What viruses most often infect the human body - infectious disease. Viruses and bacteria: which is more dangerous? The most dangerous viral diseases

Viruses are an integral part of human life. The body fights them, becoming strong. After an illness, the immune system is strengthened, so the activity of bacteria brings certain benefits. But sometimes they are too powerful. And then irreversible consequences occur in the body. What are the most dangerous viruses in the world for humans?

10 Rotavirus

9 Arboviruses of the family Flaviviridae

8 Virus of the family Flaviviridae

7 Hepatitis C virus (HCV)

6 Hepatitis B virus (HBV)

5 Influenza virus

4 Variola virus

3 AIDS virus

2 Rabies virus

1 Ebola virus

In our lives there are so many scary stories about evil spirits, ghosts, brownies. But unlike these tales, which still have no evidence, there are truly scary and inexplicable things in the world - mysterious viruses. What is a virus anyway? This is a microscopically small, pathogenic microorganism, which for the most part does not have a cellular structure.

In this article we will look at 10 of the most mysterious viruses on the planet.

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Black Widow Virus

Recently, scientists made a unique discovery. The WO virus, which infects bacteria (bacteriophage), has appropriated the gene for the venom of the Black Widow spider. Previously, it was generally accepted that bacteriophages do not exchange genes with animals, but recently American scientists informed the world that this bacteriophage is capable of taking pieces of other genes, combining them together, thereby forming a new gene. This is a very unique phenomenon that scientists have recently discovered.

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Infertility is the inability of a man and a woman to conceive a child during regular sexual activity.

Infertility is divided into two categories - absolute and relative. In women, it can be primary (when pregnancy never occurred) and secondary (there was a pregnancy, even if it ended in a miscarriage or ectopic pregnancy).

Italian scientists conducted research and concluded that one of the causes of infertility may be the HHV-6A virus, one of the herpes viruses. It causes immune reactions that prevent the fetus from attaching to the uterine wall. Treatment is carried out with antiviral therapy and injections of the hormone estradiol.

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Scientists have discovered an incredibly tenacious microbe in the SIRV2 virus. It is able to survive even in boiling acid. Survives even at temperatures of 175 degrees Celsius. It is also resistant to UV radiation. Scientists have found striking similarities between SIRV2 and bacterial spores from diseases that are difficult to treat, such as anthrax. They intend to study the virus in more detail in order to further use it for gene therapy.

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Multicomponent virus

This virus is very unusual, because the usual virus is one, but this one is divided into five parts. To become infected, a cell must be exposed to at least four genes.

The virus was found in the genes of a mosquito, meaning a person needs at least 4 mosquito bites to become infected with the disease. The study was part of a larger project aimed at finding out what viruses mosquitoes can carry, but it brought this unexpected discovery.

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8% of the human genome comes from ancient viruses. Retroviruses target human sperm and eggs in order to further gain a foothold in the DNA of a new person and be passed on from generation to generation. Even though millions of years have passed, the virus may reappear. Researchers do not know the exact time of awakening - this can happen during the emergence of new diseases and as a result of the work of a viral cell that attaches itself to the DNA of our body.

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In the summer of 2014, a Bourbon County resident was bitten by a tick. He went to the hospital complaining of vomiting, rash and high fever. He developed pulmonary and kidney failure and died on the 11th day. A new virus was isolated from his blood and assigned to the Thogotovirus species, which includes the causative agents of meningitis and encephalitis that affect the membranes of the brain. But unlike them, the bourbon virus infects leukocytes. To date, this is the only case of infection with the bourbon virus.

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A French research team has discovered a virus in the Siberian permafrost that is as much as 30,000 years old! But there is nothing to be afraid of - the virus is not capable of infecting animal or human cells. It affected single-celled amoebae during the Upper Paleolithic or Neolithic. The Siberian virus is wider in diameter than other giants. It has a genome of 600,000 base pairs, which can create 500 proteins.

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These viruses are the cause of death for most prokaryotes in the deep ocean, scientists say. As in the entire biosphere of the planet, in the deep ocean viruses are the most common biological creatures. Partial genetic matches have been found between Californian and Norwegian waters.

