While working on this article, the author recalled a lecture by his university teacher, a prominent crystal physicist Yakov Geguzin. Subsequently, based on the materials of this lecture, Yakov Evseevich created a wonderful work "Living Crystal", where, using the example of viruses and crystals, he brilliantly showed the fragility of the boundaries between living and nonliving in nature. Today, all of this has suddenly turned from academic research to topical material. Needless to say, the whole world has been in fear of the coronavirus for a long time, and many are asking the question: what are the mysterious "half-dead" organisms that have struck humanity?
Organisms at the edge of life
The origin of life is the greatest secret of the universe. At the same time, the appearance of viruses on the evolutionary tree of life is the same burning riddle of natural science. Some scientists even consider viruses to be a special form of life. However, viruses do not have a cellular structure and metabolism, because of this it is difficult to classify them as living. Therefore, they are figuratively called "organisms at the edge of life."
Meanwhile, the encyclopedia indicates that in Latin "virus" means "poison". Today, science knows more than five thousand viruses that fill everything around and strongly affect the flora and fauna. Viruses are found in every type of living creature, including fungi, mosses, bacteria, and lichens.
Under what conditions and when viruses "decide" to strike a person - not a single virologist knows. Generally speaking, viral attacks never stop, because a virus is not a bacterium or a microorganism. It is a piece of genetic information packed into a protein coat. He does not have a cell, and outside a living organism he behaves like a kind of "zombie", frozen in a "borderline" state. The virus cannot develop independently, for this it vitally needs a foreign cell.
At the same time, unlike the popular opinion, any virus is not a microscopic "serial killer" at all, and its main task is not to destroy a living cell, but, using its resources, to create the maximum number of copies of its own. Meanwhile, the person does not even suspect that fragments of genetic information are bombarding him every second. Once in the cell, the virus soon subjugates it. At the same time, it is imperative for him to suppress the antiviral defense system, as well as prevent the microorganism from self-destruction, having received a signal about someone else's invasion. Or the cell can signal to other cells that something is wrong with it, and inflammation begins. Viruses also suppress this mechanism, but with varying degrees of success. There are actually many more attempts to capture cells by viruses than cases when the disease begins. More often the cell winsand we will not even know that a virus entered us. But how, then, do epidemics arise? And why was the coronavirus suddenly raging in China?
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Banal coincidence
Strange as it sounds, but epidemiological experts for the most part believe that the development of global epidemics or pandemics is associated with a banal coincidence. At the same time, viruses really become deadly for humans only if they manage to move from one type of animal to another. In fact, this is a rather rare event. For example, viruses from plants to animals are passed no more often than once in a million years. However, for closely related species, say, from primates to humans, a successful transition can occur annually and repeatedly. Less often, once a decade, this can be the case for mammals and humans. But Ebola can be brought to humans by colonies of bats flying foxes. You can also remember bird and swine flu.
Generally speaking, outbreaks of epidemics are extremely uneven and can occur for several years in a row, and once every couple of decades. Thus, for every successful transition of the virus, there are more than a million unsuccessful ones.
It is such a rare situation, according to Chinese virologists, that arose in the case of the coronavirus. An exceptionally successful interspecies transition took shape, in which, through the mediation of swamp snakes, mice and pangolins, the virus from bats got to humans. At the same time, the general unfavorable epidemiological situation played a great role: extreme overcrowding of the population, low level of household hygiene and close contact between people and animals. It turns out that due to the specifics of the Chinese food markets, the "alien" virus "hooked" on a person, and then quickly spread among the mass of market buyers and sellers.
In other countries, there are no such specific conditions, although it is well known that bats infected with approximately the same dangerous viruses live not only in Southeast Asia, but also in southern Europe, including the North African Mediterranean. In addition, there are few places where bats, snakes and pangolins are delicacies and where they are butchered in unsanitary markets.
Meanwhile, a colossal number of viruses can pass to a person. Microbiologists believe that their number can be estimated by multiplying the number of all mammalian species by 1000. But if conditions are not favorable for the spread of a viral infection, in principle there is nothing to be afraid of.
Heritage of the ancient world
Scientists in the middle of the last century came to the conclusion that viruses are the oldest heritage of the primary flora and fauna. Most likely, they appeared before the birth of the first cells, about four billion years ago. Moreover, the human genome mostly consists of viruses or their residues. This means that they were the basis for the development of life on Earth. It has been proven that man as a mammal owes its existence to them, since thanks to viruses, the most important organs began to form in our ancestors.
In addition, viruses have greatly increased the efficiency of evolution. They transferred genetic information much more efficiently than they did only during natural reproduction. That is, they passed successful genes not to the offspring of the species, but immediately into a new organism.
Viruses mutate. Scientists say that in many of them, each new genome has an additional mutation. The virus changes sometimes within a few hours. There are no identical viruses inside one cell, within one reproduction cycle! In order to be able to adapt to new conditions, the virus changes, producing a variety of variants in the population. Mutation for viruses Typical is an indispensable part of their life cycle. Viruses' own genome is a million times smaller than that of a human, and in order to compete with us, they create many variants that can be "useful" in different conditions.
Virologists believe that variability is one of the main qualities of viruses. They can become more or less dangerous, change points of application, adapt, look for more and more new ways of survival. This is evidenced by the history of epidemics of the present century, including various aggressive viruses. But gradually a person nevertheless adapts to them, although it costs him great sacrifices. So the course of the disease became less severe. The same awaits the evolution of the coronavirus: it will mutate, choosing more and more new victims, while becoming less dangerous.
Biological bases of viral infection
The transmission of the virus from person to person usually occurs through airborne droplets when we cough and sneeze. However, the same coronavirus can enter the environment with particles of saliva or phlegm only if it has already begun to reproduce in the human body in noticeable quantities.
A logical contradiction arises here. A person is sick from a new virus because the virus multiplies in his lungs, simultaneously destroying the cells, which he forces to continuously reproduce their copies. The virus itself cannot multiply - for this it needs to use the cells of the host's organism. The question arises: where, then, in a person without symptoms of the disease, viruses that are carried by air to another person can appear?
Usually, the answer to this question is this: in the early stages of virus reproduction, human cells can already create copies of it, but not yet have time to die from this work or from the retaliatory strike of the immune system that reacts to such "printing" of copies of the virus in our cells. And then the person will not yet have symptoms, but will already be moderately infectious.
The concept of "can be dangerous and the patient without symptoms" emerged during the research of common influenza epidemics. A third of the people who contract his virus - the healthiest and strongest - do not feel at all that they are sick. They have no noticeable temperature or other symptoms.
For a long time, doctors thought that such people ensure the spread of the influenza virus by isolating it in small quantities. People with coronavirus, in theory, could also begin to secrete viral capsids (protein membranes in the form of a crown, "clinging" to cells) with droplets of saliva or phlegm - as "asymptomatic" infected with the flu.
According to scientists, the fight against other diseases could be the reason for the rapid spread of coronavirus. Influenza A and B have virtually disappeared over the past 15 years thanks to powerful vaccinations. This "empty space" was taken by the coronavirus.
It turns out that medicine has practically destroyed the common flu, and strains of coronavirus have appeared in its place. In the sense - a holy place is never empty. Generally speaking, after overcoming the current pandemic, an even more dangerous virus or even a whole family of strains may appear. Just like the coronavirus turned out to be stronger than the flu, but the next disease may turn out to be even more massive and aggressive …
Magazine: Secrets of the 20th century №22. Author: Oleg Faig