Bird Flu Is More Widespread Among Dairy Cows, Sewage Tests Suggest

  • Wastewater monitoring showed hints of virus before cattle
  • Countries used sewage to track Covid-19 during pandemic
Infections have been reported in 51 herds of cows from nine states.Photographer: Sean Gallup/Getty Images
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A Michigan farmworker who tested positive for bird flu is just the second person to have been infected since an outbreak in US cattle appeared in March. Surveillance of sewage suggests the virus may be more widespread among dairy cows than reported, raising workers’ risk.

Academic and industry-run labs have been leading the way toward more nuanced and complete information about the H5N1 virus’s range by analyzing wastewater. They found bird flu in sewage samples collected before the virus had been identified in US cows. They’re seeing signs in cities that are far from infected cattle herds. And they’re already giving the Centers for Disease Control and Prevention better information about where to focus its efforts.