Animal health experts said bird flu outbreaks have been reported in two other provinces of Vietnam and warned a high risk of recurrence of the H5N1 virus in the country.
The outbreak in northern Nam Dinh province's My Phuc commune killed 210 out of the 400 young duckling flocks last Sunday. Tests results showed they had the deadly virus, the national animal health department said in a report received Thursday.
In the Mekong delta's province of Tra Vinh, the virus has killed also 400 out of the 500 two-month-old ducks in a farm of Thanh My commune last Monday. Samples taken from the ducks tested positive for H5N1, the online report said.
In October, outbreaks of bird flu had already been reported in small farms in northern Cao Bang and central Quang Tri provinces. The infected poultry were mostly ducks, the reservoir for the virus in Vietnam, experts said.
Animal health experts expressed big concerns this week that a new nationwide epidemic could take hold during the winter to come with a cooler weather facilitating the spread of the virus in northern provinces.
Vietnam, once the country worst hit by bird flu in Southeast Asia, had managed to control the situation with mass culls and vaccination campaigns.
But the deadly virus strongly hit the country again last spring.
The human death toll from bird flu in Vietnam has reached 46 since the country was first hit by the virus in late 2003. The global death toll is 204, according to the World Health Organisation.