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SARS, Ebola, Zika, H1N1 … How did the previous epidemics end?

Before the current coronavirus pandemic, other viruses wreaked havoc, but did not reach the scale of Covid-19. Most ended up disappearing on their own, but thanks to what? While everyone is wondering about the way out of the crisis, can we learn from past epidemics?

The major pandemics of the 20th and 21st centuries In this ehealth, go back in time to discover the pandemics that have marked our history over the past hundred years. Influenza viruses, Ebola, or even HIV, they have infected the whole world.

This is the question to which everyone would like to have the answer: how will the epidemic of Covid-19, which has affected more than 2 million people worldwide? One thing is certain: the virus of SARS-CoV-2 will never go away forever. " Viruses transmitted by animals cannot be eradicated because their reservoir persists, recalls Étienne Decroly, director of research at the CNRS, in The echoes. The only ones that can be eradicated are viruses of which humans are the only reservoir, such as that of smallpox, the measles or polio " This is rarely the case, since 75% of the emerging diseases described in humans are of animal origin. So how the previous epidemics have they finished?

SARS

The first epidemic due to Sars virus mainly struck Asia with more than 8,000 cases and 774 deaths worldwide between 2002 and 2003. Despite a death rate much higher than that of the Sars-Cov-2 (9.6% against 1% to 2% for the coronavirus current), its contagiousness was much lower. Unlike Covid-19, where many cases asymptomatic could not be detected, it seems that only close and prolonged contact with very sick people led to contagion. Early quarantine of the sick from the start of the epidemic in China and Hong Kong, as well as reinforced border controls, have therefore prevented massive spread. Finally, the seasonal factor seems to have played a role, the epidemic having naturally stopped In early spring.

MERS-Cov

The Middle East respiratory syndrome, caused by another coronavirus detected in 2012 in Saudi Arabia, affected more than 2,500 people. MERS is mainly spread by close contact with the camel, thehost intermediary of the virus, although rare cases of human-to-human transmission have been recorded in a hospital in South Korea. Its spread has therefore remained very limited, although cases have been recorded in 27 countries (including 2 in France). Rare sporadic cases are regularly recorded in the Middle East.

Ebola

Discovered in 1979 and responsible for a first epidemic in Sudan and the Democratic Republic of Congo (RCD), the Ebola virus reappeared in 2014 in West Africa, causing 11,000 deaths between 2014 and 2016. A very heavy toll due in particular the high mortality of the virus, greater than 60%. Unlike Covid-19, the virus is not transmitted aerosol but by close contact with blood, secretions soiled or wild animals. It is therefore much easier to contain it by applying strict hygiene measures. Ebola still rampant in DRC, But several vaccines have been developed.

Zika

The virus Zika, from the same family as that of the dengue where the yellow fever, triggered an epidemic in more than thirty countries located in South America, Central America and the Caribbean in 2015. Between 20,000 and 35,000 cases have been recorded, including rare cases in Europe for patients returning from infected areas . Transmitted by mosquito and causing symptoms flu-like (fever, headache, body aches), however, it triggers serious complications on the newborn, and in pregnant women. An effective mosquito control (which only thrives part of the year) to eradicate the epidemic, even if the virus remains present in the region.

H1N1 flu (avian flu)

The swine flu H1N1 is caused by a type A influenza virus usually found in birds and pigs. The disease was transmitted to humans accidentally in 2009, triggering a pandemic. Spread by aerosol like seasonal flu, H1N1 has been found to be three times less contagious and its impact remained limited, with 18,156 death in 213 countries according toWHO. First because of the vaccine, even if the 94 million doses that France had commanded almost remained on his arms. On the other hand, " some people had already met either theepitope H1, i.e. N1, and therefore already had a certain immunityExplains Etienne Decroly on LCI.

Staphylococcus aureus, terror of hospitals Staphylococcus aureus, Staphylococcus aureus, is not an inherently dangerous bacterium for humanity. Most of the time, it only causes small, minor infections. But this sneaky one sometimes hides in hospitals, and takes advantage of an injury to fit into a weakened patient to colonize him and lead to sepsis. There is always time to subject her to antibiotics … but she is becoming more and more insensitive to the drugs that are opposed to her and is developing increasing resistance! © NIAID, Flickr, cc by 2.0

Neisseria meningitidis, main responsible for meningitis Meningitis knows not one, but several culprits. Among the most serious bacterial forms, the main defendant is Neisseria meningitidis, involved in 90% of cases. If there were no treatment, the infection would almost certainly be fatal. Despite antibiotics, one in five newborns and one in four adults die from this meninges infection. © Sanofi Pasteur, Flickr, CC by-nc-nd 2.0

The hepatitis B virus, this terribly infectious STD We talk about it less than HIV, however, it deserves our full attention. The hepatitis B virus is transmitted a hundred times better than the AIDS virus during sex and then attacks the liver cells. Most often, the disease does not progress much and the patient feels nothing. But sometimes hepatitis becomes chronic, as in more than 300 million patients, and gradually destroys the liver cells, leading to cirrhosis or liver cancer, which is very difficult to treat. © Sanofi Pasteur, Flickr, CC by-nc-nd 2.0

