After a marathon debate over a pair of studies that show how the avian H5N1 influenza virus could become transmissible in mammals, and an unprecedented recommendation by a government review panel to block publication, one of the studies was finally and fully published May 3, 2012 in the journal Nature. Publication caps an epic public conversation that pitted some infectious diseases experts against flu and public health researchers who argued that publication was not only important, but also essential to informing influenza surveillance and preparedness for a virus that could evolve to infect humans and cause a global pandemic（普遍的） .

"Our study shows that relatively few amino acid（氨基酸） mutations are sufficient for a virus with an avian H5 hemagglutinin（血球凝集素） to acquire the ability to transmit in mammals," says Yoshihiro Kawaoka, a University of Wisconsin-Madison flu researcher whose study of H5N1 virus transmissibility was at the center of the debate. "This study has significant public health benefits and contributes to our understanding of this important pathogen. By identifying mutations that facilitate transmission among mammals, those whose job it is to monitor viruses circulating in nature can look for these mutations so measures can be taken to effectively protect human health."

However, Kawaoka cautions there may be other unknown mutations that also enable the virus to transmit in mammals. It is therefore critical, he argues, to continue research to identify additional mutations that have the same effect, and to understand how they work.

The study, conducted by an international team of researchers led by Kawaoka, a UW-Madison professor of pathobiological sciences and a leading expert on influenza, shows that some viruses now circulating in nature require just four mutations to the hemagglutinin protein, which sits on the virus surface and enables it to bind to host cells, to become an even greater threat to human health. A subset of the mutations identified by the Wisconsin group has, in fact, already been detected in some viruses circulating in poultry（家禽） flocks in Egypt and parts of Southeast Asia, underscoring the urgency of science-based surveillance, Kawaoka says.