A 24-year-old Beijing man classified as having died of Sars in November 2003 in fact died of H5N1 bird flu, mainland doctors wrote in yesterday's issue of the New England Journal of Medicine.
The researchers, who include PLA doctors, asked at the last minute for their report to be withdrawn from publication. The team leader could not be contacted but one of the researchers, reached for comment, said 'military discipline' meant he could not speak.
If the man had bird flu rather than severe acute respiratory syndrome, it would mean the current H5N1 outbreak in Asian poultry, thought to have begun in South Korea in December 2003 and to have spread to humans in Vietnam that month, in fact started earlier.
Genetic sequencing of H5N1 samples taken from the man found it to be a 'mixed virus' with a lineage traceable to the 1996 Guangdong goose virus, the researchers reported. That virus was the genetic precursor of the H5N1 flu that first jumped the species barrier in 1997 in Hong Kong, killing six of 18 people infected.
The Beijing strain was closely related to H5N1 strains that killed poultry between January and March 2004 in Guangdong, Hubei and Jilin, and to virus strains in human cases in Thailand and Vietnam in 2004 and last year, the researchers wrote.
Editors of the journal said they received earlier yesterday 'a communication from the authors seeking to withdraw their letter'.
Ministry of Health spokesman Deng Haihua said: 'The ministry has not received any information about this case before. We are paying great attention to it.'