The Reduction of SARS-CoV-2 RNA Concentration in the Presence of Sewer Biofilms

Wastewater surveillance has been widely used to track the prevalence of SARS-CoV-2 in communities. Although some studies have investigated the decay of SARS-CoV-2 RNA in wastewater, understanding about its fate during wastewater transport in real sewers is still limited. This study aims to assess the impact of sewer biofilms on the dynamics of SARS-CoV-2 RNA concentration in naturally contaminated real wastewater (raw influent wastewater without extra SARS-CoV-2 virus/gene seeding) using a simulated laboratory-scale sewer system. The results indicated that, with the sewer biofilms, a 90% concentration reduction of the SARS-CoV-2 RNA was observed within 2 h both in wastewater of gravity (GS, gravity-driven sewers) and rising main (RM, pressurized sewers) sewer reactors. In contrast, the 90% reduction time was 8–26 h in control reactors without biofilms. The concentration reduction of SARS-CoV-2 RNA in wastewater was significantly more in the presence of sewer biofilms. In addition, an accumulation of c.a. 260 and 110 genome copies/cm2 of the SARS-CoV-2 E gene was observed in the sewer biofilm samples from RM and GS reactors within 12 h, respectively. These results confirmed that the in-sewer concentration reduction of SARS-CoV-2 RNA in wastewater was likely caused by the partition to sewer biofilms. The need to investigate the in-sewer dynamic of SARS-CoV-2 RNA, such as the variation of RNA concentration in influent wastewater caused by biofilm attachment and detachment, was highlighted by the significantly enhanced reduction rate of SARS-CoV-2 RNA in wastewater of sewer biofilm reactors and the accumulation of SARS-CoV-2 RNA in sewer biofilms. Further research should be conducted to investigate the in-sewer transportation of SARS-CoV-2 and their RNA and evaluate the role of sewer biofilms in leading to underestimates of COVID-19 prevalence in communities.

Detection and quantification of sars-cov-2 wastewater treatment plants from different cities in chile, towards to a permanent sentinel surveillance.

Background: The quantification of SARS-CoV-2 in wastewater is a tool that allows determining the trend of viral circulation in a particular geographical area. Aim(s): To quantify the SARS-CoV-2 virus in 15 wastewater treatment plants in different Chilean cities to establish a comparison with the variables of: I) Active cases per 100,000 inhabitants;ii) daily positivity (novel cases);and iii) phases of the lockdown strategy. Method(s): SARS-CoV-2 was concentrated from wastewater samples. To obtain the number of virus genomes per liter, absolute quantification was performed using qRT-PCR. Result(s): Between January and June 2021, 253 samples were processed, all of which were positive for the presence of the virus. Likewise, it will be determined that the rate of active cases per 100,000 inhabitants is the variable that best fits the trends obtained with the quantification of the viral load in wastewater. Conclusion(s): The quantification of SARS- CoV-2 in wastewater as a continuous strategy is an efficient tool to determine the trend of the viral circulation in a delimited geographical area and, combined with genomic surveillance, it can constitute an ideal sentinel surveillance alert on future outbreaks.Copyright © 2022, Sociedad Chilena de Infectologia. All rights reserved.

The effects of COVID-19 on the water sector

The COVID-19 pandemic affected public health, economy, social life, and the environment. It infected and killed millions of people around the world. Most of the recent literature has focused on the medications to combat this virus, including antivirals and vaccines, but studies about its effect on the environment are still rare, particularly on the water sector. Most of the studies concentrate on the effect of water availability on COVID-19, the effect of the used medications on the water, and the probability of transmission of SARS-CoV-2 through water. Herein, we have summarized the effects of COVID-19 on the water sector from many perspectives. We show different methods to detect the effect of the pandemic on water and also methods to investigate the presence of the virus or its RNA in the water. We also show the different effects of its presence in the wastewater, the probability of transmission, the detection of different variants, and the prediction of new waves. We also show the disadvantages and advantages of the pandemic in the water sector. We finally suggest some recommendations to face this pandemic and the future pandemics for the governments and water policymakers, water treatment plants, general population, and researchers. The aim of this review is to show the different aspects of the pandemic in order to give a general idea about what must be done in order to minimize its effect and any probable pandemic in the future.

