The New York Times examines several studies published in the journals Nature and Science looking at how the H5N1 bird flu virus could mutate to become more virulent among humans and outlines the history of controversy surrounding the studies. “While scientists have offered two possible ways in which H5N1 might become a human flu, they’re almost certainly not the only two,” the newspaper writes, adding, “There is no checklist of mutations that any bird flu must acquire to start infecting humans.” According to the newspaper, “Anthony S. Fauci, director of the National Institute of Allergy and Infectious Diseases, hopes scientists will be able to amass a longer list of potential mutations, and even find a common denominator in how they alter H5N1,” which might make it “possible to monitor emerging strains for signs that they are about to cross over into humans” (Zimmer, 6/25).