The United States Government has taken the unprecedented step of asking scientists to censor key parts of their work describing how they managed to mutate the H5N1 bird flu virus into a strain that could be highly infectious.
Officials have become so alarmed at the prospect of the information falling into the hands of terrorists that they have asked for critical details of the experiments to be deleted before publication.
Two groups of scientists, in the Netherlands and the US, have submitted scientific papers describing how they managed to convert the virus, which does not spread easily between people, into an airborne form that can be transmitted in coughs and sneezes.
In a statement released yesterday, the US National Institutes of Health, which funded the research, says there are concerns that the virus could evolve naturally into a form that is transmissible between humans, which could result in a devastating pandemic.
"While the public health benefits of such research can be important, certain information obtained through such studies has the potential to be misused for harmful purposes," the statement says. "These manuscripts ... concluded that the H5N1 virus has greater potential than previously believed to gain a dangerous capacity to be transmitted among mammals, including perhaps humans."
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