HIV/AIDS & H1N1: wikipedia entry on 1918 flu epidemic (050)

wikipedia-encyclopedia-webchers—

i include this Wikipedia article in a collection of articles about HIV/AIDS and the H1N1 virus because the 1918 H1N1 flu epidemics is the second historical model used to understand the spread of HIV/AIDS. the first is the bubonic plague, or black plague.

notice how infection of different segments of the population affect the whole population.

namaste

—rk

1918 flu pandemic
From Wikipedia, the free encyclopedia

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.[1] 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.[2]

The pandemic lasted from March 1918 to June 1920,[3] spreading even to the Arctic and remote Pacific islands. It is estimated that anywhere from 50 to 100 million people were killed worldwide which is from three to seven times the casualties of the First World War (15 million).[4][5][6][7][8] An estimated 50 million people, about 3% of the world’s population (approximately 1.6 billion at the time), died of the disease. An estimated 500 million, or 1/3 were infected.[5]

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.[9]

Mortality

W-1918_curveThe global mortality rate from the 1918/1919 pandemic is not known, but it is estimated that 10% to 20% of those who were infected died. With about a third of the world population infected, this case-fatality ratio means that 3% to 6% of the entire global population died.[12] Influenza may have killed as many as 25 million in its first 25 weeks. Older estimates say it killed 40–50 million people[4] while current estimates say 50—100 million people worldwide were killed.[13] This pandemic has been described as “the greatest medical holocaust in history” and may have killed more people than the Black Death.[14]

1918_spanish_flu_wavesAs many as 17 million died in India, about 5% of India’s population at the time.[15] In Japan, 23 million people were affected, and 390,000 died.[16] In the U.S., about 28% of the population suffered, and 500,000 to 675,000 died.[17] In Britain as many as 250,000 died; in France more than 400,000.[18] In Canada approximately 50,000 died.[19] Entire villages perished in Alaska[20] and southern Africa.[which?] Ras Tafari (the future Haile Selassie) was one of the first Ethiopians who contracted influenza but survived,[21] although many of his subjects did not; estimates for the fatalities in the capital city, Addis Ababa, range from 5,000 to 10,000, with some experts opining that the number was even higher,[22] while in British Somaliland one official there estimated that 7% of the native population died from influenza.[23] 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.[4] 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.”[13] 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.[10]

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%.[10][13] 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.[24] This is unusual since influenza is normally most deadly to the very young (under age 2) and the very old (over age 70), and may have been due to partial protection caused by exposure to a previous Russian flu pandemic of 1889.[25]

Origins of Name

Although the first cases of the disease were registered in the continental U.S, and the rest of Europe long before getting to Spain, the 1918 Flu received its nickname “Spanish flu” because Spain, a neutral country in WWI, had no special censorship for news against the disease and its consequences. Hence the most reliable news on the disease came from Spain, giving the false impression that Spain was the most—if not the only—affected zone.[26]

History

While World War I did not cause the flu, the close troop quarters and massive troop movements hastened the pandemic and probably increased transmission, augmented mutation and may have increased the lethality of the virus. Some researchers speculate that the soldiers’ immune systems were weakened by malnourishment as well as the stresses of combat and chemical attacks, increasing their susceptibility to the disease.[27] Price-Smith has made the controversial argument that the virus helped tip the balance of power in the latter days of the war towards the Allied cause. Specifically, he provides data that the viral waves hit the Central Powers before they hit the Allied powers, and that both morbidity and mortality in Germany and Austria were considerably higher than in Britain and France.[28]

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

Geographic Sources

Some scholars have theorized that the flu probably originated in the Far East.[29] Dr. C. Hannoun, leading expert of the 1918 flu for the Institut Pasteur, theorized that the former virus was likely to have come from China, mutated in the United States near Boston, and spread to Brest, France, Europe’s battlefields, Europe, and the world using Allied soldiers and sailors as main spreaders.[30] Hannoun considered several other theories of origin, such as Spain, Kansas, and Brest, as being possible but not likely.

