Spanish flu
Overview
 
The 1918 flu pandemic (the "Spanish" flu) was an influenza pandemic
Influenza pandemic
An influenza pandemic is an epidemic of an influenza virus that spreads on a worldwide scale and infects a large proportion of the human population. In contrast to the regular seasonal epidemics of influenza, these pandemics occur irregularly, with the 1918 Spanish flu the most serious pandemic in...

, and the first of the two pandemics involving H1N1 influenza virus (the second was the 2009 flu pandemic
2009 flu pandemic
The 2009 flu pandemic was an influenza pandemic, and the second of the two pandemics involving H1N1 influenza virus , albeit in a new version...

, an outbreak of Swine Flu). It was an unusually severe and deadly pandemic that spread across the world. Historical and epidemiological
Epidemiology
Epidemiology is the study of health-event, health-characteristic, or health-determinant patterns in a population. It is the cornerstone method of public health research, and helps inform policy decisions and evidence-based medicine by identifying risk factors for disease and targets for preventive...

 data are inadequate to identify the geographic origin. Most victims were healthy young adults, in contrast to most influenza outbreaks, which predominantly affect juvenile, elderly, or weakened patients.
Encyclopedia
The 1918 flu pandemic (the "Spanish" flu) was an influenza pandemic
Influenza pandemic
An influenza pandemic is an epidemic of an influenza virus that spreads on a worldwide scale and infects a large proportion of the human population. In contrast to the regular seasonal epidemics of influenza, these pandemics occur irregularly, with the 1918 Spanish flu the most serious pandemic in...

, and the first of the two pandemics involving H1N1 influenza virus (the second was the 2009 flu pandemic
2009 flu pandemic
The 2009 flu pandemic was an influenza pandemic, and the second of the two pandemics involving H1N1 influenza virus , albeit in a new version...

, an outbreak of Swine Flu). It was an unusually severe and deadly pandemic that spread across the world. Historical and epidemiological
Epidemiology
Epidemiology is the study of health-event, health-characteristic, or health-determinant patterns in a population. It is the cornerstone method of public health research, and helps inform policy decisions and evidence-based medicine by identifying risk factors for disease and targets for preventive...

 data are inadequate to identify the geographic origin. Most victims were healthy young adults, in contrast to most influenza outbreaks, which predominantly affect juvenile, elderly, or weakened patients. The flu pandemic was implicated in the outbreak of encephalitis lethargica
Encephalitis lethargica
Encephalitis lethargica or von Economo disease is an atypical form of encephalitis. Also known as "sleepy sickness" , it was first described by the neurologist Constantin von Economo in 1917. The disease attacks the brain, leaving some victims in a statue-like condition, speechless and motionless...

 in the 1920s.

The pandemic lasted from June 1918 to December 1920, spreading even to the Arctic
Arctic
The Arctic is a region located at the northern-most part of the Earth. The Arctic consists of the Arctic Ocean and parts of Canada, Russia, Greenland, the United States, Norway, Sweden, Finland, and Iceland. The Arctic region consists of a vast, ice-covered ocean, surrounded by treeless permafrost...

 and remote Pacific islands. Between 50 and 100 million died, making it one of the deadliest natural disasters in human history. Even using the lower estimate of 50 million people, 3% of the world's population (which was 1.86 billion at the time) died of the disease. Some 500 million, or 27%, were infected.

Tissue samples from frozen victims were used to reproduce the virus for study. This research concluded, among other things, that the virus kills through a cytokine storm
Cytokine storm
A cytokine storm, or hypercytokinemia is a potentially fatal immune reaction consisting of a positive feedback loop between cytokines and immune cells, with highly elevated levels of various cytokines.-Symptoms:...

 (overreaction of the body's immune system
Immune system
An immune system is a system of biological structures and processes within an organism that protects against disease by identifying and killing pathogens and tumor cells. It detects a wide variety of agents, from viruses to parasitic worms, and needs to distinguish them from the organism's own...

), which perhaps explains its unusually severe nature and the concentrated age profile of its victims. The strong immune system reactions of young adults ravaged the body, whereas the weaker immune systems of children and middle-aged adults resulted in fewer deaths.

Origins of name

The first cases of influenza were registered in the continental U.S. and the rest of Europe before getting to Spain. The 1918 pandemic received its nickname "Spanish flu" because of the early perceptions of the disease's severity in Spain. Spain was a neutral country in World War I
World War I
World War I , which was predominantly called the World War or the Great War from its occurrence until 1939, and the First World War or World War I thereafter, was a major war centred in Europe that began on 28 July 1914 and lasted until 11 November 1918...

 and had no censorship of news regarding the disease and its consequences. Germany, Britain and France all had media blackouts on news that might lower morale and did not want to disclose information about disease and the number of deaths to their enemies.

