General, Research, Technology

What is a virus and why do scientists grow it?

I must say right away that in this article we will not be inOnce again, focus on the currently raging coronavirus in China. Better we will generally talk about what kind of animal it is and how to deal with it. The fact is that in society there are many prejudices about this. Many people think that certain methods of control / prevention are effective, but in reality everything turns out differently. As a result, the virus is not treated, and the person only gets worse. This happens all the time. Therefore, let's try to dispel some myths. Especially about the prevention of diseases associated with viruses, and the viruses themselves.

It’s better to work with viruses in such a suit.

To begin with, let's decide what isIn general, the virus, what it looks like, where the name comes from and what it is, in fact, dangerous to humans. This is especially true in the modern world, in which we move simply with insane speeds. After all, only 150 years ago, to be on the other side of the Earth, it was necessary to spend at least several months, and 600 years ago it was not even clear whether there was anything beyond the horizon.

In those days, if an epidemic broke out, it died outa village or a small town, but nothing more. Now the virus is spreading all over the world. Not for nothing that many militants and thrillers describe just such a plot in which the villain infects an airplane with people with a virus, the incubation period of which is several days. As a result, some should infect everyone around. No matter how fantastic this plot looked before, now it has ceased to be so incredible.

Content

  • 1 What is a virus
  • 2 Virus History
  • 3 The contribution of viruses to the study of evolution
  • 4 Why dangerous relic viruses
  • 5 Where did the virus come from?
  • 6 Viral life form
  • 7 The largest epidemics
  • 8 How to treat the virus? How to protect yourself from the virus?

What is a virus?

So there you go! What is a virus in itself? There are many definitions, among which the main can be called the following:

Virus (lat. Virus - poison) is a non-cellular infectious agent that can be reproduced only inside living cells. Viruses infect all types of organisms, from plants and animals to bacteria and archaea.

In addition to viruses that infect complex livingorganisms, there are viruses that infect bacteria. They are called bacteriophages. In some cases, they can even be used for medical purposes. Such work is also underway.

This is how a bacteriophage works.

Viruses capable of replicating only in the presence of other viruses (satellite viruses) have also been detected. In this case, being their carrier, a person may not even suspect it.

The virus, called virology, which is a section of microbiology, opens up viruses and studies them. The first discoveries in this area were made in 1892.

During this time, more than six thousand species were discovered.viruses. True, it is believed that there are more than one hundred thousand species. New, or rather well-forgotten old viruses are found even in permafrost, during the sampling of ice at great depths.

Even climate can “create” new viruses: Global warming can revive ancient viruses

Viruses are found in almost every ecosystem. At the same time, there is a possibility that the rest were simply poorly searched. The immune system of humans and animals itself is quite actively fighting many types of viruses. At the same time, antibodies are produced that allow the virus to be defeated when re-entering the body. True, this does not always work with mutated forms of the same virus. Some viruses may initially bypass the immune system. For example, some types of herpes and HIV.

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Special antiviral drugs can fight viruses relatively effectively. It is worth remembering that during a viral disease, the use of antibiotics will only make it worse.

Virus history

I said above that there are viruses thatallow you to fight bacteria. This makes some types of viruses a potential means of controlling diseases like typhoid and cholera. Similar experiments were carried out, including by the English bacteriologist Frederick Tworth at the beginning of the twentieth century, who discovered such properties of viruses. Interestingly, at that time, these studies lost their meaning due to the fact that penicillin was invented, which very successfully fought with many pathogens.

The danger of viruses cannot be underestimated. Some of them are deadly.

An interesting property of the virus that has been discoveredback in the nineteenth century, it became that for survival and reproduction he needed a living organism. Later, scientists were able to grow viruses for the production of vaccines on lymph, suspensions from chicken kidneys or on fragments of corneal tissue from guinea pigs. Such viruses were grown to create a vaccine. Similar studies are still ongoing.

