The researcher also looked at studies dating back to the 1940s of airborne flu virus survival.

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His group will attempt to nail down exactly how many mutations - and which - are sufficient to make the H5N1 avian flu virus airborne, and whether these particular mutations can also make other bird flu viruses airborne.

CNN: Bird flu research resumes -- but not in U.S.

While the Nature study looked at how a bird flu virus could become airborne through mutations and re-assortment with other viruses, the Science study suggests mutations alone could do the trick.

CNN: Bird flu research resumes -- but not in U.S.

Also keep in mind, this is mainly an airborne thing or something that lives on inanimate objects, so people touch the virus, then they touch their mouth, they touch their nose, they touch their eyes.

CNN: The story