Influenza A virus subtype H5N1, also known as "bird flu", A(H5N1) or simply H5N1, is a subtype of the influenza A virus which can cause illness in humans and many other animal species. A bird-adapted strain of H5N1, called HPAI A(H5N1) for "highly pathogenic avian influenza virus of type A of subtype H5N1", is the causative agent of H5N1 flu, commonly known as "avian influenza" or "bird flu". It is enzootic in many bird populations, especially in Southeast Asia. One strain of HPAI A(H5N1) is spreading globally after first appearing in Asia. It is epizootic (an epidemic in nonhumans) and panzootic (affecting animals of many species, especially over a wide area), killing tens of millions of birds and spurring the culling of hundreds of millions of others to stem its spread. Most references to "bird flu" and H5N1 in the popular media refer to this strain.
At the end of last year, controversy sparked among the medical scientific community when an unprecedented event occurred. Two separate and independent studies made by a team of scientists lead by Yoshihiro Kawaoka of the University of Wisconsin and TIME 100 honoree Ron Fouchier of Erasmus University in the Netherlands, respectively, had their papers’ postponed and censored for publishing. The [...]