Large amount of bird flu virus in milk suggests asymptomatic cows are infected with H5N1
Since March, when the first reported cases of H5N1 bird flu began showing up in dairy cattle in Texas, the Food and Drug Administration has been asking farmers to discard any milk from infected animals. Initially, spotting tainted milk was believed to be fairly easy because cows that get sick with H5N1 begin producing milk that is thick and yellowish.
But in recent weeks, studies have found genetic traces of H5N1 in a large percentage of commercial milk products. Significant amounts of viral material from the avian influenza have also turned up in wastewater in Texas, specifically in areas where dairy processing plants are located. The presence of these viral fragments doesn’t mean H5N1 is biologically active in these samples or capable of causing disease. All the evidence generated to date indicates that pasteurization is effective at inactivating H5N1 in milk, though the FDA continues to study the issue.
