China is investigating three potential cases of human infection with the H5N1 virus. The Chinese government said it could not rule out bird flu in the death of a 12-year old girl, and the illnesses of two other people.
Beijing invited the World Health Organization to investigate three suspicious cases of pneumonia in the southern province of Hunan, where avian influenza was found among birds last month.
Authorities had earlier denied any connection between the pneumonia cases and the deadly H5N1 virus. But state media said Chinese health officials had decided samples from the girl, her brother, and a schoolteacher needed more analysis.
According to the World Health Organization, it's not unusual for someone to initially test negative for H5N1, but later test positive. Final results on the suspected cases could take weeks.
If confirmed, the cases would be China' first reported human infections with the H5N1 virus.
Because of the size of the country and its overstretched health-care system, there has been concern that bird flu could move quickly into humans in China before it was detected.
There also has been fear among many international disease experts that Chinese officials in rural areas would hide flu outbreaks, much the way the central government tried to hide news about the appearance of SARS in 2003. The disease appeared first in China, but spread around the world before Beijing answered WHO questions about it.
Alarmed by four outbreaks in one month, the country has stepped up its fight against the avian flu. China announced Monday it has killed six million birds in the northeastern province of Liaoning, where the country's latest outbreak had been detected last week. Authorities also ordered the immediate closure of Beijing's 168 live poultry markets.