Historian Alfred W. Crosby observed that the flu seems to have originated in Kansas.[31] Political scientist Andrew Price-Smith published data from the Austrian archives suggesting that the influenza had earlier origins, beginning in Austria in the spring of 1917.[32] Popular writer John Barry echoed Crosby in describing Haskell County, Kansas as the likely point of origin.[33] In the United States the disease was first observed at Fort Riley, Kansas, on March 4, 1918,[34] and Queens, New York, on March 11, 1918. In August 1918, a more virulent strain appeared simultaneously in Brest, France, in 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.[35]

Investigative work by a British team, led by virologist John Oxford[36] of St Bartholomew’s Hospital and the Royal London Hospital, has suggested that a principal British troop staging camp in Étaples, France was at the center of the 1918 flu pandemic, or was the location of a significant precursor virus.[37]

Patternsof Fatality

The influenza strain was unusual in that this pandemic killed many young adults and otherwise healthy victims; typical influenzas kill mostly weak individuals, such as infants (aged 0–2 years), the elderly, and the immunocompromised. Older adults may have had some immunity from the earlier Russian flu pandemic of 1889.[25] Another oddity was that the outbreak was widespread in the summer and autumn (in the Northern Hemisphere); influenza is usually worse in winter.[38]

In fast-progressing cases, mortality was primarily from pneumonia, by virus-induced pulmonary consolidation. 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.[39]

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,[40] the virus had mutated to a much more deadly form. This has been attributed to the circumstances of the First World War.[41] 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 flu quickly spread around the world again.[42] It was the same flu, in that most of those who recovered from first-wave infections were immune, 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.[43] Consequently, during modern pandemics, health officials pay attention when the virus reaches places with social upheaval, looking for deadlier strains of the virus.[42]

Devastated Communities

Even in areas where mortality was low, so many people were incapacitated that much of everyday life stopped. Some communities closed all stores or required customers to leave their orders outside. There were many reports of places where the health-care workers could not tend the sick nor the grave-diggers bury the dead because they too were ill. Mass graves were dug by steam shovel and bodies buried without coffins in many places.[44] Several Pacific island territories were particularly hard-hit. The pandemic reached them from New Zealand, which was too slow to implement measures to prevent ships carrying the flu from leaving its ports. From New Zealand the flu reached Tonga (killing 8% of the population), Nauru (16%) and Fiji (5%, 9,000 people). Worst affected was Western Samoa, 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 by a commander who imposed a blockade.[45] 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%) .[46]

Less Affected Areas

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.

In the Pacific, American Samoa[47] and the French colony of New Caledonia[48] also succeeded in preventing even a single death from influenza through effective quarantines. In Australia, nearly 12,000 perished.[49]

End of the Pandemic

After the lethal second wave struck in the autumn of 1918, the disease died down abruptly. New cases almost dropped to nothing after the peak in the second wave.[9] 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 states 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 general tendency for pathogenic viruses to become less lethal as time goes by, providing more living hosts. According to this theory, this happened very quickly for the 1918 virus.[9]

Cultural 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.[50] This has led some historians to label the Spanish flu a “forgotten pandemic”.[31] One of the few major works of American literature written after 1918 that deals directly with the Spanish flu is Katherine Anne Porter’s Pale Horse, Pale Rider. In 1935 John O’Hara wrote a long short story, “The Doctor’s Son”, about the experience of his fictional alter ego during the flu epidemic in a Pennsylvania coal mining town. In 1937 American novelist William Keepers Maxwell, Jr. wrote They Came Like Swallows, a fictional reconstruction of the events surrounding his mother’s death from the flu. Mary McCarthy, the American novelist and essayist, wrote about her parents’ deaths in Memories of a Catholic Girlhood. Bodie and Brock Thoene‘s “Shiloh Legacy” series led off with an account of the Spanish flu in New York and Arkansas in their novel In My Father’s House (1992). In 1997 David Morrell‘s short story “If I Die Before I Wake”—dealing with a small American town during the second wave—was published in the anthology Revelations, which was framed by Clive Barker. In 2006 Thomas Mullen published a novel called The Last Town on Earth about the impact of the Spanish flu on a fictional mill town in Washington.

Several theories have been offered as to why the Spanish flu may have been “forgotten” by historians and the public over so many years. These include the rapid pace of the pandemic (it killed most of its victims in the United States, for example, within a period of less than nine months), previous familiarity with pandemic disease in the late 19th and early 20th centuries, and the distraction of the First World War.[51]

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 of the era, they saw the war or post-war 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.[52] 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. During this time period pandemic outbreaks were not uncommon: typhoid, yellow fever, diphtheria, and cholera all occurred near the same time period. These outbreaks probably lessened the significance of the influenza pandemic for the public.[53]

eight posts on HIV/AIDS & H1N1 at HAVVACC

  1. weho news: free flu shots tuesday by cedars (056)
  2. cdc recommendations for HIVers (full text) (055)
  3. about.com — difference between  seasonal & swine flus (054)
  4. AIDS-meds no evidence HIV worsens H1N1 severity (053)
  5. natap-sickest H1N1 patients have comorbidities (052)
  6. weho news – michael mooney on vaccine drawbacks (051)
  7. wikipedia: 1918 flu epidemic (050)
  8. cdc swine flu social media toolkit (049)
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