China had its first case of human bird flu infection in 2003, not 2005 when the first case was officially reported to the World Health Organization, according to eight Chinese scientists who wrote to the New England Journal of Medicine.

The patient was a 24-year-old man in November, 2003. It had been thought he had died of SARS. The letter does not mention whether samples were analyzed. This means human bird flu infection hit China before Vietnam, which reported its first case in December, 2003. During the SARS outbreak in 2003 the UN criticised China for its slow response.

The authors of the letter to the New England Journal of Medicine have requested that it be withdrawn. However, as the journal´s issue has already been printed this is not possible.

The WHO says it is vital to clarify this as it puts into question exactly how accurate the total number of confirmed cases really is. Confirmed cases of human bird flu infection have reached 228, of which 130 have been fatal. Does this figure really reflect the true numbers or does it only represent the minimum?

Tracking human infection is crucial in our fight against the mutation of H5N1. The more people who get infected the greater the virus´ chances of mutating. If we do not know about all the human infections our efforts are seriously undermined. If H5N1 mutates we could be facing a serious flu pandemic.

Chinese authorities are much more forthcoming now. International agencies are working much better with Chinese agencies and experts compared to a few years ago. Parts of southern China, where population density is high, require precise monitoring.