An ongoing bird flu outbreak has swept through 700 dairy herds in 15 states. (Jim Vondruska/Reuters)
Federal disease trackers reported Tuesday that the first child diagnosed with bird flu in an ongoing U.S. outbreak was infected with a virus strain moving rapidly through dairy cattle, even though there is no evidence the youngster was exposed to livestock or any infected animals.
The finding by the Centers for Disease Control and Prevention about the child, who lives in California, deepened the mystery about the spread of H5N1 bird flu, a viral ailment that epidemiologists have watched warily for more than two decades, fearing it could spark a pandemic.