History

World War I did not cause the flu, but the close troop quarters and massive troop movements hastened the pandemic and probably both increased transmission and augmented mutation; it may also have increased the lethality of the virus. Some speculate that the soldiers' immune systems were weakened by malnourishment, as well as the stresses of combat and chemical attacks, increasing their susceptibility. Andrew Price-Smith has made the controversial argument that the virus helped tip the balance of power in the later days of the war towards the Allied cause. He provides data that the viral waves hit the Central Powers before they hit the Allied powers, and that both morbidity and mortality
Mortality rate
Mortality rate is a measure of the number of deaths in a population, scaled to the size of that population, per unit time...

 in Germany and Austria were considerably higher than in Britain and France.

A large factor in the worldwide occurrence of this flu was increased travel. Modern transportation systems made it easier for soldiers, sailors, and civilian travelers to spread the disease.

In the United States, the disease was first observed at Haskell County, Kansas
Haskell County, Kansas
Haskell County is a county located in Southwest Kansas, in the Central United States. As of the 2010 census, the county population was 4,256...

, in January 1918. On 4 March 1918, company cook Albert Gitchell reported sick at Fort Riley, Kansas. Within days, 522 men at the camp had reported sick. By March 11, 1918 the virus had reached Queens
Queens
Queens is the easternmost of the five boroughs of New York City. The largest borough in area and the second-largest in population, it is coextensive with Queens County, an administrative division of New York state, in the United States....

, New York
New York
New York is a state in the Northeastern region of the United States. It is the nation's third most populous state. New York is bordered by New Jersey and Pennsylvania to the south, and by Connecticut, Massachusetts and Vermont to the east...

.

In August 1918, a more virulent strain appeared simultaneously in Brest, France
Brest, France
Brest is a city in the Finistère department in Brittany in northwestern France. Located in a sheltered position not far from the western tip of the Breton peninsula, and the western extremity of metropolitan France, Brest is an important harbour and the second French military port after Toulon...

, in Freetown, Sierra Leone
Freetown
Freetown is the capital and largest city of Sierra Leone, a country in West Africa. It is a major port city on the Atlantic Ocean located in the Western Area of the country, and had a city proper population of 772,873 at the 2004 census. The city is the economic, financial, and cultural center of...

, and in the U.S. at Boston, Massachusetts
Boston
Boston is the capital of and largest city in Massachusetts, and is one of the oldest cities in the United States. The largest city in New England, Boston is regarded as the unofficial "Capital of New England" for its economic and cultural impact on the entire New England region. The city proper had...

. The Allies of World War I
Allies of World War I
The Entente Powers were the countries at war with the Central Powers during World War I. The members of the Triple Entente were the United Kingdom, France, and the Russian Empire; Italy entered the war on their side in 1915...

 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
Censorship
thumb|[[Book burning]] following the [[1973 Chilean coup d'état|1973 coup]] that installed the [[Military government of Chile |Pinochet regime]] in Chile...

.

Theories about source

Some theorized the flu originated in the Far East. Dr. C. Hannoun, leading expert of the 1918 flu for the Institut Pasteur, asserted that the former virus was likely to have come from China, mutated in the United States near Boston, and spread to Brest, France
Brest, France
Brest is a city in the Finistère department in Brittany in northwestern France. Located in a sheltered position not far from the western tip of the Breton peninsula, and the western extremity of metropolitan France, Brest is an important harbour and the second French military port after Toulon...

, Europe's battlefields, Europe, and the world using Allied soldiers and sailors as main spreaders. Hannoun considered several other theories of origin, such as Spain, Kansas, and Brest, as being possible, but not likely.

Historian Alfred W. Crosby speculated the flu originated in Kansas.

Political scientist Andrew Price-Smith published data from the Austrian archives suggesting the influenza had earlier origins, beginning in Austria in the spring of 1917.

Popular writer John Barry
John M. Barry
John M. Barry is an American author and historian, perhaps best known for his books on the Great Mississippi Flood of 1927 and the influenza pandemic of 1918....

 echoed Crosby in describing Haskell County, Kansas
Haskell County, Kansas
Haskell County is a county located in Southwest Kansas, in the Central United States. As of the 2010 census, the county population was 4,256...

 as the likely point of origin.