The first experiment on human fetal tissueheld in 1949 by John Franklin Anders, Thomas Weller and Frederick Robbins. They received poliovirus, first grown not on animal tissues or eggs. A little later, this enabled Jonas Salk to create an effective polio vaccine (polio vaccine).

At the dawn of the search for viruses, many scientists thought thatviruses are liquids because they cannot be seen through a microscope. There were opinions that these particles were just very small, but it was difficult to prove it. It was proved only with the advent of electron microscopes. At the same time, the first images of viruses were obtained, which made it possible to learn a lot about their structure.

A little about the main thing today: Artificial Intelligence has predicted the outbreak of a new coronavirus in China

In general, the golden age of virology was the secondhalf of the twentieth century. At this time, not only about 2000 types of viruses were discovered and their description was given, but vaccines against many of them were also invented. True, many viruses still cannot be defeated. In particular, the retrovirus and their most famous representative of HIV, isolated in 1983 by a group of scientists led by Luke Montagnier from the Pasteur Institute in France.

The contribution of viruses to the study of evolution

As an outstanding biologist of the last century saidTheodosius Dobzhansky: "Nothing in biology makes sense, except in the light of evolution." For viruses, this statement is true, as nowhere else. The explanation for this looks a bit florid, but try to give it shorter.

Traces of viruses can be found in this chain.

Hundreds, thousands and millions of years ago, livingorganisms were also exposed to viruses. In addition to the fact that it facilitated natural selection, made it possible to “clean” the population and helped living organisms to develop, it left an imprint that now allows one to study the origin of species and sequences of evolutionary chains.

The fact is that viruses that have got intothe body of ancient animals could have killed them. If they did not kill them, then they remained in organisms as a safe virus that lost its properties. He was becoming a sort of retired soldier. If such retroviruses appeared in the reproductive system, they could be transmitted to new generations and change their DNA. Thus, they did not just enter the body, but also wandered through its descendants for millions of years.

When humanity was able to decrypt DNA,it turned out that such traces, regardless of the type of living organism, were in one place. As a result, this led to the fact that finding connections between animals on this basis, we can conclude that these animals had a common ancestor. The probability of accidental coincidence of such a record in DNA is negligible. So much so that she can be neglected.

Thus, biologists have received another way to prove the existence of evolution and the common origin of species. As they say, "where did not wait."

Why dangerous relic viruses

Moreover, such “viral information” is notsafe because there is a reverse transcription mechanism discovered in 1970 by two Nobel laureates, American scientists Howard Temin and David Baltimore. Thanks to this mechanism, viruses can return in a mutated form, possibly even in the form of a supervirus that will cause a global epidemic. The virus seems to be saying: "This is not my war." After that, he still takes a machine gun and goes to war.

The look of a virus that has resigned, but he was told to return.

Often such a “rebellion” is carried out at the expense ofsome cooperation of viruses. Previously, it was considered impossible, but now the opposite has been proved. A really existing virus enters the body, and the relict virus contained in DNA, for example, supplies it with protein structures.

It is because of the presence of living organisms in the DNArelict viruses, many scientists strongly oppose organ transplants from animals to humans. Such a combination of tissues can contribute to the emergence of a supervirus, which will be simply impossible to defeat.

Where did the virus come from?

Many are interested in the question of where the viruses came from, that is, how they appeared and where they came from. There is no unequivocal opinion on this question, but there are three main hypotheses.

The first hypothesis is called regressive (also itscalled the hypothesis of reduction or degeneration). According to her, at first there were small cells that parasitized on larger living organisms. Later, these bacteria simplified, losing functions that are not needed for a parasitic lifestyle. Evidence of this hypothesis is the existence of rickettsia and chlamydia. They are essentially bacteria, but they behave like viruses, propagating only inside a living cell with its protein structures.

