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Flu

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The 1918 flu pandemic (commonly referred to as the Spanish flu) was a category 5 influenza pandemic that started in the United States, appeared in West Africa and France and then spread to nearly every part of the globe. It was caused by an unusually severe and deadly Influenza A virus strain of subtype H1N1. Many of its victims were healthy young adults, in contrast to most influenza outbreaks which predominantly affect juvenile, elderly, or otherwise weakened patients.

The Spanish flu pandemic lasted from March, 1918, to June, 1920,^[1] spreading even to the Arctic and remote Pacific islands. While older estimates put the number of killed at 40–50 million people, current estimates are that 50 million to 100 million people worldwide died, possibly more than that taken by the Black Death. This extraordinary toll resulted from the extremely high infection rate of up to 50% and the extreme severity of the symptoms, suspected to be caused by cytokine storms.

Chart of deaths in major cities

The disease was first observed at Fort Riley, Kansas on March 4, 1918,^[2] and Queens, New York, on March 11, 1918. In August, 1918, a more virulent strain appeared simultaneously in Brest, France, in West Africa at Freetown, Sierra Leone, and in the U.S. at Boston, Massachusetts. The Allies of World War I came to call it the Spanish Flu, primarily because the pandemic received greater press attention after it moved from France to Spain in November, 1918. Spain was not involved in the war and had not imposed wartime censorship.^[3]

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, which explains its unusually severe nature and the unusual age profile of its victims (the virus caused an overreaction of the body's immune system - strong immune systems ravaged the body, while weaker ones did far less damage).

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).^[4]

The global mortality rate from the 1918/1919 pandemic is not known, but is estimated at 2.5 to 5% of the human population, with 20% or more of the world population suffering from the disease to some extent. Influenza may have killed as many as 25 million in its first 25 weeks (in contrast, AIDS killed 25 million in its first 25 years). Older estimates say it killed 40–50 million people^[5] while current estimates say 50 million to 100 million people worldwide were killed.^[6] This pandemic has been described as "the greatest medical holocaust in history" and may have killed as many people as the Black Death.^[7]

An estimated 7 million died in India, about 2.78% of India's population at the time. In the Indian Army, almost 22% of troops who caught the disease died of it^{[citation needed]}. In the U.S., about 28% of the population suffered, and 500,000 to 675,000 died. In Britain as many as 250,000 died; in France more than 400,000. In Canada approximately 50,000 died. Entire villages perished in Alaska and southern Africa. In Australia an estimated 12,000 people died and in the Fiji Islands, 14% of the population died during only two weeks, and in Western Samoa 22%.

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.^[5] 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."^[6] 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.^[4]

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%.^[4][6] 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.^[8] This is unusual since influenza is normally most deadly to the very young (under age 2) and the very old (over age 70).

While World War I did not cause the flu, the close quarters and mass movement of troops quickened its spread. Researchers speculate that the soldiers' immune systems were weakened by the stresses of combat and chemical attacks, increasing their susceptibility to the disease.

A large factor in the spread of the disease was the increased amount of travel. The modernization of transportation made it easier for sailors to spread the disease more quickly and to a wider range of communities.

American Red Cross nurses tend to flu patients in temporary wards set up inside Oakland Municipal Auditorium, 1918

Two poems, dedicated to the Spanish flu, were popular in those days:

I had a little bird,
Its name was Enza,
I opened the window,
And in-flew-enza.
-American Skipping Rhyme circa 1918

Obey the laws
And wear the gauze.
Protect your jaws
From septic paws.

The influenza strain was unusual in that this pandemic killed many young adults and otherwise healthy victims — typical influenzas kill mostly infants (aged 0-2 years), the old, and the immunocompromised. Another oddity was that this influenza outbreak struck hardest in summer and fall (in the Northern Hemisphere). Typically, influenza is worse in the winter months.

People without symptoms could be struck suddenly and within hours be too feeble to walk; many died the next day. Symptoms included a blue tint to the face and coughing up blood caused by severe obstruction of the lungs. In some cases, the virus caused an uncontrollable hemorrhaging that filled the lungs, and patients drowned in their body fluids. In still others, the flu caused an uncontrollable loss of bowel functions and the victim would die from losing critical intestinal lining.

In fast-progressing cases, mortality was primarily from pneumonia, by virus-induced consolidation. Slower-progressing cases featured secondary bacterial pneumonias, and there may have been neural involvement that led to mental disorders in a minority of cases. Some deaths resulted from malnourishment and even animal attacks in overwhelmed communities.

Street car conductor in Seattle not allowing passengers aboard without a mask in 1918.

