Study shows the presence of COVID-19 in wastewater in Brazil in 2019

Researchers from the Spanish University of Burgos (center) and the Brazilian Federal University of Santa Catarina have coordinated a study that demonstrates the presence of the SARS-CoV-2 virus in wastewater in Brazil in November 2019.

As reported by the Spanish institution today, the study, published in the journal Science of the Total Environment, has analyzed the presence of SARS-CoV-2 virus in wastewater in Florianópolis (Brazil) at the end of November 2019.

The results indicate that SARS-CoV-2 probably circulated undetected in Brazil since November 2019, almost two months before the first reported case in America (January 21, 2020), and one before the notification of the first cases. clinics in the Chinese city of Wuhan, at the end of December 2019.

In this study, human wastewater from Florianópolis (Santa Catarina, Brazil) collected directly from the sewer system has been analyzed for the detection of the SARS-CoV-2 virus from October 2019 to March 2020.

The virus was detected using different RT-qPCR systems recommended by the American Center for Disease Control and European authorities, and the results of all positive samples were further confirmed in an independent laboratory.

To corroborate the veracity of the results, the RT-qPCR products were sequenced to confirm identity with SARS-CoV-2 and a direct and complete sequencing study was performed on the virus-positive wastewater samples.

The SARS-CoV-2 virus RNA was detected on November 27, 2019, and the detection was confirmed in an independent laboratory and by sequencing analysis of the wastewater sample.

Also the samples in the three subsequent analyzes (December 2019, February 2020 and March 2020) were positive in all RT-qPCR assays, even with a strong increase in samples taken in early March.

The relevance of this study lies in the fact that it is the first detection of the presence of RNA of the SARS-CoV-2 virus worldwide, on November 27, 2019 and also implies the presence and circulation of the virus in the American continent at less from that date, 56 days before the first official notification of a clinical case of covid-19 in that continent and more than 90 days before in the case of Brazil.

It also reveals the presence and possible circulation of the virus before the official notification of the first clinical cases of covid-19 in the city of Wuhan, reported to the WHO at the end of December 2019.

In this way, the findings suggest that SARS-CoV-2 circulated unnoticed in the community for a few months before the pandemic status was declared.

The results also show that the SARS-CoV-2 viral load remained constant until early March, then increased coinciding with the onset of COVID-19 cases in the Santa Catarina region, where Florianópolis is located.

This study highlights the interest of monitoring the presence of the SARS-CoV-2 virus in wastewater as a non-invasive early warning tool for evaluating the trend of COVID-19 infection.