The second hypothesis is called the cellular hypothesisorigin. According to her, viruses emerged from the genome of a larger organism. Without going into details, there are molecules in DNA that can move from cell to cell or within the genome. It was this molecule that could mutate and secrete itself into what became a virus.

Take a look, maybe there is a virus.

The third hypothesis is that virusesappeared at the dawn of the existence of life, that is, at about the same time as the origin of cell life. Moreover, many researchers are inclined toward this theory. Although, the debate does not subside and there is still no definite answer to the question of where the virus came from.

Viral life form

As mentioned above, the virus cannotexist outside the cells of a living organism, since it does not have its own metabolism. To synthesize its own molecules, he needs a host cell. Outside of such a cell, the virus behaves like a particle of a biopolymer and does not show signs of a living creature.

While the virus is outside the cell, it exists inas an independent particle. The size of this particle is so small that it is simply impossible to make out most of the viruses in a simple light microscope. Its size is about 100 times smaller than the size of the bacteria, and its shape varies from simply spiral to more complex structures. One of their forms is similar to a crown. It is she who is the very coronavirus.

Some scientists call the virus organisms onfacets of the living. On the one hand, they are not living, but on the other, they can multiply, evolve, and lead vital activity, albeit due to external nutrition of the host cell protein structures.

The basis of the life cycle of the virus is justseveral stages. The first is called attachment. At this stage, bonds are created between the proteins of the viral capsid and the surface of the host cell. Sometimes viruses only interact with certain cells, such as HIV with white blood cells.

At the second stage, penetration ofhost cell. After that, the virus is released from its capsid. Simply put, it crawls out of its shell and launches its genome into the cell. The method of capsid release is different. The shell can be dissolved by enzymes of the virus itself or by using elements inside the cell.

After that, the virus replicates (multiplies),synthesizing the early genes of the virus. Then it gathers into structures and at the last stage leaves the cell after its death. Often, this is due to rupture of the cell membrane.

Thus, the virus enters the cell and releases its genome.

Many viruses do not destroy cells anduntil a certain time they do not manifest themselves. They can exist for years inside the cell, causing chronic diseases. Examples of such viruses can be herpes, which appears only with a certain combination of factors, or papillomavirus, which in some cases can lead to the development of cancer. Another example of such viruses is the Epstein-Barr virus. It leads to accelerated cell division, but without signs of malignancy.

An example of a case where the virus can be a positive hero: Zika virus can help defeat brain cancer

The largest epidemics

Viruses can both cause diseasesome people or animals, and to epidemics. There have been several major epidemics in history that have claimed hundreds of thousands of lives. By the way, according to some data, called from the "Old World" viruses, up to 70 percent of the indigenous population of America was killed after its discovery. This is already a sign of a pandemic that should not be confused with a simple epidemic.

A pandemic is a global epidemic.

The most famous epidemic is thatwas caused by the Spanish flu in 1918-1919. It was caused by a very aggressive form of the influenza A virus. Unlike ordinary flu, which is dangerous, first of all, for weaker people (elderly, children, people with chronic diseases), the Spanish flu carried away healthy middle-aged people. Altogether, according to various estimates, from 50 million to 100 million people died. That is about 5 percent of the world's population at that time.

This is how improvised hospitals from the time of the "Spanish" looked.

According to definitions and figures, HIV can be considereda real pandemic, because now, according to various estimates, there are almost 40 million people infected on our planet. Since the moment of the first disease in 1981, so many people have died of this virus that this virus can be considered the most deadly in the entire history of mankind. At the same time, it is believed that this virus appeared during the twentieth century in Africa, south of the Sahara. Perhaps it came from one of the relic viruses that I mentioned above.

The Chinese coronavirus 2019-nCoV is raging now.which, at the time of writing, infected almost 8,000 people, of whom 170 died. Not the biggest indicators, if you look at the story, but if you can’t localize it, it’s not known what it can lead to. Let me remind you, the first cases were identified among visitors to the city market in Wuhan. Rare animals were sold on the market. Perhaps they became the source of the virus.

