Bird flu has stricken Vietnam's northern Ha Tay province, raising the total number of current affected localities in the country to three.

The disease either killed or sickened 550 chickens in a farm in Thach That district, the Department of Animal Health under the Vietnamese Ministry of Agriculture and Rural Development said Tuesday.

Specimens from the fowls, which had not been vaccinated against the disease, have been tested positive to bird flu virus strain H5N1, said the department.

The provincial Veterinary Bureau has slaughtered all of the infected fowls, and detoxificated and disinfected the farm to prevent the disease's spread.

Bird flu outbreaks in Vietnam, starting in December 2003, have killed and led to the forced culling of dozens of millions of fowls in the country, said the department.

Source: Xinhua