Kludging a Killer

How scientists re-created ultra-lethal influenza

At the height of World War I, nature unleashed the most effective bioweapon ever known. The 1918 influenza pandemic killed more than 20 million people. Then it disappeared, leaving behind corpses and lingering anxieties. Why was this particular flu so severe? Would it recur? Could we stop it if it did?

Last year, virologists from the University of Wisconsin investigated some of those questions. The 1918 strain's genetic blueprint had been gleaned from RNA in the preserved lung tissues of American soldiers who had died of the disease. In the confines of a Canadian Biosafety Level 4 lab, Yoshihiro Kawaoka and his team isolated two of the genes that they thought might be responsible for the 1918 flu's deadliness. They inserted each gene into a relatively benign strain of flu, then exposed mice to these new viruses. The two genes they chose each code for a different protein on the surface of the flu virus.

When mice were exposed to one of these lab-created berbugs, they contracted the massive lung infections and hemorrhages typical of the 1918 flu. The lethal ingredient turned out to be hemagglutinin, a protein that helps the virus attach to cells during infection. Some scientists hailed the discovery, which they said will make
it easier to identify early signs of an emerging superbug and prevent its return. Other, less sanguine scientists point out that the 1918 strain might never reappear and that re-creating it has put humanity at risk. Although most influenza strains are unlikely bioweapons, this extra-lethal one might be turned to that purpose. It now resides in a high-security lab in Madison, Wisconsin. One accident, or one lab worker bent on sabotage, and we could have another epidemic --sparked this time not by nature but by our desire to outsmart it.