The rabies virus, the bite that causes carnage Thanks to the work of Louis Pasteur, rabies has declined significantly around the world. There are still more than 50,000 human deaths on the Planet in 2004 due to the rhabdoviridae family virus. Transmitted by bite, it rushes straight into the nervous system and wreaks havoc there so much that death is almost inevitable. Fortunately, the vaccines are here! © Sanofi Pasteur, Flickr, CC by-nc-nd 2.0

Yersinia pestis, the bacteria responsible for plague epidemics Who does not remember these History courses evoking the plague epidemics in the Middle Ages? Behind all this hides Yersinia pestis, a bacterium that first attacks rodents before attacking humans. The disease most often existing in bubonic form (a bubo being an inflammation and the enlargement of a ganglion), it can develop into septicemic plague and become more deadly and more contagious. In the history of mankind, its mortality is difficult to assess but it is very probably responsible for more than 100 million victims. © NIAID

Bacillus anthracis, the bacteria behind anthrax Anthrax, or anthrax, is caused by a bacteria called Bacillus anthracis, or anthrax. Most often, it enters the body through a wound in the skin. The body then manages to get rid of it on its own. When the bacteria's spores are swallowed or breathed, however, it's a whole different story. By air, it is not far from being fatal in 100% of cases. That’s why it inspires bioterrorists so much. © Janice Haney Carr, CDC

Hantaviruses and their terrible pulmonary syndrome The hantaviruses are a little different from the other pathogens presented in this slideshow: they prefer to attack rodents but, sometimes, unfortunately, they can infest a Man. In these cases, their action can be overwhelming. Causing hemorrhagic fevers or hantavirus pulmonary syndrome, they are occasionally very aggressive and commonly fatal. The Sin nombre virus, or Sin Nombre virus (SNV), which we can see in the picture, rarely strikes, but surely. © Brian et al., CDC

The Marburg virus, a real killing machine The Marburg virus is designed to kill but is still a little less deadly than its cousin Ebola. Also causing hemorrhagic fevers, this filovirus kills more than 80% of the people it infects. Its transmission from Man to Man is nevertheless relatively difficult since it requires very close contact between individuals, with transmission by stool, vomiting, urine or saliva. © Frederic Murphy, CDC

The dengue virus is gaining ground It is far from the deadliest and most pathogenic on this list, but it should not be overlooked. The dengue virus, transmitted by Aedes mosquitoes, infects between 50 and 100 million people worldwide. For 500,000 people, especially children, the disease presents itself in a severe form which takes 10,000 souls. A major problem: it has been on the increase in recent decades. It, which was limited to nine countries before 1970, now affects around a hundred states. © Sanofi Pasteur, Flickr, CC by-nc-nd 2.0

Ebola, the virus with the highest mortality? Known since 1976, the Ebola virus, named after a Congolese river, is one of the most deadly. Some of its strains cause hemorrhagic fevers which kill in 90% of cases. This virus has caused several epidemics in Africa, particularly in Sierra Leone, Guinea and Liberia, killing several thousand people. Unfortunately, there is no preventive or therapeutic treatment for this terrible plague. © Frederic Murphy, CDC

The Spanish flu virus, this devastating epidemic of 1918 The year 1918 was a very deadly one, on the one hand because the fighting was still taking place in Europe and even beyond, on the other hand because a particularly virulent strain of influenza H1N1 prevailed in the whole world. It is believed to have infected one in two Terrans, or 500 million people at the time, and is estimated to have killed between 30 and 100 million people. A real weapon of mass destruction … © Terrence Tumpey, CDC

Clostridium botulinum, the bacteria that poisons botox Clostridium botulinum has a technique of its own for committing murders: the bacteria prefer poisoning. Indeed, it produces one of the most powerful toxins in the world, botulinum toxin. This molecule resists high heat and the acidity of the digestive system, so that, when ingested, it integrates the circulation and will block nerve communication, resulting in paralysis which is sometimes fatal. © CDC

Mycobacterium tuberculosis, the deadly agent of tuberculosis Having become rare in France as in rich countries since the introduction of BCG, tuberculosis nevertheless continues its deadly work throughout the world. In 2010 alone, the bacteria responsible, Mycobacterium tuberculosis, infected 8.8 million people and killed 1.4 million of them, attacking their lungs. The bacteria has been rife for 3 million years. © Janice Haney Carr, CDC

The H5N1 virus, the source of the world-shaking flu Appearing in 1997 in Hong Kong, it was only 9 years later that the H5N1 flu caused panic to the whole Earth. The virus (here in gold in dog cells), transmitted to humans only by contaminated birds, is fatal in 60% of cases. In August 2012, WHO counted 608 people who had contracted the virus since its inception, for 359 deaths, even if many mild or asymptomatic cases could have been not counted. Scientists remain concerned, however, because the pathogen is still circulating in nature and it is known that a few mutations may be enough for it to become contagious in humans. In this case, the deaths could be counted in millions… © CDC

HIV: the AIDS virus and its 30 million victims Since 1981 and the date of its discovery, HIV (the little green balls in the picture) has killed around 30 million people worldwide and is still spreading. This retrovirus generates AIDS (Acquired Immunodeficiency Syndrome) and especially ravages poor countries, those of the African continent in the lead. However, there are therapies that block the progression of the virus in the body and allow patients to live with HIV without declaring AIDS for very long years. But these are struggling to export outside of the rich countries. © Goldsmith et al., CDC

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