Investigative work by a British team led by virologist John Oxford of St Bartholomew's Hospital
St Bartholomew's Hospital
St Bartholomew's Hospital, also known as Barts, is a hospital in Smithfield in the City of London, England.-Early history:It was founded in 1123 by Raherus or Rahere , a favourite courtier of King Henry I...

 and the Royal London Hospital
Royal London Hospital
The Royal London Hospital was founded in September 1740 and was originally named The London Infirmary. The name changed to The London Hospital in 1748 and then to The Royal London Hospital on its 250th anniversary in 1990. The first patients were treated at a house in Featherstone Street,...

, suggested a major British troop staging camp in Étaples
Étaples
Étaples or Étaples-sur-Mer is a commune in the Pas-de-Calais department in northern France. It is a fishing and leisure port on the Canche river.There is a separate commune named Staple, Nord.-History:...

, France was at the center of the 1918 flu pandemic or was the location of a significant precursor virus.

Mortality

The global mortality rate
Mortality rate
Mortality rate is a measure of the number of deaths in a population, scaled to the size of that population, per unit time...

 from the 1918/1919 pandemic is not known, but an estimated 10% to 20% of those who were infected died. With about a third of the world population infected, this case-fatality ratio
Case fatality
In epidemiology, case fatality or fatality rate, is the ratio of deaths within a designated population of people with a particular condition, over a certain period of time. An example of a fatality rate would be 9 deaths per 10,000 people at risk per year...

 means 3% to 6% of the entire global population died. Influenza may have killed as many as 25 million people in its first 25 weeks. Older estimates say it killed 40–50 million people, while current estimates say 50—100 million people worldwide were killed. This pandemic
Pandemic
A pandemic is an epidemic of infectious disease that is spreading through human populations across a large region; for instance multiple continents, or even worldwide. A widespread endemic disease that is stable in terms of how many people are getting sick from it is not a pandemic...

 has been described as "the greatest medical holocaust in history" and may have killed more people than the Black Death
Black Death
The Black Death was one of the most devastating pandemics in human history, peaking in Europe between 1348 and 1350. Of several competing theories, the dominant explanation for the Black Death is the plague theory, which attributes the outbreak to the bacterium Yersinia pestis. Thought to have...

.

As many as 17 million died in India
India
India , officially the Republic of India , is a country in South Asia. It is the seventh-largest country by geographical area, the second-most populous country with over 1.2 billion people, and the most populous democracy in the world...

, about 5% of the population. In Japan
Japan
Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...

, 23 million people were affected, and 390,000 died. In the U.S.
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...

, 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 50,000 died. Entire villages perished in Alaska
Alaska
Alaska is the largest state in the United States by area. It is situated in the northwest extremity of the North American continent, with Canada to the east, the Arctic Ocean to the north, and the Pacific Ocean to the west and south, with Russia further west across the Bering Strait...

. In West Africa, an influenza epidemic killed at least 100,000 people in Ghana
Ghana
Ghana , officially the Republic of Ghana, is a country located in West Africa. It is bordered by Côte d'Ivoire to the west, Burkina Faso to the north, Togo to the east, and the Gulf of Guinea to the south...

. In the Dutch East Indies
Dutch East Indies
The Dutch East Indies was a Dutch colony that became modern Indonesia following World War II. It was formed from the nationalised colonies of the Dutch East India Company, which came under the administration of the Netherlands government in 1800....

 (now Indonesia
Indonesia
Indonesia , officially the Republic of Indonesia , is a country in Southeast Asia and Oceania. Indonesia is an archipelago comprising approximately 13,000 islands. It has 33 provinces with over 238 million people, and is the world's fourth most populous country. Indonesia is a republic, with an...

), 1.5 million were assumed to have died from 30 million inhabitants. In Tahiti
Tahiti
Tahiti is the largest island in the Windward group of French Polynesia, located in the archipelago of the Society Islands in the southern Pacific Ocean. It is the economic, cultural and political centre of French Polynesia. The island was formed from volcanic activity and is high and mountainous...

, 14% of the population died during only two months. Similarly, in Samoa
Samoa
Samoa , officially the Independent State of Samoa, formerly known as Western Samoa is a country encompassing the western part of the Samoan Islands in the South Pacific Ocean. It became independent from New Zealand in 1962. The two main islands of Samoa are Upolu and one of the biggest islands in...

 in November 1918, 20% of the population of 38,000 died within two months.

