Posted on 11/16/2006 2:40:06 PM PST by blam
BBC
International scientists believe they have identified some of the key steps needed for bird flu to develop into the deadly pandemic strain of the disease.
The team pinpoints two genetic mutations that would need to occur to the H5N1 virus for it to potentially spread readily between humans.
Writing in the journal Nature, the scientists said the findings would help them to detect pandemic strains.
At present, H5N1 can pass only from bird-to-bird or, rarely, bird-to-human.
So far, there have been a total of 258 cases of H5N1 in humans, causing 153 deaths, according to figures from the World Health Organization.
But flu viruses mutate and evolve quickly, and scientists believe the virus could acquire the ability to pass between humans.
They fear this could trigger a repeat of the devastation of the 1918 flu pandemic, which is thought to have killed 50 million people.
Docking station
To investigate how the virus might do this, the researchers looked at samples of H5N1 that had been taken from birds and also from infected humans.
In a small number of the human samples, they found the virus had acquired small changes to a protein called haemaggluttinin, which sits on the surface of the H5N1 molecule.
This protein helps the flu virus to spread by binding the receptors on cells, which are like docking stations, allowing the virus to invade and infect the cell.
While the haemaggluttinin in most of the samples could only bind to bird cell-receptors, the researchers discovered that in some of the human samples, the haemaggluttinin had acquired the ability to bind to both bird and human cell-receptors.
It is thought this is a key step needed for H5N1 to be able to spread from human-to-human.
Further analysis revealed two separate mutations at different positions on the protein had enabled H5N1 to recognise human receptors.
The researchers said the discovery of the location of the mutations would help identify H5N1 strains that may be on the way to developing pandemic potential.
Pandemic pathway
Lead researcher Yoshihiro Kawaoka, a virologist at the University of Wisconsin-Madison School of Veterinary Medicine, said more mutations would be required for the virus to fully adapt to humans, but it is not known how many mutations are needed for such a change.
The team thought these changes were most likely to occur when a human influenza virus mingled with H5N1, particularly if it could already bind to human receptors.
Dr Wendy Barclay, a molecular virologist from Reading University, said: "This work shows that at least two changes in the haemaggluttinin protein are needed for H5N1 to transform to strain that could infect humans, and knowing what these are will help to inform surveillance."
But, she said, the fact these mutations had already been seen in viruses isolated from human H5N1 cases, and a pandemic had not yet struck, suggested a number of other steps may be needed for the virus to be able to pass from human-to-human.
"The 1957 and 1968 pandemics claimed about 100,000 total combined."
Shortly after this bird flu scare became noteworthy, I went to Books A Million and got several on the last bad pandemic, which was in 1918, I think. The books were very enlightening about viruses in general, how they work, how they mutate, how vaccines work, and so on. I would recommend doing this, because it is quite interesting, and very scary. Definitely worth anyone's time.
I tracked it down. It looks like a rough translation from an Indoneasian language...which I can't read.
>>"Ah bloody hell I just quit smoking twelve days ago"
>You're going to die.
But aren't we all going to?
1918 may as well be 1818, the way the world has changed since the last big pandemic.
As scary as the natural mutations are, I'm much more inclined to think that the real danger comes from work being done to "medicinize" existing bugs. The effort to turn AIDS virus into an AIDS killer comes to mind.
While on the subject of flu, remember the time in 2004 when John Kerry saved us from George Bush's engineered flu outbreak with a terse round of criticism and self-righteous indignation? That was awesome. Children, the elederly, minorities and the working poor all saved by the people's candidate.
Isn't it funny how many people just have to come to H5N1 threads and scorn and scoff?
I've had so many years of minimalist "survival" kind of existence that it's no skin off my nose to make a few preparations - just in case.
(I've lived years without electricity, using water catchment, cooking with a camp stove, outhouses or trench latrines, bucket baths, and the like anyway. I think more people would have a clue if they've had experience like that, even if only on extended camping trips.)
It'll probably be up somewhere soon in a readable manner.
Read this: http://www.fumento.com/disease/flu2005.html
I'm way more scared of the DemoSocialistMarxistLyingLibs....and I ain't THAT scared of them.....
ping...
ABC Article_Bird Flu's Pandemic Potential
Have you ever seen what happens on a thread I post that has the word 'evolution' in the title?
Interesting read. Thanks.
FRegards,
The big difference between the 1918 and 57/68 episodes was not only the mortality rate (~2% of those infected) but the impact on the 20-29 year old group. The robustness of the young's immune system sealed their doom as their body's response caused them to drown. 1 in 66 soldiers in the Army died during the few weeks of the pandemic.
We actually have changed for the worse. Society is much more fragile (how many folks grow / raise their own food etc.) and our ability to respond is not much better. There will be no vaccine,there wil not be even be enough of the uncertain treatment Tamiflu. Ask your local hosptital how much spare capability it maintains, especially respirators. Finally, assuming an infection rate of 30%, each 1% of mortality = ~1 million dead Americans.
No, that was for the beatles crawling out of the lungs (X-Files episode).
Just depends on how lethal the final mutation is.
I don't touch evolution threads. Not me!
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