Viral diseases - a list of common ailments and the most dangerous viruses. MedAboutMe - Viruses: diversity of species, diseases, treatment and prevention Viruses, etc.

Viruses are non-cellular infectious agents that have a genome (DNA and RNA), but are not endowed with a synthesizing apparatus. To reproduce, these microorganisms need cells from more highly organized organisms. Once in cells, they begin to multiply, causing the development of various diseases. Each virus has a specific mechanism of action on its host. Sometimes a person does not even suspect that he is a virus carrier, since the virus does not cause harm to health; this condition is known as latency, for example, herpes.

To prevent viral diseases, it is important to maintain a healthy lifestyle and strengthen the body’s defenses.

Origin and structure

There are several hypotheses about the origin of viruses. Science offers a version about the emergence of viruses from fragments of RNA and DNA that were released from a large organism.

Coevolution suggests that viruses emerged simultaneously with living cells as a result of the construction of complex sets of nucleic acids and proteins.

Questions about how it reproduces and is transmitted are studied by a special branch of microbiology - virology.

Each virus particle has genetic information (RNA or DNA) and a protein membrane (capsid) that acts as protection.

Viruses come in different shapes, ranging from a simple helical shape to an icosahedral one. The standard value is approximately 1/100 the size of the average bacterium. However, most viruses are very small, making them difficult to examine under a microscope.

Is living matter a virus?

There are two definitions of the life forms of viruses. According to the first, extracellular agents are a collection of organic molecules. The second definition states that viruses are a special form of life. It is impossible to answer the question of what viruses exist specifically and definitively, since biology presupposes the constant emergence of new species. They are similar to living cells in that they have a special set of genes and evolve according to the method of natural set. They require a host cell to exist. The absence of its own metabolism makes it impossible to reproduce without outside help.

Modern science has developed a version according to which certain bacteriophages have their own immunity, capable of adaptation. This is proof that viruses are a form of life.

Viral diseases - what are they?

Viruses of the plant world

If you ask yourself what viruses are, then, in addition to the human body, you can distinguish a special type of viruses that infect plants. They are not dangerous to humans or animals, since they are able to reproduce only in plant cells.

Artificial viruses

Artificial viruses are created to produce vaccines against infections. The list of viruses that are created artificially in the arsenal of medicine is not fully known. However, it is safe to say that creating an artificial virus could have a lot of consequences.

Such a virus is obtained by introducing an artificial gene into a cell, which carries the information necessary for the formation of new types.

Viruses that infect the human body

What viruses are on the list of extracellular agents dangerous to humans and causing irreversible changes? This is the aspect of studying modern science.

The simplest viral disease is the common cold. But against the background of weakened immunity, viruses can cause quite serious pathologies. Each pathogenic microorganism affects the body of its host in a certain way. Some viruses can live in the human body for years without causing harm (latency).

Certain latent species are even beneficial to humans because their presence generates an immune response against bacterial pathogens. Some infections are chronic or lifelong, which is purely individual and is determined by the protective ability of the virus carrier.

Spread of viruses

Transmission of viral infections in humans is possible from person to person or from mother to baby. The rate of transmission or epidemiological status depends on the population density of the region, weather conditions and season, and the quality of medicine. It is possible to prevent the spread of viral pathologies if you timely clarify which virus is currently detected in most patients and carry out appropriate preventive measures.

Kinds

Viral diseases manifest themselves in completely different ways, which is associated with the type of extracellular agent that caused the disease, the location of the disease, and the speed of development of the pathology. Human viruses are classified as lethal and indolent. The latter are dangerous because the symptoms are unexpressed or weak, and the problem cannot be detected quickly. During this time, the pathogenic organism can multiply and cause serious complications.

Below is a list of the main types of human viruses. It allows you to clarify which viruses exist and which pathogenic microorganisms cause diseases dangerous to health:

1. Orthomyxoviruses. This includes all types of influenza viruses. Special tests will help you find out which influenza virus caused the pathological condition.
2. Adenoviruses and rhinoviruses. They affect the respiratory system and cause ARVI. The symptoms of the disease are similar to the flu and can cause severe complications such as pneumonia and bronchitis.
3. Herpes viruses. Activated against the background of reduced immunity.
4. Meningitis. The pathology is caused by meningococci. The mucous membrane of the brain is affected; the cerebrospinal fluid is the nutrient substrate for the pathogenic organism.
5. Encephalitis. It has a negative effect on the lining of the brain, causing irreversible changes in the central nervous system.
6. Parvovirus. The diseases caused by this virus are very dangerous. The patient experiences convulsions, inflammation of the spinal cord, and paralysis.
7. Picornaviruses. Causes hepatitis.
8. Orthomyxoviruses. They provoke mumps, measles, parainfluenza.
9. Rotavirus. The extracellular agent causes enteritis, intestinal flu, and gastroenteritis.
10. Rhabdoviruses. They are causative agents of rabies.
11. Papoviruses. Causes papillomatosis in humans.

