(dpa) - Bird flu has killed a flock of ducks in a central Vietnamese province, raising the number of provinces in which outbreaks of the H5N1 virus have been detected to 13 since the beginning of this year, an official said Monday.
Avian influenza killed 137 ducks last week on a farm in Quang Nam province, 860 kilometers south of Hanoi, according to the director of the province's animal health department, Pham Ngoc Anh.
"Tests on the samples taken from the ducks late last week showed they were positive for H5N1," Anh said.
Anh said the ducks were 75 days old and had not been vaccinated yet. The farm's owners of the farm have shown no symptoms of bird flu, but are being monitored.
"We have culled the remaining 200 ducks at the farm and have taken all the necessary measures to keep the virus from spreading further to surrounding farms," Anh said.
Bird flu outbreaks throughout Vietnam have prompted authorities to cull tens of thousands of birds since the beginning of this year. The virus also killed four endangered civets in Cuc Phuong National Park last week.
Bird flu has infected 105 people in Vietnam, killing 51, since it first appeared in the country in late 2003.
Last week, Prime Minister Nguyen Tan Dung issued an urgent directive to all provinces and related ministries to step up measures to fight bird flu in humans.
H5N1 mainly affects poultry and wild birds, but can infect humans who have close contact with sick fowl. Scientists fear that if it spreads unchecked, the disease could mutate into a form which could be transmitted between humans, leading to a worldwide pandemic that could kill millions.