The 1918 flu pandemic, commonly referred to as the Spanish flu, was a category 5 influenza pandemic caused by an unusually severe and deadly Influenza A virus strain of subtype H1N1.
The difference between the influenza mortality age-distributions of the 1918 epidemic and normal epidemics. Deaths per 100,000 persons in each age group, United States, for the interpandemic years 1911–1917 (dashed line) and the pandemic year 1918 (solid line).
The Spanish flu pandemic lasted from 1918 to 1919, although Price-Smith's data suggest it may have begun in Austria in the Spring of 1917. Older estimates say it killed 40–50 million peoplewhile current estimates say 50 million to 100 million people worldwide were killed. This pandemic has been described as "the greatest medical holocaust in history" and may have killed as many people as the Black Death , although the Black Death is estimated to have killed over a fifth of the world's population at the time , a significantly higher proportion. This huge death toll was caused by an extremely high infection rate of up to 50% and the extreme severity of the symptoms, suspected to be caused by cytokine storms.Indeed, symptoms in 1918 were so unusual that initially influenza was misdiagnosed as dengue, cholera, or typhoid. One observer wrote, "One of the most striking of the complications was hemorrhage from mucous membranes, especially from the nose, stomach, and intestine. Bleeding from the ears and petechial hemorrhages in the skin also occurred." The majority of deaths were from bacterial pneumonia, a secondary infection caused by influenza, but the virus also killed people directly, causing massive hemorrhages and edema in the lung.
The Spanish flu pandemic was truly global, spreading even to the Arctic and remote Pacific islands. The unusually severe disease killed between 2 and 20% of those infected, as opposed to the more usual flu epidemic mortality rate of 0.1%. Another unusual feature of this pandemic was that it mostly killed young adults, with 99% of pandemic influenza deaths occurring in people under 65, and more than half in young adults 20 to 40 years old.This is unusual since influenza is normally most deadly to the very young (under age 2) and the very old (over age 70). The total mortality of the 1918–1919 pandemic is not known, but it is estimated that up to 1% of the world's population was killed. As many as 25 million may have been killed in the first 25 weeks; in contrast, HIV/AIDS has killed 25 million in its first 25 years.
The difference between the influenza mortality age-distributions of the 1918 epidemic and normal epidemics. Deaths per 100,000 persons in each age group, United States, for the interpandemic years 1911–1917 (dashed line) and the pandemic year 1918 (solid line).
The Spanish flu pandemic lasted from 1918 to 1919, although Price-Smith's data suggest it may have begun in Austria in the Spring of 1917. Older estimates say it killed 40–50 million peoplewhile current estimates say 50 million to 100 million people worldwide were killed. This pandemic has been described as "the greatest medical holocaust in history" and may have killed as many people as the Black Death , although the Black Death is estimated to have killed over a fifth of the world's population at the time , a significantly higher proportion. This huge death toll was caused by an extremely high infection rate of up to 50% and the extreme severity of the symptoms, suspected to be caused by cytokine storms.Indeed, symptoms in 1918 were so unusual that initially influenza was misdiagnosed as dengue, cholera, or typhoid. One observer wrote, "One of the most striking of the complications was hemorrhage from mucous membranes, especially from the nose, stomach, and intestine. Bleeding from the ears and petechial hemorrhages in the skin also occurred." The majority of deaths were from bacterial pneumonia, a secondary infection caused by influenza, but the virus also killed people directly, causing massive hemorrhages and edema in the lung.
The Spanish flu pandemic was truly global, spreading even to the Arctic and remote Pacific islands. The unusually severe disease killed between 2 and 20% of those infected, as opposed to the more usual flu epidemic mortality rate of 0.1%. Another unusual feature of this pandemic was that it mostly killed young adults, with 99% of pandemic influenza deaths occurring in people under 65, and more than half in young adults 20 to 40 years old.This is unusual since influenza is normally most deadly to the very young (under age 2) and the very old (over age 70). The total mortality of the 1918–1919 pandemic is not known, but it is estimated that up to 1% of the world's population was killed. As many as 25 million may have been killed in the first 25 weeks; in contrast, HIV/AIDS has killed 25 million in its first 25 years.
The 1918 flu pandemic (commonly referred to as the Spanish flu) was an influenza pandemic that spread to nearly every part of the world. It was caused by an unusually virulent and deadly Influenza A virus strain of subtype H1N1. Historical and epidemiological data are inadequate to identify the geographic origin of the virus. Most of its victims were healthy young adults, in contrast to most influenza outbreaks which predominantly affect juvenile, elderly, or otherwise weakened patients. The flu pandemic has also been implicated in the sudden outbreak of Encephalitis lethargica in the 1920s.
The pandemic lasted from March 1918 to June 1920, spreading even to the Arctic and remote Pacific islands. It is estimated that anywhere from 50 to 100 million people were killed worldwide, or the approximate equivalent of one third of the population of Europe.An estimated 500 million people, one third of the world's population (approximately 1.6 billion at the time), became infected.
Scientists have used tissue samples from frozen victims to reproduce the virus for study. Given the strain's extreme virulence there has been controversy regarding the wisdom of such research. Among the conclusions of this research is that the virus kills via a cytokine storm (overreaction of the body's immune system) which explains its unusually severe nature and the concentrated age profile of its victims. The strong immune systems of young adults ravaged the body, whereas the weaker immune systems of children and middle-aged adults caused fewer deaths.
The pandemic lasted from March 1918 to June 1920, spreading even to the Arctic and remote Pacific islands. It is estimated that anywhere from 50 to 100 million people were killed worldwide, or the approximate equivalent of one third of the population of Europe.An estimated 500 million people, one third of the world's population (approximately 1.6 billion at the time), became infected.
Scientists have used tissue samples from frozen victims to reproduce the virus for study. Given the strain's extreme virulence there has been controversy regarding the wisdom of such research. Among the conclusions of this research is that the virus kills via a cytokine storm (overreaction of the body's immune system) which explains its unusually severe nature and the concentrated age profile of its victims. The strong immune systems of young adults ravaged the body, whereas the weaker immune systems of children and middle-aged adults caused fewer deaths.
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