A boy in southern Vietnam has become the second reported bird flu victim this week in the communist nation, bringing to 22 the number of people killed here by the deadly H5N1 strain of the disease since late 2003. 

A six-year-old boy from the southern Dong Thap province died on Dec 30 after suffering high fever and respiratory failure, only three hours after being admitted for treatment, Nguyen Ngoc Diep, the deputy director of the provincial hospital, said Thursday.

Deputy Director of the Hospital of Tropical Diseases in Ho Chi Minh City, Tran Tinh Hien, confirmed to AFP that tests conducted on the boy a few days later proved that he was positive with the H5N1 virus.

"However, the reason for the boy´s contraction of the virus was not clear as no evidence of his direct contact with infected poultry has been found," Diep said.

The first bird flu death reported in Vietnam in 2005 was nine-year-old boy, Thach Phung, from the southern province of Tra Vinh. He died on Tuesday night.

Doctors confirmed Wednesday that Phung had been in direct contact with infected poultry in his native village before being treated in hospital for high fever.

A 16-year-old girl from southern Tay Ninh province has also tested positive for H5N1 and is in critical condition in Ho Chi Minh City.

Despite confirmation by doctors, Hanoi denied the two deaths, saying the 16-year-old girl was the only victim of the deadly virus.

Government health officials said more tests were needed before they could confirm the two boys died of the H5N1 bird flu strain.

No officials from the World Health Organisation were available for comment.

New outbreaks of bird flu have been reported in 11 provinces in Vietnam, mostly in the Mekong Delta.

At least 28,000 poultry have been culled since December to try to contain the disease, according to local officials.

"The demand for poultry consumption always booms when Vietnamese people prepare for the traditional lunar new year festival in early February," the Agriculture Ministry´s Animal Health Department Director Bui Quang Anh warned Wednesday.

"However, the cold and humid weather has facilitated the spreading of bird flu in the country in this period," he said.

Prime Minister Phan Van Khai has ordered a ban on the transportation of sick poultry from affected areas to keep outbreaks in check and asked concerned authorities to step up their vigilance, particularly in regions along the border with China.

The government said in October that it had brought bird flu under control.

It had made a similar announcement on March 30 but later admitted that the declaration had been premature after three people, including two children, died in August after being infected with the H5N1 virus.

International experts said avian influenza has entrenched itself in much of Asia and is unlikely to disappear anytime soon.

More than 120 million birds were killed or culled in two huge outbreaks throughout Asia last year of the H5N1 avian flu which claimed at least 32 lives in 2004.