Bird flu virus likely mutated within Louisiana patient who became severely ill, CDC says PBS NewsHourGenetic Sequences of Highly Pathogenic Avian Influenza A(H5N1) Viruses Identified in a Person in Louisiana CDCWe ‘have our head in the sand’: Health experts warn US isn’t reacting fast enough to threat of bird flu CNNBird Flu Samples From Very Ill Patient Had ‘Concerning’ Mutations The New York TimesBird flu virus shows mutations in first severe human case in US, CDC says Reuters