Sewage testing shows a country flush with Covid cases

Based on testing, it’s already clear that daily coronavirus case counts are rising -- but sewage testing suggests things are going to get a whole lot worse.   "It's a leading indicator," said Rosa Inchausti, whose colleagues have been testing wastewater in Tempe, Arizona. "The proof is in the poop."   Across the country, cities and universities are testing sewage to monitor the virus. Studies suggest it's a useful way to augment standard person-by-person coronavirus testing. While a sewage sample cannot point to an infected individual, it can give an indication that infections are circulating in an area, a neighborhood, or even in an individual building.   Early on in the pandemic, it became clear that the Covid-19 virus makes its way into the digestive system and could be found in human feces. From there, it's just a quick flush into the sewers.   Mariana Matus, co-founder and CEO of Biobot Analytics, which is analyzing sewage for dozens of customers, said sewage testing can show virus is starting to circulate even before people start showing up at hospitals and clinics and before they start lining up for Covid-19 tests.   "People start shedding virus pretty quickly after they are infected and before they start showing symptoms," Matus told CNN.   The results are clear on the Massachusetts Water Resources Authority website, which displays Biobot's analysis of data covering 2 million MWRA customers in the Boston area. It shows a spike in viral samples in April and May, falling back through the summer. Now the virus is showing up again, with samples at levels close to what was seen at the height of the pandemic in the spring.   "We are seeing an upturn in the wastewater data, which I think broadly matches what we are seeing across the country," Matus said. "It's been interesting seeing this almost second wave."