Bird flu causes fatal immune storm - study

[Guest guest]

Hi All,

 

Herbalists, acupuncturists & homeopaths: put your thinking caps on re

antivirals + immunosuppressants!

 

See http://tinyurl.com/8xnvb [Thanks to Will Morris for the alert]

 

Bird flu causes fatal immune storm - study Fri Nov 11, 2005 5:46 AM

GMT By Maggie Fox, Health and Science Correspondent

 

WASHINGTON (Reuters) - Scientists in Hong Kong say they may have

helped explain 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.

 

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. " We have to see if it is true and if we

can do anything about it, " cautioned Dr. Anthony Fauci, head of the U.S.

National Institute of Allergy and Infectious Diseases, who was not

involved in the research.

 

But if the experiment does accurately show what happens in people, it

may mean patients with H5N1 infections will need drugs that depress

the immune response in addition to antivirals, Fauci said.

 

The H5N1 flu has swept through flocks of poultry but has so far infected

only 124 people in four countries and killed 64 since it re-emerged in

2003. It does not easily infect people, but when it does, it kills about half

of them.

 

" The reasons for this unusual severity of human disease have remained

unclear, " Michael Chan and Malik Peiris of the University of Hong Kong

and colleagues wrote in their report. They took samples of H5N1 from a

patient who died of the infection in a 1997 outbreak, from two patients

infected in Vietnam in 2004, and a sample of a Hong Kong patient with

ordinary H1N1 seasonal flu. They used the virus to infect lung tissue

samples taken from other, non-flu patients.

 

CHEMICAL STORM The H5N1 viruses brought in a storm of cytokines -

- the immune system's inflammatory chemicals -- including IP-10,

interferon beta, RANTES and interleukin-6. The H1N1 virus caused a

much smaller effect. And the later, Vietnamese strains caused a bigger

cascade than the 1997 H5N1 strain. This could be because of continued

mutations, the researchers said.

 

" The H5N1 viruses have continued to reassort, acquiring different

internal genes from other influenza viruses of avian origin, " the

researchers wrote.

 

The study, published on the Internet at http://respiratory-research.com/

may explain the severe respiratory distress suffered by H5N1 patients,

who often say they struggle to breathe.

 

Michael Osterholm, an infectious disease expert at the University of

Minnesota who has been advising the U.S. government on the risks of a

flu pandemic, said the study supports predictions that any possible

H5N1 pandemic would be especially severe. It means being young and

healthy could actually work against people who become infected.

 

" Anyone could experience this very severe, life-threatening illness, "

Osterholm said in a telephone interview. " This is looking more and more

like an H1N1 1918. "

 

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, depending on the estimate.

 

In comparison, a pandemic in 1957 killed 2 million and one caused by

an H3N2 virus in 1968 killed 1 million.

 

" In 1918, even among the very young and the very old, there was a ten-

fold increase in deaths, " Osterholm said. " There was a 1,000-fold

increase in young adults. " Fauci said researchers are now testing

various drugs that may affect the immune system to see if they would

help patients better survive H5N1. © Reuters 2005. .

 

Best regards,

 

 

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Ireland.

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