The World Health Organization (WHO) confirmed today it would help investigate a possible human case of bird flu in China.
China has yet to report any human cases of bird flu but said yesterday it would invite WHO experts to investigate three suspicious cases of pneumonia in the southern province of Hunan, the site of one of the recent outbreaks among birds.
More than six million birds were culled in an area hit by the country's fourth outbreak of the virus in a month.
Beijing had previously denied any connection between the deadly H5N1 form of the bird flu virus and the pneumonia cases.
Tests on the three did not show the presence of H5N1, the official Xinhua news agency said, but it added the virus could not be ruled out due to the fact the three lived close to the site of the outbreak.
One of the pneumonia patients, a 12-year-old girl, died. Tests on the girl's brother did reveal a "suspicious positive", and WHO would now work with Chinese health authorities to establish if he had contracted H5N1.
Authorities have placed 192 people in Hunan, one of whom has acute bronchitis, under medical observation, the China Dailysaid. They all had contact either with the three pneumonia cases or dead birds.
In the northeastern province of Liaoning, all poultry within a three-kilometre radius of the site where the H5N1 virus was found last week had been killed, it was reported.
Bird flu has killed more than 60 people in Asia and infected at least 123 since late 2003. In almost every case, the virus appears to have been transmitted to humans through contact with birds.