After endless toing and froing over whether two studies that demonstrated how bird flu, also known as avian H5N1 influenza, or avian flu, should be published, one of them has appeared in the latest issue of the journal Nature in its entirety. The studies show how the bird flu virus could become transmissible from mammal-to-mammal; as humans are mammals, the same would apply to humans. This is the end of a marathon debate, mainly between infectious disease experts versus influenza and public health researchers who stressed that not only was publication important, but also vital. To properly develop influenza surveillance and preparedness for a pathogen that could turn into a global, human pandemic, the scientists insisted that publication had to occur. University of Wisconsin-Madison flu researcher, Yoshihiro Kawaoka, whose study of H5N1 virus transmissibility was at the center of the controversy, said: \"Our study shows that relatively few amino acid mutations are sufficient for a virus with an avian H5 hemagglutinin to acquire the ability to transmit in mammals. 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.\" Other mutations we do not know about which might make the virus mammal-transmissible may be possible, Kawaoka cautions. It is because of this that further research into additional potential mutations are important. Kawaoka led an international team of researchers for this study. They say it shows that some of the viruses now in circulation in nature only need four mutations to the hemagglutinin protein, which is located on the surface of the virus and makes it possible for it to bind to host cells, and then to become a vastly more dangerous threat to human health. Some viruses, which currently circulate in poultry flocks in Egypt and Southeast Asia, already appear to have a subset of the mutations that were identified by the Wisconsin group - this fact alone underlines the importance of science-based surveillance, Kawaoka explained. In this latest Nature article, the Wisconsin scientists describe a bird flu/human flu hybrid virus that was modified in the lab; the virus has the capacity to become transmissible in an animal model for human infection with just a few mutations. Flu viruses that naturally exist in the environment are forever changing as they circulate - they exchange genes with other flu viruses. There is a chance that one day they swap genes in such a way that they become human-transmissible - the chances of this happening are much bigger than a great many experts believe, says Kawaoka.