స్పానిష్ ఫ్లూ: కూర్పుల మధ్య తేడాలు
Content deleted Content added
పంక్తి 107:
2016 లో చైనా మెడికల్ అసోసియేషన్ జర్నల్లో ప్రచురించిన ఒక నివేదికలో ఐరోపాలో ఈ మహమ్మారి ప్రారంభానికి ముందుగా 1918 లో చైనీయులు, ఆగ్నేయాసియా సైనికులు, కార్మికుల ద్వారా ఈ వైరస్ ఐరోపాకు దిగుమతి చేయబడిందని ఆధారాలు లేవని తెలియజేయబడింది.
<ref name="JotCMA79"/> ఐరోపాలోని చైనీయులు, ఆగ్నేయాసియా కార్మికులలో తక్కువ ఫ్లూ మరణాల శాతం (వెయ్యిలో ఒకటి) కనుగొనబడిందని 2016 అధ్యయనం సూచించింది అంటే 1918 లో ప్రాణాంతకమైన ఇన్ఫ్లుఎంజా మహమ్మారి ఆ కార్మికుల నుండి ఉద్భవించి ఉండకపోవచ్చని భావించబడింది.<ref name="JotCMA79"/> వ్యాప్తి చెందుతున్న వ్యాధికి వ్యతిరేకంగా లభించిన మరికొన్ని ఆధారాలు చైనా కార్మికులు ఇతర మార్గాల ద్వారా ఐరోపాలోకి ప్రవేశించారని ఇది గుర్తించదగిన వ్యాప్తికి దారితీయలేదని భావించారు. తద్వారా వారు అసలు అతిధేయులుగా ఉండే అవకాశం లేదని పేర్కొనబడింది.<ref name="WorobeyStudy"/>
==Epidemiology and pathology==
===Transmission and mutation===
[[File:U.S. Army Field Hospital No. 29, Hollerich, Luxembourg Interior view- Influenza ward.jpg|thumb|As U.S. troops deployed en masse for the [[United States in World War I|war effort in Europe]], they carried the Spanish flu with them.]]
The [[basic reproduction number]] of the virus was between 2 and 3.<ref>{{cite journal | vauthors = Mills CE, Robins JM, Lipsitch M | title = Transmissibility of 1918 pandemic influenza | journal = Nature | volume = 432 | issue = 7019 | pages = 904–6 | date = December 2004 | pmid = 15602562 | pmc = 7095078 | doi = 10.1038/nature03063 | url = https://pubmed.ncbi.nlm.nih.gov/15602562/?dopt=Abstract | bibcode = 2004Natur.432..904M }}</ref> The close quarters and massive troop movements of [[World War I]] hastened the pandemic, and probably both increased transmission and augmented mutation. The war may also have reduced people's resistance to the virus. Some speculate the soldiers' immune systems were weakened by malnourishment, as well as the stresses of combat and chemical attacks, increasing their susceptibility.{{sfn|Qureshi|2016|p=42}}{{sfn|Ewald|1994}} A large factor in the worldwide occurrence of the flu was increased travel. Modern transportation systems made it easier for soldiers, sailors, and civilian travelers to spread the disease.<ref>{{Cite web|title=The Spanish Flu pandemic of 1918|url=https://www.thehistorypress.co.uk/articles/the-spanish-flu-pandemic-of-1918/|url-status=live|access-date=2021-02-20|website=The History Press}}</ref> Another was lies and denial by governments, leaving the population ill-prepared to handle the outbreaks.<ref name="Illing">{{cite web | vauthors = Illing S |title=The most important lesson of the 1918 influenza pandemic: Tell the damn truth |url=https://www.vox.com/coronavirus-covid19/2020/3/20/21184887/coronavirus-covid-19-spanish-flu-pandemic-john-barry |website=Vox |archive-url=https://web.archive.org/web/20200325172129/https://www.vox.com/coronavirus-covid19/2020/3/20/21184887/coronavirus-covid-19-spanish-flu-pandemic-john-barry |archive-date=25 March 2020|date=20 March 2020 |quote=John M. Barry : The government lied. They lied about everything. We were at war and they lied because they didn’t want to upend the war effort. You had public health leaders telling people this was just the ordinary flu by another name. They simply didn’t tell the people the truth about what was happening. |url-status=live}}</ref>
