The object of study of virology is the cat causative agent of influenza. Virology is the science that studies

To prevent viral infection - smallpox was proposed by an English doctor E. Jenner in 1796, almost a hundred years before the discovery of viruses, the second vaccine - anti-rabies, was proposed by the founder of microbiology L. Pasteur in 1885 - seven years before the discovery of viruses.

The honor of discovering viruses belongs to our compatriot DI. Ivanovsky, who for the first time in 1892 proved the existence of a new type of pathogen using the example of tobacco mosaic disease.

As a student at St. Petersburg University, he traveled to Ukraine and Bessarabia to study the causes of tobacco disease, and then, after graduating from university, he continued his research at the Nikitsky Botanical Garden near Yalta. He found no bacteria in the contents of the affected leaf, but the sap of the diseased plant caused damage to healthy leaves. Ivanovsky filtered the juice of the diseased plant through a Chamberlant candle, the pores of which retained the smallest bacteria. As a result, he discovered that the pathogen passed even through such pores, since the filtrate continued to cause disease in tobacco leaves. Its cultivation on artificial nutrient media turned out to be impossible. DI. Ivanovsky comes to the conclusion that the pathogen has an unusual nature: it is filtered through bacterial filters and is not able to grow on artificial nutrient media. He called the new type of pathogen “filterable bacteria.”

Ivanovsky established that the tobacco disease, widespread in Crimea, is caused by a virus that is highly infectious and has a strictly defined specificity of action. This discovery showed that, along with cellular forms, there are living systems that are invisible in conventional light microscopes, passing through finely porous filters and devoid of cellular structure.

6 years later in 1898 after the discovery of D.I. Ivanovsky Dutch scientist M. Beijerinck confirmed the data obtained by the Russian scientist, coming, however, to the conclusion that the causative agent of tobacco mosaic is liquid living contagion. Ivanovsky did not agree with this conclusion. Thanks to his remarkable research, F. Leffler and P. Frosch in 1897, the viral etiology of foot-and-mouth disease was established and it was shown that the causative agent of foot-and-mouth disease also passes through bacterial filters. Ivanovsky, analyzing these data, came to the conclusion that the agents of foot-and-mouth disease and tobacco mosaic are fundamentally similar. In a dispute with M.V. Beyerinck, Ivanovsky turned out to be right.

Experiments by D.I. Ivanovsky were the basis for his dissertation “On two diseases of tobacco,” presented in 1888, and presented in a book of the same name, published in 1892 This year is considered the year of the discovery of viruses.

Subsequently, the causative agents of many viral diseases of humans, animals and plants were discovered and studied.

Ivanovsky discovered a plant virus. Leffler and Frosch discovered a virus that infects animals. Finally, in 1917 D'Herrel discovered a bacteriophage - a virus that infects bacteria. Thus, viruses cause diseases of plants, animals, and bacteria.

The word “virus” means poison; it was used by Louis Pasteur to denote an infectious principle. Later, the name “ultravirus” or “filtering virus” began to be used, then the definition was discarded, and the term “virus” took root.

In 1892, Pasteur’s contemporary and closest collaborator I.I. Mechnikov N.F. Gamaleya(1859-1949) discovered the phenomenon of spontaneous dissolution of microbes, which, as was established by D'Herelle, was caused by the action of a bacterial virus - a phage.

Under the leadership of I.I. Mechnikova N.F. Gamaleya participated in the creation of the first bacteriological station in Russia and the second Pasteur station in the world. His research is devoted to the study of infection and immunity, bacterial variability, prevention of typhus, smallpox, and other diseases.

In 1935 W. Stanley isolated tobacco mosaic virus (TMV) in crystalline form from tobacco juice infected with mosaic disease. For this he was awarded the Nobel Prize in 1946.

In 1958 R. Franklin and K. Holm, while studying the structure of the ETM, they discovered that the ETM is a hollow cylindrical formation.

In 1960 Gordon and Smith found that some plants are infected with free TMV nucleic acid, rather than the whole nucleotide particle. In the same year, a prominent Soviet scientist L.A. Zilber formulated the main provisions of the virus genetic theory.

In 1962, American scientists A. Siegel, M. Tseitlin and O. I. Zegal experimentally obtained a variant of TMV that does not have a protein shell, and found that in defective TMV particles the proteins are arranged randomly, and the nucleic acid behaves like a full-fledged virus.

In 1968 R. Shepard discovered a DNA virus.

One of the largest discoveries in virology is the discovery of most of the structures of various viruses, their genes and encoding enzymes - reverse transcriptase. The purpose of this enzyme is to catalyze the synthesis of DNA molecules on a molecule template.

