The deadliest outbreak in the world in history

Approximately 90 years before the 2009 swine flu pandemic killed more than 200,000 people, reports of an especially dangerous form of influenza began to appear around the world. Kansas was the site of the first U.S. case, in March 1918. Appearing in multiple countries around the world, the disease spread quickly, ushered along even faster due to the close living quarters of troops fighting in World War I.