Video: 'Influenza 1918 | PBS American Experience | Documentary 2017' (Mar. 11, 1918, at 6:51)

(Monday, March 11, 1918) — The first documented case of the 1918 flu pandemic, which would kill 50–100 million people worldwide, was made this morning when U.S. Army mess cook Private Albert Gitchell complained of a sore throat, fever and headache today at a hospital at Camp Funston, Fort Riley, Kansas, an American military facility that at the time was training American troops during World War I.

However, cases of the flu were observed as early as January 1918 in Haskell County, Kansas.

The 1918 flu pandemic would eventually claim an estimated 20 to 40 million lives, making it one of the deadliest natural disasters in human history.