Presence of SARS-CoV-2 in urban effluents in south-east Buenos Aires, Argentina, May 2020 to March 2022

Abstract

Objectives. Establish and apply appropriate and low-cost protocols for the sampling and concentration of wastewater from different locations on the southeast coast of the province of Buenos Aires, Argentina, to achieve the detection of SARS-CoV-2.Methods. In order to analyze samples from General Pueyrredon district, 400 mL of wastewater were taken with an automatic sampler for 24 hours, while in Pinamar 20 L in total, 2,2 L at 20-minute intervals were taken. In both places, samples were collected once a week. The samples were concentrated by methods based on polyaluminum chloride driven flocculation. RNA purification and target gene amplification were performed using detection systems by RT-qPCR for clinical diagnosis of human nasopharyngeal swabs.Results. In both districts, the presence of SARS-CoV-2 was detected in wastewater. In particular, in General Pueyrredon it was able to detect it in the Epidemiological Week (EW) 28, 2020, 20 days before the start of the increase in cases of the first wave (EW 31) and 9 EW before the maximum amount of laboratory-confirmed cases. Until now, the established protocol is used for SARS-CoV-2 monitoring in General Pueyrredon district wastewater.Conclusions. The early detection of the SARS-CoV-2 virus genome in wastewater was possible, demonstrating the usefulness of the application of wastewater epidemiology for SARS-CoV-2 long-term detection and monitoring.