Tafari Makonnen (the future Haile Selassie, Emperor of Ethiopia) was one of the first Ethiopia
Ethiopia
Ethiopia , officially known as the Federal Democratic Republic of Ethiopia, is a country located in the Horn of Africa. It is the second-most populous nation in Africa, with over 82 million inhabitants, and the tenth-largest by area, occupying 1,100,000 km2...

ns who contracted influenza but survived, although many of his subjects did not; estimates for the fatalities in the capital city, Addis Ababa
Addis Ababa
Addis Ababa is the capital city of Ethiopia...

, range from 5,000 to 10,000, or higher, while in British Somaliland
British Somaliland
British Somaliland was a British protectorate in the northern part of present-day Somalia. For much of its existence, British Somaliland was bordered by French Somaliland, Ethiopia, and Italian Somaliland. From 1940 to 1941, it was occupied by the Italians and was part of Italian East Africa...

 one official estimated that 7% of the native population died.

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 storm
Cytokine storm
A cytokine storm, or hypercytokinemia is a potentially fatal immune reaction consisting of a positive feedback loop between cytokines and immune cells, with highly elevated levels of various cytokines.-Symptoms:...

s. Symptoms in 1918 were so unusual that initially influenza was misdiagnosed as dengue, cholera
Cholera
Cholera is an infection of the small intestine that is caused by the bacterium Vibrio cholerae. The main symptoms are profuse watery diarrhea and vomiting. Transmission occurs primarily by drinking or eating water or food that has been contaminated by the diarrhea of an infected person or the feces...

, 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
Petechia
A petechia is a small red or purple spot on the body, caused by a minor hemorrhage ."Petechiae" refers to one of the three major classes of purpuric skin conditions. Purpuric eruptions are classified by size into three broad categories...

 in the skin also occurred." The majority of deaths were from bacterial pneumonia
Bacterial pneumonia
Bacterial pneumonia is a type of pneumonia caused by bacterial infection.-Sign and symptoms:*Fever*Rigors*Cough*Dyspnea*Chest pain*Pneumococcal pneumonia can cause Hemoptysis-Gram positive:...

, a secondary infection caused by influenza, but the virus also killed people directly, causing massive hemorrhages
Bleeding
Bleeding, technically known as hemorrhaging or haemorrhaging is the loss of blood or blood escape from the circulatory system...

 and edema
Edema
Edema or oedema ; both words from the Greek , oídēma "swelling"), formerly known as dropsy or hydropsy, is an abnormal accumulation of fluid beneath the skin or in one or more cavities of the body that produces swelling...

 in the lung.

The unusually severe disease killed up to 20% of those infected, as opposed to the usual flu epidemic mortality rate
Mortality rate
Mortality rate is a measure of the number of deaths in a population, scaled to the size of that population, per unit time...

 of 0.1%. According to historian John M. Barry, the most vulnerable of all, "those most likely, of the most likely", to die, were pregnant women. He reported that in thirteen studies of hospitalized women in the pandemic, the death rate ranged from 23% to 71%. Of the pregnant women who survived childbirth, over one-quarter (26%) lost the child.

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 two) and the very old (over age 70), and may have been due to partial protection caused by exposure to the previous Russian flu pandemic of 1889. Modern analysis has shown the virus to be particularly deadly because it triggers a cytokine storm
Cytokine storm
A cytokine storm, or hypercytokinemia is a potentially fatal immune reaction consisting of a positive feedback loop between cytokines and immune cells, with highly elevated levels of various cytokines.-Symptoms:...

, which ravages the stronger immune system of young adults.

Patterns of fatality

Typical influenzas kill weak individuals, such as infant
Infant
A newborn or baby is the very young offspring of a human or other mammal. A newborn is an infant who is within hours, days, or up to a few weeks from birth. In medical contexts, newborn or neonate refers to an infant in the first 28 days after birth...

s (aged 0–2 years), the elderly, and the immunocompromised. In the 1918 pandemic, though, older adults may have had some immunity from the earlier Russian flu pandemic of 1889. Another oddity was that the outbreak was widespread in the summer and autumn (in the Northern Hemisphere
Northern Hemisphere
The Northern Hemisphere is the half of a planet that is north of its equator—the word hemisphere literally means “half sphere”. It is also that half of the celestial sphere north of the celestial equator...

); influenza is usually worse in winter.

In fast-progressing cases, mortality was primarily from pneumonia
Pneumonia
Pneumonia is an inflammatory condition of the lung—especially affecting the microscopic air sacs —associated with fever, chest symptoms, and a lack of air space on a chest X-ray. Pneumonia is typically caused by an infection but there are a number of other causes...

