As winter ends, several viruses are still continuing to rise across the U.S., according to data from WastewaterSCAN, a network of wastewater surveillance sites. Norovirus, one type of influenza, and another respiratory virus are all increasing or have recently peaked in samples from the network’s 190 wastewater treatment facilities, which are located in 41 states.
“What we’re seeing right now for the major viruses we are monitoring is that there are similar patterns across the country,” says Marlene Wolfe, assistant professor of environmental health at Emory University and one of WastewaterSCAN’s program directors. “We’re not seeing widely divergent patterns geographically.”
When people are infected, they shed viruses in their excretions, and analyzing samples from wastewater treatment plants is an efficient way to get almost real-time information on what’s ailing people in a given community. This type of data is especially useful when people don’t get tested at hospitals or doctors’ offices—and therefore aren’t registered in official case counts.
In general, the samples are picking up fewer cases of COVID-19 and influenza A, the type of flu that tends to cause more serious disease. RSV rates have also been steadily declining. Those patterns are typical as winter comes to a close.