My e-book looks at scientific efforts to isolate the 1918 Spanish flu virus. A mutated version of H1N1, the 1918 influenza is so virulent it can kill mice. Most flu viruses are mild. Many aren't strong enough to ruffle the fur of mice. The Spanish flu that coincided with the end of World War I, killed 500,000 Americans, and as many as 20 million people worldwide. One of the most intriguing studies of the 1918 strain was conducted in the early 1950s by a team of researchers at the University of Iowa. This group studied preserved flu tissue in the bodies of Eskimos that was preserved in the frozen Alaskan permafrost.