Ron Fouchier, a virologist at the Erasmus Medical Centre in Rotterdam, deliberately mutated the virus before passing it from one group of ferrets to another, which led to five mutations in two genes. His work was submitted to Science, while the manuscript of a similar study carried out by Yoshihiro Kawaoka of Wisconsin and Tokyo universities was submitted to Nature.
While supportive of preventing research details falling into the wrong hands, Bruce Alberts and Philip Campbell, editors-in-chief of Science and Nature respectively, spoke of concerns about withholding potentially important public health information from responsible researchers.
Some scientists question whether such research should have been done in a university that does not have sophisticated anti-terrorist security. They also warn that viruses kept in seemingly secure laboratories have escaped in the past to cause epidemics - such as a 1977 flu outbreak.
"The fear is that if you create something this deadly and it goes into a global pandemic, the mortality and cost to the world could be massive," a senior scientific adviser to the US Government told the Independent. "The worst-case scenario here is worse than anything you can imagine."
The H5N1 strain of avian influenza has killed hundreds of millions of birds since 1996, but has so far infected only 600 people who came into direct contact with infected poultry. It has killed about 60 per cent of those people, making it one of the most lethal known forms of influenza in modern history - a deadliness moderated only by its inability, so far, to spread easily.
Scientists are in little doubt that the new strain has the potential to kill tens of millions of people. Independent