, by virus-induced pulmonary consolidation
Consolidation (medicine)
Consolidation is a clinical term for solidification into a firm, dense mass. It is more specifically used in reference to a region of lung tissue that, normally compressible, has filled with liquid, a condition marked by induration of a normally aerated lung...

. Slower-progressing cases featured secondary bacterial pneumonias, and there may have been neural involvement that led to mental disorders in some cases. Some deaths resulted from malnourishment and even animal attacks in overwhelmed communities.

Deadly second wave

The second wave of the 1918 pandemic was much deadlier than the first. The first wave had resembled typical flu epidemics; those most at risk were the sick and elderly, while younger, healthier people recovered easily. But in August, when the second wave began in France, Sierra Leone and the United States, the virus had mutated
Mutation
In molecular biology and genetics, mutations are changes in a genomic sequence: the DNA sequence of a cell's genome or the DNA or RNA sequence of a virus. They can be defined as sudden and spontaneous changes in the cell. Mutations are caused by radiation, viruses, transposons and mutagenic...

 to a much deadlier form. This has been attributed to the circumstances of the First World War. In civilian life, evolutionary pressures favour a mild strain: those who get really sick stay home, and those mildly ill continue with their lives, go to work and go shopping, preferentially spreading the mild strain. In the trenches, the evolutionary pressures were reversed: soldiers with a mild strain remained where they were, while the severely ill were sent on crowded trains to crowded field hospitals, spreading the deadlier virus. So the second wave began and the flu quickly spread around the world again. It was the same flu, in that most of those who recovered from first-wave infections were immune
Immunity (medical)
Immunity is a biological term that describes a state of having sufficient biological defenses to avoid infection, disease, or other unwanted biological invasion. Immunity involves both specific and non-specific components. The non-specific components act either as barriers or as eliminators of wide...

, but it was now far more deadly, and the most vulnerable people were those who were like the soldiers in the trenches—young, otherwise healthy adults. Consequently, during modern pandemics, health officials pay attention when the virus reaches places with social upheaval, looking for deadlier strains of the virus.

This effect was most dramatically illustrated in Copenhagen
Copenhagen
Copenhagen is the capital and largest city of Denmark, with an urban population of 1,199,224 and a metropolitan population of 1,930,260 . With the completion of the transnational Øresund Bridge in 2000, Copenhagen has become the centre of the increasingly integrating Øresund Region...

, which escaped with combined mortality rate of just 0.29% (0.02% in first wave and 0.27% in second wave) because of exposure to the less lethal first wave.

Devastated communities

Even in areas where mortality was low, so many were incapacitated that much of everyday life was hampered. Some communities closed all stores or required customers to leave orders outside. There were reports that the health-care workers could not tend the sick nor the gravediggers bury the dead because they too were ill. Mass graves were dug by steam shovel
Steam shovel
A steam shovel is a large steam-powered excavating machine designed for lifting and moving material such as rock and soil. It is the earliest type of power shovel or excavator. They played a major role in public works in the 19th and early 20th century, being key to the construction of railroads...

 and bodies buried without coffins in many places.
Several Pacific island territories were particularly hard-hit. The pandemic reached them from New Zealand
New Zealand
New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...

, which was too slow to implement measures to prevent ships carrying the flu
SS Talune
Three vessels have been named Talune. This article refers to the first SS Talune, built in 1890 and scuttled in 1925.A second SS Talune was built in 1930 for the Union Steamship company of New Zealand, and sold in 1959 to Transporte de Minerales, Panama, who renamed it the ‘Amos’...

 from leaving its ports. From New Zealand, the flu reached Tonga
Tonga
Tonga, officially the Kingdom of Tonga , is a state and an archipelago in the South Pacific Ocean, comprising 176 islands scattered over of ocean in the South Pacific...

 (killing 8% of the population), Nauru
Nauru
Nauru , officially the Republic of Nauru and formerly known as Pleasant Island, is an island country in Micronesia in the South Pacific. Its nearest neighbour is Banaba Island in Kiribati, to the east. Nauru is the world's smallest republic, covering just...

 (16%) and Fiji
Fiji
Fiji , officially the Republic of Fiji , is an island nation in Melanesia in the South Pacific Ocean about northeast of New Zealand's North Island...

