China confirmed on Tuesday, July 6, that the death of chicken in large numbers in the eastern Anhui province was caused by the deadly h5n1 strain of the bird flu virus, which has reappeared months after the disease triggered a mass cull of millions of poultry.

The latest case happened at a chicken farm in the Juchao district under Chaohu city in Anhui. Officials with the agriculture ministry said they received the report of chicken deaths on Saturday and quickly dispatched a group of experts to the affected area to guide relevant works of prevention and control of the disease.

Sources in the ministry said the local government has taken measures for slaughter or quarantine to prevent a spread of the disease, and sent samples to the authorities.

It has also isolated the area in accordance with China's law on animal epidemic prevention, the Xinhua news agency reported.

The local health authority killed all poultry within a 3km radius of the chicken farm and vaccinated all poultry within a 5km radius of the affected area.

Experts at the ministry said the farm is located on a slope close to the wide Chaohu lake and all the chicken are bought from local markets, where no avian flu case has been reported before.

They estimated that the virus might have been spread by migrants or wild water fowl.

The ministry has informed the Food and Agriculture Organisation of the United Nations, the World Health Organisation, and the relevant authorities of Hong Kong, Macao and Taiwan about the case.

The ministry confirmed the first contraction of the h5n1 strain of bird flu on January 27 at a duck farm in the Dingdang township of southern China's Guangxi Zhuang autonomous region. On March 16, China lifted the quarantine on the last two affected areas in Lhasa, Tibet, and Nanning, Guangxi's capital city.

During that period, altogether 49 cases of bird flu were confirmed and controlled. So far, no human contraction of the disease has been reported from China.