Some 10 ducks in Vietnam's central Thua Thien Hue province have died with unidentified causes in the last two days, local newspaper Pioneer reported Thursday.

Specimens from the ducks in a farm in Huong Tra district are being tested for bird flu viruses.

Now, four localities in Vietnam, namely capital city of Hanoi, the two northern provinces of Hai Duong and Ha Tay, and the southern province of Vinh Long, are being affected bird flu.

Some changes have been reported in bird flu virus strain H5N1 in some localities of the country, said Vietnamese Deputy Health Minister Trinh Quan Huan.

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 of Animal Health under the Vietnamese Ministry of Agriculture and Rural Development.

Source: Xinhua