Three brothers in northern Vietnam who contracted bird flu all drank raw duck blood at a family feast, newspapers said on Monday, calming initial fears that the killer virus had managed to jump from human to human.

Deputy Health Minister Tran Chi Liem was quoted in the Nguoi Lao Dong (Labourer) paper as saying the trio had dined on duck before one of them died of the H5N1 bird flu strain, a fact backed up by the World Health Organization (WHO).

“We can confirm that this is the clinical factor of infection,” Liem said. “Recently, through quick tests of the family members we found another member also infected with the H5N1 virus. Now samples from him are being re-tested.”

The triple outbreak in one family had sparked fears in the southeast Asian nation that a version of the virulent avian flu strain had managed to jump from person to person - a possible precursor to a killer human flu pandemic.

One of the brothers died of bird flu on Jan. 9, but then his 42-year-old younger sibling, who had been looking after him, and another brother aged 36 went down with the virus.

Only now has it emerged that the trio shared a meal of duck meat and blood, a Vietnamese delicacy.

The 42-year-old may also become the first to walk away healthy since the deadly virus resurfaced in Vietnam last month, according to VN Media ( http://www.vnmedia.vn ), an online paper which said he would be discharged in the next two to three days.

In the interview with Nguoi Lao Dong, deputy minister Liem ruled out the possibility that the virus had jumped from person to person.

“In Vietnam there has not been any case in which the H5N1 virus infection spreads from human to human,” he said.

The H5N1 poultry virus is known to have killed 27 people in Vietnam and 12 in Thailand over the past year, although the Tuoi Tre newspaper said tests showed a 35-year-old woman had died from bird flu on Jan. 21 in Ho Chi Minh City.

More than 500,000 fowl have been slaughtered or killed by the virus.

THAI RISK

While worry about person-to-person infection might have eased in Vietnam, in nearby Thailand surveillance of poultry movements was being stepped up to try and halt the spread of the virus.

“We have a high risk of new outbreaks,” Thai Deputy Prime Minister Chaturon Chaisang told reporters after a meeting of a national bird flu committee.

“Last year, Thailand had bird flu outbreaks just two to four weeks after Vietnam.”

The WHO said last week limited transmission of the virus between people could be expected but poultry-to-human during a meal was possible in the case of the Vietnamese brothers.

The Health Ministry has said eating well-cooked meat is not a risk but contact with sick chicken or ducks was a known way of poultry-to-human transmission.

The WHO’s main fear is that a virus could mutate if it infects a person sick with ordinary flu, or gets into an animal hosting a human flu virus, such as a pig.

If H5N1 merged with a human flu virus, it could produce a strain capable of sweeping through a human population without immunity, killing millions of people worldwide.

The WHO has warned more human cases would emerge in Vietnam as people travel and feast ahead of the Tet lunar new year festival early next month.

In larger cities such as Hanoi and Ho Chi Minh City, people have started to stay away from chicken but it is still on the menu in rural areas, where two thirds of Vietnam’s 82 million people live.

The WHO says the virus is now endemic in Asia and appears to be evolving in ways that increase the chances of a deadly human outbreak.