In the development of virology, a major role belongs to domestic scientists: I.I. Mechnikov (1845-1916), N.F. Gamaleya (1859-1949), L.A. Zilber (1894-1966), V.M. Zhdanov (1914-1987), Z.V. Ermolyeva (1898-1979), A.A. Smorodintsev (1901-1989), M.P. Chumakov (1909-1990) and others.

In virology, several periods of development are considered.

PERIODS OF DEVELOPMENT OF VIRUSOLOGY

Rapid progress in the field of virological knowledge, based largely on the achievements of related natural sciences, has made it possible to in-depth knowledge of the nature of viruses. Like no other science, virology demonstrates a rapid and clear change in levels of knowledge - from the level of the organism to the submolecular.

The given periods of development of virology reflect those levels that were dominant for one to two decades.

Level of the organism (30-40s of the XX century).

The main experimental model is laboratory animals (white mice, rats, rabbits, hamsters, monkeys, etc.), the main first model virus was .

In the 1940s, chicken embryos were firmly established as an experimental model in virology. They were highly sensitive to influenza viruses and some others. The use of this model was made possible thanks to the research of an Australian virologist and immunologist F. Bernet, author of the first textbook on virology, “The Virus as an Organism.” In 1960 F. Burnet and P. Medawar awarded the Nobel Prize in Virology.

Discovery in 1941 by an American virologist Hurst The phenomenon of hemagglutination greatly contributed to the study of the interaction of the virus with the cell using the influenza virus model and.

The great contribution of domestic virologists to medical virology was the study of natural focal diseases -. In 1937, the first expedition was organized, headed by Zilber, which included Levkovich, Shubladze, Chumakov, Solovyov, etc. Thanks to the research, the tick-borne encephalitis virus was discovered and its carriers were identified - ixodidae, methods of laboratory diagnosis, prevention and treatment have been developed. Soviet virologists studied viral hemorrhagic diseases and developed drugs for diagnostic, treatment and prophylactic purposes.

Cell level (40-50s of the XX century).

In 1949, a significant event occurred in the history of virology - the discovery of the possibility of cultivating cells under artificial conditions. In 1952 J. Enders, T. Weller, F. Robbins received the Nobel Prize for developing a cell culture method. The use of cell culture in virology was a truly revolutionary event, which served as the basis for the isolation of numerous new viruses, their identification, cloning, and the study of their interaction with cells. It became possible to obtain cultured vaccines. This possibility has been proven using the example of a vaccine against. In collaboration with American virologists J. Salcom and A. Sabin, Soviet virologists M.P. Chumakov, A.A. Smorodintsev and others, a production technology was developed, killed and live vaccines against. In 1959, mass immunization of the child population in the USSR (about 15 million) with live polio vaccine was carried out, as a result of which the incidence of polio sharply decreased and paralytic forms of the disease practically disappeared. In 1963, for the development and implementation of live polio vaccine, M.P. Chumakov and A.A. Smorodintsev was awarded the Lenin Prize. In 1988, she decided to globally eradicate polio. This disease has not been registered in Russia since 2002.

Another important application of the virus cultivation technique was the production J. Enders and Smorodintsev live vaccine, the widespread use of which has led to a significant reduction in the incidence of measles and is the basis for the eradication of this infection.

Other culture-based vaccines were also widely introduced into practice - encephalitis, foot-and-mouth disease, rabies, etc.

Molecular level (50-60s of the XX century).

In virology, methods of molecular biology began to be widely used, and viruses, due to the simple organization of their genome, became a common model for molecular biology. Not a single discovery of molecular biology is complete without a viral model, including the genetic code, the entire mechanism of intracellular genome expression, DNA replication, information processing (maturation), etc.

In turn, the use of molecular methods in virology has made it possible to establish the principles of the structure (architecture) of viral individuals - methods of penetration of viruses into cells and their reproduction.

Submolecular level (70-80s of the XX century).

The rapid development of molecular biology opens up the possibility of studying the primary structure of nucleic acids and proteins. Methods for DNA sequencing and determination of protein amino acid sequences are emerging. The first genetic maps of the genomes of DNA viruses are being obtained.

In 1970, D. Baltimore and simultaneously G. Temin and S. Mizutani discovered reverse transcriptase in RNA-containing oncogenic viruses, an enzyme that transcribes DNA. Gene synthesis using this enzyme on a matrix isolated from polysome mRNA becomes real. It becomes possible to rewrite RNA into DNA and sequence it.

In 1972, a new branch of molecular biology emerged - genetic engineering. This year, a report by P. Berg was published in the USA on the creation of a recombinant DNA molecule, which marked the beginning of the era of genetic engineering. It becomes possible to obtain a large number of nucleic acids and proteins by introducing recombinant DNA into the genome of prokaryotes and simple eukaryotes. One of the main practical applications of the new method is the production of cheap protein preparations that are important in medicine (interferon) and agriculture (cheap protein feed for livestock).

