The Chinese Ministry of Agriculture has questioned findings published in Nature last week suggesting that an outbreak of bird flu among wild birds originated from unreported cases of the disease in poultry farms.
The authors of last weeks paper, however, defend their findings.
The paper described an outbreak at Lake Qinghai nature reserve in western China (see China: migrant birds 'open flight path for bird flu') and said the virus found there was genetically similar to samples taken earlier this year from a poultry market in the southern Guangdong province.
The day after the paper was published, the director-general of China's agriculture ministry's Veterinary Bureau questioned its credibility because the virus had not been reported in Guangdong this year. He also said the laboratory where the research was done did not have the facilities required to handle the bird flu virus safely.
Honglin Chen of Shantou University Medical College, the lead author of the Nature paper, says his team's conclusions will be supported by data soon to be published. He adds that their procedures meet standards set by the World Health Organization.
Chen also denies news reports that the ministry is trying to close down his laboratory.