Bird flu has struck poultry in central Vietnam, just one month after the last outbreak in the Southeast Asian country, an official said on Sunday.
Nearly 200 ducks died at a private farm in the central province of Nghe An on Tuesday. Test results released by a government laboratory in the area show they were infected with the deadly H5N1 virus, said Nguyen Xuan Yem, director of Nghe An's animal health department.
The ducks had not been vaccinated, Yem said.
Authorities have slaughtered the remaining 400 ducks at the farm and disinfected the area. Control over movement and trading of poultry has been tightened, he said.
The last bird flu outbreak was reported last month in northern Vietnam. Before that, the country went without reporting a bird flu outbreak for a year until the disease killed and forced the slaughter of about 40,000 birds in eight southern Mekong Delta provinces since January.
The bird flu virus has killed at least 172 people worldwide, including 42 in Vietnam, since it began ravaging poultry stocks across Asia in late 2003, according to the World Health Organization.
It remains hard for people to catch, but experts worry the virus might mutate into a form that passes easily among humans, potentially igniting a pandemic. So far, most human cases have been traced to contact with infected birds.