Wednesday, October 05, 2005

The 1918 Flu was a bird flu, too

Deadly 1918 Epidemic Linked to Bird Flu, Scientists Say - New York Times:
Two teams of federal and university scientists announced today that they had resurrected the 1918 influenza virus, the cause of one of history's most deadly epidemics, and had found that unlike the viruses that caused more recent flu pandemics of 1957 and 1968, the 1918 virus was actually a bird flu that jumped directly to humans.

The work, being published in the journals Nature and Science, involved getting the complete genetic sequence of the 1918 virus, using techniques of molecular biology to synthesize it, and then using it to infect mice and human lung cells in a specially equipped, secure lab at the Centers for Disease Control and Prevention in Atlanta.

Medical authorities at the time [1918] found it hard even to describe the devastation. At Fort Devens, wrote one doctor, Victor Vaughan, they saw young soldiers' "bodies stacked like cordwood," dead from the flu. The epidemic, he added, "visited the remotest corners, taking toll of the most robust, sparing neither soldier nor civilian, and flaunting its red flag in the face of science."
The original Nature paper is here. Flu pandemics in the middle of the last century derived from a combination of human flu and avian flu in a single infected person. The 1918 flu was not such a chimera, but a relatively pure avian virus, with a few minor amino acid substitutions. Those substitutions match changes seen in other extremely virulent flu viruses, suggesting that these same mutations are the ones to watch for as avian flu spreads.

If it's any consolation, it seems to be from a different branch than the H5N1 strain of the current avian flu.

However, some of the special mutations were identified in H5N1 strains, so don't be too optimistic. The others will arise, and natural selection will make them more common, because they increase infectivity.

Understanding the lethality of the 1918 flu relied on the researchers understanding the evolution of flu viruses. Yet again, evolutionary hypotheses have a chance to save lives.

The current government plan? Call out the army to block off the infected regions. No Man's Land on steroids. We could also follow the Alaskan Senator's strategy and stick our fingers in our ears.

As always, the FluWiki is your source for up-to-date background.

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