Mystery thickens around report of early Chinese bird flu case

Hours before the official release of this week's issue of New England Journal of Medicine, editors at the journal received a series of e-mails from someone purporting to be Dr. Wu-Chun Cao, one of the authors of the report which had been submitted by eight Chinese scientists.

But on Friday, editors at the journal spoke by phone with someone they believe to be Cao. He categorically denied having sent the e-mails and told the journal he and his co-authors stand behind their report.

Cao, of the State Key Laboratory of Pathogens and Biosecurity, later faxed the journal a letter reaffirming those claims.

"He has not requested withdrawal of the report, and so it stands as published in the issue of June 22," Dr. Jeffrey Drazen, editor-in-chief, said in a statement.

"We are continuing to investigate."

The eight researchers reported on the molecular characteristics of an H5N1 virus isolated from a Chinese man who died in November 2003.

The report has stirred up intense interest in the scientific world because that was two full years before Beijing first reported a human H5N1 case to the World Health Organization, in November 2005.

The authors made no reference to the discrepancy between their report and China's official H5N1 timeline. Nor did they indicate whether the testing that discovered H5N1 virus in the dead man's lung was actually done around the time of death or more recently.

When the report was published the WHO's China office formally requested that the Chinese Ministry of Health explain the discrepancy and provide information about the case.

On Friday, a WHO spokesperson in Geneva declined to comment on the latest development.

Influenza experts outside China have long believed the country has hidden or missed human cases of H5N1, but they hadn't anticipated seeing proof in the pages of one of the world's most prestigious medical journals. China has officially reported 19 cases and 12 deaths.

A spokesperson for the New England Journal of Medicine said the journal had received "multiple" e-mails asking to withdraw the report. From the e-mail addresses, some seemed to be from Cao; others claimed to be from all eight authors.

"It seemed very clear that they were coming from Dr. Cao and/or that institution," Karen Pedersen said from Boston. Copies of the e-mails were also faxed to the journal.

But editors could not immediately reach Cao to explore why he wanted the report pulled and to explain it was too late - the journal had been printed and mailed to subscribers days earlier.

On Friday someone identifying himself as Cao called the journal and said he hadn't made the request and didn't want to withdraw the report. Pedersen said the journal editors believe that call was legitimate.

The editors asked Cao to submit a letter reaffirming that the report should stand, and they received that letter. Pedersen said the journal was in the process Friday of getting the remaining seven researchers to sign similar letters.