A Pteranodon ...
Posted on 11/29/2005 8:05:54 AM PST by Toidylop
Science moves in mysterious ways, and sometimes what seems like the end of the story is really just the beginning. Or, at least, that is what some researchers are thinking as they scratch their heads over the weird genetic sequence of the 1918 flu virus.
Dr. Jeffery Taubenberger, a molecular pathologist at the Armed Forces Institute of Technology who led the research team that reconstructed the long-extinct virus, said that a few things seemed clear.
The 1918 virus appears to be a bird-flu virus. But if it is from a bird, it is not a bird anyone has studied before. It is not like the A(H5N1) strain of bird flus in Asia, which has sickened at least 116 people and killed 60. It is not like the influenza viruses that infect fowl in North America.
Yet many researchers believe that the 1918 virus, which caused the worst infectious disease epidemic in human history, is a bird-flu virus. And if so, it is the only one that has ever been known to cause a human pandemic.
That, Taubenberger said, gives rise to a question. Are scientists looking for the next pandemic flu virus in all the wrong places? Is there a bird that no one ever thought about that harbors the next 1918-like flu? And if so, what bird is it, and where does it live?
"I can't even assign a hemisphere," he said. "It just came from somewhere else. Maybe it's in pigeons. Or in songbirds."
In cold storage
Taubenberger's question emerged from the science fictionlike search for the 1918 virus that eventually led to its reconstruction.
A decade ago, Taubenberger and his colleagues found shards of the extinct virus in two fingernail-size snippets of formaldehyde-soaked lung tissue from two soldiers and from the frozen lung of an Inuit woman who died of the flu in 1918 and was buried in permafrost. Slowly and painstakingly, they fished out the tiny fragments of viral genes and began reconstructing them.
The first gene they sequenced was the one that codes for the hemagglutinin protein on the virus' surface. Immediately, Taubenberger and his colleagues were struck by an oddity: The chain of nucleotides that coded for the amino acids in the protein were arranged differently from those found in any other bird flu.
The genetic code is flexible; there is more than one way that a group of three nucleotides can be arranged to code for the same amino acid. But every bird-flu virus ever studied used the same spellings for the hemagglutinin amino acids. Not the 1918 flu.
There were two possibilities, Taubenberger thought. One was that bird flus have evolved over the decades and that back in 1918, the amino acids in bird viruses were simply coded differently.
Another was that if the 1918 flu virus came from a bird, it was no bird that anyone had considered before.
Subsequently Taubenberger studied 25 waterfowl collected around 1918 at the collection of the National Museum of Natural History in Washington. Six of the birds had a flu virus. The genetic coding for the amino acids in those viruses was exactly like that in bird flu viruses today, Taubenberger found.
In fact, the viruses had not even evolved. Human influenza viruses change every year, mutating slightly so they can re-infect people who had just had the flu and developed antibodies against it. But birds, Slemons said, do not have much of an immune response to influenza, and so there is no particular pressure for the virus to mutate.
Another reason the viruses stay the same, he said, is that some birds live for only a couple of years and so, every year, the viruses have a new bird population to infect. Finally, he said, birds are chronically infected with lots of flu viruses at once, and all the viruses coexist peacefully.
"There are so many that there is no selective pressure on any virus," he said.
But if bird viruses do not evolve and if the waterfowl viruses in 1915 and 1916 look just like bird viruses today, where did the 1918 virus come from? Or was it really a bird virus?
In class of its own
At the time that he looked at the museum birds, Taubenberger had reconstructed only part of the virus' genetic sequence. Maybe when he had the whole thing, the picture would change.
It did not. The entire sequence, published last month in Nature, had the distinctive protein structures of a bird virus, he said. And it had that same peculiar way of spelling its amino acids.
When he compared the 1918 virus with today's human flu viruses, Taubenberger noticed that it had alterations in just 25 to 30 of the virus' 4,400 amino acids. Those few changes turned a bird virus into a killer that could spread from person to person.
Taubenberger noticed that, so far, the A(H5N1) viruses in Asia have just a few of those changes. They do not, however, have the unusual ways of coding the amino acid instructions that the 1918 virus had. So are the Asian bird viruses on their way to becoming pandemic viruses, or not?
Some experts like Dr. Peter Palese of the Mount Sinai School of Medicine in New York say the A(H5N1) flu viruses are a false alarm. He notes that studies of serum collected in 1992 from people in rural China indicated that millions of people there had antibodies to the A(H5N1) strain.
That means they had been infected with an H5N1 bird virus and recovered, apparently without incident.
Despite that, and the fact that those viruses have been circulating in China more than a dozen years, almost no human-to-human spread has occurred. "The virus has been around for more than a dozen years, but it hasn't jumped into the human population," Palese said. "I don't think it has the capability of doing it."
Taubenberger said he could argue it either way.
"It's a nasty virus," he said. "It is highly virulent in domestic birds and wild birds. The fact that it has killed half the humans it has infected makes it of concern, and the fact that it shares some features with the 1918 virus makes it of concern.
"But the fact that it has circulated in Asia for years and hasn't caused a pandemic argues against it. Maybe there are some biological barriers we don't understand."
"I can't even assign a hemisphere," he said. "It just came from somewhere else"
Dummy, it's from a comet.
Did you know that the 1918 flu pandemic started in Kansas?
Could the 1918 epidemic have been part of an attempt at biological warfare by the Central Powers in WWI?
They were desperate, clutching at straws, and searching for a weapon that would help them survive. They started using poison gas,
as one alternative. Did they consider using plague?
The outbreak began in the American army; it might have decimated that army worse than any battle, and rendered it unable to come to the battlefield until after the Germans had taken Paris and rendered American assistance irrelevant.
But the plague might have gotten out of control, and all records of its use been lost/destroyed.
(Just food for thought. . . )
Read the book, The Great Influenza by John Barry.
It started in Kansas, spread to a big troop facility, and thence to the rest of the world.
I saw a program linking the 1918 pandemic to the (American) use of mummy-wrappings in the production of brown paper bags - subsequently used to wrap meat. It's an interesting historical story: the link to the influenza isn't proven though.
Hmm. The Tunguska Comet impact was about this time wasn't it?
The science did not exist to use viruses in bio-warfare at the time of WWI.
Ping
Hadn't heard that one yet. Interesting...
Maybe it wasn't Tunguska? There was a big comet that exploded over Siberia in the very early 1900's. Never actually hit the earth but flattened a lot of the uninhabited countryside up there.
Tin foil hats won't protect from the flu. You need a tin foil mask sealed tightly over the nose and mouth and I guarantee - no flu.
A Pteranodon ...
Yea I think it was Tunguska. Alien flu
The truth is out there. Trust no one.
I thought this looked familiar.
Hazard in Hunt for New Flu: Looking for Bugs in All the Wrong Places
Science moves in mysterious ways, and sometimes what seems like the end of the story is really just the beginning. Or, at least, that is what some researchers are thinking as they scratch their heads over the weird genetic sequence of the 1918 flu virus.
The San Diego Union Tribune waited two weeks and gave it a new title. Since I started looking at regional papers around the country, I've noticed that a lot of regional papers seem to wait a little and slap new titles on stories from the NY Times and the Washington Post.
Check this out. For Gina Kolata, the Times gives free access to almost all of her articles. Unless you have subscribed to TimesSelect, I believe as I don't subscribe, you normally have to pay for access to articles more than a week old.
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by Gina Kolata
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