How different is the H1N1 (swine flu) virus from the H5N1 (avian/bird flu) virus?
In the last decade we’ve really had two major circulating forms of virus that we’re particularly concerned about — that is the avian flu, or bird flu, and the swine H1N1 virus. They are both influenza A viruses, but in terms of their genetic makeup and how they behave they are very, very different infections.