 (5%, 9,000 people). Worst affected was Western Samoa
Samoa
Samoa , officially the Independent State of Samoa, formerly known as Western Samoa is a country encompassing the western part of the Samoan Islands in the South Pacific Ocean. It became independent from New Zealand in 1962. The two main islands of Samoa are Upolu and one of the biggest islands in...

, a territory then under New Zealand military administration. A crippling 90% of the population was infected; 30% of adult men, 22% of adult women and 10% of children were killed. By contrast, the flu was kept away from American Samoa
American Samoa
American Samoa is an unincorporated territory of the United States located in the South Pacific Ocean, southeast of the sovereign state of Samoa...

 when Governor John Martin Poyer
John Martin Poyer
John Martin Poyer was the twelfth Naval Governor of American Samoa, from March 1, 1915 to June 10, 1919. He held the longest term of any American Samoan Governor. A Naval Academy graduate, Poyer served in numerous positions and retired in 1906 on account of failing health; however, the Navy called...

 imposed a blockade. In New Zealand itself, 8,573 deaths were attributed to the 1918 pandemic influenza, resulting in a total population fatality rate of 7.4 per thousand (0.74%).

Less-affected areas

In Japan
Japan
Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...

, 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.

In the Pacific, American Samoa
American Samoa
American Samoa is an unincorporated territory of the United States located in the South Pacific Ocean, southeast of the sovereign state of Samoa...

 and the French colony of New Caledonia
New Caledonia
New Caledonia is a special collectivity of France located in the southwest Pacific Ocean, east of Australia and about from Metropolitan France. The archipelago, part of the Melanesia subregion, includes the main island of Grande Terre, the Loyalty Islands, the Belep archipelago, the Isle of...

 also succeeded in preventing even a single death from influenza through effective quarantine
Quarantine
Quarantine is compulsory isolation, typically to contain the spread of something considered dangerous, often but not always disease. The word comes from the Italian quarantena, meaning forty-day period....

s. In Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...

, nearly 12,000 perished.

Aspirin poisoning

In a 2009 paper published in the journal Clinical Infectious Diseases, Karen Starko proposed that aspirin poisoning
Aspirin poisoning
Aspirin poisoning or salicylism can be acute or chronic. A single overdose may cause acute poisoning; continuous usage of an elevated dosage over long periods of time may cause chronic poisoning. Acute overdose has a mortality rate of 2%. Chronic overdose is more commonly lethal with a mortality...

 had contributed substantially to the fatalities. She based this on the reported symptoms in those dying from the flu, and the timing of the big "death spike" in October 1918, right after the Surgeon General, the US Army, and the Journal of the American Medical Association all recommended very large (by today's standards) dosages of aspirin. Further, Starko suggests that the wave of aspirin poisonings was due to a "perfect storm
Perfect storm
A "perfect storm" is an expression that describes an event where a rare combination of circumstances will aggravate a situation drastically. The term is also used to describe an actual phemonenon that happens to occur in such a confluence, resulting in an event of unusual magnitude.-Origin:First ...

" of events: Bayer
Bayer
Bayer AG is a chemical and pharmaceutical company founded in Barmen , Germany in 1863. It is headquartered in Leverkusen, North Rhine-Westphalia, Germany and well known for its original brand of aspirin.-History:...

's patent on aspirin ran out, so that many companies rushed in to make a profit and greatly increased the supply; this coincided with the flu pandemic; and the symptoms of aspirin poisoning (such as Reye's syndrome
Reye's syndrome
Reye's syndrome is a potentially fatal disease that causes numerous detrimental effects to many organs, especially the brain and liver, as well as causing a lower than usual level of blood sugar . The classic features are liver damage, aspirin use and a viral infection...

) were not known at the time.

This hypothesis, insofar as it sought to provide an explanation to the universally high mortality rate, was questioned in a letter to the journal published in April 2010. In it, Andrew Noymer and Daisy Carreon of the University of California, Irvine
University of California, Irvine
The University of California, Irvine , founded in 1965, is one of the ten campuses of the University of California, located in Irvine, California, USA...

, and Niall Johnson, of the Australian Commission on Safety and Quality in Health Care, questioned this universal applicability given the high mortality rate in countries such as India, where there was little or no access to aspirin at the time. On this basis, they concluded that "the salicylate [aspirin poisoning] hypothesis [was] difficult to sustain as the primary explanation for the unusual virulence of the 1918–1919 influenza pandemic". In responding, Starko pointed to anecdotal evidence of aspirin over-prescription in India and argued that even if aspirin over-prescription had not contributed to the high Indian mortality rate, it could still have been a major factor for other high rates in areas where other exacerbating factors present in India played less of a role.

