not to mention that the spanish flu cells that have survived for the past 80 years still haven't mutated a tad, so it's not as if these mutations are frequent.The irony of the avian influenza is that it's actually been spreading more and more and killing more and more people, but people really don't care because it's gone this long without mutating.I think what we should be worried (if we're worried about any disease) about is Marburg. If that disease could get into a metropolitan area that'd be the end.One of the funny things is that it's mutated from H5N1, what they were afraid of, to the benign H7N2 (which is about the intensity of a normal flu), and H5N2 (again, not terminal).The H5N1 has also gone from about a 90% death rate to a 50% death rate. It's proliferating just as much but people aren't all dying from it.