Though it was dubbed the Spanish flu, some experts think it originated in the U.S. However, nobody knows for certain.
What is known is that on March 4, 1918, a young man showed up with the flu at the hospital at Camp Funston, an Army base in Kansas where soldiers were training for combat in World War I (1914-18). Over the next few weeks, more than 1,000 men reported to the camp hospital with the same symptoms, and 38 died.
As thousands of Americans were sent to Europe to fight in the war that spring, they took the flu with them. It spread rapidly, hitting every country hard. The U.S., Britain, and other countries censored their press during wartime, making it illegal to publish anything that might hinder war efforts, including that a deadly disease was spreading among troops. But Spain, not a combatant in the war, had no censorship and its press reported extensively on the disease, so it became known as Spanish influenza.