Study detects presence of SARS-CoV-2 in Brazilian wastewater since late 2019

RIO DE JANEIRO, BRAZIL – Researchers from the Spanish university of Burgos and the Federal University of Santa Catarina have jointly led a study that detected the presence of SARS-CoV-2, the novel coronavirus that causes Covid-19, in wastewater in Brazil as early as November 2019.

On Tuesday, March 9th, the Spanish institution said that the study, published in the Science of the Total Environment journal, specifically analyzed the presence of the pathogen in wastewater in Florianópolis.

All the research results suggested that SARS-CoV-2 had most likely been circulating undetected in Brazil since that time, two months before the first case in South America was reported on January 21st, 2020, and one month before the first positives were confirmed in Wuhan, China.

The study analyzed human wastewater from Florianópolis, collected directly from the sewage system, to detect the novel coronavirus over the period spanning October 2019 and March 2020.

The pathogen was detected using different RT-qPCR systems, recommended by US, European, and other disease control centers. All positive sample results were subsequently confirmed by an independent laboratory.

RT-qPCR results were sequenced to confirm the identity against SARS-CoV-2, and a complete direct sequencing study of the wastewater samples was performed to corroborate the accuracy of the findings.

In addition, samples from three subsequent analyses (from December 2019, February and March 2020) tested positive in all RT-qPCR tests, including a marked increase in the samples taken in early March last year.

This is the first detection of the presence of SARS-CoV-2 RNA on the American continent, and signals the presence and circulation of the pathogen 56 days before the first official notification of a Covid-19 clinical case on the continent, and over 90 days before the first positive in Brazil.

The results also showed that the viral load of the novel coronavirus remained constant between November 2019 and March 2020, and then experienced an increase that coincided with the outbreak of cases in Santa Catarina.

Source: R7