BBC 1918 killer flu 'came from birds'

[Guest guest]

> * 1918 killer flu 'came from birds' *

>The Spanish flu virus that killed 50 million in

>1918-19 was probably a strain that began in

>birds, a study finds.

>Full story:

>http://news.bbc.co.uk/go/em/-/1/hi/health/4308872.stm

>

1918 killer flu 'came from birds'

The Spanish flu virus that killed 50 million

people in 1918-19 was probably a strain that

originated in birds, research has shown.

 

US scientists have found the 1918 virus shares

genetic mutations with the bird flu virus now

circulating in Asia.

 

Writing in Nature, they say their work

underlines the threat the current strain poses to

humans worldwide.

 

A second paper in Science reveals another US

team has successfully recreated the 1918 virus in

mice.

 

The virus is contained at the US Centers for

Disease Control and Prevention under stringent

safety conditions.

 

It is hoped to carry out experiments to further

understand the biological properties that made

the virus so virulent.

 

The virus was recreated from data produced by

painstaking research by a team from the US Armed

Forces Institute of Pathology.

 

Lung tissue samples

 

Working on virus samples from the remains of

victims of the 1918 pandemic, the researchers

were able to piece together the entire genetic

sequence of the virus.

 

They found the virus contained elements that

were new to humans of the time - making it highly

virulent.

 

And analysis of the final three pieces of the

virus' genetic code has revealed mutations that

have striking similarities to those found in flu

viruses found only in birds, such as the H5N1

strain currently found in south east Asia.

 

This strain has so far killed at least 65 people.

 

Many experts believe it is only a matter of time

before H5N1, or a similar strain, causes many

deaths in humans - possibly after combining with

a human flu strain.

 

Crucially, the mutations identified by the US

researchers were found in genes which control the

virus' ability to replicate in host cells.

 

The researchers say these mutations may have

helped the 1918 virus replicate more efficiently.

 

At this stage, they say the H5N1 strain shares

only some, and not all, of these mutations.

 

Increased virulence

 

But these mutations may be enough to increase

the virus' virulence - and give it the potential

to cause serious human infection without first

combining with a known human flu strain.

 

The researchers believe the two other major flu

pandemics of the 20th century - in 1957 and 1968

- were caused by human flu viruses which acquired

two or three key genes from bird flu virus

strains.

 

But they believe the 1918 strain was probably

entirely a bird flu virus that adapted to

function in humans.

 

Julie Gerberding, director of the US Centers for

Disease Control, said: " By unmasking the 1918

virus we are revealing some of the secrets that

will help us predict and prepare for the next

pandemic. "

 

And Dr Jeffery Taubenberger, lead researcher of

the Nature study, said: " Determining whether

pandemic influenza virus strains can emerge via

different pathways will affect the scope and

focus of surveillance and prevention efforts. "

 

Warning

 

Professor John Oxford, an expert in virology at

Queen Mary College, London, said the suggestion

that the virus had the potential to jump between

humans without first combining with a human virus

made it even more of a threat.

 

" This study gives us an extra warning that H5N1

needs to be taken even more seriously than it has

been up to now, " he said.

 

Dr Terrence Tumpey, of the US CDC, defended the

decision to recreate the 1918 flu virus.

 

He said: " We felt we had to recreate the virus

and run these experiments to understand the

biological properties that made the 1918 virus so

exceptionally deadly.

 

" We wanted to identify the specific genes

responsible for its virulence, with the hope of

designing antivirals or other interventions that

would work against virulent pandemic or epidemic

influenza viruses. "

 

Story from BBC NEWS:

http://news.bbc.co.uk/go/pr/fr/-/1/hi/health/4308872.stm

 

Published: 2005/10/05 17:00:59 GMT

 

© BBC MMV

 

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