Not a waste: Wastewater surveillance to enhance public health

Domestic wastewater, when collected and evaluated appropriately, can provide valuable health-related information for a community. As a relatively unbiased and non-invasive approach, wastewater surveillance may complement current practices towards mitigating risks and protecting population health. Spurred by the COVID-19 pandemic, wastewater programs are now widely implemented to monitor viral infection trends in sewersheds and inform public health decision-making. This review summarizes recent developments in wastewater-based epidemiology for detecting and monitoring communicable infectious diseases, dissemination of antimicrobial resistance, and illicit drug consumption. Wastewater surveillance, a quickly advancing Frontier in environmental science, is becoming a new tool to enhance public health, improve disease prevention, and respond to future epidemics and pandemics.

Engineering Design of a Health Service Station Sewage Treatment Station under COVID-19 Epidemic

Health service station is a place in which close contacts with the COVID-19 and other key populations are centralized quarantined for medical observation.A newly built health service station is equipped with 4 700 beds and a supporting sewage treatment station with a designed treatment scale of2 200 m~3/d.The treatment process consists of enhanced biological treatment system,sewage virus disinfection and sterilization system,aerosol disinfection and sterilization system and sludge disinfection and sterilization system.After treatment,the effluent and waste gas can meet the limit specified in Discharge Standard of Water Pollutants for Medical Organization （GB 18466-2005）.The average COD,NH3-N and SS in effluent are 14.53 mg/L,1.26 mg/L and 9.11 mg/L,respectively,and the average concentrations of H2S,NH3 and odor at the outlet are 0.01 mg/L,0.8 mg/L and 6.3,respectively.The sludge is disinfected regularly and then transported outside for disposal.This project can provide reference for sewage treatment design of emergency medical temporary isolation and observation facility and cabin hospital.

Advances in wastewater-based epidemiology in 2021

Wastewater-based epidemiology (WBE) is a powerful and cost-effective tool for investigating chemicals consumption/pathogens infection and health status of populations, and is rapidly evolving as COVID-19 continues to ravage the world. This paper reviews the significant developments and breakthroughs of WBE in 2021 including collection, pretreatment and analysis of sewage samples, materials stability, correction factors calculation and uncertainty analysis, implementation cases and so on, based on the research findings published in international top academic journals or the most influential achievements. It provides reference for clarifying the development of WBE and promoting the research and application of WBE.

Wastewater early warning system for SARS-CoV-2 outbreaks and variants in a Coruña, Spain.

Wastewater-based epidemiology has been widely used as a cost-effective method for tracking the COVID-19 pandemic at the community level. Here we describe COVIDBENS, a wastewater surveillance program running from June 2020 to March 2022 in the wastewater treatment plant of Bens in A Coruña (Spain). The main goal of this work was to provide an effective early warning tool based in wastewater epidemiology to help in decision-making at both the social and public health levels. RT-qPCR procedures and Illumina sequencing were used to weekly monitor the viral load and to detect SARS-CoV-2 mutations in wastewater, respectively. In addition, own statistical models were applied to estimate the real number of infected people and the frequency of each emerging variant circulating in the community, which considerable improved the surveillance strategy. Our analysis detected 6 viral load waves in A Coruña with concentrations between 103 and 106 SARS-CoV-2 RNA copies/L. Our system was able to anticipate community outbreaks during the pandemic with 8-36 days in advance with respect to clinical reports and, to detect the emergence of new SARS-CoV-2 variants in A Coruña such as Alpha (B.1.1.7), Delta (B.1.617.2), and Omicron (B.1.1.529 and BA.2) in wastewater with 42, 30, and 27 days, respectively, before the health system did. Data generated here helped local authorities and health managers to give a faster and more efficient response to the pandemic situation, and also allowed important industrial companies to adapt their production to each situation. The wastewater-based epidemiology program developed in our metropolitan area of A Coruña (Spain) during the SARS-CoV-2 pandemic served as a powerful early warning system combining statistical models with mutations and viral load monitoring in wastewater over time.

Next-generation sequencing for surveillance of antimicrobial resistance and pathogenicity in municipal wastewater treatment plants.

