ONCE THE CORONAVIRUS made its human debut, it wasn’t long before scientists found the virus in our poop. Fecal samples from the earliest patients, including the first known case in America, revealed people were shedding the virus not only from their noses and mouths, but also through their excrement.
This would turn out to be a pivotal discovery: If the virus was in our waste, it had to be in the sewers, too. And the sewers, scientists hoped, held information about how the virus was spreading, Guy H. Palmer, a professor of pathology and infectious diseases at Washington State University, told me. “They started saying, ‘We know this is in the wastewater. Can we measure it?’”
The answer was a