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Mysterious paralysis

In the United States in 2015, more than a hundred cases of mysterious paralysis in children were recorded. The symptoms started out like a common cold. Scientists initially suspected the EV-D68 virus because it could cause paralysis, but it was only detected in 20% of cases. Enterovirus D68, and now enterovirus C105, were found in the children's respiratory tracts but were not detected in the cerebrospinal fluid, the researchers said. The cause of the mysterious paralysis outbreak still remains a mystery.

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This is an acute febrile disease that affects blood vessels and leads to the development of thrombohemorrhagic syndrome. Last year, 129 people died from an unknown disease, but it is not yet clear whether they were carriers of the same disease.

Many viruses were identified in the blood samples of the victims. Most scientists believe that the disease is transmitted by ticks or mosquitoes, but do not rule out that the virus enters the body with bacteria. It is still unknown whether the fever is transmitted from person to person.

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Conclusion

This was an article about the strangest and most mysterious viruses on the planet. Thank you for your attention!

How are representatives of the microcosm related to each other - viruses and bacteria? Can they be considered enemies, friends, blood relatives or partners? Let's understand their interaction and role in the human body.

Most often, a person becomes acquainted with viruses and bacteria during the cold season. Acute respiratory infections are one of the most common diseases in the world. Most of these diseases occur due to viruses and bacteria that enter the human body along with inhaled air and settle on the mucous membranes of the nose or mouth 1 .

To understand the infection process, we can give an analogy with any public institution, which in our case is the human body. Through open doors, various guests - viruses and bacteria - enter the establishment. Some bacteria are intelligent people and do no harm, but some are strictly prohibited from entering: they can provoke a real conflict. As for viruses, these are, for the most part, bandits. You shouldn't expect anything good from them.

There is a security system against unwanted persons outside and inside the establishment - human immunity. Sometimes the immune system does not cope with its tasks, gets tired or is “distracted” by bacteria, allowing dangerous viruses to enter, which immediately begin a raider takeover.

So what is the main difference between them? First, you need to clearly understand what they are, and based on this, determine the difference and the principle of their effect on the body.

What are viruses

A virus is a tiny organism that can exist and reproduce only inside living cells. In the external environment, the virus is found in microparticles of biological material, but multiplies exclusively in the cells of living beings. In other words, the virus is not active until it is inside a person 2 .

And he gets there like this:

• Airborne, like most respiratory infections
• When drinking dirty water, with food, or not following hygiene rules
• From mother to unborn child
• Contact – in close contact through the skin or mucous membranes
• Parenterally - bypassing the gastrointestinal tract, by injection

After entering the body, the virus first attaches to the cell, then delivers its biological genome into it, loses its envelope, and only then multiplies. After reproduction, the virus leaves the cell, and the infectious agent spreads along with the blood, continuing total infection. Viruses can suppress the immune system 2.

What are bacteria

A bacterium is a complete, albeit single-celled, organism. It can reproduce through division, which is what it actively does in nature or within humans 3 .

Not all bacteria cause infectious diseases. Some are beneficial and live in the organs of the body. For example, lactic acid or bifidobacteria, which live in the intestines and gastric tract, are actively involved in human life and actually form part of his immune defense 3 .

The entry of bacteria into the body follows the path of viruses. But bacteria multiply more often outside the cell than inside it. The list of diseases that develop as a result of their penetration into the human body is extremely long. Bacteria can cause 3:

• Respiratory diseases (most often caused by staphylococci and streptococci)
• Gastrointestinal infections (caused by Escherichia coli and enterococci)
• Damage to the nervous system (sometimes caused by meningococci)
• A number of diseases of the reproductive system, etc.

By multiplying, they spread through the bloodstream, which leads to generalization of the infection and clinical worsening of the patient’s condition. Bacteria can also suppress the immune system, making it harder for the body to resist viruses 3 .

How does a virus differ from a bacterium?

Thus, both viruses and bacteria are capable of infecting the body, causing infection. The key difference between them is in the reproduction mechanism. Viruses cannot reproduce in the external environment, so they need to invade the cell. Bacteria reproduce by division and can live in the external environment for a long time, waiting to enter the human body. Accordingly, the mechanisms for antibacterial and antiviral protection should also differ 4 .