The severity of the second wave has been attributed to the circumstances of the First World War.{{sfn|Gladwell|1997|p=55}} In civilian life, [[natural selection]] favors a mild strain. Those who get very ill stay home, and those mildly ill continue with their lives, preferentially spreading the mild strain. In the trenches, natural selection was reversed. Soldiers with a mild strain stayed where they were, while the severely ill were sent on crowded trains to crowded field hospitals, spreading the deadlier virus. The second wave began, and the flu quickly spread around the world again. Consequently, during modern pandemics, health officials look for deadlier strains of a virus when it reaches places with social upheaval.{{sfn|Gladwell|1997|p=63}} The fact that most of those who recovered from first-wave infections had become [[Immunity (medical)|immune]] showed that it must have been the same strain of flu. This was most dramatically illustrated in [[Copenhagen]], which escaped with a combined mortality rate of just 0.29% (0.02% in the first wave and 0.27% in the second wave) because of exposure to the less-lethal first wave.<ref>{{cite web|author=Fogarty International Center|title=Summer Flu Outbreak of 1918 May Have Provided Partial Protection Against Lethal Fall Pandemic|url=http://www.fic.nih.gov/News/GlobalHealthMatters/Pages/Flu-1918.aspx|url-status=live|archive-url=https://web.archive.org/web/20110727122221/http://www.fic.nih.gov/News/GlobalHealthMatters/Pages/Flu-1918.aspx|archive-date=27 July 2011|access-date=19 May 2012|publisher=Fic.nih.gov}}</ref> For the rest of the population, the second wave was far more deadly; the most vulnerable people were those like the soldiers in the trenches – adults who were young and fit.{{sfn|Gladwell|1997|p=56}}
After the lethal second wave struck in late 1918, new cases dropped abruptly. In Philadelphia, for example, 4,597 people died in the week ending 16 October, but by 11 November, influenza had almost disappeared from the city. One explanation for the rapid decline in the lethality of the disease is that doctors became more effective in the prevention and treatment of pneumonia that developed after the victims had contracted the virus. However, John Barry stated in his 2004 book ''[[The Great Influenza: The Epic Story of the Deadliest Plague In History]]'' that researchers have found no evidence to support this position.{{sfn|Barry|2004b}} Another theory holds that the 1918 virus mutated extremely rapidly to a less lethal strain. Such [[evolution of influenza]] is a common occurrence: there is a tendency for pathogenic viruses to become less lethal with time, as the hosts of more dangerous strains tend to die out.{{sfn|Barry|2004b}} Some fatal cases did continue into March 1919, killing one player in the [[1919 Stanley Cup Finals]].
