Cool, and really worrying. spring of last year, spring of 2020, early on in the pandemic, we didn't have enough covid testing to track the virus. researchers from a biotech start-up in massachusetts. tried to fill up the surveillance gaffe on covid with wastewater. literally, with the water we flush down the toilet. it sounds super gross but it totally works. they learned that they really can carefully test sewage samples. test wastewater to find traces of covid infection. and you can tell who individually is infected in this way. but you can, reliably, find out how much covid is circulating i...