This period is characterized by important discoveries in the field of medical virology. The study focuses on the three most widespread diseases that cause enormous damage to people's health and the national economy - cancer, hepatitis.

Another Nobel Prize in 1976 was awarded to the American scientist K. Gajdushek, who established the viral etiology of one of the slow human infections - kuru, observed in one of the native tribes on the island of New Guinea and associated with a ritual rite - eating the infected brain of deceased relatives.

Since the second half of the 80s, virologists have been actively involved in the development of the problem of HIV infection that unexpectedly arose in the world. This was facilitated by the significant experience of domestic scientists working with retroviruses.

Medical microbiology, virology and largely owe research to domestic scientists such as N.F. Gamaleya (1859-1949), P.F. Zdrodovsky (1890-1976), L.A. Zilber (1894-1966), D.I. Ivanovsky (1864-1920), L.A. Tarasevich (1869-1927), V.D. Timakov (1904-1977), E.I. Martsinovsky (1874-1934), V.M. Zhdanov (1914-1987), Z.V. Ermolyeva (1898-1979), A.A. Smorodintsev (1901-1989), M.P. Chumakov (1909-1990), P.N. Kashkin (1902-1991), B.P. Pervushin (1895-1961) and many others.

SCIENTIFIC VIROLOGICAL INSTITUTIONS

The first virological laboratories in our country were created in the 30s: in 1930 - a laboratory for the study of plant viruses at the Ukrainian Institute of Plant Protection, in 1935 - a department of viruses at the Institute of Microbiology of the USSR Academy of Sciences, and in 1938 it was reorganized into the Department of Plant Viruses, which was headed by V.L. for many years. Ryzhkov. In 1935, the Central Virological Laboratory of the People's Commissariat of Health of the RSFSR was organized in Moscow, headed by L.A. Zilber, and in 1938 this laboratory was reorganized into the department of viruses of the All-Union Institute of Experimental Medicine, A.A. was appointed its head. Smorodintsev. In 1946, on the basis of the Department of Viruses, the Institute of Virology of the USSR Academy of Medical Sciences was created, which in 1950 was named after D.I. Ivanovsky.

During the 50s and 60s, scientific and industrial virological institutions were created in our country: Institute of Viral Encephalitis of the USSR Academy of Medical Sciences, Institute of Viral Preparations of the USSR Ministry of Health, Kiev Institute of Infectious Diseases, All-Union Research Institute of Influenza of the USSR Ministry of Health in Leningrad and a number of others.

An important role in the training of virologists was played by the organization in 1955 of the Department of Virology at the Central Institute for Advanced Training of Physicians of the USSR Ministry of Health. Departments of virology were created at the biological faculties of Moscow and Kyiv universities.

VIROLOGY

Virology is a branch of biology that studies viruses(from the Latin word virus - poison).

The existence of a virus (as a new type of pathogen) was first proven in 1892 by the Russian scientist D.I. Ivanovsky. 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 disease is caused by “bacteria passing through the Chamberlant filter, which, however, are not able to grow on artificial substrates.” Based on these data, the criteria were determined by which pathogens were classified into this new group: filterability through “bacterial” filters, inability to grow on artificial media, and reproduction of the disease picture with a filtrate free of bacteria and fungi. The causative agent of mosaic disease is called by D.I. Ivanovsky in different ways, the term virus had not yet been introduced, allegorically they were called either “filterable bacteria” or simply “microorganisms”.

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 1901, the first human viral disease was discovered - yellow fever. This discovery was made by the American military surgeon W. Reed and his colleagues.

In 1911, Francis Rous proved the viral nature of cancer - Rous sarcoma (only in 1966, 55 years later, he was awarded the Nobel Prize in Physiology or Medicine for this discovery).

^ Stages of development of virology

The given periods of development of virology reflect those levels that were dominant for one to two decades.

^ Body level (30-40s of the XX century). The main experimental model is laboratory animals (white mice, rats, rabbits, hamsters, etc.), the main model virus is the influenza virus.

In the 40s, chicken embryos were firmly established in virology as an experimental model due to their high sensitivity to influenza viruses, smallpox and some others. The use of this model became possible thanks to the research of the Australian virologist and immunologist F. M. Burnet, author of the virology manual “Virus as an Organism.”

The discovery of the phenomenon of hemagglutination by the American virologist Hurst greatly contributed to the study of the interaction of the virus with the cell using the model of the influenza virus and red blood cells.

