Bird flu has resurfaced in poultry in northern Vietnam killing ducks and chickens at two farms.
Nearly 4,200 chickens had been slaughtered to prevent the H5N1 virus from spreading.
The health minister said earlier this week that although there had not been any cases of bird flu in Vietnam for several months, there was a very high risk of it returning during the winter and spring in northern Vietnam.
The H5N1 strain seems to thrive best in low temperatures.
Five Vietnamese have died of bird flu so far this year out of six reported H5N1 infections and all were found in northern Vietnam.