Dozens of people in the United States have caught bird flu from animals this year, but there's no evidence that the viral disease has spread from one person to another. However, a single mutation in the virus could make human-to-human spread possible, a new study finds.
This genetic change would make the virus a much better "match" for cells in humans' airways; it would enable a protein on the surface of the virus to fit snugly into a receptor found on human cells. That would allow the virus to infect those cells more easily — and make it more likely to spark a pandemic.
