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What is the Spanish Flu?

Michael Anissimov
Michael Anissimov
Michael Anissimov
Michael Anissimov

The Spanish flu was a terrible worldwide epidemic that killed between 50-100 million people in an 18 month period throughout 1918 and 1919. This classifies it as a 5 on the Pandemic Severity Index, meaning more than 2% people who were infected died. The Spanish flu resulted in the death of 2.5-5% of the world population at the time it struck, killing more than World War I, which it occurred immediately after. The Spanish flu was in the same category of severity as the Bubonic Plague, which, when it struck as the Black Death, killed about 75 million people, 25-50 million of them in Europe.

The Spanish flu was caused by an unusually severe and deadly Influenza A virus strain of subtype H1N1. In contrast to most influenza outbreaks in history, the Spanish flu struck people down in their prime of life, rather than picking off the old and young. People with weaker immune systems, such as children and middle aged adults, had lower mortality rates, while young adults had the highest mortality rates.

Cytokine storm is the body's over-reaction to infection.
Cytokine storm is the body's over-reaction to infection.

The distribution pattern of deaths has led scientists to argue that the Spanish flu killed because of an excessive immune response, called a cytokine storm. In a cytokine storm, the immune response is so overwhelming that the overabundance of immune cells, such as macrophages, can clog local tissues, causing the buildup of fluids and eventually fatal damage. Cytokine storms are normally rare, and are thought to be caused as a reaction of the immune system to a novel and highly pathogenic invader.

Bacterial pneumonia was the primary cause of death in individuals who had contracted the Spanish flu.
Bacterial pneumonia was the primary cause of death in individuals who had contracted the Spanish flu.

In comparison to a more typical case of the flu, which kills 0.1% of those infected, the Spanish flu killed between 2-20% of sufferers. The primary cause of death was from a secondary infection of the lungs, bacterial pneumonia. The secondary cause of death was from the virus itself, which caused massive hemorrhages and edema in the lungs.

Genetic material from the Spanish flu virus has been recovered from the corpse of a flu victim in Alaskan permafrost, a woman who had collapsed in the wilderness after being struck down by the disease. This genetic material has been used to recreate the virus from scratch and sequence its entire genome, which has been published on the Internet. Some technologists, such as inventor Ray Kurzweil and Sun Microsystems co-founder Bill Joy, have expressed dismay at this development.

Michael Anissimov
Michael Anissimov

Michael is a longtime WiseGEEK contributor who specializes in topics relating to paleontology, physics, biology, astronomy, chemistry, and futurism. In addition to being an avid blogger, Michael is particularly passionate about stem cell research, regenerative medicine, and life extension therapies. He has also worked for the Methuselah Foundation, the Singularity Institute for Artificial Intelligence, and the Lifeboat Foundation.

Learn more...
Michael Anissimov
Michael Anissimov

Michael is a longtime WiseGEEK contributor who specializes in topics relating to paleontology, physics, biology, astronomy, chemistry, and futurism. In addition to being an avid blogger, Michael is particularly passionate about stem cell research, regenerative medicine, and life extension therapies. He has also worked for the Methuselah Foundation, the Singularity Institute for Artificial Intelligence, and the Lifeboat Foundation.

Learn more...

Discussion Comments

anon1002911

This was very helpful on my project. Thanks.

anon1002887

This was very helpful and had some good information.

anon148703

very helpful with a history assignment.

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    • Cytokine storm is the body's over-reaction to infection.
      By: psdesign1
      Cytokine storm is the body's over-reaction to infection.
    • Bacterial pneumonia was the primary cause of death in individuals who had contracted the Spanish flu.
      By: Zsolt Biczó
      Bacterial pneumonia was the primary cause of death in individuals who had contracted the Spanish flu.
    • Evidence suggests that some people have residual immunity to the virus that caused the 1918 pandemic.
      By: Syda Productions
      Evidence suggests that some people have residual immunity to the virus that caused the 1918 pandemic.
    • The spanish flu killed between 2 and 20% of sufferers.
      By: oneblink1
      The spanish flu killed between 2 and 20% of sufferers.