BEIJING, Feb. 10 (Xinhuanet) -- A woman in Central China's Hunan Province has died of bird flu, bringing the country's death toll of the disease to eight, China's Ministry of Health reported on Friday.

    The victim is a 20-year-old farmer surnamed Long from Suining County of Hunan. She showed symptoms of fever and pneumonia on Jan. 27 after culling poultry raised in her home. She died on Feb.4, the ministry said.

    Long's samples tested H5N1 positive by both the Hunan provincial center for disease control and prevention and China's national center.

    She had been confirmed to be infected with bird flu in accordance with the standards of the World Health Organization (WHO) and the Chinese government, said the ministry.

    Those having close contacts with Long have been put under medical observation by local health authorities. So far, no abnormal symptoms have been reported.

    The ministry has reported the new case to the WHO, Hong Kong, Macao and Taiwan, as well as several countries.

    This was the 12th human case of bird flu reported in China. Previously, the country reported 11 cases, among whom seven died.

    Chinese health officials said Friday that some cases of human infection of bird flu were caused by environmental contamination.

    The human cases found in the areas, where no outbreak of bird flu in animals had been reported, were caused by environmental contamination by sick or dead birds, said Mao Qun'an, spokesman for the Ministry of Health, at a press conference.

    About one third of the reported human cases of bird flu in the world were found in areas with no outbreak in animals, said Mao, adding the exact channels of the human infection are under investigation.

    A total of 166 cases involving 88 deaths have been reported to the World Health Organization (WHO) by Feb. 9, according to the WHO Web site. Enditem