US Government Expands Sewage-System Testing for Data on Spread of Pathogens Including Covid-19

CNN reports that wastewater-based epidemiology 'has proven to be so reliable in dozens of pilot projects across the U.S. that the government has invested millions to create the National Wastewater Surveillance System, or NWSS, a network of 400 testing sites spread across 19 states that is coordinated by the U.S. Centers for Disease Control and Prevention.'

The pilot programs have already been 'quietly operating behind the scenes, generating data for public health departments across the country, since September 2020.'
For the first time, the CDC has published data that looks at how much coronavirus is turning up in the country's wastewater. It added this testing data to its Covid-19 dashboard. Tests show that there's been a decrease in the amount of virus at two-thirds of the 255 sites reporting data from the latest 15-day period.

The NWSS includes 400 sites overall, and more than 500 more will begin submitting data in the coming weeks, the CDC says.... [G]enetic material from the virus gets flushed down the toilet into the wastewater stream, where it can be detected by the same kinds of tests labs use to detect the virus from nasal swabs: real time polymerase chain reaction tests, or RT-PCR. This kind of testing is highly sensitive. It can pick up the presence of the virus when just one person out of 100,000 in a given area, or sewershed, is infected. And because wastewater testing doesn't depend on people to realize they're sick and seek out a test, or even to have symptoms at all, it's often the earliest warning a community has that wave of Covid-19 infections is on the way. The CDC estimates that...the samples typically turn positive in an area four to six days before clinical cases show up.

'As long as people are using a toilet that's connected to a sewer, we can get information on those cases in that community,' said Amy Kirby, a CDC microbiologist who leads the NWSS project... [But] this kind of testing can't signal when a community is free from the virus because the threshold of detection — how many people have to be positive in an area to show up in a water sample — isn't known. For these reasons, the CDC says, wastewater surveillance is best used along with case-based surveillance....

Kirby says wastewater monitoring will be around long after Covid is gone, too. By the end of the year, the CDC plans to expand the number of pathogens tracked on the dashboard to include influenza, a fungal superbug called Candida auris, and foodborne threats like E. coli and salmonella.

Read more of this story at Slashdot.