===Signs and symptoms===
[[File:3548786222 7a3d3208d3 bInfluenzaGrippe.jpg|thumb|US Army symptomology of the flu]]
The majority of the infected experienced only the typical flu symptoms of sore throat, headache, and fever, especially during the first wave.{{sfn|Spinney|2018|pp=45–47}} However, during the second wave, the disease was much more serious, often complicated by [[bacterial pneumonia]], which was often the cause of death.{{sfn|Spinney|2018|pp=45–47}} This more serious type would cause ''heliotrope cyanosis'' to develop, whereby the skin would first develop two mahogany spots over the cheekbones which would then over a few hours spread to color the entire face blue, followed by black coloration first in the extremities and then further spreading to the limbs and the torso.{{sfn|Spinney|2018|pp=45–47}} After this, death would follow within hours or days due to the lungs being filled with fluids.{{sfn|Spinney|2018|pp=45–47}} Other signs and symptoms reported included spontaneous mouth and nosebleeds, miscarriages for pregnant women, a peculiar smell, teeth, and hair falling, [[delirium]], dizziness, insomnia, loss of hearing or smell, blurred vision, and impaired color vision.{{sfn|Spinney|2018|pp=45–47}} One observer wrote, "One of the most striking of the complications was [[hemorrhage]] from [[mucous membrane]]s, especially from the nose, stomach, and intestine. Bleeding from the ears and [[petechia|petechial hemorrhages]] in the skin also occurred".{{sfn|Knobler|2005}} The severity of the symptoms was believed to be caused by [[cytokine storm]]s.{{sfn|Patterson|Pyle|1991}}
The majority of deaths were from [[bacterial pneumonia]],<ref name="MorrisCleary2017">{{cite journal | vauthors = Morris DE, Cleary DW, Clarke SC | title = Secondary Bacterial Infections Associated with Influenza Pandemics | journal = Frontiers in Microbiology | volume = 8 | page = 1041 | year = 2017 | pmid = 28690590 | pmc = 5481322 | doi = 10.3389/fmicb.2017.01041 | doi-access = free }}</ref><ref>{{cite web |title=Bacterial Pneumonia Caused Most Deaths in 1918 Influenza Pandemic |url=https://www.nih.gov/news-events/news-releases/bacterial-pneumonia-caused-most-deaths-1918-influenza-pandemic |website=National Institutes of Health |date=23 September 2015 |access-date=17 April 2016 |archive-url=https://web.archive.org/web/20160422191021/https://www.nih.gov/news-events/news-releases/bacterial-pneumonia-caused-most-deaths-1918-influenza-pandemic |archive-date=22 April 2016 |url-status=live}}</ref>{{sfn|Taubenberger|Reid|Janczewski|Fanning|2001|pp=1829–1839}} a common [[secondary infection]] associated with influenza. This pneumonia was itself caused by common upper respiratory-tract bacteria, which were able to get into the lungs via the damaged [[Bronchus|bronchial tubes]] of the victims.<ref>{{cite journal | vauthors = Morens DM, Taubenberger JK, Fauci AS | title = Predominant role of bacterial pneumonia as a cause of death in pandemic influenza: implications for pandemic influenza preparedness | journal = The Journal of Infectious Diseases | volume = 198 | issue = 7 | pages = 962–70 | date = October 2008 | pmid = 18710327 | pmc = 2599911 | doi = 10.1086/591708 }}</ref> The virus also killed people directly by causing massive hemorrhages and [[edema]] in the lungs.{{sfn|Taubenberger|Reid|Janczewski|Fanning|2001|pp=1829–39}} Modern analysis has shown the virus to be particularly deadly because it triggers a cytokine storm (overreaction of the body's immune system).{{sfn|Barry|2004b}} One group of researchers recovered the virus from the bodies of frozen victims and [[transfection|transfected]] animals with it. The animals suffered rapidly progressive [[respiratory failure]] and death through a cytokine storm. The strong immune reactions of young adults were postulated to have ravaged the body, whereas the weaker immune reactions of children and middle-aged adults resulted in fewer deaths among those groups.{{sfn|Barry|2004}}<ref>{{Cite web|url=https://www.familysearch.org/ark:/61903/3:1:939Z-RFNN-8?i=1446&cc=1682798&personaUrl=%2Fark%3A%2F61903%2F1%3A1%3AQVJH-7PK1|title=FamilySearch: Sign In}}</ref>
===Misdiagnosis===
