A week-long medical observation has come to an end for 35 chicken farm workers who had close contact with dead birds in bird flu-hit Yangquan City of North China's Shanxi Province, local health authorities said Thursday.

The 35 people, who work for a chicken farm in Yijing Township in suburban Yangquan, have shown no abnormal symptoms since the medical observation ended on Tuesday, according to the Shanxi Provincial Department of Health.

The state bird flu lab confirmed on Feb. 7 that the H5N1 strain of highly pathogenic bird flu killed 15,000 fowls at the chicken farm in Yijing from Feb. 2 to 3.

All of the 35 workers with the farm who had close contact with the dead birds were put under close medical observation, and were restricted to their home where they received medical checks twice a day, the health department said.

Vet departments in Shanxi have so far culled 187,745 poultry within three km of the affected areas since the province activated its emergency reaction program upon the outbreak of the disease.

Health authorities in Yangquan are now carrying out a month-long monitoring of the human situation in the bird flu-hit areas.

To date, China has reported 12 human cases of bird flu, eight of which have resulted in death.

Since 2005, China has reported 33 bird flu outbreaks, involving 14 provinces and regions.

Source: Xinhua