The bird flu outbreak in north China's Shanxi Province is under control and the quarantine of the infected areas has been lifted, reported the Ministry of Agriculture on Thursday.

No new infections have been discovered during the 21-day surveillance period after all the poultry and poultry products in the affected areas in Changzi County of Changzhi City in Shanxi were treated according to relevant regulations, the ministry said.

The ministry urged the local veterinary authority to continue to supervise the area and teach local residents how to protect themselves against the bird flu virus.

The outbreak was identified on June 17 by the National Avian Influenza Reference Laboratory after poultry died in some farms in Changzi County.

Minister of Agriculture Du Qinglin told a national agriculture conference last Friday that 6 billion poultry and 850 million livestock have been immunized in China from January to June this year.

The six cases of bird flu in China's five provinces and regions in the first half of this year have all been controlled effectively, and the risk of an epidemic of other animal diseases has also reduced, the minister said.

Currently, epidemic supervision covers 90 percent of the country's poultry and livestock, said the minister, noting that it will cover all poultry and livestock in the second half of this year.