Haskell County, Kansas, is the first recorded instance anywhere in the world of an outbreak of influenza so unusual that a physician warned public health officials. It remains the first recorded instance suggesting that a new virus was adapting, violently, to man.
The 1918–1919 influenza pandemic killed more people than any other outbreak of disease in human history. The lowest estimate of the death toll is 21 million, while recent scholarship estimates from 50 to 100 million dead.