A bird flu virus, H9N2, has the potential to cause a human pandemic, according to a team of researchers.
Experiments suggest that H9N2 has adapted to human cells, however, cases of person-to-person transmission have not been reported yet.
The researchers say more surveillance of the virus is needed.
The focus has been on avian influenza virus H5N1, but scientists are concerned about the spread of other bird viruses, including H9N2.
Author's summary: H9N2 bird flu strain may spark human pandemic.