^ Cell level(50s). A significant event is taking place in the history of virology - the discovery of the possibility of culturing cells under artificial conditions. W. J. Enders, T. Weller, F. Robbins received the Nobel Prize for developing the cell culture method. The use of cell culture in virology was a truly revolutionary event, which served as the basis for the isolation of numerous new viruses, their identification, cloning, and the study of their interaction with cells. It became possible to obtain cultured vaccines. This possibility has been proven using the polio vaccine. In collaboration with American virologists J. Salk and A. Seibin, Soviet virologists M. P. Chumakov, A. A. Smorodintsev and others, a production technology was developed, killed and live vaccines against polio were tested and put into practice. Mass immunization of the child population in the USSR (about 15 million) with live polio vaccine was carried out, as a result the incidence of polio sharply decreased and paralytic forms of the disease practically disappeared. For the development and implementation of the live polio vaccine, M. P. Chumakov and A. A. Smorodintsev were awarded the Lenin Prize. Another important application of the virus cultivation technique was the production of live measles vaccine by J. Enders and A. A. Smorodintsev, the widespread use of which led to a significant reduction in the incidence of measles and is the basis for the eradication of this infection.

Other culture-based vaccines were also widely introduced into practice - encephalitis, foot-and-mouth disease, rabies, etc.

^ Molecular level (60s). In virology, methods of molecular biology began to be widely used, and viruses, due to the simple organization of their genome, became a common model for molecular biology. Not a single discovery of molecular biology is complete without a viral model, including the genetic code, the entire mechanism of intracellular genome expression, DNA replication, processing (maturation) of messenger RNAs, etc. In turn, the use of molecular methods in virology has made it possible to establish the principles of structure (architecture) viral individuals - virions (a term introduced by the French microbiologist A. Lvov), methods of penetration of viruses into the cell and their reproduction.

^ Submolecular level (70s). The rapid development of molecular biology opens up the possibility of studying the primary structure of nucleic acids and proteins. Methods for DNA sequencing and determination of protein amino acid sequences are emerging. The first genetic maps of the genomes of DNA viruses are being obtained.

D. Baltimore and at the same time G. Temin and S. Mizutani discovered reverse transcriptase in RNA-containing oncogenic viruses, an enzyme that transcribes RNA into DNA. Gene synthesis using this enzyme on a matrix isolated from polysome mRNA becomes real. It becomes possible to rewrite RNA into DNA and sequence it.

A new branch of molecular biology is emerging - genetic engineering. This year, a report by P. Berg was published in the USA on the creation of a recombinant DNA molecule, which marked the beginning of the era of genetic engineering. It becomes possible to obtain a large number of nucleic acids and proteins by introducing recombinant DNA into the genome of prokaryotes and simple eukaryotes. One of the main practical applications of the new method is the production of cheap protein preparations that are important in medicine (insulin, interferon) and agriculture (cheap protein feed for livestock). This period is characterized by important discoveries in the field of medical virology. The study focuses on the three most widespread diseases that cause enormous damage to people's health - influenza, cancer, and hepatitis.

The causes of regularly recurring influenza pandemics have been established. Cancer viruses of animals (birds, rodents) have been studied in detail, the structure of their genome has been established, and the gene responsible for the malignant transformation of cells, the oncogene, has been identified. It has been established that hepatitis A and B are caused by different viruses: hepatitis A is caused by an RNA-containing virus classified as a member of the picornavirus family, and hepatitis B is caused by a DNA-containing virus classified as a member of the hepadnavirus family. G. Blumberg, while studying blood antigens among the aborigines of Australia, discovered the so-called Australian antigen, which he mistook for one of the blood antigens. Later it was revealed that this antigen is the hepatitis B antigen, carriage of which is common in all countries of the world. For the discovery of the Australian antigen, G. Blumberg was awarded the Nobel Prize. Another Nobel Prize was awarded to the American scientist K. Gaidushek, who established the viral etiology of one of the slow human infections - kuru, observed in one of the native tribes on the island of New Guinea and associated with a ritual rite - eating the infected brain of deceased relatives. Thanks to the efforts of K. Gaidushek, who settled on the island of New Guinea, this tradition was eradicated and the number of patients decreased sharply.

^ Nature of viruses

General virology

General virology studies the basic principles of the structure and reproduction of viruses, their interaction with the host cell, the origin and distribution of viruses in nature. One of the most important branches of general virology is molecular virology, which studies the structure and functions of viral nucleic acids, mechanisms of viral gene expression, the nature of organisms’ resistance to viral diseases, and the molecular evolution of viruses.

Private virology

Private virology studies the characteristics of certain groups of human, animal and plant viruses and develops measures to combat the diseases caused by these viruses.

