Thursday, October 07, 2004

Identification of the 1918 pandemic's lethality factor

The New York Times > Science > Critical Gene a Suspect in Lethal Epidemic
By recreating the influenza virus that killed up to 50 million people in 1918-19, researchers may have identified the gene that turned it into one of the most lethal in human history.

The gene, one of eight in the virus, seems to have an unexpected capacity for sending the body's immune system into overdrive, causing inflammation, hemorrhage and death, the scientists report today in the journal Nature.

... Dr. Kawaoka, Dr. Taubenberger and others have been reinserting the 1918-type genes into ordinary flu viruses to see if they can pinpoint which of the genes made the virus so lethal and how it did so. In the latest of these experiments, which Dr. Kawaoka reports today, a gene called the hemagglutinin or HA gene seems to be largely responsible for the dire effects of Spanish flu, as the 1918 epidemic is also known.

... The HA gene studied by Dr. Kawaoka's team is well known to flu experts because it changes from year to year. Since the protein made by the gene is the one singled out for attack by the immune system, the body's defenses are caught off guard each year as flu virus arrives with a novel version of the protein to which the body has no prior immunity.

... What he has now found is that the Spanish flu version of the HA gene, in addition to its break-in and enter role, seems able to trigger the release of cytokines, the signaling agents with which the immune system gears itself up for massive attack against an infectious agent.

Uncontrolled overdrive can make the immune system kill the body in order to save it, through excessive inflammation. The virus carrying the Spanish flu version of the HA gene produced high levels of cytokines in mice, Dr. Kawaoka says, and this is probably what led to the inflammation and lung damage that killed them.

... Survivors of the 1918 epidemic have high levels of antibody to the engineered virus, Dr. Kawaoka reports, but people infected recently with a similar class of flu virus do not. "Thus, a large section of the population would be susceptible to an outbreak of a 1918-like influenza virus," he and his colleagues concluded.

If this is borne out by further work, Drs Kawaoka and Taubenberger may share the Nobel prize. Of course by the time they get their prize, high school students will have the facilities to create viruses that make this one seem relatively benign.

Today in central China a baby boy was born. Sixteen years from now he'll swear revenge on an unfaithful lover -- and in heartbroken spite he'll create the pathogen that saves the earth from humanity.

And some people think we should worry about al Qaeda.

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