Vigilância do SARS-COV-2 em águas residuárias provenientes do campus universitário e do município de Lavras/MG

Abstract

Tracking the SARS-CoV-2 virus is an important measure for implementing countermeasures that minimize the risk of viral spread to the human population. Therefore, knowledge about SARS-CoV-2 in environmental samples, such as sewage, is fundamental to controlling the COVID-19 pandemic. In this sense, this research aimed to detect and quantify the viral load of SARS-CoV-2 in wastewater samples collected at Sewage Treatment Stations (STSs) in Lavras- MG municipality, aiming to track the viral load of the virus. Wastewater samples were collected weekly at the entrances of municipal STSs, including STS-UFLA, located on the University Campus. Viral concentration was performed using the electronegative membrane filtration method. For the detection and quantification of SARS-CoV-2 the RT-qPCR method was used, for the detection of the N1 region of the SARS-CoV-2 genome. In the sampled material, the variables pH, Total Suspended Solids (TSS), Total Coliforms (CT), Thermotolerant Coliforms (Cterm), Surfactants, Chemical Oxygen Demand (COD), as well as a survey of the compilation of records of individuals infected between July 2021 and July 2022 in epidemiological reports, aiming at evaluating the possibility of correlation between the different variables and the viral concentration of the SARS-CoV-2 present in these samples. The results achieved showed that the monitoring of the STSs allowed the evaluation of the concentration of SARS-CoV-2 in the wastewater, showing a concentration ranging from 0 to 1,680 copies of RNA/L per sample. The results complement the monitoring via testing and showed a trend line with an increase in the number of cases and concentration circulating in the wastewaters, especially in the 2nd to 6th epidemiological weeks of 2022, which followed the end of the year festivities and Carnival. The viral concentration of the three stations increased in January and February of 2022, which may have been caused by the return of the school period and also the appearance of the variant B.1.1.529. It was possible to detect and quantify the viral load of SARS-CoV-2 in the analyzed samples, as well as its correlation with the physical, chemical and microbiological variables. Results prove that the viral load found in samples can be from known clinical cases, but also from asymptomatic cases.