U researchers testing campus sewage for COVID-19

A person wearing a mask in a science lab.
Glenn Simmons Jr., an assistant professor at the University of Minnesota Medical School in Duluth, is one of two researchers studying the presence of COVID-19 in raw wastewater in Minnesota communities.
Courtesy of University of Minnesota Medical School

The University of Minnesota is expanding an effort to look for COVID-19 in human sewage to include dormitories on its Twin Cities and Duluth campuses.

Glenn Simmons Jr. and Richard Melvin, both assistant professors at the U’s medical school in Duluth, have been testing samples of untreated wastewater from cities across Minnesota since May.

They started with about 18 cities — including Rochester, Moorhead and Duluth — and since then have expanded to more than 40, including the Twin Cities metro area.

Now, the researchers have started collecting samples of wastewater twice a week from 13 university buildings in the Twin Cities and six in Duluth. The university declined to identify which buildings.

The goal of the project is to give health officials “another tool in the toolbox” to detect a virus outbreak sooner than in-person testing provides, said Dr. Tim Schacker, vice dean for research at the University of Minnesota Medical School.

Studies have found people with COVID-19 shed the virus not only in droplets from their mouth and nose, but also in their stool, even when they have no symptoms.

“It gives you a snapshot in time of what's happening in the community, as opposed to an individual,” Schacker said.

The university researchers are trying to determine whether, if they detect a change in virus levels, public health officials could deploy resources — such as increased testing, contact tracing and targeted quarantines — and possibly help contain the spread of infection, he said.

The U scientists first focused on cities, but also wanted to narrow their research to dormitories on campus to see if they’re able to detect increases in how frequently the virus is detected.

“If we go in and test everybody in the dorm, will that make a difference?” Schacker asked. “And will we stop the spread of infections?”

The U of M is one of several colleges and universities across the United States working to develop a method for detecting COVID-19 in wastewater, hoping it could serve as an early warning system for outbreaks on campus.

Tracking disease in wastewater is not new. Scientists have used the method to detect polio outbreaks in other countries. Research during the 2002 SARS outbreak found the virus was showing up in human waste. Earlier this year, scientists in the Netherlands found traces of the coronavirus in wastewater before cases were reported.

The method of detecting COVID-19 in wastewater is similar to the nasal swab testing for individual patients, Schacker said. But instead of fluid taken from the nose, the researchers are collecting samples of wastewater before it’s treated to remove pathogens like viruses.

In the lab, they analyze the sample to detect genetic material from COVID-19, then use a process called polymerase chain reaction, or PCR, to measure how much of the virus was present.

With large cities like Minneapolis and St. Paul, it’s difficult to pinpoint changes in virus levels, because there are always likely to be pockets of infection present, Schacker said. So researchers are working with the Metropolitan Council to go “further up the pipe” and isolate testing of individual communities or even neighborhoods, he said.

“If we have a smaller group that we're sampling, we can probably detect changes earlier and with more precision,” he said.

Schacker stressed that the study is in the early stages, and researchers are still trying to figure out how to develop the wastewater testing tool in a way that benefits public health.

“We’re building an airplane while we’re flying it,” he said. “So we come up with these tools, and we’re trying to understand how they work while we’re fighting the pandemic.”


COVID-19 in Minnesota

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