End of the pandemic

After the lethal second wave struck in the autumn of 1918, new cases dropped abruptly — almost to nothing after the peak in the second wave. In Philadelphia, for example, 4,597 people died in the week ending October 16, but by November 11, influenza had almost disappeared from the city. One explanation for the rapid decline of the lethality of the disease is that doctors simply got better at preventing and treating the pneumonia which developed after the victims had contracted the virus, although John Barry stated in his book that researchers have found no evidence to support this. Another theory holds that the 1918 virus mutated extremely rapidly to a less lethal strain. This is a common occurrence with influenza viruses: there is a tendency for pathogenic viruses to become less lethal with time, providing more living hosts.

Cultural and economic impact

In the United States, the United Kingdom and other countries, despite the relatively high morbidity and mortality rates that resulted from the epidemic in 1918–1919, the Spanish flu began to fade from public awareness over the decades until the arrival of news about bird flu and other pandemics in the 1990s and 2000s. This has led some historians to label the Spanish flu a "forgotten pandemic".

Various theories of why the Spanish flu was "forgotten" include the rapid pace of the pandemic, which killed most of its victims in the United States, for example, within a period of less than nine months, resulting in limited media coverage. The general population was familiar with patterns of pandemic disease in the late 19th and early 20th centuries: typhoid, yellow fever, diphtheria, and cholera all occurred near the same time. These outbreaks probably lessened the significance of the influenza pandemic for the public. In some areas, the flu was not reported on, the only mention being that of ads for medicines claiming to cure it.

In addition, the outbreak coincided with the deaths and media focus on the First World War. Another explanation involves the age group affected by the disease. The majority of fatalities, from both the war and the epidemic, were among young adults. The deaths caused by the flu may have been overlooked due to the large numbers of deaths of young men in the war or as a result of injuries. When people read the obituaries, they saw the war or postwar deaths and the deaths from the influenza side by side. Particularly in Europe, where the war's toll was extremely high, the flu may not have had a great, separate, psychological impact, or may have seemed a mere "extension" of the war's tragedies. The duration of the pandemic and the war could have also played a role: the disease would usually only affect a certain area for a month before leaving, while the war, which most expected to end quickly, had lasted for four years by the time the pandemic struck. This left little time for the disease to have a significant impact on the economy.

One final issue that the 1918 Spanish flu outbreak had on the world was the effects on the global economy. As could be expected, statistics show many businesses in the entertainment and service industries suffered losses in revenue, but the health care industry reported profit gains.

Spanish flu research

The origin of the Spanish flu pandemic, and the relationship between the near-simultaneous outbreaks in humans and swine, have been controversial. One hypothesis is that the virus strain originated at Fort Riley
Fort Riley
Fort Riley is a United States Army installation located in Northeast Kansas, on the Kansas River, between Junction City and Manhattan. The Fort Riley Military Reservation covers 100,656 acres in Geary and Riley counties and includes two census-designated places: Fort Riley North and Fort...

, Kansas
Kansas
Kansas is a US state located in the Midwestern United States. It is named after the Kansas River which flows through it, which in turn was named after the Kansa Native American tribe, which inhabited the area. The tribe's name is often said to mean "people of the wind" or "people of the south...

, in viruses in poultry and swine which the fort bred for food; the soldiers were then sent from Fort Riley around the world, where they spread the disease. Similarities between a reconstruction of the virus and avian viruses, combined with the human pandemic preceding the first reports of influenza in swine, led researchers to conclude the influenza virus jumped directly from birds to humans, and swine caught the disease from humans. Others have disagreed, and more recent research has suggested the strain may have originated in a nonhuman, mammalian species. An estimated date for its appearance in mammalian hosts has been put at the period 1882–1913. This ancestor virus diverged about 1913–1915 into two clade
Clade
A clade is a group consisting of a species and all its descendants. In the terms of biological systematics, a clade is a single "branch" on the "tree of life". The idea that such a "natural group" of organisms should be grouped together and given a taxonomic name is central to biological...

s, which gave rise to the classical swine and human H1N1
H1N1
'Influenza A virus is a subtype of influenza A virus and was the most common cause of human influenza in 2009. Some strains of H1N1 are endemic in humans and cause a small fraction of all influenza-like illness and a small fraction of all seasonal influenza. H1N1 strains caused a few percent of...

 influenza lineages. The last common ancestor of human strains dates to between February 1917 and April 1918. Because pigs are more readily infected with avian influenza viruses than are humans, they were suggeseted as the original recipients of the virus, passing the virus to humans sometime between 1913 and 1918.