The World Health Organization (WHO) ranks antimicrobial resistance (AMR) and various pathogens among the top 10 health threats. It is estimated that by 2050, the number of human deaths due to AMR will reach 10 million annually. On the other hand, several infectious outbreaks such as SARS, H1N1 influenza, Ebola, Zika fever, and COVID-19 have severely affected human populations worldwide in the last 20 years. These recent global diseases have generated the need to monitor outbreaks of pathogens and AMR to establish effective public health strategies. This review presents AMR and pathogenicity associated with wastewater treatment plants (WWTP), focusing on Next Generation Sequencing (NGS) monitoring as a complementary system to clinical surveillance. In this regard, WWTP may be monitored at three main points. First, at the inlet (raw wastewater or influent) to identify a broad spectrum of AMR and pathogens contained in the excretions of residents served by sewer networks, with a specific spatio-temporal location. Second, at the effluent, to ensure the elimination of AMR and pathogens in the treated water, considering the rising demand for safe wastewater reuse. Third, in sewage sludge or biosolids, since their beneficial use or final disposal can represent a significant risk to public health. This review is divided into two sections to address the importance and implications of AMR and pathogen surveillance in wastewater and WWTP, based on NGS. The first section presents the fundamentals of surveillance techniques applied in WWTP (metataxonomics, metagenomics, functional metagenomics, metaviromics, and metatranscriptomics). Their scope and limitations are analyzed to show how microbiological and qPCR techniques complement NGS surveillance, overcoming its limitations. The second section discusses the contribution of 36 NGS research papers on WWTP surveillance, highlighting the current situation and perspectives. In both sections, research challenges and opportunities are presented.

A systematic review on the occurrence, fate, and remediation of SARS-CoV-2 in wastewater.

The COVID-19 has been declared a pandemic by the World Health Organization. Along with impairing the respiratory system, it also affects the gastrointestinal system. By reviewing experiments on the wastewater analysis for the detection of coronavirus, this study explores the fate, persistence, and various remediation strategies for the virus removal from the wastewater. The results indicated that the virus can be detected in the wastewater samples, feces, and sewage, even before the onset of symptoms. Coronavirus can be a potential panzootic disease, as several mammalian species get infected by the deadly virus. The disinfection strategies used earlier for the treatment of wastewater are not sufficient for the removal of viruses from the wastewater. Therefore, concerted efforts should be made to understand their fate, sources, and occurrence in the environmental matrices. To prevent the spread of the panzootic disease, revised guidelines should be issued for the remediation of the virus. Recent viral remediation methods such as membrane bioreactors and advanced oxidation methods can be used. Therefore, the present review puts a light on the current knowledge on the occurrence of coronaviruses in wastewater, the possible sources, fate, and removal strategies.

Escherichia coli ST2797 Is Abundant in Wastewater and Might Be a Novel Emerging Extended-Spectrum Beta-Lactamase E. coli.

The increasing prevalence of antibiotic-resistant bacteria is an emerging threat to global health. The analysis of antibiotic-resistant enterobacteria in wastewater can indicate the prevalence and spread of certain clonal groups of multiresistant bacteria. In a previous study of Escherichia coli that were isolated from a pump station in Norway over 15 months, we found a recurring E. coli clone that was resistant to trimethoprim, ampicillin, and tetracycline in 201 of 3,123 analyzed isolates (6.1%). 11 representative isolates were subjected to whole-genome sequencing and were found to belong to the MLST ST2797 E. coli clone with plasmids carrying resistance genes, including blaTEM-1B, sul2, dfrA7, and tetB. A phenotypic comparison of the ST2797 isolates with the uropathogenic ST131 and ST648 that were repeatedly identified in the same wastewater samples revealed that the ST2797 isolates exhibited a comparable capacity for temporal survival in wastewater, greater biofilm formation, and similar potential for the colonization of mammalian epithelial cells. ST2797 has been isolated from humans and has been found to carry extended spectrum ß-lactamase (ESBL) genes in other studies, suggesting that this clonal type is an emerging ESBL E. coli. Collectively, these findings show that ST2797 was more ubiquitous in the studied wastewater than were the infamous ST131 and ST648 and that ST2797 may have similar abilities to survive in the environment and cause infections in humans. IMPORTANCE The incidence of drug-resistant bacteria found in the environment is increasing together with the levels of antibiotic-resistant bacteria that cause infections. The COVID-19 pandemic has shed new light on the importance of monitoring emerging threats and finding early warning systems. Therefore, to mitigate the antimicrobial resistance burden, the monitoring and early identification of antibiotic-resistant bacteria in hot spots, such as wastewater treatment plants, are required to combat the occurrence and spread of antibiotic-resistant bacteria. Here, we applied a PhenePlate system as a phenotypic screening method for genomic surveillance and discovered a dominant and persistent E. coli clone ST2797 with a multidrug resistance pattern and equivalent phenotypic characteristics to those of the major pandemic lineages, namely, ST131 and ST648, which frequently carry ESBL genes. This study highlights the continuous surveillance and report of multidrug resistant bacteria with the potential to spread in One Health settings.