Retroviruses. They are the causative agents of HIV, and later AIDS.

Life-threatening viruses

Some viral diseases are quite rare, but they pose a serious danger to human life:

1. Tularemia. The disease is caused by the infectious bacillus Francisellatularensis. The clinical picture of the pathology resembles the plague. It enters the body through airborne droplets or through a mosquito bite. Transmitted from person to person.
2. Cholera. The disease is recorded very rarely. The Vibrio cholerae virus enters the body by drinking dirty water or contaminated food.
3. Creutzfeldt-Jakob disease. In most cases, the patient experiences death. Transmitted through contaminated animal meat. The causative agent is a prion - a special protein that destroys cells. Manifests itself as a mental disorder, severe irritation, and dementia.

It is possible to determine what type of virus caused the disease through laboratory tests. An important argument is the epidemic state of the region. Finding out what kind of virus is currently circulating is also important.

Signs of viral infections and possible complications

The majority of viruses provoke the occurrence of acute respiratory diseases. The following manifestations of ARVI are distinguished:

• development of rhinitis, cough with clear mucus;
• increase in temperature up to 37.5 degrees or fever;
• feeling of weakness, headaches, loss of appetite, muscle pain.

Delayed treatment can cause serious complications:

• adenovirus can cause inflammation of the pancreas, which leads to the development of diabetes;
• beta-hemolytic streptococcus, which is the causative agent of sore throat and other types of inflammatory diseases, with reduced immunity can provoke diseases of the heart, joints, and epidermis;
• influenza and ARVI are often complicated by pneumonia in children, elderly patients, and pregnant women.

Viral pathologies can cause other serious complications - sinusitis, joint damage, heart pathologies, chronic fatigue syndrome.

Diagnostics

Experts determine a viral infection by general symptoms, based on what virus is currently circulating. Virological studies are used to determine the type of virus. Modern medicine widely uses immunodiagnostic methods, including immunoindication and serodiagnosis. The specialist decides which ones to take based on a visual examination and the collected medical history.

Prescribed:

• enzyme immunoassay;
• radioisotope immunoassay;
• hemagglutination inhibition response study;
• immunofluorescence reaction.

Treatment of viral diseases

The course of treatment is chosen depending on the pathogen, specifying what types of viruses caused the pathology.

For the treatment of viral diseases the following is used:

1. Drugs that stimulate the immune system.
2. Medicines that destroy a specific type of virus. A diagnosis of a viral infection is necessary, since it is important to clarify which virus responds better to the chosen drug, which allows for more targeted treatment.
3. Medicines that increase the sensitivity of cells to interferon.

For the treatment of common viral diseases, the following is used:

1. "Acyclovir". Prescribed for herpes, it eliminates the pathology completely.
2. "Relezan", "Ingavirin", "Tamiflu". Prescribed for different types of influenza.
3. Interferons together with Ribavirin are used to treat hepatitis B. A new generation drug, Simeprevir, is used to treat hepatitis C.

Prevention

Preventive measures are selected depending on the type of virus.

Preventive measures are divided into two main areas:

1. Specific. They are carried out with the aim of developing specific immunity in a person through vaccination.
2. Non-specific. Actions should be aimed at strengthening the body's defense system by providing light physical activity, a properly composed diet and maintaining personal hygiene standards.

Viruses are living organisms that are almost impossible to avoid. To prevent serious viral pathologies, it is necessary to vaccinate according to the schedule, lead a healthy lifestyle, and organize a balanced diet.

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Viral marketing is at the peak of its popularity these days. This method of transmitting information increases the number of customers exponentially, especially in online business.

Why viral advertising? Viral does not mean harmful. If you associate the word virus with computer viruses, worms, Trojans, then I will reassure you. In our case, viral advertising is considered to be something that is transmitted between users on their own initiative. This type of advertising is very popular among marketers because of its effectiveness and low cost.

The whole difficulty lies in the fact that we cannot accurately predict the behavior of our product in an advertising campaign (whether it will go viral or not). To do this, we need to look at examples of viral products.

Examples of viral products in Russia and the world.

1. Viral clip (song). Group "Leningrad" with viral videos (on Louboutins, healthy lifestyle, drinking in St. Petersburg). Everyone liked it because it reveals the Russian soul, a lot of swearing and colloquial language, “the naked truth of life.”

2. Viral game. Game pokemon go. First of all, there are many mentions in the media. New augmented reality technology. Pleasant memories of the animated series of the 2000s, when there was also mass hysteria with stickers and posters of Pokemon.

