The 1918 Spanish influenza was one of the deadliest pandemics in human history, and researchers still don't know why that particular strain was such an effective killer. A new study suggests that flu patients' immune systems played a surprising role. Rather than striking out against just the flu virus, victims' immune systems may have launched furious attacks that devastated their lungs.
Since removing virus samples from the body of a 1918 flu victim that was excavated from permafrost in 1997, researchers have searched for unique characteristics that made the bug so deadly. Last year, a team led by Jeffery Taubenberger of the Armed Forces Institute of Pathology in Rockville, Md., finished sequencing the virus' eight unique genes and reconstructed the original killer (SN: 10/8/05, p. 227: Killer Findings: Scientists piece together 1918-flu virus).