China has lifted a bird flu quarantine in the southern city of Guangzhou after a 21-day period in which no new cases were reported, the Ministry of Agriculture (MOA) said on Thursday.

At least 632 fowl were culled after an outbreak of the deadly H5N1 bird flu virus on March 13 in Liwan District, Guangzhou, capital of Guangdong Province.

The ministry has urged local authorities to step up supervision and prevention measures and raise public awareness to prevent new outbreaks.

Bird flu, or avian influenza, is a contagious disease of animal origin caused by viruses that normally infect only birds and, less commonly, pigs. It can kill humans.

On February 25, a 44-year-old woman surnamed Zhang in Haifeng County, Guangdong, was killed by the H5N1 strain of the virus. This raised the total number of human bird flu cases recorded in China to 29, of which 19 have been fatal, according to the World Health Organization.

To curb human infections, China's food and drug regulators on Wednesday authorized a domestic pharmaceutical firm to begin commercial production of a human bird flu vaccine, after more than two years of clinical trials.

This step made China the second country with the technology and industrial capacity to produce such a vaccine.

China saw five bird flu outbreaks among poultry this year. Besides the one in Guangdong, others included one in the northwestern Xinjiang Uygur Autonomous Region, two in the southwestern Tibet Autonomous Region and one in the southwestern Guizhou Province.

The MOA last month warned that China faced a more "complicated" epidemic control situation this year with a rise in the number of reported cases.

(Xinhua News Agency April 4, 2008)