By Julie Steenhuysen
CHICAGO (Reuters) – The U.S. Centers for Disease Control and Prevention (CDC) plans to post data on influenza A found in wastewater in a public dashboard, possibly as soon as Friday, which could provide new clues to the H5N1 outbreak -bird flu in livestock herds.
Amy Kirby (NYSE:), leader of the CDC wastewater team, told Reuters on Thursday that the agency has identified spikes of influenza A, of which H5N1 is a subtype, at a handful of locations and is investigating the source. She said there is no evidence of human infection with H5N1.
Testing sewage wastewater proved to be a powerful tool for detecting mutations in the SARS-CoV-2 virus during the COVID-19 pandemic.
Kirby said the CDC has been collecting flu data in wastewater at about 600 locations since at least last fall to better track respiratory infections. That data could now be useful in tracking the H5N1 bird flu outbreak, which has infected 42 dairy herds in nine U.S. states and one dairy farm worker.
Scientists are closely watching for changes in the virus that could make it spread more easily among people.
The wastewater tests can detect many types of influenza A, including the H5N1 subtype, but the findings do not indicate the source of the virus, nor whether it came from a bird, cow, milk, farm runoff or people.
The dashboard allows individuals to monitor for increases in influenza A in their region and compare it to historical data, where available. Seasonal flu cases have fallen sharply, so spikes could be a signal of unusual flu activity.
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So far, tests have shown some increases in the presence of flu in samples that are “very localized to only a handful of locations,” Kirby said.
What is surprising, she said, is the outbreak in livestock and the presence of viruses in milk, which sometimes ends up in wastewater. The agency is now working to identify what factors contribute to the wastewater findings, including understanding the presence of milk in wastewater.
‘NO WORRY ABOUT THE COWS’
Dr. Marc Johnson, a virologist at the University of Missouri who developed a wastewater monitoring system for COVID, and other scientists have developed tests that can identify H5N1 in wastewater samples, but he said the CDC discourages the use of such tests.
Kirby said such widespread testing would be a drain on resources and ultimately fail to identify the source of the virus, although there may be times when such subtyping is necessary.
“It really doesn’t get us any further than knowing what the source of this is. Is it dairy? Or is it human? Or is it wild birds? Or is it poultry? All those things are still on the table,” she said. “It doesn’t take us any further.”
Johnson said such tests put scientists in a better position to monitor changes in the virus.
“I’m not worried about the cows. I’m not worried about the milk. But I’m worried that there are a lot of other animals he can jump to, and eventually he’ll find a combination that can make it. ” people if we are not careful,” he said.
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Academic researchers working with Verily, a health sciences unit of Alphabet (NASDAQ:), have already shown how wastewater can help with the outbreak.
Their not-yet-peer-reviewed paper, posted on medRxiv, identified the virus at three wastewater treatment plants in two Texas cities where infected livestock were present.
Using archived samples, they identified bird flu in wastewater as early as February 25, before the first reports of cattle with unknown diseases on March 7, and a full month before Texas confirmed H5N1 in dairy cattle.
“That represents a very significant lead time that we can have if we implement this work as widely and as easily as we should do as a country,” said Dr. Marlene Wolfe, of Emory University in Atlanta and program director of WastewaterSCAN, a wastewater detection program supported by Verily.
