Scientists ID Mutations that Could Allow Bird Flu Strain to Spread Among Humans (image) PLOS Share Print E-Mail Caption Three amino acid changes promote binding to human-type receptors by H7N9 HA. Credit de Vries RP, et al. (2017) Usage Restrictions CC-BY Share Print E-Mail Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.