Targeted amplicon sequencing of wastewater samples for detecting SARS-CoV-2 variants with high sensitivity and resolution.

Wastewater-based epidemiology (WBE) is a promising approach for monitoring the spread of SARS-CoV-2 within communities. Although qPCR-based WBE is powerful in that it allows quick and highly sensitive detection of this virus, it can provide limited information about which variants are responsible for the overall increase or decrease of this virus in sewage, and this hinders accurate risk assessments. To resolve this problem, we developed a next generation sequencing (NGS)-based method to determine the identity and composition of individual SARS-CoV-2 variants in wastewater samples. Combination and optimization of targeted amplicon-sequencing and nested PCR allowed detection of each variant with sensitivity comparable to that of qPCR. In addition, by targeting the receptor binding domain (RBD) of the S protein, which has mutations informative for variant classification, we could discriminate most variants of concern (VOC) and even sublineages of Omicron (BA.1, BA.2, BA.4/5, BA.2.75, BQ.1.1 and XBB.1). Focusing on a limited domain has a benefit of decreasing the sequencing reads. We applied this method to wastewater samples collected from a wastewater treatment plant in Kyoto city throughout 13 months (from January 2021 to February 2022) and successfully identified lineages of wild-type, alpha, delta, omicron BA.1 and BA.2 as well as their compositions in the samples. The transition of these variants was in good agreement with the epidemic situation reported in Kyoto city during that period based on clinical testing. These data indicate that our NGS-based method is useful for detecting and tracking emerging variants of SARS-CoV-2 in sewage samples. Coupled with the advantages of WBE, this method has the potential to serve as an efficient and low cost means for the community risk assessment of SARS-CoV-2 infection.

SARS-CoV-2 detection and inactivation in water and wastewater: review on analytical methods, limitations and future research recommendations.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been detected in wastewater. Wastewater-based epidemiology (WBE) is a practical and cost-effective tool for the assessment and controlling of pandemics and probably for examining SARS-CoV-2 presence. Implementation of WBE during the outbreaks is not without limitations. Temperature, suspended solids, pH, and disinfectants affect the stability of viruses in wastewater. Due to these limitations, instruments and techniques have been utilized to detect SARS-CoV-2. SARS-CoV-2 has been detected in sewage using various concentration methods and computer-aided analyzes. RT-qPCR, ddRT-PCR, multiplex PCR, RT-LAMP, and electrochemical immunosensors have been employed to detect low levels of viral contamination. Inactivation of SARS-CoV-2 is a crucial preventive measure against coronavirus disease 2019 (COVID-19). To better assess the role of wastewater as a transmission route, detection, and quantification methods need to be refined. In this paper, the latest improvements in quantification, detection, and inactivation of SARS-CoV-2 in wastewater are explained. Finally, limitations and future research recommendations are thoroughly described.

Actionable wastewater surveillance: application to a university residence hall during the transition between Delta and Omicron resurgences of COVID-19.

Wastewater surveillance has gained traction during the COVID-19 pandemic as an effective and non-biased means to track community infection. While most surveillance relies on samples collected at municipal wastewater treatment plants, surveillance is more actionable when samples are collected "upstream" where mitigation of transmission is tractable. This report describes the results of wastewater surveillance for SARS-CoV-2 at residence halls on a university campus aimed at preventing outbreak escalation by mitigating community spread. Another goal was to estimate fecal shedding rates of SARS-CoV-2 in a non-clinical setting. Passive sampling devices were deployed in sewer laterals originating from residence halls at a frequency of twice weekly during fall 2021 as the Delta variant of concern continued to circulate across North America. A positive detection as part of routine sampling in late November 2021 triggered daily monitoring and further isolated the signal to a single wing of one residence hall. Detection of SARS-CoV-2 within the wastewater over a period of 3 consecutive days led to a coordinated rapid antigen testing campaign targeting the residence hall occupants and the identification and isolation of infected individuals. With knowledge of the number of individuals testing positive for COVID-19, fecal shedding rates were estimated to range from 3.70 log10 gc ‧ g feces-1 to 5.94 log10 gc ‧ g feces-1. These results reinforce the efficacy of wastewater surveillance as an early indicator of infection in congregate living settings. Detections can trigger public health measures ranging from enhanced communications to targeted coordinated testing and quarantine.

20-Month monitoring of SARS-CoV-2 in wastewater of Curitiba, in Southern Brazil.