Molecular virology

In 1962, virologists from many countries gathered at a symposium in the USA to summarize the first results of the development of molecular virology. At this symposium, terms that were not entirely familiar to virologists were used: virion architecture, nucleocapsids, capsomeres. A new period in the development of virology began - the period of molecular virology. Molecular virology, or molecular biology of viruses, is an integral part of general molecular biology and at the same time a branch of virology. This is not surprising. Viruses are the simplest forms of life, and therefore it is only natural that they have become both objects of study and tools of molecular biology. Using their example, one can study the fundamental principles of life and its manifestations.

Since the late 50s, when a synthetic field of knowledge began to take shape, lying on the border of the inanimate and the living and engaged in the study of the living, the methods of molecular biology poured into virology in an abundant stream. These methods, based on the biophysics and biochemistry of living things, made it possible to quickly study the structure, chemical composition and reproduction of viruses.

Since viruses are ultra-small objects, ultra-sensitive methods are needed to study them. Using an electron microscope, it was possible to see individual viral particles, but their chemical composition can only be determined by collecting trillions of such particles together. Ultracentrifugation methods have been developed for this purpose. Modern ultracentrifuges are complex devices, the main part of which is rotors that rotate at speeds of tens of thousands of revolutions per second.

There is no need to talk about other methods of molecular virology, especially since they change and improve from year to year at a rapid pace. If in the 60s the main attention of virologists was fixed on the characteristics of viral nucleic acids and proteins, then by the beginning of the 80s the complete structure of many viral genes and genomes was deciphered and not only the amino acid sequence was established, but also the tertiary spatial structure of such complex proteins , as a glycoprotein of influenza virus hemagglutinin. Currently, it is possible not only to associate changes in the antigenic determinants of the influenza virus with the replacement of amino acids in them, but also to calculate past, present and future changes in these antigens.

Since 1974, a new branch of biotechnology and a new branch of molecular biology - genetic or genetic engineering - began to develop rapidly. She was immediately assigned to the service of virology.

^ Families including human and animal viruses

Family: Poxviridae (poxviruses)

Family: Iridoviridae (iridoviruses)

Family: Herpesviridae (herpes viruses)

Family: Aflenoviridae (adenoviruses)

Family: Papovaviridae (papovaviruses)

Putative family: Hepadnaviridae (hepatitis B virus-like viruses)

Family: Parvoviridae (parvoviruses)

Family: Reoviridae (reoviruses)

Proposed family: (double-stranded RNA viruses consisting of two segments)

Family: Togaviridae (togaviruses)

Family: Coronaviridae (coronaviruses)

Family: Paramyxoviridae (paramyxoviruses)

Family: Rhabdoviridae (rhabdoviruses)

Putative family: (Filoviridae) (Mapburg and Ebola viruses)

Family: Orthomyxoviridae (influenza viruses)

Family: Bunyaviridae (buyaviruses)

Family: Arenaviridae (arenaviruses)

Family: Retroviridae (retroviruses)

Family: Picornaviridae (picornaviruses)

Family: Caliciviridae (calciviruses)
^

http://9school.3dn.ru/news/obrashhenie_direktora_shkoly/2009-11-27-159

http://www.bajena.com/ru/articles/1085/flu-2/

Flu

Flu(Italian influenza, Latin influentia, literally - influence, Greek Γρίππη) is an acute infectious disease of the respiratory tract caused by the influenza virus. Included in the group of acute respiratory viral infections (ARVI). Periodically spreads in the form of epidemics and pandemics. Currently, more than 2000 variants of the influenza virus have been identified, differing in their antigenic spectrum.

Often, the word “flu” in everyday life is also used to refer to any acute respiratory disease (ARVI), which is erroneous, since in addition to influenza, more than 200 types of other respiratory viruses (adenoviruses, rhinoviruses, respiratory principle viruses, etc.) have been described to date, causing influenza-like illnesses. diseases in humans. Presumably, the name of the disease comes from the Russian word “wheezing” - the sounds made by patients. During the Seven Years' War (1756–1763), this name spread into European languages, denoting the disease itself rather than a separate symptom.

A micrograph of an influenza virus taken using an electron transmission microscope, magnified approximately one hundred thousand times.
^

Influenza virus

The influenza virus belongs to the family of orthomyxoviridae (lat. Orthomyxoviridae) and includes three serovars A, B, C. Viruses of serovars A and B constitute one genus, and serotype C forms another. Each serovar has its own antigenic characteristics, which are determined by nucleoprotein (NP) and matrix (M) protein antigens. Serovar A includes subtypes that differ in their hemagglutinin (H) and neuraminidase (N) characteristics. Viruses of serovar A (less often B) are characterized by frequent changes in the antigenic structure when they remain in natural conditions. These changes lead to many subtype names, which include the place of primary appearance, number and year of isolation, HN characteristics - for example A/Moscow/10/99 (H3N2), A/New Caledonia/120/99 (H1N1), B/Hong Kong/ 330/2001.

