WHO spokesperson calls new Asian bird flu study encouraging

HANOI, Vietnam -- Health officials are hoping a chicken flu that has killed at least three people in Vietnam won't start spreading from person to person, and a genetic study has provided encouragement, a health agency spokesman says.

The human infections are thought to have come from contact with the droppings of sick birds. The avian flu has killed millions of chickens in South Korea, Vietnam and Japan, where officials have ordered mass slaughters to try to contain the outbreak.

There has been no sign of person-to-person spread, the World Health Organization said.

Health officials routinely monitor bird flu closely because once a bird flu virus enters humans, it could mix genetic material with a human flu virus. The result could be a hybrid that can spread from person to person, and which is different enough from previous human flu viruses that people would have no natural immunity. That could be the start of a worldwide flu outbreak, called a pandemic, which can be very deadly.

But analysis of the flu virus recovered from an infected person in the current bird flu episode shows all the genetic material is still avian, said Dick Thompson, spokesman for the WHO infectious diseases section in Geneva.

What's more, he said, nobody taking care of people infected with the avian virus has contracted the disease.

"The likelihood that it will be human-to-human is low," Thompson said Wednesday.

Earlier, WHO regional coordinator Peter Cordingley had warned in Manila, Philippines, that if the virus does acquire the ability to spread person-to-person it could become a bigger problem for the region than SARS.

Alan Hay, director of the London-based World Influenza Center, agreed the virus could become more potent if mixed with a human virus, but added "we know relatively little about what is actually necessary for that to happen."

The three avian flu deaths in Vietnam -- an adult and two children -- were confirmed Tuesday as Influenza A or the H5N1 strain, the same virus found in sick chickens in the country's south, WHO said. The same strain of bird flu killed six people in Hong Kong in 1997, when more than 1 million chickens and ducks were destroyed.

WHO says tests are being conducted to determine if the deaths of six additional people in Vietnam are linked to the bird flu.

"What must be a great concern is the frequency with which we are seeing H5N1-like viruses in the human population," Hay said. "The concern is that it will become transmissible. The more instances there are of it jumping from bird to human, the more likely it is it will acquire that ability."

The bird flu scare comes as China grapples with new cases of severe acute respiratory syndrome, another ailment believed to have originated in animals and which ravaged the region's economy in a major outbreak last year.

China last week confirmed its first SARS case of the season, and has since announced two additional suspected cases, all in southern Guangdong province, next to Hong Kong.

The bird flu's symptoms in humans include fever and coughing and eventual pneumonia -- similar to SARS.

Health officials say they believe there is no danger from eating properly cooked meat or the eggs of affected chickens. Still, governments and businesses in the region sought to bolster consumer confidence in their poultry industries.

"There is no case reported of humans infected by taking chicken meat or eggs," Japanese Agriculture Minister Yoshiyuki Kamei said. "Therefore, I wish for the citizens of Japan to react in a calm manner on this issue."

Japanese officials said 10,000 chickens had died from the bird flu and thousands of others would be slaughtered.

The disease is spreading fast among poultry in Vietnam, where more than 1 million chickens have died in the latest outbreak. Farmers have been ordered to destroy all sick birds.

An official at Ho Chi Minh City's only crematorium said the facility has been running at full capacity, 24 hours a day, over the past few days, incinerating more than 2 tons of dead chickens a day.

Thailand, among the world's largest poultry exporters, declared itself free of bird flu.

An outbreak starting last month in South Korea led to the slaughter of 1.1 million chickens and ducks in an attempt to contain the disease.