WASHINGTON (AP) - The 1918 influenza virus that killed more than 20 million people worldwide originated from American pigs and is unlike any other known flu bug, say researchers. They warn that it could strike again.
Using lung tissue taken at autopsy 79 years ago from an Army private killed by the flu, scientists at the Armed Forces Institute of Pathology made a genetic analysis of the virus and concluded it is unique, though closely related to the ''swine'' flu.
"This is the first time that anyone has gotten a look at this virus which killed millions of people in one year, making it the worst infectious disease episode ever," said Dr. Jeffery K. Taubenberger, leader of the Armed Forces Institute team. "It does not match any virus that has been found since."
Although the disease that caused the worldwide epidemic was called "Spanish flu," the virus apparently is a mutation that evolved in American pigs and was spread around the globe by U.S. troops mobilized for World War I, said Taubenberger.
The Army private whose tissue was analyzed contracted the flu at Fort Jackson, S.C. For that reason, Taubenberger and his colleagues suggest in the journal Science that the virus be known as Influenza A/South Carolina.
Science is publishing the study today.
Army doctors in 1918 conducted autopsies on some of the 43,000 servicemen killed by the flu and preserved some specimens in formaldehyde and wax.
Taubenberger said his team sorted through 30 specimens before finding enough virus in the private's lung tissue to partially sequence the genes for hemagglutinin and neuraminidase, two key proteins in flu virus.
"The hemagglutinin gene matches closest to swine influenza viruses, showing that this virus came into humans from pigs," said Taubenberger.
The finding supports a widespread theory that flu viruses from swine are the most virulent for humans.
Most experts believe that flu viruses reside harmlessly in birds, where they are genetically stable. Occasionally, a virus from birds will infect pigs. The swine immune system attacks the virus, forcing it to change genetically to survive. The result is a new virus. When this new bug is spread to humans, it can be devastating, said Taubenberger.
Two other flu viruses spread all over the world since 1918 - Asian flu in 1957 and the Hong Kong flu in 1968 - and both mutated in pigs. ((Source))
Using lung tissue taken at autopsy 79 years ago from an Army private killed by the flu, scientists at the Armed Forces Institute of Pathology made a genetic analysis of the virus and concluded it is unique, though closely related to the ''swine'' flu.
"This is the first time that anyone has gotten a look at this virus which killed millions of people in one year, making it the worst infectious disease episode ever," said Dr. Jeffery K. Taubenberger, leader of the Armed Forces Institute team. "It does not match any virus that has been found since."
Although the disease that caused the worldwide epidemic was called "Spanish flu," the virus apparently is a mutation that evolved in American pigs and was spread around the globe by U.S. troops mobilized for World War I, said Taubenberger.
The Army private whose tissue was analyzed contracted the flu at Fort Jackson, S.C. For that reason, Taubenberger and his colleagues suggest in the journal Science that the virus be known as Influenza A/South Carolina.
Science is publishing the study today.
Army doctors in 1918 conducted autopsies on some of the 43,000 servicemen killed by the flu and preserved some specimens in formaldehyde and wax.
Taubenberger said his team sorted through 30 specimens before finding enough virus in the private's lung tissue to partially sequence the genes for hemagglutinin and neuraminidase, two key proteins in flu virus.
"The hemagglutinin gene matches closest to swine influenza viruses, showing that this virus came into humans from pigs," said Taubenberger.
The finding supports a widespread theory that flu viruses from swine are the most virulent for humans.
Most experts believe that flu viruses reside harmlessly in birds, where they are genetically stable. Occasionally, a virus from birds will infect pigs. The swine immune system attacks the virus, forcing it to change genetically to survive. The result is a new virus. When this new bug is spread to humans, it can be devastating, said Taubenberger.
Two other flu viruses spread all over the world since 1918 - Asian flu in 1957 and the Hong Kong flu in 1968 - and both mutated in pigs. ((Source))