The influenza virus has a spherical shape with a diameter of 80-120 nm, in the center there are RNA fragments enclosed in a lipoprotein shell, on the surface of which there are “spikes” consisting of hemagglutinin (H) and neuraminidase (N). Antibodies produced in response to hemagglutinin (H) form the basis of immunity against a specific subtype of influenza pathogen.

Spreading

All age categories of people are susceptible to influenza. The source of infection is a sick person with an obvious or erased form of the disease, releasing the virus by coughing, sneezing, etc. The patient is contagious from the first hours of the disease until the 3-5th day of illness. It is characterized by an aerosol (inhalation of tiny drops of saliva, mucus that contain the influenza virus) transmission mechanism and extremely rapid spread in the form of epidemics and pandemics. Influenza epidemics caused by serotype A occur approximately every 2-3 years, and those caused by serotype B occur every 4-6 years. Serotype C does not cause epidemics, only isolated outbreaks in children and weakened people. It occurs more often in the form of epidemics in the autumn-winter period. The frequency of epidemics is associated with frequent changes in the antigenic structure of the virus when it remains in natural conditions. High-risk groups are children, the elderly, pregnant women, people with chronic heart disease, lung disease, and individuals with chronic renal failure.

History of epidemics, serotype A

Influenza has been known since the end of the 16th century.

Year Subtype Distribution

1889-1890 H2N8 Severe epidemic

1900-1903 H3N8 Moderate epidemic

1918-1919 H1N1 Severe pandemic (Spanish flu)

1933-1935 H1N1 Medium epidemic

1946-1947 H1N1 Medium epidemic

1957-1958 H2N2 Severe pandemic (Asian flu)

1968-1969 H3N2 Mild pandemic (Hong Kong flu)

1977-1978 H1N1 Medium pandemic

1995-1996 H1N1 and H3N2 Severe pandemic

2009 H1N1 Mild pandemic (Swine flu)

Development of the disease - pathogenesis

The entry gates for the influenza virus are the cells of the ciliated epithelium of the upper respiratory tract - the nose, trachea, and bronchi. The virus multiplies in these cells and leads to their destruction and death. This explains irritation of the upper respiratory tract, coughing, sneezing, and nasal congestion. Penetrating into the blood and causing viremia, the virus has a direct, toxic effect, manifested in the form of fever, chills, myalgia, and headache. In addition, the virus increases vascular permeability, causes the development of stasis and plasma hemorrhages. It can also cause inhibition of the body’s defense systems, which leads to secondary infection and complications.

Pathological anatomy

Throughout the entire tracheobronchial tree, detachment of the epithelium, the formation of arcade-shaped structures of the epithelium of the trachea and bronchi due to uneven edema and vacuolization of the cytoplasm and signs of exudative inflammation are observed. A common characteristic symptom is hemorrhagic tracheobronchitis of varying severity. In foci of influenza pneumonia, the alveoli contain serous exudate, erythrocytes, leukocytes, and alveolocytes. In areas of inflammation, vascular thrombosis and necrosis are common.

Clinical picture

Symptoms of influenza are not specific, that is, without special laboratory tests (isolation of the virus from throat swabs, direct and indirect immunofluorescence on smears of the epithelium of the nasal mucosa, a serological test for the presence of anti-influenza antibodies in the blood), it is impossible to reliably distinguish influenza from other acute respiratory viral infections. In practice, the diagnosis of “influenza” is established on the basis only of epidemic data, when there is an increase in the incidence of ARVI among the population of a given area. The difference between the diagnoses of “flu” and “ARVI” is not fundamental, since the treatment and consequences of both diseases are identical, the differences lie only in the name of the virus that caused the disease. The flu itself is one of the Acute Respiratory Viral Infections.

The incubation period can range from several hours to 3 days, usually 1-2 days. The severity of the disease varies from mild to severe hypertoxic forms. Some authors indicate that a typical influenza infection usually begins with a sharp rise in body temperature (up to 38 ° C - 40 ° C), which is accompanied by chills, fever, muscle pain, headache and a feeling of fatigue. As a rule, there is no discharge from the nose; on the contrary, there is a pronounced feeling of dryness in the nose and throat. Usually a dry, tense cough appears, accompanied by pain in the chest. With a smooth course, these symptoms persist for 3-5 days, and the patient recovers, but for several days a feeling of severe fatigue persists, especially in elderly patients. In severe forms of influenza, vascular collapse, cerebral edema, hemorrhagic syndrome develop, and secondary bacterial complications occur. Clinical findings during an objective examination are not pronounced - only hyperemia and swelling of the mucous membrane of the pharynx, pallor of the skin, injected sclera. It should be said that influenza poses a great danger due to the development of serious complications, especially in children, elderly and weakened patients.

