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changturtle.blogspot.com/2009/10/1918influenza-during-ww1...
Scientists probe why 1918 flu was so deadly
Last Updated Fri, 06 Feb 2004 12:33:05
VANCOUVER - A new study of the 1918 influenza epidemic that killed 20 million people suggests that it may be easier for bird flu viruses to develop the ability to spread between people than originally thought.
* INDEPTH: Flu
Two teams of researchers in Britain and the U.S. analysed samples of the virus from victims of the 1918 outbreak to reconstruct the 3D structure of a key infectious protein.
50,000 Canadians died in the 1918 flu epidemic
The 1918 flu virus was probably so deadly because of its unique, bird-like protein, the scientists say.
Like the current outbreak of bird flu in east Asia, the 1918 influenza appears to have jumped from birds to people with few changes along the way.
The study doesn't directly relate to today's bird flu strain, which doesn't seem to be able to easily infect many people.
* RELATED STORY: UN agencies call for poultry vaccination to fight bird flu
But the findings suggests it may take fewer genetic adaptations than thought for bird flu to gain the ability to spread between people.
The research "underscores our concern that influenza viruses from a bird reservoir can adapt to humans, can become a major threat," said Dr. Danuta Skowronski of the B.C. Centre for Disease Control.
Bird flu vs. human flu
Sugar cube-sized lung samples were preserved from victims of the 1918 flu. Researchers at Scripps Institute in La Jolla, Calif., and at Britain's Medical Research Council used the samples to study the 1918 flu in detail, and compare it with other bird and human flu strains.
Scientists believe small mutations in the spike-like protein, called hemagglutinin or H1, allowed the 1918 flu virus to infect new species. How our immune systems recognize and react to hemagglutinin also helps determine how deadly the strain is.
The 1918 strain "looks more like an avian virus – with some human characteristics," said Scripps lead investigator Ian Wilson, a molecular biology professor.
Importance of surveillance
One of the main questions researchers have about the 1918 flu is whether it entered humans from pigs or another mammal that caught it from birds, or if it jumped directly from birds to humans.
Direct bird-to-human transmission is rare and has the potential to be more deadly. Wilson said the findings don't rule out that the 1918 flu made a brief stop in pigs before infecting people.
The hemagluttinin from the 1918 virus is in a different family, H1, than the H5-bird flu now affecting Asia, said the lead British investigator, Sir John Skehel, director of MRC.
"The results show us how the [1918] virus was able to bind to human receptors and to spread from one human cell to another human cell," said Skehel.
Both teams say understanding what makes the virus so deadly and able to live and spread in humans is key to preventing and controlling future epidemics.
The research appears in the Feb. 5 online edition of the journal Science.
virus_flu
changturtle.blogspot.com/2009/10/1918influenza-during-ww1...
Scientists probe why 1918 flu was so deadly
Last Updated Fri, 06 Feb 2004 12:33:05
VANCOUVER - A new study of the 1918 influenza epidemic that killed 20 million people suggests that it may be easier for bird flu viruses to develop the ability to spread between people than originally thought.
* INDEPTH: Flu
Two teams of researchers in Britain and the U.S. analysed samples of the virus from victims of the 1918 outbreak to reconstruct the 3D structure of a key infectious protein.
50,000 Canadians died in the 1918 flu epidemic
The 1918 flu virus was probably so deadly because of its unique, bird-like protein, the scientists say.
Like the current outbreak of bird flu in east Asia, the 1918 influenza appears to have jumped from birds to people with few changes along the way.
The study doesn't directly relate to today's bird flu strain, which doesn't seem to be able to easily infect many people.
* RELATED STORY: UN agencies call for poultry vaccination to fight bird flu
But the findings suggests it may take fewer genetic adaptations than thought for bird flu to gain the ability to spread between people.
The research "underscores our concern that influenza viruses from a bird reservoir can adapt to humans, can become a major threat," said Dr. Danuta Skowronski of the B.C. Centre for Disease Control.
Bird flu vs. human flu
Sugar cube-sized lung samples were preserved from victims of the 1918 flu. Researchers at Scripps Institute in La Jolla, Calif., and at Britain's Medical Research Council used the samples to study the 1918 flu in detail, and compare it with other bird and human flu strains.
Scientists believe small mutations in the spike-like protein, called hemagglutinin or H1, allowed the 1918 flu virus to infect new species. How our immune systems recognize and react to hemagglutinin also helps determine how deadly the strain is.
The 1918 strain "looks more like an avian virus – with some human characteristics," said Scripps lead investigator Ian Wilson, a molecular biology professor.
Importance of surveillance
One of the main questions researchers have about the 1918 flu is whether it entered humans from pigs or another mammal that caught it from birds, or if it jumped directly from birds to humans.
Direct bird-to-human transmission is rare and has the potential to be more deadly. Wilson said the findings don't rule out that the 1918 flu made a brief stop in pigs before infecting people.
The hemagluttinin from the 1918 virus is in a different family, H1, than the H5-bird flu now affecting Asia, said the lead British investigator, Sir John Skehel, director of MRC.
"The results show us how the [1918] virus was able to bind to human receptors and to spread from one human cell to another human cell," said Skehel.
Both teams say understanding what makes the virus so deadly and able to live and spread in humans is key to preventing and controlling future epidemics.
The research appears in the Feb. 5 online edition of the journal Science.