The COVID-19 pandemic resulted in the collapse of healthcare systems and led to the development and application of several approaches of wastewater-based epidemiology to monitor infected populations. The main objective of this study was to carry out a SARS-CoV-2 wastewater based surveillance in Curitiba, Southern Brazil Sewage samples were collected weekly for 20 months at the entrance of five treatment plants representing the entire city and quantified by qPCR using the N1 marker. The viral loads were correlated with epidemiological data. The correlation by sampling points showed that the relationship between the viral loads and the number of reported cases was best described by a cross-correlation function, indicating a lag between 7 and 14 days amidst the variables, whereas the data for the entire city presented a higher correlation (0.84) with the number of positive tests at lag 0 (sampling day). The results also suggest that the Omicron VOC resulted in higher titers than the Delta VOC. Overall, our results showed that the approach used was robust as an early warning system, even with the use of different epidemiological indicators or changes in the virus variants in circulation. Therefore, it can contribute to public decision-makers and health interventions, especially in vulnerable and low-income regions with limited clinical testing capacity. Looking toward the future, this approach will contribute to a new look at environmental sanitation and should even induce an increase in sewage coverage rates in emerging countries.

Prevalence of Antibiotic-Resistant Pathogenic Bacteria and Level of Antibiotic Residues in Hospital Effluents in Selangor, Malaysia: Protocol for a Cross-sectional Study.

BACKGROUND: Antimicrobial resistance (AMR) has emerged as a major global public health challenge due to the overuse and misuse of antibiotics for humans and animals. Hospitals are among the major users of antibiotics, thereby having a large contribution to AMR. OBJECTIVE: The aim of this study is to determine the prevalence of antibiotic-resistant pathogenic bacteria and the level of antibiotic residues in the hospital effluents in Selangor, Malaysia. METHODS: A cross-sectional study will be performed in the state of Selangor, Malaysia. Tertiary hospitals will be identified based on the inclusion and exclusion criteria. The methods are divided into three phases: sample collection, microbiological analysis, and chemical analysis. Microbiological analyses will include the isolation of bacteria from hospital effluents by culturing on selective media. Antibiotic sensitivity testing will be performed on the isolated bacteria against ceftriaxone, ciprofloxacin, meropenem, vancomycin, colistin, and piperacillin/tazobactam. The identification of bacteria will be confirmed using 16S RNA polymerase chain reaction (PCR) and multiplex PCR will be performed to detect resistance genes (ermB, mecA, blaNDM-L, blaCTX-M, blaOXA-48, blaSHV, VanA, VanB, VanC1, mcr-1, mcr-2, mcr-3, Intl1, Intl2, and qnrA). Finally, the level of antibiotic residues will be measured using ultrahigh-performance liquid chromatography. RESULTS: The expected outcomes will be the prevalence of antibiotic-resistant Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter (ESKAPE) bacterial species from the hospital effluents, the occurrence of antibiotic resistance genes (ARGs) from the isolated ESKAPE bacteria, and the level of antibiotic residues that may be detected from the effluent. Sampling has been conducted in three hospitals. Data analysis from one hospital showed that as of July 2022, 80% (8/10) of E. faecium isolates were resistant to vancomycin and 10% (1/10) were resistant to ciprofloxacin. Further analysis will be conducted to determine if the isolates harbor any ARGs and effluent samples are being analyzed to detect antibiotic residues. Sampling activities will be resumed after being suspended due to the COVID-19 pandemic and are scheduled to end by December 2022. CONCLUSIONS: This study will provide the first baseline information to elucidate the current status of AMR of highly pathogenic bacteria present in hospital effluents in Malaysia. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): DERR1-10.2196/39022.

Temporal study of wastewater surveillance from September 2020 to March 2021: an estimation of COVID-19 patients in Lahore, Pakistan.

The first aim of study was to quantify the viral load in the wastewater samples by RT-qPCR testing in Lahore population to estimate the number of patients affected and predict the next resurgence of COVID-19 wave in the city. The second aim of the study was to determine the hotspot areas of Lahore which remained positive more often for virus with high viral load. In this study, n = 420 sewage samples were collected on an average of two weeks intervals from 30 different sewage water disposal stations (14 sampling events) from Sept 2020 to March 2021. RNA was extracted and quantified by RT-qPCR without concentrating the virus in samples. Number of positive disposal sites (7-93%), viral load from sewage samples (100.296 to 103.034), and estimated patients (660-17,030) ranged from low to high according to the surge and restrain of 2nd and 3rd COVID-19 waves in the country. The viral load and estimated patients were reported high in January 2021 and March 2021 which were similar to the peak of 2nd and 3rd waves in Pakistan. Site 18 (Niaz Baig village DS) showed the highest viral load among all sites. Findings of the present study helped to estimate the number of patients and track the resurgence in COVID-19 waves in Lahore particularly, and in Punjab generally. Furthermore, it emphasizes the role of wastewater-based epidemiology to help policymakers strengthen the quarantine measures along with immunization to overcome enteric viral diseases. Local and national stake holders should work in collaboration to improve the environmental hygiene to control the disease.

