Guide Note

The Spanish Flu was an avian flu pandemic that was first diagnosed in the United States. The flu eventually spread across the entire world and reached every continent. The Spanish Flu claimed at least 50 million lives, killing more people than any other illness in history.¹

Fast Facts

1. Also known as 1918 Flu, La Grippe
2. Caused by Influenza A Virus strain H1N1²
3. First diagnosed in Kansas military bases³
4. Considered a pandemic flu
5. Infected about one-third of the world's population¹
6. Death toll higher than World War I⁴

Scientists believe that the Spanish Flu was a mutated strain of avian flu known as H1N1 that jumped the species barrier and began to infect humans. This is believed to be part of the explanation of why the Spanish Flu was so virulent. Scientists believe that the Spanish Flu is similar to the strain that caused the China bird flu outbreak in 2005, known as H1N5. Scientists continue to study the Spanish Flu in order to gain clues to prevent or temper a future flu epidemic.²