Because the virus that caused the disease was too small to be seen under a microscope at the time, there were problems with correctly diagnosing it.{{sfn|Spinney|2018|p=61}} The bacterium ''[[Haemophilus influenzae]]'' was instead mistakenly thought to be the cause, as it was big enough to be seen and was present in many, though not all, patients.{{sfn|Spinney|2018|p=61}} For this reason, a vaccine that was used against that bacillus did not make an infection rarer but did decrease the death rate.<ref>{{Cite web |title=Washington State Board of Health pessimistic about influenza pandemic in a report to the governor on January 1, 1919. |url= https://www.historylink.org/File/20313 |access-date=2020-07-21 |website=www.historylink.org}}</ref>
During the deadly second wave there were also fears that it was in fact [[Plague (disease)|plague]], [[dengue fever]], or [[cholera]].{{sfn|Spinney|2018|p=62}} Another common misdiagnosis was [[typhus]], which was common in circumstances of social upheaval, and was therefore also affecting Russia in the aftermath of the [[October Revolution]].{{sfn|Spinney|2018|p=62}} In Chile, the view of the country's elite was that the nation was in severe decline, and therefore doctors assumed that the disease was typhus caused by poor hygiene, and not an infectious one, causing a mismanaged response which did not ban mass gatherings.{{sfn|Spinney|2018|p=62}}
===The role of climate conditions===
Studies have shown that the immune system of Spanish flu victims was weakened by adverse climate conditions which were particularly unseasonably cold and wet for extended periods of time during the duration of the pandemic. This affected especially WWI troops exposed to incessant rains and lower-than-average temperatures for the duration of the conflict, and especially during the second wave of the pandemic. Ultra-high-resolution climate data combined with highly detailed mortality records analyzed at [[Harvard University]] and the Climate Change Institute at the [[University of Maine]] identified a severe climate anomaly that impacted Europe from 1914 to 1919, with several environmental indicators directly influencing the severity and spread of the Spanish flu pandemic.<ref name="The Impact of a Six‐Year Climate An"/> Specifically, a significant increase in precipitation affected all of Europe during the second wave of the pandemic, from September to December 1918. Mortality figures follow closely the concurrent increase in precipitation and decrease in temperatures. Several explanations have been proposed for this, including the fact that lower temperatures and increased precipitation provided ideal conditions for virus replication and transmission, while also negatively affecting the immune systems of soldiers and other people exposed to the inclement weather, a factor proven to increase likelihood of infection by both viruses and pneumococcal co-morbid infections documented to have affected a large percentage of pandemic victims (one fifth of them, with a 36% mortality rate).<ref>{{cite journal | vauthors = Foxman EF, Storer JA, Fitzgerald ME, Wasik BR, Hou L, Zhao H, Turner PE, Pyle AM, Iwasaki A | display-authors = 6 | title = Temperature-dependent innate defense against the common cold virus limits viral replication at warm temperature in mouse airway cells | journal = Proceedings of the National Academy of Sciences of the United States of America | volume = 112 | issue = 3 | pages = 827–32 | date = January 2015 | pmid = 25561542 | pmc = 4311828 | doi = 10.1073/pnas.1411030112 | bibcode = 2015PNAS..112..827F | doi-access = free }}</ref><ref>{{cite journal | vauthors = Lowen AC, Steel J | title = Roles of humidity and temperature in shaping influenza seasonality | journal = Journal of Virology | volume = 88 | issue = 14 | pages = 7692–5 | date = July 2014 | pmid = 24789791 | pmc = 4097773 | doi = 10.1128/JVI.03544-13 | doi-access = free }}</ref><ref>{{cite journal | vauthors = Brown JD, Goekjian G, Poulson R, Valeika S, Stallknecht DE | title = Avian influenza virus in water: infectivity is dependent on pH, salinity and temperature | journal = Veterinary Microbiology | volume = 136 | issue = 