Complications of influenza

The incidence of complications of the disease is relatively low, but if they develop, they can pose a significant danger to the patient’s health. Moderate, severe and hypertoxic forms of influenza can cause serious complications. The causes of complications with influenza may be the following features of the infectious process: the influenza virus has a pronounced capillary-toxic effect, is capable of suppressing the immune system, and destroys tissue barriers, thereby facilitating tissue aggression by resident flora.

^ There are several main types of complications from influenza:

Pulmonary: bacterial pneumonia, hemorrhagic pneumonia, lung abscess formation, empyema formation.

Extrapulmonary: bacterial rhinitis, sinusitis, otitis, tracheitis, viral encephalitis, meningitis, neuritis, radiculoneuritis, liver damage, Reye's syndrome, myocarditis, toxic-allergic shock.

Most often, deaths from influenza occur among children under 2 years of age and elderly people over 65 years of age.

Treatment

Until recently, treatment was usually symptomatic, in the form of antipyretics, expectorants, and antitussives, as well as vitamins, especially vitamin C in large doses. The CDC recommends that patients rest, drink plenty of fluids, and avoid smoking and drinking alcohol.

^ Immune-stimulating drugs

Prevention and early treatment of colds with high doses of vitamin C (ascorbic acid) was advocated by Linus Pauling, a two-time Nobel Prize winner. Thanks to his authority, this method became widespread. It is usually recommended to take no more than 1g of ascorbic acid per day.

There are also a number of more modern immunostimulants that can be used for prevention and treatment in the early stages of influenza. Among them are arbidol (a relatively weak immunomodulator) and groprinosin (a stronger immunomodulator, the use of which requires medical supervision).

^ Antiviral drugs

It is assumed that antiviral drugs that act on one or another phase of the development of a viral infection in vitro can also show effectiveness in vivo, especially as a prophylactic agent. In general, treatment with antiviral drugs should begin before the onset of clinical manifestations of influenza; starting them later is practically ineffective.

^ Neuraminidase inhibitors

One of the drugs that has proven effectiveness in treating influenza is oseltamivir ( Tamiflu) and zanamivir ( Relenza). These neuraminidase inhibitors are effective against many strains of influenza, including avian influenza. These drugs suppress the spread of the virus in the body, reduce the severity of symptoms, shorten the duration of the disease and reduce the incidence of secondary complications. However, there is evidence that these drugs cause a number of side effects, such as nausea, vomiting, diarrhea, as well as mental disorders: impaired consciousness, hallucinations, psychosis.

Immunoglobulins

Special strictly controlled studies have shown that only donor serum and anti-influenza gamma globulin, containing high titers of antibodies, have a clear antiviral and therapeutic effect on influenza. Gamma globulin should be prescribed intramuscularly as soon as possible: children 0.15-0.2 ml/kg, adults 6 ml. In the same doses, normal (placental) gamma globulin and serum polyglobulin can be used.

^ Interferon preparations

This substance has antiviral and immunostimulating effects. Interferons are most effective in the initial phase (first three days) of the disease.

^ Symptomatic treatment

To facilitate nasal breathing, naphthyzine, sanorin, and galazolin are effective. However, they should not be used regularly, but as needed (when the nose is stuffy), otherwise bleeding will occur.

^ Flu prevention

The traditional way to prevent influenza is vaccination. It is carried out with an influenza vaccine corresponding to the leading strain and, as a rule, contains antigens of three strains of influenza virus, which are selected based on the recommendations of the World Health Organization. A vaccine for the prevention of influenza has been proposed in the form of a liquid, killed, subjective vaccine. Vaccination is especially indicated in risk groups - children, elderly people, patients with chronic heart and lung diseases, as well as doctors. It is usually carried out when the epidemiological forecast indicates the advisability of mass events (usually in mid-autumn). A second vaccination is also possible in the middle of winter.

The effectiveness of vaccination depends on how well the creators can predict the strains circulating in a given epidemiological season. In addition to vaccination, intrazonal administration of interferon is used for emergency prevention of influenza and Acute Respiratory Viral Infection. This method is used if there is a fear of getting sick after contact with patients with a respiratory infection, during an epidemic rise in incidence. In this case, interferon blocks the replication of viruses at the site of their introduction into the nasal cavity.

