The research, led by Yoshihiro Kawaoka of the University of Wisconsin, was one of two experiments that a federal advisory panel had asked journals to hold off publishing because the papers might provide a how-to guide for terrorists or mischief-makers. (Firdia Lisnawati/AP) 
 
 The journal Nature, after much debate and delay, on Wednesday published a paper in which scientists describe how they engineered a part of the deadly H5N1 “bird flu” virus to become more transmissible in mammals. He and his team developed a hybrid bird flu virus that combined an H5 hemagglutinin gene — which helps viruses bind to host cells — with genes from 2009's pandemic H1N1 flu, also known as swine flu. The publication of Kawaoka's paper comes after months of debate over his research and experiments conducted in the lab of Dutch virologist Ron Fouchier, who has also developed strains of bird flu that can pass between ferrets. Since it emerged in Hong Kong in 1997, H5N1 influenza has killed millions of chickens, mostly in Asia. Very few people — 602, according to the latest World Health Organization estimate — have been infected since the latest outbreak in 2003, but 355 of them died. The National Science Advisory Board for Biosecurity, a panel of independent experts that advises the federal government, in December asked the two journals to hold off publishing the papers while researchers and governments thought about how to handle this kind of research. One of the mutations his team identified is already circulating in viruses in the Middle East and Asia, he said.
– The journal Nature has published a controversial paper describing how University of Wisconsin scientists created an airborne strain of H5N1—aka "bird flu"—that was transmissible in mammals. A federal panel had asked Nature not to publish the study, and a similar one from a Dutch virologist, fearing they might provide a handy DIY guide for bioterrorists, the Washington Post reports. They eventually dropped their objections, however, once they realized that the more-contagious virus was also less deadly. Researchers added two mutations to a deadly H5N1 strain, mixed in some swine flu genes, and released it on a group of ferrets. The ferrets caught the virus easily—but didn't die or even get very sick. The research was conducted to understand how the virus might mutate in nature—and indeed, scientists say the process was simple enough to occur naturally, the LA Times reports. "It's a great place to start looking for exactly what's going on," says one virologist.