1–2 | pages = 20–6 | date = April 2009 | pmid = 19081209 | doi = 10.1016/j.vetmic.2008.10.027 | doi-access = free }}</ref><ref>{{cite journal | vauthors = Foxman EF, Storer JA, Vanaja K, Levchenko A, Iwasaki A | title = Two interferon-independent double-stranded RNA-induced host defense strategies suppress the common cold virus at warm temperature | journal = Proceedings of the National Academy of Sciences of the United States of America | volume = 113 | issue = 30 | pages = 8496–501 | date = July 2016 | pmid = 27402752 | pmc = 4968739 | doi = 10.1073/pnas.1601942113 | doi-access = free }}</ref><ref>{{cite journal | vauthors = Klugman KP, Chien YW, Madhi SA | title = Pneumococcal pneumonia and influenza: a deadly combination | journal = Vaccine | volume = 27 Suppl 3 | issue = s3 | pages = C9–C14 | date = August 2009 | pmid = 19683658 | doi = 10.1016/j.vaccine.2009.06.007 | doi-access = free }}</ref> A six-year climate anomaly (1914–1919) brought cold, marine air to Europe, drastically changing its weather, as documented by eyewitness accounts and instrumental records, reaching as far as the [[Gallipoli campaign]], in Turkey, where [[ANZAC]] troops suffered extremely cold temperatures despite the normally Mediterranean climate of the region. The climate anomaly likely influenced the migration of H1N1 avian vectors which contaminate bodies of water with their droppings, reaching 60% infection rates in autumn.<ref>{{cite journal | vauthors = Bengtsson D, Safi K, Avril A, Fiedler W, Wikelski M, Gunnarsson G, Elmberg J, Tolf C, Olsen B, Waldenström J | display-authors = 6 | title = Does influenza A virus infection affect movement behaviour during stopover in its wild reservoir host? | journal = Royal Society Open Science | volume = 3 | issue = 2 | page = 150633 | date = February 2016 | pmid = 26998334 | pmc = 4785985 | doi = 10.1098/rsos.150633 | bibcode = 2016RSOS....350633B | doi-access = free }}</ref><ref>{{cite journal | vauthors = Tolf C, Bengtsson D, Rodrigues D, Latorre-Margalef N, Wille M, Figueiredo ME, Jankowska-Hjortaas M, Germundsson A, Duby PY, Lebarbenchon C, Gauthier-Clerc M, Olsen B, Waldenström J | display-authors = 6 | title = Birds and viruses at a crossroad—surveillance of influenza A virus in Portuguese waterfowl | journal = PLOS ONE | volume = 7 | issue = 11 | page = e49002 | year = 2012 | pmid = 23145046 | pmc = 3492218 | doi = 10.1371/journal.pone.0049002 | bibcode = 2012PLoSO...749002T | doi-access = free }}</ref><ref>{{cite journal | vauthors = Tucker MA, Böhning-Gaese K, Fagan WF, Fryxell JM, Van Moorter B, Alberts SC, etal | title = Moving in the Anthropocene: Global reductions in terrestrial mammalian movements | journal = Science | volume = 359 | issue = 6374 | pages = 466–469 | date = January 2018 | pmid = 29371471 | doi = 10.1126/science.aam9712 | bibcode = 2018Sci...359..466T | doi-access = free }}</ref> The climate anomaly has been associated with an anthropogenic increase in atmospheric dust, due to the incessant bombardment; increased nucleation due to dust particles ([[cloud condensation nuclei]]) contributed to increased precipitation.<ref>{{cite news | vauthors = Blakemore E |title=Catastrophic effect of 1918 flu may have been aided by peculiar influx of cold air into Europe during WWI |url= https://www.washingtonpost.com/science/spanish-flu-1918-climate/2020/10/02/9b730432-0339-11eb-a2db-417cddf4816a_story.html |newspaper=The Washington Post |access-date=29 November 2020 |date=3 October 2020}}</ref><ref>{{cite news | vauthors = Kent L |title=How environmental conditions like cold and wet weather can affect pandemics, and what that means for COVID-19 |url=https://www.cnn.com/2020/09/28/health/climate-affects-pandemics-new-study-trnd-scn/index.html |publisher=[[CNN]] |access-date=29 November 2020 |date=28 September 2020}}</ref><ref>{{cite web | vauthors = Powell A |title=Six-year deluge linked to Spanish flu, World War I deaths |url=https://news.harvard.edu/gazette/story/2020/10/study-offers-clues-to-how-climate-affected-1918-pandemic/?utm_medium=Feed&utm_source=Syndication |website=Harvard Gazette |access-date=29 November 2020 |date=5 October 2020}}</ref>
== మూలాలు ==
|