Authorities have detected the H5N1 avian flu virus in ducks in the central Vietnamese province of Nghe An, the third outbreak of bird flu in Vietnam since September 1, a government official said Tuesday.
Bui Quang Anh, director of Vietnam's Animal Health Department, said the outbreak had killed some 300 ducks, reported dpa.
"The ducks had only been vaccinated once," said Anh. "They need at least three injections to become resistant to H5N1."
The local health department culled the ducks and disinfected the area to guard against further outbreaks.
On September 7, the Animal Health Department announced it had detected bird flu in a flock of 600 ducks on a farm in the southern province of Ben Tre, adjacent to Ho Chi Minh City.
On September 22, inspectors found bird flu in a flock of 500 ducks on a farm in the southern province of Ca Mau.
According to Nam, bird flu outbreaks have been detected in 26 Vietnamese provinces since the beginning of 2008, killing 5 people and forcing authorities to cull more than 60,000 ducks.
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.
Bird flu has infected 105 people in Vietnam and killed at least 51 of them since it first appeared in the country in late 2003.