A Single Mutation Could Bring Bird Flu a Critical Step Closer to a New Pandemic ScienceAlertWhy hasn’t the bird flu pandemic started? ScienceInfluenza A(H5N1) shedding in air corresponds to transmissibility in mammals Nature.comUnder certain conditions, a single H5N1 flu virus mutation could lead to spread among people University of Minnesota Twin CitiesHealth officials say bird flu risk is low for Texans, caution those who work closely with animals KXAN.com