H5N1 tracking turns to wastewater

Amid outbreaks of H5N1 bird flu in cattle , public health officials are turning to wastewater surveillance as testing of cows and farmworkers remains slow. On May 14, the US Centers for Disease Control and Prevention (CDC) launched a dashboard that tracks the influenza A virus —including its subtype, H5N1—in wastewater treatment plants at about 600 sites across the country. Detecting viral genetic material through such surveillance can serve as an early indicator of disease presence and spread. "Wastewater is a really good, unbiased way of keeping tabs on where [the virus] is," says Marc Johnson, a molecular virologist at the University of Missouri. So far, the CDC's wastewater surveillance system doesn't specifically detect H5N1, but the agency is comparing weekly influenza A levels in wastewater at each site to that of the prior flu season. If these levels are high—meaning the 80th percentile or higher relative to virus concentrations