H1N2 currently poses a tremendous public health concern because it has spread to both human and pig populations. Influenza is a highly contagious respiratory infection that causes severe illness, particularly in people who are either very young or very old and people who already have an existing health condition.
A bird-adapted strain of H5N1, called HPAI A(H5N1) for highly pathogenic avian influenza virus of type A of subtype H5N1, is the highly pathogenic causative agent of H5N1 flu, commonly known as avian influenza ("bird flu"). It is enzootic (maintained in the population) in many bird populations, especially in Southeast Asia.
Influenza is a contagious respiratory illness, and any influenza virus, including H7N2, has the potential to cause mild to severe illness or severe flu complications. Of the two previously known cases of human infection with H7N2 virus infection (which occurred in 2002 and 2003 [185 KB, 4 pages]), both experienced mild to moderate illness and both recovered.