An effort to recreate the 1918 flu strain (a subtype of avian strain H1N1) was a collaboration among the Armed Forces Institute of Pathology
Armed Forces Institute of Pathology
The Armed Forces Institute of Pathology was a US government institution concerned with diagnostic consultation, education, and research in the medical specialty of pathology. It was founded in 1862 as the Army Medical Museum and was located in Washington, DC on the grounds of the Walter Reed Army...

, Southeast Poultry Research Laboratory and Mount Sinai School of Medicine
Mount Sinai School of Medicine
Mount Sinai School of Medicine is an American medical school in the borough of Manhattan in New York City, currently ranked among the top 20 medical schools in the United States. It was chartered by Mount Sinai Hospital in 1963....

 in New York City; the effort resulted in the announcement (on October 5, 2005) that the group had successfully determined the virus's genetic sequence, using historic tissue samples recovered by pathologist Johan Hultin
Johan Hultin
Johan Hultin is a retired pathologist known for discovering tissues containing traces of the 1918 influenza virus that killed millions worldwide, and for this he has been described as the "Indiana Jones of the scientific set."-Biography:...

 from a female flu victim buried in the Alaskan permafrost
Permafrost
In geology, permafrost, cryotic soil or permafrost soil is soil at or below the freezing point of water for two or more years. Ice is not always present, as may be in the case of nonporous bedrock, but it frequently occurs and it may be in amounts exceeding the potential hydraulic saturation of...

 and samples preserved from American soldiers.

On January 18, 2007, Kobasa et al. reported that monkeys (Macaca fascicularis) infected with the recreated strain exhibited classic symptoms of the 1918 pandemic, and died from a cytokine storm
Cytokine storm
A cytokine storm, or hypercytokinemia is a potentially fatal immune reaction consisting of a positive feedback loop between cytokines and immune cells, with highly elevated levels of various cytokines.-Symptoms:...

—an overreaction of the immune system
Immune system
An immune system is a system of biological structures and processes within an organism that protects against disease by identifying and killing pathogens and tumor cells. It detects a wide variety of agents, from viruses to parasitic worms, and needs to distinguish them from the organism's own...

. This may explain why the 1918 flu had its surprising effect on younger, healthier people, as a person with a stronger immune system would potentially have a stronger overreaction.

On September 16, 2008, the body of Yorkshire
Yorkshire
Yorkshire is a historic county of northern England and the largest in the United Kingdom. Because of its great size in comparison to other English counties, functions have been increasingly undertaken over time by its subdivisions, which have also been subject to periodic reform...

man Sir Mark Sykes was exhumed to study the RNA of the Spanish flu virus in efforts to understand the genetic structure of modern H5N1
H5N1
Influenza A virus subtype H5N1, also known as "bird flu", A or simply H5N1, is a subtype of the influenza A virus which can cause illness in humans and many other animal species...

 bird flu. Sykes had been buried in 1919 in a lead coffin which scientists hoped to have helped preserve the virus.

In December 2008, research by Yoshihiro Kawaoka of the University of Wisconsin linked the presence of three specific genes (termed PA, PB1, and PB2) and a nucleoprotein derived from 1918 flu samples to the ability of the flu virus to invade the lungs and cause pneumonia. The combination triggered similar symptoms in animal testing.

In June 2010, a team at the Mount Sinai School of Medicine reported the 2009 flu pandemic vaccine
2009 flu pandemic vaccine
The 2009 flu pandemic vaccines are the set of influenza vaccines that have been developed to protect against the pandemic H1N1/09 virus. These vaccines either contain inactivated influenza virus, or weakened live virus that cannot cause influenza. The killed vaccine is injected, while the live...

 provided some cross-protection against the 1918 flu pandemic strain.

See also

  • List of epidemics
  • List of wars and disasters by death toll
  • SS Talune
    SS Talune
    Three vessels have been named Talune. This article refers to the first SS Talune, built in 1890 and scuttled in 1925.A second SS Talune was built in 1930 for the Union Steamship company of New Zealand, and sold in 1959 to Transporte de Minerales, Panama, who renamed it the ‘Amos’...

  • Viola Pettus
    Viola Pettus
    Viola Pettus was an African-American woman, born about 1886, who lived in Marathon, Brewster County, Texas. Viola is remembered in Texas for her courageous work as a nurse during the 1918 flu pandemic...


External links

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