Bird Flu Could Return
At Any Time
By Maggie Fox
Health and Science Correspondent

WASHINGTON (Reuters) - ``Bird flu'' that killed six people in Hong Kong and prompted the slaughter of more than one million birds could happen again any time, a U.S. expert warnedTuesday. But world health authorities are well-prepared to fight flu and could move quickly to contain any outbreak, said Nancy Cox, chief of the influenza branch at the Centers for Disease Control and Prevention (CDC) in Atlanta.
``We have come to view this episode as a dress rehearsal for the next pandemic of global influenza,'' Cox told a news briefing sponsored by the National Foundation for Infectious Diseases.
Authorities ordered the destruction of 1.4 million birds, mostly chickens, in Hong Kong after experts confirmed a flu virus, known as H5N1, had jumped from poultry to people. Cox flew to Hong Kong to study the outbreak and identified two separate strains infecting people.
She said that bird flu is a common infection in poultry andspreads easily in modern intensive farms. Cox said flocks around the world were infected with various types of bird flu and any of them could cross to people. ``We know that influenza viruses of 15 different sub-types exist in the avian reservoir worldwide and many of these viruses haven't previously circulated in humans,'' she said.
``There is a potential for these viruses to either jump directly to humans as with H5N1 or to move to another mammalian species such as the pig and then move to humans.'' Experts believe that is where most influenza strains originate -- first in birds, usually in ducks, passing through pigs and then into humans.
Cox said the cull was the right reaction -- especially when it became clear that killing only sick chickens would not be enough. ``The authorities in Hong Kong made a decision that may have averted a worldwide epidemic,'' she said. But she noted it took six months from the first case in Hong Kong last May until the second human case in November. ``It should make us cautious about assuming that H5N1 is over,'' she said.
The last confirmed case was Dec. 28, just before the chicken cull started. The good news, Cox said, was that world health authorities were prepared.
``The World Health Organization's global influenza surveillance network did function successfully,'' she said. The first human case of the virus was caught quickly and experts moved in immediately.
They were able to make up tests for the H5N1 strain and distribute them around the world to make sure that the virus did not leave Hong Kong via an infected airline passenger. But there was more that could be done. Cox said someone should develop a vaccine against the H5 strain of flu in general and test it to see what doses might be useful. Vaccinating all vulnerable people, especially the elderly, against flu should also be a priority, she said. Flu epidemics have a tremendous potential for killing people. The 1918 pandemic caused 25 million cases in the United States alone and killed 500,000 people, many of them young, healthy adults. ``Hospitals were overflowing,'' Cox said. A 1968 pandemic of Hong Kong flu killed more than 46,000 people worldwide. Pandemics are epidemics that spread over a large area. A bad flu season, such as the one that just passed, could cause up to 200,000 cases and 40,000 deaths, Cox said.

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