A Vietnamese man feeds ducks at his private farm in Phu Xuyen district

Vietnamese health officials say bird flu has been detected in ducks in the country's south just one day after authorities lifted a ban on hatching ducks and other waterfowl.

Authorities say tests showed 800 ducks in the Mekong delta province of Vinh Long were infected with bird flu, but it is not immediately clear if they had the deadly H5N1 strain of the virus. All the birds have been slaughtered.

Earlier this week, authorities announced an outbreak of bird flu in the country's north. Vietnam plans to begin a massive new poultry vaccination campaign in the coming week.

Meanwhile, officials in Burma say crows and sparrows may have carried the H5N1 virus to a poultry farm in the suburbs of Rangoon sparking an outbreak.

More than 160 people have died from bird flu worldwide since the outbreak began in late 2003.