HANOI, Aug. 28 (Xinhua) -- Bird flu has stricken Vietnam's southern Tra Vinh province, raising the total number of localities being currently affected by the disease to four, according to a local veterinary agency on Tuesday.

    The disease killed 150 out of 450 ducks raised by a household in Tra Cu district since Aug. 20, the Department of Animal Health under the Ministry of Agriculture and Rural Development said, noting that specimens from the affected poultry have been tested positive to bird flu virus H5N1.

    The local veterinary bureau has culled all fowls in the flock, 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.