Testing for SARS-CoV-2, the official name for coronavirus, has been a sticking point since the respiratory virus entered the United States at the beginning of 2020. The fact that anyone can have the virus, even after testing negative, coupled with the fact that nearly 25% of those with it are asymptomatic, leaves many questioning whether or not medical testing will ever give us an accurate measurement of the virus in the community.
In order to keep an eye on COVID-19 cases in East Baton Rouge Parish, LSU Civil and Environmental Engineering Professor John Pardue is working with LSU School of Veterinary Medicine Professor Gus Kousoulas and other LSU faculty to test wastewater from various areas of the parish to see how many cases exist.
“We need an early surveillance system that can detect SARS-CoV-2 in the community that minimizes the challenges and biases of individual medical testing,” Pardue said. “We are testing daily and have initial data that is very interesting. We hope to be a key metric for any potential second wave of the virus in Baton Rouge.”
Since SARS-CoV-2 is present in sewage, Pardue’s team collaborated with the City of Baton Rouge Department of Environmental Services to develop a testing method for SARS-CoV-2 with samples taken from subbasins, or the sewershed, as part of a high-resolution early warning system for new cases in the community.
The first step is taking the flow-composited wastewater sample and pasteurizing it, followed by performing an RNA extraction. A reverse transcription is then conducted to obtain cDNA, followed by the qPCR detection of SARS-CoV-2. The samples are tested at the GeneLab, a multi-faceted core laboratory directed by the Division of BioMMED at LSU SVM that engages in specific research and training projects.
“COVID-19-impacted patients shed the virus in fecal matter and continue to shed the virus for up to five weeks after negative respiratory samples,” Pardue said. “One single wastewater measurement can test an area of 300,000 people or an area that has only has 400 people living in it. It’s scalable and allows the researchers to know whether or not the numbers are going up or down each day.”
According to Pardue, environmental engineering faculty from universities in Houston, Oregon, and Michigan are doing similar testing for the cities they live in.
“Most cities have a gravity system, where the sewage flows down to one place, but cities like Baton Rouge and New Orleans are so flat that we don’t have that situation,” he said.
This means that Louisiana cities have their own individual pumping stations that collect wastewater from their area. Baton Rouge alone has more than 500 pumping stations, “so we can get precise with our sampling,” Pardue said.
There is also a new station for LSU’s campus and the surrounding area that can help track cases when students return in the fall.
Though the hope is to not have another COVID-19 outbreak, Pardue and his team of researchers are taking no chances. Their super-epidemiology method will put Baton Rouge ahead of the game so that LSU students and the city of Baton Rouge will know how quickly SARS-CoV-2 is spreading and take the necessary precautions to keep everyone safe until the virus is eradicated.