The Spanish flu virus that killed 50 million people in 1918-19 was probably a strain that originated in birds, research has shown.Posted by Ithildin at October 5, 2005 12:02 PM | PROCURE FINE OLD WORLD ABSINTHE
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.
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.
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."