I hope that fear of terrorism will not lead to the suppression of valuable research about engineering the H5N1 virusA few months ago, Dutch virologist Ron Fouchier made what he hoped would be a low-key announcement at a conference on influenza in Malta. After a series of painstaking experiments, Fouchier announced he had achieved the holy grail of influenza research: engineering the H5N1 bird flu virus so that it could pass easily between mammals.

The "airborne" virus had been created, Fouchier explained, not by using sophisticated, lab-based genetic technology but by the relatively low-tech method of passaging H5N1 repeatedly through ferrets.

The significance of the discovery was not lost on the assembled delegates. If ferrets could be infected this way, then so could humans ...