- Deadly bird flu is mutating to spread from person to
person, bringing a disastrous global pandemic closer, experts fear.
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- Evidence from South-east Asia suggests that the virus,
which could kill tens of millions of people worldwide, is becoming less
virulent, but at the same time more infectious to people.
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- Death rates from the virus have plunged in northern Vietnam,
says the World Health Organisation (WHO), though it is still killing more
of its victims than any previous outbreak. The instances where it appears
to have spread from person to person are rising.
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- Six weeks ago, The Independent on Sunday revealed that
the Government had told mortuaries and emergency services to prepare for
up to 750,000 deaths from the disease in Britain. Flu pandemics occur when
three developments take place: a virus emerges to which humans have little
or no immunity; it is able to infect people; and it mutates to spread efficiently
among them.
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- The bird flu virus - codenamed H5NI - has crossed the
first two barriers, and experts fear it is now about to breach the third.
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- "It's a very different virus that might suddenly
become extremely transmissible," said Peter Horby, of the WHO office
in Hanoi.
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- He said that it was impossible to predict when that might
happen, but there were "a number of indications" that the virus
was already becoming more dangerous.
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- Ironically, one of the main ones is that the virus is
becoming a less ruthless killer. By allowing more of its victims to survive,
it enables them to live to infect other people.
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- Up to now about 70 per cent of those infected have died.
But the WHO reports that the death rate in northern Vietnam has fallen
to 20 per cent, though it has remained the same in the south of the country.
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- Even the reduced level would make it by far the worst
flu pandemic ever to hit the world. "Spanish flu", which killed
40 million people in 1918, had a mortality rate of just 5 per cent.
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- A second ominous indication is that the flu has been
widening its targets in northern Vietnam. Previously it mainly attacked
children and young adults, but now it is affecting all age groups.
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- Third, while almost all previous victims have been infected
directly by chickens or ducks, there is a steadily increasing number of
clusters of disease, where it appears to have spread between people. There
are now at least seven of these, almost all in the northern province of
Haiphong. WHO officials say this is unprecedented.
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- Finally, the virus itself seems to have changed physically.
Vietnamese health experts say that it has evolved in the north of the country
by dropping an amino acid.
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- The US government's Centers for Disease Control and Prevention,
which has analysed many of specimens of the virus from Vietnam, adds that
new strains of it "are becoming more capable of causing disease for
mammals".
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- Both it and the WHO stress that there is no conclusive
proof yet that the virus is spreading efficiently between people. But scientists
are agreed that it is only a matter of time before it does and that then
jet travel will spread it rapidly around the globe.
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- ©2005 Independent News & Media (UK) Ltd.
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- http://news.independent.co.uk/world/environment/story.jsp?story=634680
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