Thousands of wastewater samples from sewage systems across the US get flown and trucked to a lab in Cambridge, Massachusetts, every week. Inside the facility, which is owned by the company Biobot Analytics, employees in white lab coats prepare to test the samples for traces of the virus that causes covid-19. Since 2020, the lab has helped track the ongoing pandemic. Now, Biobot and other labs hope to expand the use of wastewater to track a wider array of diseases including the seasonal surges of …