Why did the Spanish flu kill millions of people?

Why did the Spanish flu kill millions of people?

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        In 1918, the Spanish flu pandemic swept the world, and in a short time, millions of victims were killed. If you are old enough to read this article, you often have experienced at least one of the global influenza pandemics, and may not be the causative virus The epidemic is less able to spread from the virus that causes the deadly influenza epidemic that erupted in 1918. Another pandemic broke out in 1957, called "Asian flu", followed by a wave of "Hong Kong flu" in 1968. Forty years later, Swine flu outbreaks in 2009. The story of an influenza pandemic that The features of the twentieth century
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All four flu pandemics are similar to their origins. Each of these pandemics began in some way because of an avian influenza virus that has evolved to be able to spread and infect one person to another. But there is no comparison between the 1918 pandemic and the number of victims of subsequent pandemics. The 1918 flu pandemic reportedly killed between 40 and 50 million people, while the next two waves, Hong Kong and Asian flu claimed 2 million lives. Swine flu in 2009 killed 600,000 people. The 1918 pandemic left so many casualties that many doctors call it "the deadliest medical disaster in human history." But why was the 1918 pandemic so severe and so virulent? Is it possible that the study of these epidemics and how to develop them can help us to be vigilant in anticipation of similar waves of flu? Without the huge jumps of medicine during the 20th century, we would have been able to understand how the virus evolved into a widespread epidemic. In 1918, viruses were still being discovered, says Wendy Barclay at Imperial College in London. "Doctors, of course, did not realize, of course, that viruses caused them."
                
                
                
                
                
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                    The 1968 pandemic, which was faster and more widespread, did not leave as many victims as the 1918 pandemic
                
            However, the flu may also lead to the lives of sufferers in many cases due to "secondary bacterial infection," as bacteria invade the body swollen by the influenza virus, and multiply Causing secondary inflammation such as pneumonia. Antibiotics, such as penicillin, were discovered in 1928 and are used by doctors to reduce the risk of secondary infection, but in 1918 these treatments and vaccines that protected the most vulnerable groups were not yet discovered. The United States Centers for Disease Control and Prevention said: "Health care systems and disease diagnosis and treatment tools are more advanced than they were in the early 20th century." However, the absence of diagnostic and therapeutic tools in 1918 was not the only cause of the high number of victims of the influenza epidemic Za, but it also added to the deterioration of the living conditions in this difficult era of human history, which fought World War trenches Alooly.az was a breeding ground for bacteria and viruses that cause diseases among soldiers. "The viruses emerged when the battlefield brought together people they had never met before," said Patrick Saunders Hastings of the University of Carleton, Ottawa, and many people infected with the flu virus were treated for other infections and were malnourished. He added that there was a close relationship between vitamin B deficiency and mortality rates in the recent epidemic waves. However, the 1918 pandemic affected civilians not taking part in the fighting, as the closed and overcrowded environments in which people lived away from battlefields did not accelerate the transmission of the virus "It is known that the greater the dose of viruses that enter the body, the more severe the symptoms and the deterioration of the condition of the infected, because the virus in this case will overwhelm the immune system and multiply and spread strongly in different parts of the body," Barkley said. .
                
                
                
                
                
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                    Medical services and public health campaigns, which in many societies have become more sophisticated than they were in 1918, were able to curb the outbreak of epidemics that emerged later
                
            "There is no doubt that industrial development, and the consequent significant improvement in personal hygiene, public health care and overall low levels of poverty, have contributed to a decline in mortality rates from infectious diseases than in early years," said Keira Grantz of the University of Florida. 20th century. By analyzing records from Chicago dating back to 1918 during the outbreak of the epidemic, Grantz discovered that many factors increased the chances of person-to-person transmission, such as population density and unemployment. Strangely enough, she noted from records that the mortality rate in some areas of the city was associated Closely linked to illiteracy rates. This may be due to the strong link between illiteracy and poverty, or ignorance may play a direct role in exacerbating the symptoms of the disease. "Public health officials have done their best to address the outbreak of the epidemic in Chicago, building health bureaus across the city, shutting down schools, and banning social events, but all these measures will only help reduce the spread of the disease, People. "Add to all these factors the ferocity of the virus itself, as many scientists believe that the virus that caused the influenza epidemic in 1918 was exceptionally lethal and rapid, but we did not understand the reasons for his passion only a hundred years after his appearance. Although Techniques for collection, storage and analysis of viruses It has been shown only after the long-term disappearance of the original strain of the virus. Recent advances in genetic engineering have enabled scientists to re-activate an effective virus from old inert virus samples and inject laboratory animals such as monkeys with the virus that caused an epidemic. In 1918 to study its effects. Scientists note that the virus is not only able to reproduce very quickly, but also seems to induce an excessive immune response called cytokine secretion syndrome or cytokine storm, the rapid and sequential secretion of vast amounts of immune cells and molecules Which regulates the immune response called cytokines. When effective immune response helps fight infection, excessive excretion of active immune cells in the body can lead to acute infections and fluid accumulation in the lungs, increasing the risk of secondary bacterial infection, such as secondary pneumonia. This is probably why healthy young people were the most affected by the 1918 influenza pandemic. In this case, their strong immune systems, which usually help them to get rid of the disease, caused a syndrome of secretion of cytokine or acute cytokine. Influenza Influenza Influenza Cause Influenza 1918, we will look at its origins.
                
                
                
                
                
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                    Scientists are exploring new forms of flu vaccination, including "universal vaccine", which protects against multiple strains of influenza virus
                
            Scientists believe that the strain of the virus that caused the 1918 pandemic evolved from a strain of bird flu, mutating and gaining the ability to infect the upper respiratory tract in humans. The strain can be easily transmitted from one person to another through cough and sneezing. This is important for two reasons. Firstly, the immune system in the body will not be able to identify the virus and generate the appropriate response if the host has not already been infected. Second, the virus itself was not fully adapted to life within the human body. Contrary to expectations, it is not in the interest of the influenza virus to kill the host. "The virus does not want to kill the host as soon as he enters his body, because it will reduce his chances of moving to another host," Barkley said. In contrast, the virus needs to remain inside the host's body for as long as possible so that it can move through coughing and sneezing to another host. That's why most viruses evolve over time to become less effective. But in 1918, the influenza virus had not yet acquired these characteristics. In contrast, the viruses that caused the subsequent epidemics were adapted to become less deadly so that they could spread from person to person and from country to country around the world. For example, the virus that caused the 1957 pandemic The human flu strain of human influenza has acquired some of the influenza virus strains in birds. This genetic combination has resulted in the emergence of a new highly contagious strain, but less lethal than the strain of the avian influenza virus because of its human virus strain. The virus that causes the epidemic of 1968 , Known as the Hong Kong flu. This hybrid virus had many virus genes already present, and the original viruses had adapted and became less aggressive than the previous strains. The flu pandemic of 2009 was caused by the swine flu virus and because of course pigs are closer to humans At least as far as birds are concerned, this swine flu virus has developed to become less virulent than previous viruses. Given this close look at the evolution of viruses, we may be able to understand the causes of epidemics in the past and find out the genetic characteristics of the virus that makes it capable On "We see that studying viruses that have caused human disasters in the past will help us make the right decisions and guide us to the best ways to avoid them in the future," says Bessler. "He said. You can read the original BBC News website —————————————— ———– You can receive notifications of the most important subjects after downloading the latest version of the BBC Arabic application on your mobile phone.
                                                                                                        

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