"Even sporadic cases of human-to-human transmission indicate a big change in the virus and suggest it is exploring new ...

U.S. health officials have run into obstacles in their efforts to determine whether a Missouri person infected with H5N1 bird ...

The latest developments are highly concerning, as they raise the possibility that the H5N1 virus has evolved the ability to ...

Missouri officials are under growing pressure from national public health experts to pinpoint the source of the state’s first ...

Missouri officials are under growing pressure from national public health experts to pinpoint the source of the state’s first ...

The CDC said an investigation into a human H5N1 bird flu infection in Missouri has found four additional health care workers ...

Chances are low that human-to-human spread of bird flu occurred in a group of people who were exposed to a patient infected ...

Seven people fell ill with flu-like symptoms after contact with someone infected with H5N1, raising fears that the virus has ...

Testing is ongoing among five health care workers and a household member exposed to the infected person who all came down ...

More than a month after a person in Missouri mysteriously fell ill with H5-type bird flu, investigators in the state are ...

None of the health care workers or other contact have tested positive for avian flu antibodies so far — but could their ...

In what could be the first cases of bird flu spreading between humans in the United States, a group of potential H5N1 ...