3. Funny short video (memes). Like a virus, we constantly downloaded video jokes to each other’s mobile phones (“Chumazik”, “Aha Airship”, “Irreplaceable Slavik”, “The Door Sang”). Nowadays, the popularity of a certain video does not take a long period of time due to the huge flow of new videos. But funny videos spread online at great speed, and we constantly remember and discuss many videos.

4. Viral news. In 2008, when Russia and the world were gripped by a financial crisis, a rumor appeared that buckwheat and salt would rise in price. People bought buckwheat and salt in bulk for several years in advance. The same thing happened in 2015, when people rushed to buy household appliances, some bought three refrigerators. I think these rumors were started for a reason. A smart marketing move.

And so, we have identified several examples of viral products. Now you can identify the general similarities and main features of the virus.

Signs of viral products

A product can be called a virus when:

1. The product does not need support to grow as such. The product is self-distributed.

2. The product evokes emotions, no matter whether they are positive or negative (sexual arousal, fear, happiness, laughter, sadness, disgust, hatred).

3. The product is novel and interesting. It gives something without which it is no longer possible to imagine the modern world.

4.The product idea is simple and easy to remember.

5.The product is as accessible as possible to people. Or rather, on the contrary, any user is available to the product.

If a product has the above-described signs, it can be assumed that it has spread virally.

This is where the concept of “virus capacity” comes from.

“Virus capacity is a property that forces us to spread information about it to friends and acquaintances.

Its essence is that the greater the gap between price and quality (better quality, service, design and at the same time lower price), the greater the virus capacity of this product or establishment.

The marketer’s task is to launch a viral product with the highest virus capacity.

Now I will give some tips that you can use in your advertising programs to achieve high virus capacity.

Advertising techniques to increase virus capacity.

Celebrities.

Maximum involvement of the media.

Creative.

One of the important factors influencing the virality of a product is the creativity in its advertising. Come up with something that no one has done before and people will be interested in it. Everything new is always exciting. To achieve viral success, an advertisement must stand out from all other advertisements, and not just from its direct competitors.
Hype.

If a product is discussed by everyone, everywhere, then they know it and will advertise it. The discussion can be different, both positive and negative. Therefore, the danger of this method is that it can negatively affect the rating of the brand itself. But, as they say, it is impossible to be good to everyone.

On the verge of a foul.

This factor is best described as a video that most people wouldn't show their mom. Such videos are on the verge of social acceptability. Some may find them offensive, shocking, distasteful or have a "sick imagination". What's important, however, is that they combine this kind of brinksmanship with good humor. The shock element contained in the video is generally perceived as humorous rather than inappropriate. This also includes advertising with direct sexual overtones.

Luck.

History of research

The existence of a virus (as a new type of pathogen) was first proven in 1892 by the Russian scientist D.I. Ivanovsky and others. After many years of research into diseases of tobacco plants, in a work dated 1892, D. I. Ivanovsky comes to the conclusion that tobacco mosaic is caused by “bacteria passing through the Chamberlant filter, which, however, are not able to grow on artificial substrates.”

Five years later, while studying diseases of cattle, namely foot and mouth disease, a similar filterable microorganism was isolated. And in 1898, when reproducing the experiments of D. Ivanovsky by the Dutch botanist M. Beijerinck, he called such microorganisms “filterable viruses.” In abbreviated form, this name began to denote this group of microorganisms.

In subsequent years, the study of viruses played a vital role in the development of epidemiology, immunology, molecular genetics and other branches of biology. Thus, the Hershey-Chase experiment became decisive evidence of the role of DNA in the transmission of hereditary properties. Over the years, at least six more Nobel Prizes in physiology or medicine and three Nobel Prizes in chemistry have been awarded for research directly related to the study of viruses.

Structure

Simply organized viruses consist of a nucleic acid and several proteins that form a shell around it - capsid. An example of such viruses is the tobacco mosaic virus. Its capsid contains one type of protein with a small molecular weight. Complexly organized viruses have an additional shell - protein or lipoprotein; sometimes the outer shells of complex viruses contain carbohydrates in addition to proteins. Examples of complexly organized viruses are the pathogens of influenza and herpes. Their outer shell is a fragment of the nuclear or cytoplasmic membrane of the host cell, from which the virus exits into the extracellular environment.

The role of viruses in the biosphere

Viruses are one of the most common forms of existence of organic matter on the planet in terms of numbers: the waters of the world's oceans contain a colossal number of bacteriophages (about 250 million particles per milliliter of water), their total number in the ocean is about 4 10 30, and the number of viruses (bacteriophages) in bottom sediments of the ocean practically does not depend on depth and is very high everywhere. The ocean is home to hundreds of thousands of species (strains) of viruses, the vast majority of which have not been described, much less studied. Viruses play an important role in regulating the population size of some species of living organisms (for example, the wilding virus reduces the number of arctic foxes several times over a period of several years).

