- Hello Jeff: The work below, i.e. how the virus infects
birds and humans etc: is that of Dr. Don C. Wiley. It was one of his last
projects, if not, the last one before his death.
-
- Patty
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- The British researchers used x-ray crystallography to
determine the three-dimensional structure of the haemagglutinin.
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- Mystery Of 1918 Flu Pandemic Solved
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- Scientists Identify Key Factor In Switch From
Birds To Humans
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- By Tim Radford
Science Editor
The Guardian - UK
2-6-4
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- British scientists have solved a secret of an avian flu
virus which killed up to 40 million people worldwide 86 years ago. They
now know more about how a disease of birds switched to humans to trigger
the most lethal outbreak in history.
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- A team from the National Institute for Medical Research
at Mill Hill, north London, used pathological samples taken from victims
of the Spanish influenza pandemic of 1918 to recreate the structure of
a haemagglutinin protein vital in the leap between species.
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- "This tells us more about the transmission from
birds to humans," said Sir John Skehel, leader of the team.
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- "However, it will not have an immediate impact on
the situation currently unfolding in the far east with the chicken flu
known as H5 since, from our previous work, we know that the 1918 and H5
haemagglutinins are quite different."
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- The research is published in the online edition of the
US journal Science today. It is backed up by a study from the Scripps Research
Institute in La Jolla, California.
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- Viruses smuggle themselves into a host cell to replicate
and then spread infection. Haemagglutinin is a spike-like molecule on the
surface of the virus which sticks to receptors on the cells of birds or
humans.
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- The teams worked with DNA preserved in the Alaskan permafrost
and in preserved tissue taken from young American soldiers who died in
1918.
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- The British researchers used x-ray crystallography to
determine the three-dimensional structure of the haemagglutinin.
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- The American team started from a different point and
studied the precursor protein that becomes haemagglutinin.
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- Between them, they have thrown light on one of history's
great puzzles. Flu kills thousands of Britons every year but those most
at risk are the elderly, the very young or those suffering from some other
illness.
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- But the 1918 strain was different: it hit the young,
healthy and well nourished of neutral countries as fiercely as it ravaged
the refugee camps in wartorn Europe.
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- It first appeared in March 1918 in a military camp in
Kansas, in the US, and 522 soldiers were ill within two days. In the end
it killed about 700,000 people in the US and about 230,000 in Britain.
The French called it la grippe, the Russians, "the Spanish lady".
Mortality rates were huge: in some communities up to 70% died. The virus
disappeared within 18 months as mysteriously as it came, leaving 20-40
million dead.
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- Flu is a disease of birds as well as humans and other
mammals. The virus was first found at Mill Hill in 1933, in a ferret. The
infection mutates swiftly, with new strains appearing almost every year.
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- The latest research is not likely to lead to better drugs
or vaccines, but it will help researchers and could pay off in more effective
surveillance of successive variations in the virus.
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- The British researchers also looked at haemagglutinin
structures from two viruses isolated just after the 1918 pandemic, one
from swine, one from humans.There have been several lethal pandemics since
1918, including the Asian flu outbreak of 1957 and Hong Kong flu in 1968.
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- Sir John said: "Bird viruses recognise different
receptors than human viruses. So when they transfer into the human population
they have got to change their binding capacity. With the Asian flu and
Hong Kong flu in 1957 and 1968, we think we know how they do that.
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- "But in the case of the 1918-1957 viruses, where
the Asian and Hong Kong flu changed, these ones stayed the same: they looked
just like the avian progenitor. So the mystery is: what happened to allow
them to infect humans?"
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- Guardian Unlimited © Guardian Newspapers Limited
2004
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- http://www.guardian.co.uk/birdflu/story/0,14207,1142137,00.html
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