What’s Really Going on With Bird Flu Wastewater Data

Wastewater, which can measure how much virus humans excrete, has become a valuable disease-tracking tool.

But using that tool to track our current viral threat, the H5N1 bird flu that has begun circulating in cows, is much trickier. Finding even high levels of bird flu in wastewater does not necessarily mean an area is experiencing an outbreak. Rather, it sets off a hunt for the source.

That’s still valuable information, particularly amid the paucity of testing that has made it nearly impossible to gauge the state of the outbreak. But it’s also leading to some confusion and even alarmist interpretations.

...