https://www.scientificamerican.com/article/to-spot-future-coronavirus-flare-ups-search-the-sewers/

Mariana Matus has spent years studying what comes out of human bodies in order to better understand what is happening inside us. The computational biologist helped develop heavy-duty devices that are about the size of a milk crate and can be lowered into manholes to dangle over wastewater—steadily sucking up a stream of urine and feces through a strawlike tube.

Matus and her colleagues originally set out to scour sewers for chemical signatures of drug use. But in February reports emerged that it was possible to detect the genetic signature of the novel coronavirus in human stool. So Matus and a company she co-founded, Biobot Analytics, turned their attention to tracking the COVID-19 pandemic. They are now sampling sewage collected from 400 waste treatment plants, which, Matus says, cover an estimated 10 percent of the U.S. population.