Bat-borne influenza viruses enter host cells by utilizing surface exposed MHC-II molecules of various species, including humans. Now, an international research team from Germany (Medical Center—University of Freiburg and Friedrich-Loeffler-Institut, island of Riems) and the United States (Colorado State University, Fort Collins and Kansas State University, Manhattan) addressed concerns about the zoonotic spill-over potential and discovered an unexpected high genetic plasticity of the bat influenza virus H18N11 with unpredictable consequences.