The influenza outbreaks of 1918 to 1919 also known as Spanish flu pandemic. First reported in Haskell County in Kansas in March of 1918 the disease spread throughout the world and may have killed as many as 25 million people
Influenza A Virus, H1N1 Subtype -- prevention & control : The 2009 H1N1 influenza vaccination campaign : summary of a workshop series / Clare Stroud, Lori Nadig, and Bruce M. Altevogt, rapporteurs ; Forum on Medical and Public Health Preparedness for Catastrophic Events, Board on Health Sciences Policy, Institute of Medicine of the National Academies