Lab scientists have determined that an emerging strain of bird flu could mutate to become more infectious in humans, reports Stat News.

Flu viruses attach to receptors found on the cells of their intended victims. Bird flu viruses attach to one type of receptor. The cells found in the human upper respiratory tract — where a flu infection takes hold — are mostly lined with a different type of receptor, which explains why these viruses don’t easily infect people.

The Scripps team, however, found that by tweaking the genetic code of H7N9’s hemagglutinin gene, they could change the receptors the virus latched on to, from the bird type to the human version.

The proteins made by the two modified hemagglutinin genes attached as well to human receptors as the human virus H1N1, which caused the 2009 flu pandemic, noted Ron Fouchier, a leading influenza virologist from Erasmus Medical Center in Rotterdam, the Netherlands.