SARS-CoV-2 RNA detected in untreated wastewater from Louisiana

Date:
August 26, 2020
Source:
Hokkaido University
Summary:
Scientists have detected genetic material from SARS-CoV-2 in
untreated wastewater samples collected in April 2020 from two
wastewater treatment plants in Louisiana.



FULL STORY ==========================================================================
A group of scientists has detected genetic material from SARS-CoV-2 in untreated wastewater samples collected in April 2020 from two wastewater treatment plants in Louisiana, USA.


========================================================================== Wastewater-Based Epidemiology (WBE) is a process by which the spread of
disease in human populations is tracked by testing wastewater. It has been
used to track the spread of polio and norovirus infections. Many groups
around the world are working on developing methods to adapt WBE to track COVID-19. Using these methods, SARS-CoV-2 has been detected in municipal wastewater from Australia, Spain, Italy, the Netherlands and Japan.

In a paper published in the journal Science of the Total Environment,
a group of researchers -- including Samendra P. Sherchan of Tulane
University, USA, and Masaaki Kitajima of Hokkaido University -- have
reported the detection of SARS- CoV-2 RNA in untreated wastewater samples collected in April 2020 from southern Louisiana. This is the first report
of detection of the virus in wastewater in North America.

Samples were collected monthly between January and April 2020 from two anonymous wastewater treatment plants, which serve populations of 244,627
(WWTP A) and 45,694 (WWTP B) respectively. The samples included untreated wastewater, treated wastewater before chlorination, and chlorinated
effluent wastewater.

The scientists attempted to recover SARS-CoV-2 from these samples by one
of two methods: ultrafiltration (filtering samples through extremely
fine filters to collect the virus) or adsorption elution (passing the
sample through a membrane that binds the virus, and then collecting the
virus by rinsing it out). The amount of virus recovered was determined
by reverse transcription-quantitative PCR, the standard method to test
for SARS-CoV-2.

Out of a total of 15 samples, the scientists detected SARS-CoV-2
in just two samples. The viruses were detected in samples that were
processed by ultrafiltration, but not in the samples concentrated by adsorption-elution.

Further, the virus was only detected in untreated waste, but not in any
of the treated wastewater samples -- indicating that standard wastewater processing may be sufficient to remove and/or destroy the virus. Finally,
the virus was only detected in samples collected in April (WWTP A on April
29 and WWTP B on April 8). Over the sampling period, the total number of confirmed cases in the areas served by the wastewater treatment plants
was highest in this month.

The scientists concluded that ultrafiltration was the superior method
for recovery of the virus, but other factors may interfere with the
detection of the virus. However, further tests are required on larger
sample sizes to understand the limits of this method, and to compare it
to other methods currently being tested for the same purpose. In general,
for the WBE of COVID- 19, better virus concentration methods and virus detection methods are required.

"Recent reports on the detection of SARS-CoV-2 RNA from multiple countries including Japan and US have validated the concept of WBE for COVID-19 surveillance," says Masaaki Kitajima. "I hope COVID-19 WBE studies will
be accelerated on a global scale through international collaborations." Assistant Professor Kitajima is currently involved in a number of
studies related to applying WBE to tracking the spread of the COVID-19 pandemic. He has collaborated with a number of scientists and research
groups across the world in this endeavour, and was part of the team that
first detected SARS-CoV-2 in wastewater in Japan.


========================================================================== Story Source: Materials provided by Hokkaido_University. Note: Content
may be edited for style and length.


========================================================================== Journal Reference:
1. Samendra P. Sherchan, Shalina Shahin, Lauren M. Ward, Sarmila
Tandukar,
Tiong G. Aw, Bradley Schmitz, Warish Ahmed, Masaaki Kitajima. First
detection of SARS-CoV-2 RNA in wastewater in North America: A
study in Louisiana, USA. Science of The Total Environment, 2020;
743: 140621 DOI: 10.1016/j.scitotenv.2020.140621 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/08/200826101630.htm

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