Deadly Bird Flu Can Spread Between People

But Virus Does Not Yet Spread Efficiently Among Humans, Say Experts

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Jan. 24, 2005 -- A deadly bird flu virus can spread from person to person, say global health experts. That could mean it's a race against time to stop the virus before it gains a foothold among people, with the potential to strike millions.

The virus is called influenza A (H5N1). In 2004, it infected 44 people, killing 32, in eight Asian countries. Most of those people had close contact with poultry, which probably gave them the disease.

But two people who died apparently had no direct exposure to birds, suggesting they got the virus from another person, say researchers in the Jan. 27 issue of The New England Journal of Medicine.

Luckily, the bird flu virus doesn't seem to be very good at jumping between people. It doesn't spread efficiently between people, say the researchers, who included Kumnuan Ungchusak, MD, MPH, of Thailand's Ministry of Public Health.

At least, not yet.

Information, Action Needed Now, Say Experts

The clock is ticking, says Arnold Monto, MD, of the University of Michigan. No one knows if or when the Asian bird flu virus will start spreading among humans, he writes in an editorial in The New England Journal of Medicine.

"But we must be ready to stop it if we can," says Monto, "and if we cannot, at least to mitigate its effects through the use of stockpiled antiviral drugs and, eventually, ... vaccine."

"We need to put up safeguards while the storm is still gathering," agrees Klaus Stöhr, PhD, writing in the journal. Stöhr works with the Global Influenza Programme of the World Health Organization (WHO).

The WHO has warned that millions of people -- and maybe even tens of millions -- could die if this strain of bird flu spreads among humans. This strain appears to be more resistant to older antiviral medications like amantadine or rimantadine, says Monto.

That could match the toll of past flu pandemics. In 1918, the so-called Spanish flu killed 20 million to 40 million people. Flu pandemics in 1957 and 1968 each claimed about 1 million lives. All three diseases came from bird viruses, says Monto.


Thai Family's Flu Tragedy

Could another pandemic be brewing? The latest clue came from a Thai family devastated by the bird flu last fall.

An 11-year-old girl in Thailand fell ill with the bird flu in September 2004. At first, her symptoms were fever, cough, and a sore throat. She didn't improve in the hospital. Her condition worsened until she died.

The girl had lived with her 32-year-old aunt. Her family owned chickens that died from the disease a few weeks earlier. Although the girl reportedly didn't handle the chickens directly, she played and slept in the area directly under an elevated house where the chickens were often present.

Before the girl died, her 26-year-old mother -- who lived far away in a Bangkok suburb -- rushed to her side. She made a 4-hour drive to the hospital, where she comforted her daughter for as long as possible. Nurses say she sat on her daughter's hospital bed, hugging and kissing her and wiping her mouth for 16-18 hours.

The mother didn't protect her own health. Neither did the girl's aunt, who also kept a hospital bedside vigil.

The girl was transferred to a regional hospital for more advanced care, but she died. After the funeral, the girl's mother returned home. By then, she already had a fever and headache. She was later hospitalized in her own town and died. The girl's aunt was also hospitalized but survived.

Spreading the Flu

Later, doctors investigated. They talked to the girl's surviving family and health care workers. They also tested samples from the aunt and the dead mother and girl. Their conclusion: The mother and aunt probably got the bird flu from the girl. The mother, a garment worker, hadn't been around poultry. She was only in the girl's house for 10 minutes.

Likewise, the aunt had no poultry exposure for 17 days before falling ill. That's longer than the typical two to 10 days before symptoms usually appear after infection with this virus.

It's probably not the first time bird flu has spread among people. Inefficient spread of the bird flu could have happened among Hong Kong health care workers in 1997, some without obvious signs or symptoms of the illness, and in a few clusters of families in Vietnam.


But this is the first solid evidence of person-to-person transmission of the virus.

If the virus adapts to spread more easily among people, there's a chance its deadliness could change. No one knows if it would remain highly lethal, but "it is nevertheless incumbent on the global community to try to contain it," says Monto.

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SOURCES: Ungchusak, K. The New England Journal of Medicine, Jan. 27, 2005; vol 352: pp 333-340. Monto, A. The New England Journal of Medicine, Jan. 27, 2005; vol 352: p 323.
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