Let's summarize briefly. The differences between a virus and a bacteria are as follows:

• Size and form of existence. A virus is the simplest life form, a bacterium is a single-celled living creature.
• Life activity. The virus exists only inside the cell and infects it, after which reproduction (cloning) occurs. The bacterium lives a full life, reproducing by division, and the body for it is only a favorable place of existence.
• Form of manifestation. Viruses tend to manifest themselves by increased body temperature, general weakness, muscle and joint pain. Bacteria manifest themselves as unhealthy discharge (purulent or as a specific plaque).

Typical viral diseases: ARVI, influenza, herpes, measles and rubella. These also include encephalitis, hepatitis, smallpox, HIV, etc.

Typical bacterial diseases: syphilis, whooping cough, cholera, tuberculosis, diphtheria, typhoid and intestinal infections, STIs.

It happens that both of them cause one disease together. Such a symbiosis requires special treatment. Examples include: sinusitis, tonsillitis, meningitis, pneumonia and other diseases 5.

Fighting viruses and bacteria

It is impossible to completely protect yourself from viruses and bacteria. A person is constantly attacked by a huge number of microorganisms and the main barrier to their path is immunity. Therefore, it is important to strengthen and keep the immune system in a “fighting” state, especially during the cold season and during periods of seasonal diseases.

The immunomodulator IRS®19 will become an assistant on the path to a healthy and strong immune system. It contains a mixture of bacterial lysates, which are specially isolated parts of pest bacteria. Lysates activate the immune system and direct it to fight bacteria and viruses. The drug has a high level of safety and can be prescribed to prevent infections in adults and children over 3 months of age. It has been tested many times and has shown excellent results in the fight against infections, including ARVI 6.

A mild cough is often where diseases, outbreaks of epidemics and even pandemics begin, which can spread across entire continents. However, modern medicine and hygiene rules have given us the opportunity to repel the most destructive infections.

Today it seems that we have the epidemic situation under control. Indeed, humanity has coped, for example, with smallpox, eradicated the plague and other deadly dangers. However, most infections still remain with us, periodically manifesting themselves in the poorest (and therefore vulnerable) countries.

What infectious diseases have claimed the greatest number of lives on our planet? From which infections has humanity suffered more than from all the wars that have ever happened on Earth?

And another, most important question: what infections can become potential killers of humanity? What infectious diseases currently claim millions of lives every year? We present to your attention a list of the 27 most famous and terrible infectious diseases.

Black pox

In one hospital in Dhaka, the capital of Bangladesh, the mortality rate was 46 percent. In 1959, there was a small outbreak of smallpox in Moscow, where the infection came from India (it was “brought” by a citizen of the USSR who visited India). Thanks to the efforts of Soviet doctors, the disease was stopped, although three people still died.

Some scientists believe that smallpox, which leaves characteristic scars on human skin, began its destructive path from Egypt three thousand years ago. The blackpox virus, which is the cause of smallpox, killed at least a third of those infected. The rest were left disfigured.

The World Health Organization (WHO) announced in 1980 that the disease had been completely eradicated thanks to an unprecedented vaccination campaign that took decades. The latest strains of the virus are stored in special centers under certain conditions in Russia and the United States of America.

Plague

There are three types of plague, but the best known form is bubonic plague, which causes painful inflammation of the lymph nodes, called buboes. Plague still occurs in representatives of the animal world throughout the planet, but especially in the western United States and Africa.

In September 2016, WHO reported 783 cases of plague worldwide, 126 of which were fatal. In Russia, the bubonic plague manifested itself quite recently, in Altai, where a 10-year-old boy became infected with it through contact with a sick animal. In total, according to historians, in our era the plague took the lives of about 150 million people (mainly during major epidemics).

Malaria

Rabies used to be called hydrophobia, since the sound of pouring water causes a spasm, it is impossible to take a sip. To date, medicine knows of fewer than ten cases of survival after a person infected with rabies exhibited the symptoms described above.

Regardless, there is a rabies vaccine that has been shown to be most effective as a preventative measure and also as a method of treating an infected person before he or she develops the symptoms discussed above.

