Sewershed surveillance as a tool for smart management of a pandemic in threshold countries. Case study: tracking SARS-CoV-2 during COVID-19 pandemic in a major urban metropolis in northwestern Argentina

CECILIA CRUZ; DIEGO SANGUINO-JORQUERA; MONICA APARICIO; VERONICA IRAZUSTA; HECTOR ANTONIO CRISTÓBAL; VERONICA B RAJAL

SCIENCE OF THE TOTAL ENVIRONMENT

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2022

0048-9697

Wastewater-based epidemiology is an economical and effective tool for monitoring theCOVID-19 pandemic. In this study we proposed sampling campaigns that addressedspatial-temporal trends within a metropolitan area. This is a local study of detection andquantification of SARS-CoV-2 in wastewater during the onset, rise, and decline ofCOVID-19 cases in Salta city (Argentina) over the course of a twenty-one-week period(13 Aug to 30 Dec) in 2020. Wastewater samples were gathered from 13 sewermanholes specific to each sewershed catchment, prior to convergence or mixing withother sewer lines, resulting in samples specific to individual catchments with definedareas. The 13 sewershed catchments selected comprise 118,832 connected users tothe network throughout the city, representing 84.7% (534,747 individuals) of the totalpopulation. Number of COVID19-related exposure and symptoms cases in each areawere registered using an application developed for smartphones by the provincialgovernment. Geographical coordinates provided by the devices were recorded, andconsequently, it was possible to geolocalize all app-cases and track them down towhich of the 13 sampling catchments belonged. RNA fragments of SARS-CoV-2 weredetected in every site since the beginning of the monitoring, anticipating viralcirculation in the population. Over the course of the 21-week study, the concentrationsof SARS-CoV-2 ranged between 1.77×104 and 4.35×107 gc/L. There was acorrespondence with the highest viral load in wastewater and the peak number ofcases reported by the app for each catchment. The associations were evaluated withcorrelation analysis. The viral loads of SARS-CoV-2 in wastewater were a feasiblemeans to describe the trends of COVID-19 infections. Surveillance at sewershed scale,provided reliable and strategic information that could be used by local healthstakeholders to manage the COVID-19 pandemic.