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How What You Flush Is Helping Track The Coronavirus


Communities around the country are looking for better ways to track their coronavirus outbreaks. One potential source could be in what you flush. NPR's Lauren Sommer reports on a new effort to measure the spread of the coronavirus through sewage.

LAUREN SOMMER, BYLINE: If you're infected with the coronavirus, it leaves your body through coughs and sneezes. But it also comes out the other end.

STEPHANIE LOEB: There's really a lot of information in our waste.

SOMMER: Stephanie Loeb is a postdoc at Stanford University. Her field of tracking human pathogens through our waste has been getting a lot of attention lately.

LOEB: Normally, when I tell people I work with poo, they're not super interested (laughter).

SOMMER: In her lab, which she showed me on Skype, she opens a freezer full of small vials of solids, as she calls them.

LOEB: Yep. It's all sorts of shades of that same color, sometimes darker and sometimes lighter (laughter).

SOMMER: Yeah, it's a freezer of raw sewage sampled from 25 wastewater treatment plants around California. But look at it another way. It's a health record for tens of thousands of people.

KRISTA WIGGINTON: It's this perfect mix. You know, the entire community is putting samples in at the same time.

SOMMER: Krista Wigginton is a professor of environmental engineering at the University of Michigan who is also working on the Stanford project. They're testing all those sewage samples for the coronavirus. The idea is that the more coronavirus cases spread in a community, the more shows up in the sewer system.

WIGGINTON: What's nice about that is it's a real-time measurement of what's happening in the community and what's being excreted in a community.

SOMMER: Which could provide an earlier warning than the tests that are run at a doctor's office.

WIGGINTON: Sometimes those are delayed by quite a bit of time because people don't go get checked until maybe their illness has progressed quite a bit.

SOMMER: This approach is already being used to detect outbreaks of polio in some countries. And the Stanford group isn't the only one trying to track coronavirus this way.

NEWSHA GHAELI: We have a lot of nicknames (laughter). I think some of our customers joke around that, you know, we're the sewer girls.

SOMMER: Newsha Ghaeli is a co-founder of Biobot, a startup that's testing sewage from 150 communities around the U.S. Originally, the company was using sewage to monitor the opioid crisis but quickly started offering coronavirus testing.

GHAELI: It really caught fire. Within 10 days, we hit internal capacity.

SOMMER: Ghaeli says in some cities, they've been able to detect coronavirus in sewage the same week the first cases popped up. They're working on using that information to extrapolate about how many people have the virus in a community. Scientifically, that's a bit trickier because you need to know how much virus a person usually sheds and for how long. But the company sees this technology playing a big role in detecting new waves of the outbreak.

GHAELI: Even once we do open up our cities again and we do go back to work again, it's very valuable for us to have a robust surveillance system in place.

DOUG YODER: I think it is potentially a new role that utilities can play.

SOMMER: Doug Yoder is deputy director of the Miami-Dade Water and Sewer Department in Florida. He's been sending samples to Biobot for six weeks now, which have shown their virus levels are going up and down a bit.

YODER: This data may not yet be ready for prime time in terms of community decision-making but that it definitely has potential and promise for being able to see trends.

SOMMER: Health officials are eager for the information, he says, as one more way to gauge what's really happening with their local outbreaks.

Lauren Sommer, NPR News.

(SOUNDBITE OF LEIFUR JAMES' "MUMMA DON'T TELL") Transcript provided by NPR, Copyright NPR.

Lauren Sommer covers climate change for NPR's Science Desk, from the scientists on the front lines of documenting the warming climate to the way those changes are reshaping communities and ecosystems around the world.