Rabies has been known to mankind since time immemorial. The specificity of infection (through animal saliva) saved our species from massive pandemics of this infection. However, even in our time, there are reports of surges of this infection in a number of backward countries or even tribes. Usually the cause is contact with one or another infected animal.

Pneumonia

Many people underestimate the danger of pneumonia. If powerful outbreaks of plague have sunk into oblivion, then, according to WHO, almost a million children around the world died from lung disease in 2015. In general, this disease claims seven million lives a year, with almost half a billion people affected.

Rotavirus infection

According to WHO, in 2013, rotavirus killed 215 thousand children under the age of five worldwide. About 22 percent of deaths occurred in India. This viral infection leads to dehydration of the body resulting in severe diarrhea and vomiting. In total, there are up to 25 million cases of this infection per year in the world; 660 to 900 thousand die.

Causative agents of infectious diseases in humans

Ebola

Some Ebola patients experienced bleeding from the mouth and nose during the later stages of the disease, a condition known as hemorrhagic syndrome. The most recent Ebola outbreak occurred in South Africa in 2014; This is by far the largest outbreak in history.

By April 2016, 28,652 cases were known. Of these, almost 11,300 people died. Ebola is transmitted from person to person through body fluids. There is also a risk of contracting the virus through contact with the blood of an infected person, saliva, sweat (or by touching, for example, clothing or bedding that has absorbed an infected substance).

Creutzfeldt-Jakob disease

These infections tend to be transmitted from animals (cattle) to people. The word “spongy” in the name appeared because infections lead to the degradation of brain tissue and the appearance of characteristic holes in the cerebral cortex, which, when enlarged, resemble a sponge.

A person can become infected with this infection, for example, by eating beef contaminated with bovine spongiform encephalopathy. Essentially, this is the same disease, only in animals.

As mentioned above, this is a rare infection. Its geography is not particularly tied to backward countries, as is the case with, say, malaria. For example, between 1996 and March 2011, 225 cases of the disease were recorded in the UK. Cases of infection have also been reported in France.

It is noteworthy that until 1996, scientists had no idea that a person could acquire spongiform encephalopathy by eating meat contaminated with spongiform encephalopathy. Before this, it was known only about the hereditary nature of the disease, and also that the disease could be introduced into the body of the person being operated on during surgery on the brain or eyes.

Despite its non-prevalence, this infection is extremely merciless. It is known that in the case of mild forms of mad cow disease, the survival rate of patients is 85 percent. If we are talking about a severe form of this disease, then the death of the patient is inevitable.

Marburg hemorrhagic fever

The fever itself is transmitted from person to person through body fluids (like Ebola). In general, the Marburg virus has a lot in common with Ebolavirus, which is not surprising, since the latter also belongs to the filovirus family.

Humans can become infected with this disease from bats of the fruit bat family. Some of those infected exhibit acute hemorrhagic fever. According to various sources, the mortality rate for this disease ranges from 60 to 90 percent.

This virus was first identified in Germany in 1967. Then, employees of a scientific laboratory who conducted experiments with monkeys from Uganda became infected with Marburg disease. As it turned out, monkeys, just like people, are susceptible to this infection.

But in bats, which are carriers of the virus, it does not cause the corresponding disease (as is the case with Ebola). Despite appropriate treatment, fever leads to serious complications, which may include long-term mental disorders.

Middle East respiratory syndrome

This disease first became known in 2012, after cases of infection in Saudi Arabia. Three years later, WHO published information about 1,154 cases of infection in 23 countries, of which 431 cases were fatal.

Some people who become infected with this infection may not show any symptoms. But most often, those infected develop a fever, cough, and shortness of breath. In more severe cases, organs (for example, kidneys) fail to function and breathing stops.

An infectious disease that threatens billions of people

Dengue fever

It is noteworthy that without the complicity of these two species, a healthy person cannot catch dengue fever from an infected person. The symptoms are initially almost the same as for the flu: the patient has a fever, he coughs, the temperature rises, and chills appear.

