The Ministry of Agriculture said Monday it has received the reports of 12 bird flu cases this year, warning a more "complicated" epidemic control situation.

Three of the 12 cases have been confirmed, with two in Tibet Autonomous Region and one in Guizhou Province, both in southwest China, said Li Jinxiang, director of the ministry's veterinary department, on the sidelines of the annual session of China's top legislature.

He said three factors shall be blamed for the outbreak of bird flu cases.

First, south China was hit by unprecedented snowstorm and cold snap from the beginning of this year, which made bird flu virus active;

Secondly, snow storm and cold snap affected regular immunization work, as it was conducted usually in February and March;

Thirdly, snow and ice disaster harmed the living conditions of livestock, bringing risks of epidemic spread.

The official said currently relevant government departments across the country are actively launching spring epidemic control and immunization work.

Th ministry has prepared 5 billion milliliters of vaccine for immunization efforts.

Epidemic surveillance has also been strengthened to rule out hidden dangers in time, he said.

(Xinhua News Agency March 11, 2008)