While in most places less than one-third of the population was infected, only a small percentage of whom died, in a number of towns in several countries entire populations were wiped out.

Even in areas where mortality was low, those incapacitated by the illness were often so numerous as to bring much of everyday life to a stop. Some communities closed all stores or required customers not to enter the store but place their orders outside the store for filling. There were many reports of places with no health care workers to tend the sick because of their own ill health and no able-bodied grave diggers to bury the dead. Mass graves were dug by steam shovel and bodies buried without coffins in many places.

In Japan, 257,363 deaths were attributed to influenza by July 1919, giving an estimated 0.425% mortality rate, much lower than nearly all other Asian countries for which data are available. The Japanese government severely restricted maritime travel to and from the home islands when the pandemic struck. The only sizeable inhabited place with no documented outbreak of the flu in 1918–1919 was the island of Marajó at the mouth of the Amazon River in Brazil. In the Pacific, American Samoa^[9] and the French colony of New Caledonia ^[10] also succeeded in preventing even a single death from influenza through effective quarantines.

Main article: Spanish flu research

One theory is that the virus strain originated at Fort Riley, Kansas, by two genetic mechanisms — genetic drift and antigenic shift — in viruses in poultry and swine which the fort bred for local consumption. But evidence from a recent reconstruction of the virus suggests that it jumped directly from birds to humans, without traveling through swine.^[11] On October 5, 2005, researchers announced that the genetic sequence of the 1918 flu strain, a subtype of avian strain H1N1, had been reconstructed using historic tissue samples.^[12][13][14] On 18 January 2007, Kobasa et al reported that infected monkeys (Macaca fascicularis) exhibited classic symptoms of the 1918 pandemic and died from a cytokine storm.^[15]

• Guillaume Apollinaire, French poet († November 9, 1918)
• Felix Arndt, American pianist († October 16, 1918)
• Sophie Freud, daughter of Austrian psychoanalyst Sigmund Freud, († 1920)
• Harold Gilman, British painter († February 12, 1919)
• Henry G. Ginaca, American engineer, inventor of the Ginaca machine († October 19, 1918)
• Charles Tomlinson Griffes, American composer († April 8, 1920)
• Joe Hall, Montreal Canadiens defenceman, a member of the Hockey Hall of Fame († April 6, 1919).
• Phoebe Hearst, mother of William Randolph Hearst, († April 13, 1919)
• Francisco Marto, Fátima child († April 4, 1919)
• Jacinta Marto, Fátima child († February 20, 1920)
• Edmond Rostand, French dramatist, best known for his play Cyrano de Bergerac, († December 2, 1918)
• Egon Schiele, Austrian painter († October 31, 1918). His wife Edith, who was six months pregnant, succumbed to the disease only three days before.
• Yakov Sverdlov, Bolshevik party leader and official of pre-USSR Russia († March 16, 1919)
• Max Weber, German political economist and sociologist († June 14, 1920)

Wikimedia Commons has media related to:

Spanish flu

• Video from Expert Panel Discussion on Avian Flu
• Nature "Web Focus" on 1918 flu, including new research
• Influenza Pandemic on stanford.edu
• Article: The Deadliest Fall
• Influenza 1918 in the United States on pbs.org
• Secrets of the Dead: Killer Flu (PBS)
• Flu by Eileen A. Lynch. The devastating effect of the Spanish flu in the city of Philadelphia, PA, USA
• Dialog: An Interview with Dr. Jeffery Taubenberger on Reconstructing the Spanish Flu
• The Deadly Virus - The Influenza Epidemic of 1918, by the National Archives and Records Administration (see actual pictures and records of the time).
• The 1918 Influenza Pandemic in New Zealand - includes recorded recollections of people who lived through it
• Experts Unlock Clues to Spread of 1918 Flu Virus - The New York Times
• PBS - recovery of flu samples from Alaskan flu victims
• An Avian Connection as a Catalyst to the 1918-1919 Influenza Pandemic
• Alaska Science Forum - Permafrost Preserves Clues to Deadly 1918 Flu
• Pathology of Influenza in France, 1920 Report
• "Deadly secret of 1918 flu virus unmasked", Cosmos magazine, September 2006
• Yesterday's News blog, 1918 newspaper account on impact of flu on Minneapolis
• "Lethal secrets of 1918 flu virus" BBC News, January 2007
• "Study uncovers a lethal secret of 1918 influenza virus" University of Wisconsin - Madison, January 17, 2007
• "The site of origin of the 1918 influenza pandemic and its public health implications" Journal of Translational Medicine, January 20, 2004