flu
As the world focuses on the deadly H5N1 bird flu, another avian influenza virus—H9N2—is quietly gaining new abilities. Once considered a mild strain limited to birds, H9N2 is showing signs…
As the world focuses on the deadly H5N1 bird flu, another avian influenza virus—H9N2—is quietly gaining new abilities. Once considered a mild strain limited to birds, H9N2 is showing signs…