HANOI - BIRD flu killed a Vietnamese man this week, the country's second victim of the H5N1 strain in 2008, raising the national death toll from the virus to 49, health officials said on Thursday.

The 40-year-old man died of pneumonia and kidney failure on Wednesday at the National Contagious and Tropical Diseases Hospital in Hanoi after four days of treatment there, said the hospital's deputy director Nguyen Hong Ha.

'The man from Hai Duong province died of H5N1 type-A influenza,' said Nguyen Huy Nga, head of the Preventive Medicine Department at the Ministry of Health.

The man had been treated at home and in a provincial hospital after handling chicken, said Mr Nga, adding that people who were in close contact with him were now also being tested for bird flu and given the drug Tamiflu.

'The man's family had seven sick chickens. They sold five and kept two,' said an official from Vietnam's Institute of Tropical and Infectious Diseases.

'The man handled the two chickens and ate them with his family.'

The World Health Organisation (WHO) has been notified of the death and invited to accompany government health officials to visit the man's house and investigate the case, said WHO spokesman Dida Connor.

'The case shows that while the virus remains in the environment, people need to stay vigilant,' said Ms Connor. 'The public protection measures remain as important as ever because the risk hasn't gone away.'

Northern Vietnam has been in the grip of a month-long cold snap that experts say has aided the spread of flu and other respiratory diseases because immune systems are weakened and people tend to spend more time indoors together.

Last week's traditional Tet lunar New Year, the country's biggest festival, was seen as a particularly high-risk period for the spread of the virus because the movement of poultry products, and of people, rises sharply.

Bird flu outbreaks among poultry have hit in recent weeks in the northern province of Thai Nguyen and in central Quang Binh, authorities have said, but no outbreak among birds had been reported in Hai Duong.

'Prevention measures have now been tightened, and the poultry flock in the area has been killed,' said Mr Hoang Van Nam, deputy director of the Animal Health Department of the Ministry of Agriculture and Rural Development.

'Poultry in nearby communes are being vaccinated and local veterinary officials are taking test samples.'

To avoid infection, people should handle poultry with care, wash their hands before and after, cook meat and eggs well, avoid contact with sick birds and promptly report all suspicious cases, said Mr Connor.

'It's important people heed these measures because the threat is as serious as it was, it has not gone away,' she said.

In January, 18 bird flu killed a 32-year-old man from Tuyen Quang province northwest of Hanoi. He had suffered severe pneumonia symptoms after reportedly preparing and eating poultry he found dead near his house.

The WHO has so far confirmed 360 human cases of H5N1 bird flu worldwide, of whom 226 have died, not including the latest Vietnam fatality, according to WHO figures published online.

The virus is mainly an animal disease, but scientists fear it could mutate to easily jump from human to human, sparking a deadly global pandemic. -- AFP