(Reuters) -- Vietnam has detected the lethal H5N1 bird flu virus in chickens and ducklings in two Mekong Delta provinces, the country's first infections since August, the Agriculture Ministry said in a report.
The H5N1 virus was found in more than 6,000 dead chickens and ducklings hatched more than a month ago but which had not been vaccinated against bird flu, the ministry's Animal Health Department said in the report seen on Wednesday.
Vietnam has been free of human bird flu cases since late 2005. In August, it found the H5N1 virus on a small duck farm in the southern province of Ben Tre in the Mekong Delta, reports Trend.
An H5 subtype avian flu virus resurfaced in Vietnam earlier this year, mainly in ducks and wild storks. Bird flu first arrived in the Mekong delta in late 2003 and has since killed 93 people in the country.
Health officials said earlier this month that a small density of the H5N1 virus existed in some birds despite a comprehensive poultry vaccination campaign which had helped Vietnam avoid infections of the virus now endemic in parts of Asia.
The Animal Health Department said all the poultry found dead were hatched illegally in the provinces of Ca Mau and Bac Lieu and tests had confirmed the presence of the H5N1 virus.
"The risk of bird flu widely spreading in the Mekong Delta is extremely high because farmers have thrown dead poultry into water channels for a long time," it said.
Temperatures were falling in the southern region incorporating the Mekong delta, which would also help the spread of a virus that thrives bests in cooler temperatures