Nobel scientist warns on bird flu

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http://www.guardian.co.uk/uk_news/story/0,3604,1458092,00.html

 

Nobel scientist warns on bird flu

 

Tim Radford in Lyon

Wednesday April 13, 2005

The Guardian

 

Avian flu - caught directly from birds, and which kills in seven cases

out of 10 - could suddenly sweep through the human population, killing

70 million people according to World Health Organisation estimates, a

Nobel laureate warned yesterday.

 

Peter Doherty, of the University of Melbourne, who shared the 1996

Nobel prize for medicine, was speaking at an assembly of laureates in

Lyon, France, 50 years to the day after the first announcement of an

effective vaccine against the crippling disease poliomyelitis. World

health teams hope to eliminate polio altogether by the end of 2005.

But, Prof Doherty warned the Biovision conference, there were more

immediate hazards.

 

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Avian flu has killed people who worked with poultry in south-east

Asia. Prof Doherty warned that a simultaneous epidemic of human and

bird flu could prove a lethal mix, opening the way for the two viruses

to mutate into a dangerous infection that could spread swiftly through

the human population.

 

" If it comes, it will probably come out of somewhere like south-east

Asia and it will probably come very fast, " he said. " It is highly

lethal in birds, and in humans, when they catch it, it is something

like 70% lethal. So it is very dangerous. "

 

Influenza is a very simple virus with a genetic code in eight segments

that can only replicate in an infected host. If a human infected with

flu from ducks was also infected with human flu, then the two viruses

could reassort themselves: swap genes. It happened 30 years ago, with

Hong Kong flu, which also began in ducks, he said. In countries like

Cambodia and Vietnam, where influenza vaccines were rare, a human

version of avian flu would spread rapidly.

 

Governments had begun to stockpile an antiviral called Tamiflu, which

was effective if taken early enough. " But if we got a real outbreak

.... with massive numbers of cases there would probably be enough

Tamiflu to protect key medical professionals, perhaps politicians ...

it is whether there is enough of it around, " he said.

 

Scientists in Britain, China and the US were racing to devise new

vaccines. Researchers at the National Institute for Biological

Standards in London are using a new technique called reverse genetics,

to detach proteins from the surface of a standard strand of flu

vaccine, and replace it with proteins from avian flu. This would mean

that vaccines could be " grown " very swiftly.

 

" The interesting thing is that it would be, as a vaccine, a genuinely

genetically modified organism, a GMO. Will the Europeans take a GMO

when it is injected in their arms and saving their lives from flu? We

shall see, " Prof Doherty said.

 

Three years ago, severe acute respiratory syndrome - Sars - had been

dangerous but slow to infect, he said. But influenza moved swiftly. In

the world's most catastrophic pandemic, the Spanish influenza outbreak

of 1918, the global death toll was estimated at more than 40 million.

People travelled slowly then - by sea - but the virus still reached

almost the entire world. Now people moved from one continent to

another in a day, the global population had trebled, and people were

more likely to defy attempts to impose quarantine.

 

" We may duck the bullet. We may be lucky. But I think it is a

reasonably high probability, because you have a lot of human flu, "

Prof Doherty said. " We will always have flu epidemics. Once the thing

hits, we would deal with it extraordinarily well. "