WASTEwater as a source of knowledge on SARS-CoV-2 and other potentially

The COVID-19 pandemic has highlighted the importance of having optimal strategies to deal with health and social crises in time. The effectiveness of mitigation measures depends significantly on science-based decision-making, where the key factors are the rapid identification of outbreaks and infected people to limit the spread of the disease. In addition, the zoonotic origin of the current COVID-19 pandemic should serve as a call to work together under a One Health approach.

Since the first reports of shedding of SARS-CoV-2 in feces, wastewater surveillance has become a potential tool for monitoring current and future outbreaks of COVID-19 in the framework of epidemiology-based in waste water (WBE, by its acronym in English). However, many questions remain unanswered before WBE can be fully implemented as a reliable early warning tool. One of VIRWASTE’s goals is to answer these questions. The historical data obtained during the monitoring of 10 wastewater treatment plants (WWTPs) of different sizes distributed in Catalonia for the detection of the presence of SARS-CoV-2 (from March to December 2020) will be used to build an epidemiological model that allows a reliable estimate of the actual number of cases from SARS-CoV-2 concentrations in wastewater. To feed and refine this model, VIRWASTE plans to analyze: 1) faecal samples from patients with COVID-19 to determine excretion rates; 2) wastewater from hospitals with a recorded number of patients with COVID-19 to use as a reference; and 3) SARS-CoV-2 dynamics in laboratory and real-scale wastewater. The model will then be validated after semi-automated selection of extraction sites in neighborhood-scale wastewater networks to determine whether SARS-CoV-2 abundance in wastewater is a reliable predictor of cases of COVID-19 in all population sizes. Wastewater can also be a useful tool for studying viral diversity and searching for new viral species using cutting-edge metagenomics techniques. VIRWASTE will use targeted and untargeted metagenomic sequencing as well as deep amplicon sequencing to uncover the wastewater virome and describe the diversity of circulating strains of SARS-CoV-2 as well as other human coronaviruses (CoVs) and viral families with pandemic potential. Abattoir wastewater will be used to study the potential shedding of CoV and other potentially zoonotic viruses by livestock (sheep, cattle, pigs, poultry). In addition, and assuming that evolutionary analysis suggests that SARS-CoV-2 arose from a lineage of CoV present in bats before jumping to humans via an unknown intermediate animal host, VIRWASTE will analyze fecal samples from bats and small mammals in our geographic area to search for the presence of phylogenetic relatives of SARS-CoV-2 and other viral families with pandemic potential. Finally, we plan to integrate the project data into a Digital Observatory for the surveillance of SARS-CoV-2 in wastewater. Aware that health authorities will have to manage new pathogens and emerging threats in the coming years, the tools developed by VIRWASTE will help in the decision-making process to deal with current and future pandemics. The project consortium is made up of the UB (coordinator), ICRA, EURECAT and UdG.