1918 Spanish Flu

About 1918 Spanish Flu

The 1918 Spanish flu pandemic was caused by the H1N1 influenza A virus and infected approximately 500 million people worldwide, nearly a third of the global population. Estimates of the death toll range from 17 million to 50 million, and possibly as high as 100 million, exceeding military deaths in World War I. The pandemic occurred in three waves: a mild spring wave, a deadly fall wave, and a winter wave in 1919. Unusual features included a W shaped mortality curve with high death rates in healthy adults aged 20 to 40. The name Spanish Flu came from Spains neutrality in WWI, which meant its press was not censored and reported the disease freely. Human influenza virus was not isolated until 1933. In 2005, scientists reconstructed the 1918 virus using genetic material that included samples from a victim buried in Alaskan permafrost, enabling study of the genetic basis of its virulence.