Nguyen Luong Trai, head of the southern province’s Animal Health Department, said Tuesday that infected chicken were incinerated and buried.

Veterinary staff have also sprayed disinfectant and lime powder on affected livestock farms to contain the spread of the deadly virus strain, he said.

The H5N6 strain, which has been spreading in neighboring China, was detected at a farm owned by Dao Thi Khanh in Xuyen Moc District last week after a flock of 9,000 chicken raised for around four months died suddenly. Later, around 1,500 other chicken in a poultry farm in the same locality tested positive for the H5N6 virus.

It could be that the infected birds had not been fully vaccinated, the official said.

Before the outbreak was detected, Khanh’s family had sold a few thousand chicken for meat; however, there have been no human infections reported in epidemic areas so far, Trai said.

Veterinary staff have prepared more than 230,000 doses of vaccines for poultry farmd in neighboring localities and tighten the purchase and sale, transport of poultry in epidemic areas.

Local health authorities have been asked to closely monitor human influenza and prevent the H5N6 virus from spreading to people.

Currently, poultry population in the province, which borders Ho Chi Minh City, is about 5 million.

This year, bird flu outbreaks have occurred in the central province of Quang Nam and in the northern provinces of Lang Son and Thai Binh. In March, more than 7,000 chicken and and ducklings were killed in Quang Nam.

The northern mountainous region is most vulnerable, given its cool climate and proximity to China, officials said.

China confirmed in June an outbreak of highly pathogenic H5N6 bird flu in Horgos in the far western Xinjiang region. About 1,015 out of 2,545 fowl raised by farmers in Horgos had to be killed, Reuters reported.

According to the World Health Organization, the H5N6 bird flu virus has killed people in China, but there is no evidence thus far that it can be transmitted from person to person.

Bird flu has killed at least 65 people in Vietnam since it first occurred in 2003, then one of the highest fatality rates in the world. No human deaths have been reported in the last two years, but occasional outbreaks have lead to thousands of birds being culled.

Health officials have urged the public to avoid consuming poultry of unknown origin and immediately seek help if they find sick or dead birds.