September 30, 2020

Anatomy of a murderer

It was 2015, and Bill Gates already said that the greatest risk of a global catastrophe was a highly contagious virus (rather than a war) because of its ability to kill some 10 million people in the coming decades. The new coronavirus that jumped from an animal to a human in Wuhan at the end of 2019 has managed to get all the attention. The epidemic is evolving very rapidly and with it, the knowledge we have. By not knowing anything in early 2020, the scientific community has already managed to isolate, sequence, identify, and develop tests to diagnose it. At the moment it is not known which animal caused the SARS-CoV-2 outbreak, but everything points to what happened in China and that the species was a bat. When these pathogens jump to other species, their immune systems don’t know how to fight them, and an epidemic can start if the virus is evolutionarily able to spread. An unprecedented change in the human population (nearly 200 million people moved to urban areas in East Asia during the first decade of the 21st century) is one of the reasons why more diseases originate in Asia and Africa. Wild animals, which often harbor viruses, encounter other domestics and the human population. And viruses, which jump from species to species, can ultimately infect people. Coronaviruses are an extensive family of viruses that can cause disease in animals and humans. They are named for a kind of spike on the surface of the virus that resembles a crown and that is a chain of genetic material (RNA) covered by a membrane of proteins that protect it and from which other proteins that help it to bind protrude. entering human cells. In humans, several coronaviruses are known to cause respiratory infections ranging from the common cold to serious illnesses such as MERS and SARS, with higher mortality. This coronavirus causes coronavirus disease COVID-19. The new coronavirus uses the ACE2 protein as its gateway, which is like a lock in which a key is inserted: the S protein. Each type of coronavirus has a slightly different S protein, which is one of the elements that accumulates the most mutations due to to its importance to start the infection. This allows you to open locks on human cells. Once inside the first human cell, a coronavirus can generate up to 100,000 copies of itself in less than 24 hours. Every time this process happens, the invaded cell is destroyed and this is what can cause pneumonia and the other symptoms of Covid-19.


Older people and those with underlying medical conditions, such as high blood pressure, heart problems, or diabetes, are more likely to develop serious illness. About 2% of those who have contracted the disease have died. The vaccines and antivirals that are being developed focus on interfering with the molecular process of infection. One of the more advanced vaccines is based on introducing a messenger RNA that produces the protein S of the virus, but not the rest of the pathogen. This allows the immune system to identify and remember it, so that if a real virus enters the body, the antibodies bind to that protein and begin the process to destroy the virus. But many more vaccines are being sought. But I don’t think any are ready for use soon, so they can only be used if the pathogen resurfaces next winter or if it becomes a seasonal disease, like the flu. Recent evidence suggests that, unlike SARS, which is transmitted only when the person has symptoms, it can be transmitted before symptoms appear. This makes containment measures difficult and has triggered alarm measures. SARS-CoV2 has shown that it can be easily transmitted from one to the other. The WHO estimates the contagion rate to be 1.4 to 2.5, others speak of a range between 2 and 3, although there may be «super-contagious» capable of infecting up to 16 people. The WHO has estimated that the incubation period (between infection and the appearance of symptoms) is between two and fourteen days, but the vast majority develop them between 5 and 7. According to the WHO, previous analyzes know that coronaviruses do not They survive a long time on objects, although a study published in January 2020 says they can survive on inanimate surfaces such as metal, glass or plastic for 9 days “but can be efficiently removed by surface disinfection.” The study does not analyze the survival time of the outbreak-causing coronavirus started in Wuhan, but of other variants of this virus family. Another study found viable viruses in aerosols (particles suspended in the air) up to 3 hours later, up to 4 hours in copper, 24 hours in cardboard and 2 or 3 days in plastic and stainless steel, but viruses always mutate. And there are open questions about what the progression of covid-19 will be like. One of the most disturbing is whether it could mutate into a more aggressive form that increases the frequency of cases with severe symptoms. And in this environment, one of the most important effects it causes is panic. We hope to overcome them. We will have to fight staying at home and with hygienic measures. #I stay at home


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