The H5N1 bird flu virus has killed hundreds of people, despite the fact that the virus can’t spread easily between people. The death toll could become much worse if the virus became airborne. A study reveals a minimal set of mutations allowing H5N1 to be transmitted through the air from one ferret to another. The findings will be invaluable for future surveillance programs and may provide warning signals of the emergence of potential pandemic strains.

“By gaining fundamental knowledge about how the influenza virus adapts to mammals and becomes airborne, we may ultimately be able to identify viruses that pose a public health risk among the large number of influenza viruses that are circulating in animals,” says senior study author Ron Fouchier of Erasmus Medical Center. “If we can do this, we might be able to prevent some pandemics in the future.”