The position of viruses in the living system

Origin of viruses

Viruses are a collective group that does not have a common ancestor. Currently, there are several hypotheses explaining the origin of viruses.

The origin of some RNA viruses is associated with viroids. Viroids are highly structured circular RNA fragments that are replicated by the cellular RNA polymerase. It is believed that viroids are “escaped introns” - insignificant sections of mRNA cut out during splicing, which accidentally acquired the ability to replicate. Viroids do not encode proteins. It is believed that the acquisition of coding regions (open reading frame) by viroids led to the appearance of the first RNA viruses. Indeed, there are known examples of viruses containing pronounced viroid-like regions (hepatitis Delta virus).

Examples of icosahedral virion structures.
A. A virus that does not have a lipid envelope (for example, picornavirus).
B. Enveloped virus (eg, herpesvirus).
The numbers indicate: (1) capsid, (2) genomic nucleic acid, (3) capsomere, (4) nucleocapsid, (5) virion, (6) lipid envelope, (7) membrane envelope proteins.

Squad ( -virales) Family ( -viridae) Subfamily ( -virinae) Genus ( -virus) View ( -virus)

Baltimore classification

Nobel laureate biologist David Baltimore proposed his own scheme for classifying viruses based on differences in the mechanism of mRNA production. This system includes seven main groups:

• (I) Viruses that contain double-stranded DNA and do not have an RNA stage (for example, herpesviruses, poxviruses, papovaviruses, mimivirus).
• (II) Double-stranded RNA viruses (eg rotaviruses).
• (III) Viruses containing a single-stranded DNA molecule (eg, parvoviruses).
• (IV) Viruses containing a single-stranded RNA molecule of positive polarity (for example, picornaviruses, flaviviruses).
• (V) Viruses containing a single-stranded RNA molecule of negative or double polarity (for example, orthomyxoviruses, filoviruses).
• (VI) Viruses containing a single-stranded RNA molecule and having in their life cycle the stage of DNA synthesis on an RNA template, retroviruses (for example, HIV).
• (VII) Viruses containing double-stranded DNA and having in their life cycle the stage of DNA synthesis on an RNA template, retroid viruses (for example, hepatitis B virus).

Currently, both systems are used simultaneously to classify viruses, as complementary to each other.

Further division is made on the basis of such characteristics as genome structure (presence of segments, circular or linear molecule), genetic similarity with other viruses, the presence of a lipid membrane, taxonomic affiliation of the host organism, and so on.

Viruses in popular culture

In literature

• S.T.A.L.K.E.R. (fantasy novel)

In cinema

• Resident Evil" and its sequels.
• In the science fiction horror film “28 Days Later” and its sequels.
• The plot of the disaster film "Epidemic" features a fictional virus "motaba", the description of which is reminiscent of the real Ebola virus.
• In the movie "Welcome to Zombieland".
• In the film "The Purple Ball".
• In the film "Carriers".
• In the film "I am Legend".
• In the movie "Contagion".
• In the film "Report".
• In the movie "Quarantine".
• In the movie "Quarantine 2: Terminal".
• In the series "Regenesis".
• In the television series "The Walking Dead".
• In the television series "Closed School".
• In the film "Carriers".

In animation

In recent years, viruses have often become the “heroes” of cartoons and animated series, among which are, for example, “Osmosis Jones” (USA), 2001), “Ozzy and Drix” (USA, 2002-2004) and “The Virus Attacks” (Italy, 2011).

Notes

1. In English . In Latin, the question of the plural of this word is controversial. The word is lat. virus belongs to a rare variety of the II declension, neuter words in -us: Nom.Acc.Voc. virus, Gen. viri,Dat.Abl. viro. Lat is also inclined. vulgus and lat. pelagus; in classical Latin the plural is fixed only in the latter: lat. pelage, a form of ancient Greek origin, where η<εα.
2. Taxonomy of viruses at the International Committee on Taxonomy of Viruses (ICTV) website.
3. (English)
4. Cello J, Paul AV, Wimmer E (2002). “Chemical synthesis of poliovirus cDNA: generation of infectious virus in the absence of natural template.” Science 297 (5583): 1016–8. DOI:10.1126/science.1072266. PMID 12114528.
5. Bergh O, Børsheim KY, Bratbak G, Heldal M (August 1989). "High abundance of viruses found in aquatic environments." Nature 340 (6233): 467–8. DOI:10.1038/340467a0. PMID 2755508.
6. Elements - science news: By destroying bacterial cells, viruses actively participate in the circulation of substances in the depths of the ocean