The general public health threat remains low, but some infectious disease experts worry about a thinning line that's kept bird flu from spreading between people.

A California child was confirmed to be the first U.S. child to become infected with bird flu, the U.S. Centers for Disease Control and Prevention announced Friday.

A rare case of avian influenza, commonly known as bird flu, has been confirmed in a child in the United States, according to the Centers for Disease Control and Prevention (CDC). The child, who is a resident of California,

California's public health department had reported the case on Tuesday, but said there was no evidence of human-to-human transmission of the virus. The CDC affirmed that currently there was no evidence of person-to-person spread of H5N1 bird flu from this child to others,