At more serious stages, the symptoms become much more numerous. Sometimes the virus leads to a potentially fatal condition known as severe dengue. We are talking about dengue hemorrhagic fever, which causes stomach pain, vomiting, bleeding and difficulty breathing.

According to WHO, an average of 400 million people suffer from dengue fever each year. Some scientists who are seriously studying the ways of dengue spread claim that almost 4 billion people in 128 countries of the world are at risk of spreading this fever.

Yellow fever

This fever got its name due to one of the symptoms (recorded, by the way, in a small percentage of people who get sick) - the appearance of yellowness of the skin and eyes. However, the vast majority of those who have encountered this disease have never encountered such a symptom.

The color of the skin and whites of the eyes changed in those people who had a second, more severe phase of fever, which has a destructive effect on human organs, including the liver and kidneys. According to the WHO, half of patients in the second phase of yellow fever (hemorrhagic fever) died within seven to ten days.

The mortality rate for this disease is quite high: for every two hundred thousand infected, there are 30 thousand deaths. Almost 90% are in Africa. Fortunately for many people in the 47 countries at risk (including Central and South America), there is a highly effective vaccine against the disease.

This was not the case at all in the 17th century, when the yellow fever virus, which first appeared in North America and then in Europe, caused severe epidemic outbreaks of the disease, sending many thousands of people to the next world.

Hantavirus pulmonary syndrome

The world first learned about one of these viruses, most often causing hantavirus pulmonary syndrome (Sin Nombre Virus), after its discovery in the United States in 1993. Then, several young people died mysteriously in the southwestern region of the country, called the “four corners.”

24 people were taken to the hospital, half of whom subsequently died. Then the world first learned about a new virus, which was later dubbed the Sin Nombre virus (actually, “unnamed virus” in Spanish), leading to a severe respiratory infection.

Outside the United States—in Asia, Europe, and parts of Central and South America—hantaviruses also cause a serious illness known as hemorrhagic fever with renal syndrome.

The initial symptoms of this disease are similar to those of hantavirus pulmonary syndrome (fever, vomiting, nausea), but it can cause bleeding and kidney failure. The disease is extremely dangerous, since diseases from hantaviruses are tens of times more common than rabies, for example.

Spread of infectious diseases

anthrax

Humans usually become infected while caring for animals or from animal products. Bacterial spores can penetrate a person's skin, but sometimes they can be inhaled (for example, when working with animal skins or hair). The pulmonary form of the disease is much more deadly - death occurs in 92 percent of cases of infection.

Anthrax has been known about for a long time. A similar disease was mentioned in Chinese manuscripts about five thousand years ago. The bacterium Bacillus anthracis is believed to have wiped out entire animal species. It is no coincidence that anthrax spores are considered a bacteriological weapon intended for the mass destruction of the enemy.

Whooping cough

However, the fungal type of meningitis is not contagious, although it can cause an outbreak of this disease, as happened, for example, in the United States in 2012, when hundreds of patients were infected through injections of a drug containing fungal spores. Several dozen people died.

Meningococcal meningitis is caused by the bacterium Neisseria meningitidis, which causes flu-like symptoms - nasal discharge, nausea, sensitivity to light, and confusion. A fatal outcome remains possible, although the situation has changed dramatically over a hundred years: then the mortality rate could exceed 90 percent.

Syphilis

Syphilis can now be cured quite simply, but it is a very insidious disease. If the infection is started, it leads to severe complications. At the first stage of the disease, syphilitic ulcers appear on the patient's genitals and anus.

They are usually very small, although painful, and go away on their own. A sick person can immediately forget about temporary inconveniences, attributing them to temporary pimples that popped up for some reason not worth attention.

At the second stage of this disease, syphilis begins to express itself clearly - a rash begins to appear in one or different parts of the body. However, even in this case, the rash may not be very bright and may not be accompanied by itching. The patient may not even pay attention to these rednesses.

In other cases, the rash may be accompanied by fever, swollen lymph nodes, and muscle pain. And if syphilis was not treated during the development of the first and second stages, subsequent problems for the patient will be simply catastrophic.