Establishment of wastewater-based SARS-CoV-2 monitoring system over two years: Case studies in South Korea.

With the global COVID-19 pandemic, wastewater surveillance has received a considerable attention as a method for the early identification of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in wastewater treatment plant (WWTP) and sewer systems. For the first time in Korea, this study utilized the wastewater surveillance technique to monitor the COVID-19 outbreak. Sampling efforts were carried out at the WWTPs in the capital city of Korea, Seoul, and Daegu the place where the first severe outbreak was reported. The RNA of Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been extracted from the collected wastewater influent and primary sewage sludge samples. The outcomes were contrasted with the COVID-19 cases in the WWTPs served area. Additionally, whole transcriptome sequencing was used to compare the microbial community alterations before and after the COVID-19 outbreak and SARS-CoV-2 variations. The results demonstrated that the changes in SARS-CoV-2 RNA concentrations in the influent and sludge matched the trends of reported COVID-19 cases, especially sludge showed high-resolution data, which is well-matched when fewer COVID-19 cases (0-250) are reported. Interestingly, one month before the clinical report, we found that the SARS-CoV-2 Beta variant (South Africa, B.1.351) in the wastewater. In addition, the Aeromonas bacterial species was dominated (21.2%) among other bacterial species in wastewater after the COVID-19 outbreak, suggesting a potential indirect microbial indicator of the COVID-19 outbreak.

The use of technological innovation in bio-based industries to foster growth in the bioeconomy: a South African perspective

Several countries around the world are taking advantage of emerging technologies to leverage the use of natural resources to develop and grow bio-based industries. As a result, these activities have become the backbone of bioeconomy-growth strategies in the developing world. Adoption of the concepts and technological aspects of this facet of the Fourth Industrial Revolution (4IR) across government, academia, and industry has fostered innovation in the health, agricultural, and manufacturing sectors. However, the relationship between the technological catalysis of innovation and the bioeconomy from the perspective of a developing country has been left unexplored. In this context, this review explores the contribution of technological advances toward a sustainable, valuable bioeconomy and the current policy mandates. We focus our attention on South Africa because the country has a holistic, well-defined bioeconomy strategy that is consistent with the conditions of developed nations more generally. The review suggests that developing countries could adopt a multidisciplinary approach to designing their bioeconomy strategies. We further assert that developing holistic strategies that address the recent COVID-19 pandemic and potential future world crises could be beneficial in achieving sustainable development goals.

Monitoring influenza and respiratory syncytial virus in wastewater. Beyond COVID-19.

Wastewater-based surveillance can be a valuable tool to monitor viral circulation and serve as an early warning system. For respiratory viruses that share similar clinical symptoms, namely SARS-CoV-2, influenza, and respiratory syncytial virus (RSV), identification in wastewater may allow differentiation between seasonal outbreaks and COVID-19 peaks. In this study, to monitor these viruses as well as standard indicators of fecal contamination, a weekly sampling campaign was carried out for 15 months (from September 2021 to November 2022) in two wastewater treatment plants that serve the entire population of Barcelona (Spain). Samples were concentrated by the aluminum hydroxide adsorption-precipitation method and then analyzed by RNA extraction and RT-qPCR. All samples were positive for SARS-CoV-2, while the positivity rates for influenza virus and RSV were significantly lower (10.65 % for influenza A (IAV), 0.82 % for influenza B (IBV), 37.70 % for RSV-A and 34.43 % for RSV-B). Gene copy concentrations of SARS-CoV-2 were often approximately 1 to 2 logarithmic units higher compared to the other respiratory viruses. Clear peaks of IAV H3:N2 in February and March 2022 and RSV in winter 2021 were observed, which matched the chronological incidence of infections recorded in the Catalan Government clinical database. In conclusion, the data obtained from wastewater surveillance provided new information on the abundance of respiratory viruses in the Barcelona area and correlated favorably with clinical data.