rates. When percent of positive droplets was between 0.024% and 0.5% (as was the case for SARS-CoV-2 genes during the Delta surge), measurements obtained with 3 or more wells were similar to those obtained using 10. When percent of positive droplets was less than 0.024% (as was the case prior to the Delta surge), then 6 or more wells were needed to obtain similar results as those obtained using 10 wells. When COVID-19 incidence rate is low (~ 10 −5 ), as it was before the Delta surge and SARS-CoV-2 gene concentrations are <10 4 cp/g, using 6 wells will yield a detectable concentration 90% of the time. Overall, results support an adaptive approach where assay sensitivity is increased by running 6 or more wells during periods of low SARS-CoV-2 gene concentrations, and 3 or more wells during periods of high SARS-CoV-2 gene concentrations. 

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