Eight Chinese scientists have asked a leading US medical journal to withdraw a letter published Thursday alleging that China knew about a human case of bird flu two years before the first case was officially announced.
The New England Journal of Medicine said its editors were "investigating the situation" after receiving a communication from the scientists Wednesday requesting that the letter to the editor be pulled from the publication.
"We do not yet have an explanation from the authors, but because the article is already printed in this weeks issue, we are alerting you," the journal's editor-in-chief, Jeffrey Drazen, said in a statement to the media.
In the letter, the scientists said the death of a 24-year-old man in Beijing in November 2003 had initially been blamed on the respiratory disease SARS.
But the man actually had the deadly H5N1 bird flu similar to what was found in chickens in China in 2004, the scientists said.
The World Health Organization sought explanations from Beijing Thursday on the 2003 human case.
"I don't think this is a surprise, that there may have been a human case in 2003 in China, the virus has been in the environment in China for quite a while," WHO spokesman Roy Wadia said.
"I think the surprise will be if this case was indeed confirmed at that time and it was not reported," he said.
The first human bird flu case reported to the WHO by China was in November 2005. The nation has now had a total of 19 human cases of whom 12 have died.