It also happens that syphilis does not reach the late stage for a very long time. According to some reports, this can last from 10 to 30 years. However, at a later stage, the patient loses the ability to coordinate muscle contractions, paralysis, rigor, bleeding occurs, and dementia is noted. If internal organs are damaged, the patient may die.

According to data for 2016, up to three hundred thousand patients with syphilis are registered in Russia annually. Currently, the disease is only fatal if left untreated (in about a third of patients with advanced disease). During the Renaissance, syphilis destroyed tens of millions of people, being almost the main cause of death in some periods of history.

Infectious diseases causing deformities

Leprosy

Leprosy affects the affected person's skin, peripheral nerves, upper respiratory tract and eyes. If left untreated, it leads to muscle atrophy, physical deformities and permanent damage to the nervous system.

Although people at one time tried to protect themselves from contact with people with leprosy, this infectious disease is not so contagious. The infection is spread through airborne droplets when an infectious person sneezes or coughs.

If you simply touch someone with leprosy, there is no particular risk of becoming infected. Moreover, according to WHO, the immune system of a healthy person is usually able to resist this infection when the bacteria gets inside. However, the most vulnerable category is children.

According to WHO, in 2017, more than two hundred thousand new cases of leprosy were registered in the world. In approximately 40 percent of cases, patients face disability. If there is no proper treatment, a person is doomed within 5-10 years.

Measles

The infection leads to the appearance of a characteristic rash on the skin, which is accompanied by general intoxication of the body. Other symptoms of this dangerous disease are not much different from the symptoms of a common cold.

Measles is such a contagious disease that simply being indoors with an infected person can be dangerous. According to WHO, 134,200 people died from measles in 2016. Before the spread of vaccination (that is, in 1980), this disease claimed the lives of 2.6 million people.

Fortunately, vaccination has proven to be extremely successful in combating this viral infection. It is known that out of every thousand people vaccinated against measles, 997 have never encountered this disease.

Atypical pneumonia

Bats help spread this disease (as in the case of the Ebola virus, Marburg fever and Middle East respiratory syndrome). In this case, the distributors are the so-called horseshoe bats.

The virus began its movement from China, but quickly spread to other countries and continents due to the fact that the Chinese authorities initially tried to hide information about the outbreak of this disease. The SARS case showed humanity how important it is to act together when it comes to such formidable opponents as viral and bacterial infections.

Staphylococcal infection

The main problem is that this Staphylococcus aureus (as it is called for simplicity) is able to resist most antibiotics. The history of the “fight” of staphylococcus with antibiotics began back in 1940, when doctors began treating staphylococcal infections with penicillin.

An overdose of the drug (or its misuse) led to the fact that microbes developed resistance to penicillin over a period of ten years, which forced scientists to try a new way to combat staphylococci - using an antibiotic called methicillin.

However, staphylococci have also demonstrated the ability to develop resistance to this drug. Today, this microbe is able to resist the effects of many antibiotics of the penicillin group, such as amoxicillin, oxacillin, dicloxacillin and all other beta-lactam antibiotics.

As a result, humanity has received a powerful enemy in the form of a sort of super microbe that causes infections that are difficult to diagnose and disguise themselves as other diseases. They reduce the body's defenses, facilitating the penetration of toxins into the blood and tissues, causing many dangerous pathologies.

Staph skin infections usually start as small red rashes that can develop into pus-filled boils that require surgery. These infections can cause even more serious consequences by affecting the blood, heart, bones and other internal organs of a person. Sometimes they lead to the death of the patient.

Zika virus

It belongs to the genus of flaviviruses transmitted by the already known genus of biting mosquitoes (Aedes). The disease caused by this virus, called Zika disease, is not particularly dangerous for most people. But today the disease has pandemic status.

According to research, every fifth person infected with the Zika virus eventually develops the disease of the same name. However, the virus threatens serious complications for the human body developing in the womb and for newborn children.

Those infected experience a fever, a rash, joint pain, and conjunctivitis, but these symptoms are mild and last only a few days. However, the virus causes miscarriages in pregnant women and leads to congenital malformations (for example, microcephaly).

The site provides reference information for informational purposes only. Diagnosis and treatment of diseases must be carried out under the supervision of a specialist. All drugs have contraindications. Consultation with a specialist is required!