Bird flu in China: It's been there a long time

China has downplayed the presence of bird flu and kept the world at large in the dark. A death from the flu was never reported to the World Health Organization. This means the flu has had even more time to mutate to a human infection then originally believed.

A man died of H5N1 flu in Beijing in November 2003 - two full years before China admitted any human cases of H5N1. The death of the 24-year-old from bird flu came months before China even admitted H5N1 was circulating in its poultry. The man was tested for respiratory illness because of concern in the wake of the SARS epidemic.

It is not clear when the Chinese scientists who reported the finding discovered this, but they tried to withdraw their paper from the New England Journal of Medicine at the last minute on Wednesday. It was too late to prevent publication.

The case suggests that, as has long been suspected, many more people have caught H5N1 flu in China than have been reported, and for a longer time. The more human cases there are, the more chances the virus has to evolve into a human pandemic strain of flu.

"It's a very important issue that needs to be clarified urgently,'' Roy Wadia, a spokesman for the World Health Organization, said on Thursday in Beijing. "It raises questions as to how many other cases may not have been found at the time or may have been found retrospectively in testing."