How to treat the virus? How to protect yourself from the virus?

First of all, it’s worth understanding that inIn most cases, the virus enters the body through the respiratory tract, i.e. it is respiratory. In this case, the mucous membranes begin to produce secretions and the person begins to feel generally ill. The virus itself affects the body due to the excitation of certain diseases. Often this is pneumonia. But before the immediate illness, the symptoms are a defensive reaction of the body. At this point, serious consequences can be avoided and it is better to consult a doctor. The highest activity of viral diseases is observed from September to April, when the body is weakened and there are many other factors for the development of the disease. Including climatic.

As a rule, diseases caused by viruses,pass very easily. In general, according to statistics, every fifth person at least once a year picks up the virus. Of course, this statistics is only for those cases when the patient went to the doctor. In most cases, people simply lie down at home for several days. There are those who continue to go to work. It is because of these “heroes” that viruses spread.

Doing this, stay home!

As a treatment, you can and should usesome simple tools. For starters, you just need to stay at home. High fever (low-grade) helps fight the disease. It is not worth knocking her down if she does not threaten her life or simply does not become unbearable. It must be understood that up to values ​​of about 38-38.5 degrees, it helps the body fight. If it rises higher, it is already worth knocking down. You can take antipyretic even at a lower temperature, but you must be aware that, contrary to advertising, this will not allow you to fight the disease, but only relieve symptoms. Actually, advertisements usually say so. To avoid liability, the word “symptoms” is often used. In short, if the temperature is below 38 degrees and you can tolerate it - bear it!

You also need to drink plenty of fluids. It not only removes toxins from the body caused by the activity of the virus (and not only), but also helps moisturize the mucous membranes through which most of the virus is excreted. This allows you to blow your nose or clear your throat, thereby clearing the airways. It is recommended to drink decoctions and just water. The temperature of the drink should be about 45 degrees so that it is better absorbed by the stomach. But abuse lemons and sour berries (including their decoctions and tinctures) is not worth it. They will irritate the foci of inflammation. Everything should be in moderation. Smoking and vodka with pepper will also be bad partners in the treatment.

In fact, the main advice issee a doctor. It would not seem that you know yourself better, there is a chance that you have picked up a special strain of the virus that appear every year. They do not reach the scale of SARS and the new Chinese virus, but can be very serious. If the temperature rises above 40 degrees and there are sharp pains, for example, in the ears, you should not pull. In some cases, procrastination is indeed like death.

As a treatment, do not takeantibiotics, as they are completely powerless in the fight against the virus. They are aimed at combating other pathogens and can not fight viruses, from the word at all. On the contrary, you will only make yourself worse by harming the intestinal microflora. This will generally weaken the body and may bring out some of what helps in the fight against the virus.

In such places you can buy something that will help in the fight against the virus. The main thing is to do it wisely.

Do not rely heavily on vitamin C, sohow it can only harm, especially children, causing liver pathology in some cases. Usually a person needs just the amount of this vitamin that he gets from normal food with proper nutrition. Moreover, drinks and tablets with vitamin C again have a negative effect on the foci of inflammation.

There are special drugs to fight viruses.but they also need to be selected wisely. The strongest of them are oseltamivir and zanamavir, but they should be taken only after consulting a doctor, since they are used only to combat the most powerful viruses.

If we talk about means of prevention, hopethe mask is not worth it. An ordinary mask from a pharmacy cannot protect the body one hundred percent, as it can not fit snugly to the face. The mask should be with a filter and fastened very tightly, but wearing it under normal conditions is hardly worth it. Nevertheless, there is still some benefit from the usual mask, especially during periods of increasing incidence. Let's just say it will be a good complement to a strong body, although not a panacea. The key word is “strong body”. If you follow it, it will be much more difficult to get sick, since the best medicine is a good immune system.