Wastewater-based epidemiology: Detection of SARS-CoV-2 RNA in different stages of domestic wastewater treatment in Santa Fe, Argentina

RENO, U.; REGALDO, L.; OJEDA, G.; SCHMUCK, J.; ROMERO, N.; POLLA, W.; KERGARAVAT, S.V.; CASTRO, G.R.; GAGNETEN, A.M.

Guwahati

Conferencia; International Conference on Biotechnology for Sustainable Bioresources and Bioeconomy (BSB2-2022) and the XIX Annual Convention of the Biotech Research Society, India (BRSI); 2022

Indian Institute of Technology

An efcient treatment of DWW has become a great challenge with the outbreak of the COVID-19pandemia, which affected human life at every level. For the first time in Argentina, we analyzed genetic markers (N and ORF1ab, RNA genes) of SARS-CoV-2 in domestic wastewaters (DWW) in San Justo City (Santa Fe, Argentina), using reverse transcription-quantitative real-time PCR. The assay targets specific SARS-CoV-2 genomic regions: nucleocapsid gene (N) and open reading frame gene 1ab (ORF1ab). The cycle threshold values (Ct) for the two viral genes (N and ORF1ab) were considered positive when they were below 40 Ct. Out of the 30 analyzed samples, 30% were positive for SARS- CoV-2 RNA. Of the total positive samples, 77% correspond to untreated DWW, 23% to pre- chlorination, and no SARS-CoV-2 RNA was registered at the post-chlorination sampling site. The viral loads of N and OFR1ab genes decreased significantly along the treatment process, and the increase in the number of viral copies of the N gene could anticipate, by 6 days, the number of clinical cases in the population. The efficiency of WBE confirms the need to control and increase DWW treatment systems on a regional and global scale, especially in developing countries. This work could contribute to building a network for WBE to monitor SARS-CoV-2 in wastewaters during the pandemic waves and the epidemic remission phase.