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Deadly bird flu strain causes immune 'storm'

Scientists in Hong Kong say they may have found why the H5N1 bird flu virus kills so many healthy young adults -- it apparently causes a “storm” of immune system chemicals that overwhelms the patient.
/ Source: Reuters

Scientists believe they may know why H5N1 bird flu kills so many young adults while Kuwait said on Friday it had found the deadly virus in a flamingo.

It is the first known case of H5N1 bird flu in the Gulf Arab region. The highly pathogenic form of the virus has killed more than 60 people in Asia and 150 million birds.

It has recently spread to eastern Europe and experts said it was only a matter of time before migratory birds carried it to the Middle East and Africa.

Kuwait said it had found H5N1 in one of two infected birds culled by authorities.

“The H5N1 (case) was highly pathogenic,” Mohammad Muhanna, an official at Kuwait’s agriculture authority, told Reuters.

Although the H5N1 virus cannot move easily between people, experts fear it could mutate into one which can and set off a pandemic in which millions might die. The virus in its current form has killed around half of the people it has infected.

Scientists in Hong Kong said H5N1 apparently causes a “storm” of immune system chemicals that overwhelms the patient.

The H5N1 virus caused proteins known as cytokines to rush to infected lung tissue -- evidence of a so-called cytokine storm, an immune system overreaction that can be fatal.

The study, published in the online medical journal Respiratory Research, might suggest that if H5N1 does cause a pandemic, it could disproportionately affect the young and healthy as compared with seasonal flu, which kills many elderly people but few young adults.

It also raises questions about how effective drugs will be in controlling such a pandemic, experts said.

Michael Osterholm, an infectious disease expert at the University of Minnesota, said the study supports predictions that any possible H5N1 pandemic would be especially severe.

“This is looking more and more like an H1N1 1918,” he said in a telephone interview.

The worst recorded influenza epidemic was in 1918, when an H1N1 strain swept the globe in a few months, killing anywhere between 20 million and 100 million people.

Asia prepares
Experts are not surprised at the spread of the virus.

“The Middle East and Africa are on the flyways (of migratory birds), and the FAO (U.N. Food and Agriculture Organization) has said that they expected to see H5N1 in those areas,” World Health Organization spokesman Dick Thompson said in Geneva.

Dr. Julie Gerberding, U.S. Centers for Disease Control and Prevention Director, said she expects H5N1 to spread around the globe eventually.

“It won’t be at all surprising if some day we see a bird arrive here in our own country with H5N1,” she told reporters.

For the moment, Asia is the main battleground in the fight against bird flu.

Vietnam, where bird flu has killed 42 people, treated two more people on Friday showing symptoms of the virus.

Vietnam said the two were in hospital in the northern Bac Giang province, where more than 134,000 birds died or were slaughtered after several outbreaks in the last week.

China, the world’s most populous nation, reported its seventh outbreak of the H5N1 in poultry since the beginning of last month as Asia struggles to contain the spread of the virus.

From confiscating backyard chickens to stockpiling antiviral drugs, governments in Asia are responding to dire warnings of a looming flu pandemic.

In China, millions of birds have been culled and big cities have banned the sale of live poultry.

But for many poor Asian nations, fear of a political backlash and the age-old practice of keeping backyard chickens and ducks have made it very difficult to order mass culls.

Indonesia, which has five confirmed bird flu deaths, said on Friday it wanted grants from the international community to fight bird flu, turning down a $10 million loan.