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Mutated bird flu virus may cause global concern

By PAUL RECER
The Associated Press

WASHINGTON, Feb. 21 -- The Earth may be on the brink of a worldwide epidemic from a bird flu virus that may mutate to become as deadly and infectious as viruses that killed millions during three influenza pandemics of the 20th century, a federal health official said Monday.

Vietnamese duck vendors prepare their street side stall in Ho Chi Minh city in southern Vietnam on Feb.21. So far, the avian virus has killed 45 people from Vietnam, Thailand and Cambodia. Vietnam will host this week an international conference on bird flu organized by the UN's Food and Agriculture Organization and the World Animal Health Organization to stem the spread of the disease and help coordinate foreign assistance. (AP Photo/Richard Vogel)

The avian flu now spreading in Asia is part of what is called the H1 family of flu viruses. It is a pathogen that is notorious in human history.

So far, 45 people from Vietnam, Thailand and Cambodia have died from the H5N1 strain of the virus, though all but one case is believed to have been transmitted through contact with sick birds.

The H5N1 strain of the virus, first reported in Vietnam in late 2003, swept through 10 countries in Asia last year, devastating poultry farms and forcing the slaughter of about 100 million birds.

Vietnam and Thailand have been hardest hit after two more outbreaks, despite declarations from governments that the disease had been eliminated. Vietnam has the region's highest number of deaths, with 32 in the past year. Thailand reported 12 fatalities, while Cambodia had one.

Last month, the Hanoi government sent a letter to the United Nations asking for international assistance to stem the disease and help coordinate foreign assistance to Vietnam.

The UN agencies believe the international community should throw resources and funding at a disease that could potentially threaten the world. The major pandemics of the past century -- the 1918-19 Spanish flu pandemic, the 1957 Asian flu and 1968 Hong Kong flu -- killed more than 50 million people combined. U.N. officials said an outbreak of a potential mutant bird flu could claim between 2 million and 100 million lives.

The conference will be looking at a variety of issues, including mass vaccinations, flu research, farm hygiene, animal husbandry practices, and improving coordination between animal health and human health agencies.

One of the biggest challenges will be revamping how most farms operate in Asia, where chickens are packed into farmyards with other livestock and hygiene is minimal.

Dr. Julie L. Gerberding, head of the Centers for Disease Control and Prevention, said scientists expect that a flu virus that has swept through chickens and other poultry in Asia will genetically change into a flu that can be transmitted from person to person.

In Asia, there have already been a number of deaths among people who caught the flu from chickens or ducks. The mortality rate is very high -- about 72 percent of identified patients, said Gerberding. There also have been documented cases of this strain of flu being transferred from person-to-person, but the outbreak was not sustained, she said.

The genes of the avian flu change rapidly, she said, and experts believe it is highly likely that the virus will evolve into a pathogen deadly for humans.

"We are expecting more human cases over the next few weeks because this is high season for avian influenza in that part of the world," said Gerberding. Although cases of human-to-human transmission have been rare, "our assessment is that this is a very high threat."

This assessment, she said, is based on the known history of the flu virus.

"Each time we see a new H1 antigen emerge, we experience a pandemic of influenza," said Gerberding. In 1918, H1 appeared and millions died worldwide. In 1957, the Asian flu was an H2, and the Hong Kong flu in 1968 was a H3.

There had been small appearances of the H1-type of avian viruses in other years, but nothing like the H5 now rampaging through the birds of Asia.

"We are seeing a highly pathogenic strain of influenza virus emerge to an extraordinary proportion across the entire western component of Asia," she said. "The reason this is so ominous is because of the evolution of flu.... You may see the emergence of a new strain to which the human population has no immunity."

The CDC chief said her agency is getting ready for a possible pandemic next year.

A special flu team, organized last year, continues to monitor the spread of the avian flu and to analyze the strains as they appear.

The government has ordered 2 million doses of vaccine that would protect against the known strains of avian flu. Gerberding said this would give manufacturers a head start on making the shots that would be needed to combat a full-blown epidemic of an H1-type of flu in this country.

CDC is also plugged into an international communication and monitoring system that, it is hoped, will give an early warning of the emergence of a deadly new flu.

The agency is helping to produce the 180 million or so doses of regular flu that are needed annually. Gerberding said the timeline for producing the regular vaccine yearly is very tight, with little room for problems. To produce a new vaccine in response to the sudden emergence of an H1-flu bug would require an extraordinary new effort, she said.

"We don't now have the capacity to do both," said Gerberding.

Story Produced by: Doug Bell

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