Bird flu has reappeared in domestic ducks in southern Vietnam just two weeks after the H5N1 virus was declared under control, an official said Friday.
The latest outbreak at a duck farm in Vinh Long province, 140 km south of Ho Chi Minh City, followed the reappearance of the virus in northern Vietnam.
Nearly 70 ducks were found dead at a farm in Vinh Long province last weekend and tests results this week showed they were positive for the H5N1 avian influenza virus, said Ngo My Dung, director of the province's animal department.
The dead ducks are part of a flock of 800, which are 45-days-old and had not been vaccinated.
"We have culled all the other ducks in the flock and disinfected the farm to prevent the virus from spreading further," Dung said.
"No one having contacts with the dead ducks are sick," he added.
On Tuesday, an official from Hai Duong province, 50 km east of Hanoi, confirmed that over 100 chickens had died from bird flu in the province last month - the first outbreak in northern Vietnam in more than a year.
International health officials are monitoring the H5N1 virus carefully for the potential it may mutate into a new human influenza virus that could kill millions of people with no immunity.
Human's now can be infected with H5N1 through contact with sick poultry, but it is still rare - with less than 300 cases reported worldwide - and the virus is not easily passed from person to person. But some fear the virus could adapt itself to humans, and it has an unusually high fatality rate, killing half of those infected.
Vietnam once had the highest number of human bird flu fatalities at 42 people dead since 2003.
However, no human cases have been confirmed since October 2005. So far, none of the new poultry outbreaks have been accompanied by human infection, although Vietnam's health-care system is on alert to look for the symptoms.