BEIJING, China (CNN) -- A 29-year-old man in southwest China is in critical condition after testing positive for bird flu, making him the country's sixth confirmed case of the virus this month, state media said Sunday.
Chickens at a market in Kaili, Guizhou province on January 22. China has the world's largest poultry population.
The man fell ill on January 15 in Guizhou province, and tested positive for the H5N1 virus on Sunday, the Xinhua news agency said.
Authorities are monitoring others who came in contact with the man, but no one else has been found ill, Xinhua said.
In recent days, China's health ministry has moved to allay fears over a bird flu outbreak. The ministry said that although further human bird flu cases were possible throughout China, there wouldn't be a large-scale outbreak, Xinhua and CCTV said.
The country also announced it was setting up a nationwide network to test for the virus.
On Saturday, health officials said a 31-year-old woman from Xinjiang Uygur Autonomous Region in the far northwest died from the virus. And a 16-year-old boy, who had fallen ill on January 8, died in the city of Huaihua in central Hunan province.
One week ago, a 27-year-old woman from eastern China died of bird flu, and on January 5, a 19-year-old Beijing woman died after handling poultry, officials said.
In addition, the World Health Organization said a two-year-old girl in northern Shanxi province had tested positive for bird flu.
Since the end of 2003, the H5N1 virus has infected numerous species of birds in more than 60 countries in Asia, Europe and Africa.
It has not been found in birds in North or South America or the Caribbean, according to the Food and Agriculture Organization of the United Nations.
Human-to-human transmission of avian flu is rare, but in some cases the virus has passed from poultry to humans. It has killed more than 200 people since 2003.
China reported its first human-to-human infection case in 2005. Of the 34 cases confirmed to date in the country, 23 have been fatal, the World Health Organization said Saturday.