Two more people have died of bird flu in China, bringing the total number of fatalities there to five, the World Health Organization has said.
China is inoculating millions of birds to try to stamp out bird flu
The two victims reportedly died in December - one in Guangxi province and the other in Jiangxi province.
Meanwhile the agriculture ministry said 16,000 quails had already died of bird flu this year in Guizhou province.
Officials have culled another 42,000 birds in the area to try to stem the spread of the virus, the ministry said.
More than 70 people in South East Asia are known to have died of bird flu since late 2003.
People outside the region are also becoming infected, with two confirmed human bird flu deaths in Turkey last week.
Contact with birds
On Monday, China reported that a six-year-old boy in the central province of Hunan had become the country's eighth human bird flu case. He is currently said to be in a critical condition in hospital.
An investigation by the state news agency Xinhua found that poultry raised by the boy's family had died before he became ill.
Most human bird flu infections have been linked to direct contact with sick poultry.
But scientists fear the deadly H5N1 bird flu virus could mutate from a disease that largely affects birds to one that can pass easily between people, leading to a human pandemic.
China is seen as a potential flashpoint for such a pandemic, because it has the world's largest poultry population, and many of its birds are farmed in primitive conditions where humans and animals live in close proximity.
China's Ministry of Health admits that the system it has in place at present is at fault, blaming the latest human infections on ineffective surveillance and the delayed reporting of bird flu outbreaks among poultry.
The China Daily said on Wednesday that only two-thirds of China's township hospitals were part of the network for monitoring and reporting infectious diseases.
A Health Ministry spokesman told the newspaper that bird flu infections were typically being mis-diagnosed as pneumonia, allowing the window of opportunity for treatment to be missed.