As a non-specific prophylaxis, wet cleaning is carried out in the room where the flu patient is located using any disinfectant that has a virucidal effect. Ultraviolet irradiation, aerosol disinfectors and catalytic air purifiers are used to disinfect the air. Patients who sneeze and cough are dangerous to others. Prevention of influenza must necessarily include removing them from public places (by calling for people to be conscious). There are often cases of going to court against patients who came to work while still on sick leave.

Forecast

With uncomplicated influenza, the prognosis is favorable. In severe cases of influenza and complications, death may occur.

^ SWINE FLU

WITH Blame the flu(English: Swine flu) is the conventional name for a disease in humans and animals caused by strains of the influenza virus. The title was widely circulated in the media in early 2009. Strains associated with outbreaks of the so-called. “swine flu”, found among influenza viruses of serotype C and subtypes of serotype A (A/H1N1, A/H1N2, A/H3N1, A/H3N2 and A/H2N3). These strains are known collectively as swine flu virus. Swine flu is common among domestic pigs in the United States, Mexico, Canada, South America, Europe, Kenya, mainland China, Taiwan, Japan and other Asian countries. In this case, the virus can circulate among people, birds and other species; this process is accompanied by its mutations.

^ A/H1N1 virus under an electron microscope. The diameter of the virus is 80-120 nm.

Epidemiology

Transmission of the virus from animal to human is rare, and properly cooked (heat-treated) pork cannot be a source of infection. When transmitted from animals to humans, the virus does not always cause disease and is often detected only by the presence of antibodies in human blood. Cases where transmission of the virus from an animal to humans leads to illness are called zoonotic swine flu. People who work with pigs are at risk of contracting the disease, but only about 50 such cases have been reported since the mid-1920s (when influenza virus subtypes first became possible to identify). Some of the strains that have caused disease in humans have become capable of being transmitted from person to person. Swine flu causes symptoms in humans that are typical of influenza and ARVI. The swine flu virus is transmitted both through direct contact with infected organisms and by airborne droplets (see Mechanism of transmission of the infectious agent).

Etiology

Swine flu symptoms. The 2009 outbreak of a new strain of influenza virus, known as “swine flu,” was caused by the H1N1 subtype of virus, which is most genetically similar to the swine flu virus. The origin of this strain is not precisely known. However, the World Organization for Animal Health reports that epidemic spread of the virus of the same strain could not be established among pigs. Viruses of this strain are transmitted from person to person and cause illness with symptoms common to the flu. Pigs can be infected with the human influenza virus, and this is what may have happened during both the Spanish flu pandemic and the 2009 outbreak.

Pathogenesis

In general, the mechanism of action of this virus is similar to that of other strains of the influenza virus. The entry gate of infection is the epithelium of the mucous membranes of the human respiratory tract, where its replication and reproduction occur. Superficial damage to the cells of the trachea and bronchi is observed, characterized by processes of degeneration, necrosis and rejection of the affected cells.

The development of the pathological process is accompanied by viremia, lasting 10–14 days, with a predominance of toxic and toxic-allergic reactions from internal organs, primarily the cardiovascular and nervous systems. The main link in the pathogenesis is damage to the vascular system, manifested by increased permeability and fragility of the vascular wall, and impaired microcirculation. These changes manifest themselves in patients with the appearance of rhinorrhagia (nosebleeds), hemorrhages on the skin and mucous membranes, hemorrhages in the internal organs, and also lead to the development of pathological changes in the lungs: edema of the lung tissue with multiple hemorrhages in the alveoli and interstitium. A decrease in vascular tone leads to venous hyperemia of the skin and mucous membranes, congestive plethora of internal organs, impaired microcirculation, diapedetic hemorrhages, and in later stages - thrombosis of veins and capillaries. These vascular changes also cause hypersecretion of cerebrospinal fluid with the development of circulatory disorders leading to intracranial hypertension and cerebral edema.

Clinic

The main symptoms are the same as the usual flu symptoms - headache, fever, cough, vomiting, diarrhea, runny nose. A significant role in the pathogenesis is played by damage to the lungs and bronchi due to increased expression of a number of factors - inflammatory mediators (TLR-3, γ-IFN, TNFα, etc.), which leads to multiple damage to the alveoli, necrosis and hemorrhage. The high virulence and pathogenicity of this strain of the virus can be due to the ability of the non-structural protein NS1 (inherent in this virus) to inhibit the production of type I interferons by infected cells. Viruses defective in this gene are significantly less pathogenic.

Diagnostics

Clinically, the course of this disease generally coincides with the course of the disease when infected with other strains of the influenza virus. A reliable diagnosis is established by serotyping the virus

Prevention

For the purpose of primary specific prevention (primarily for persons at risk), the Russian Federation and abroad are accelerating the development and registration of specific vaccines based on the isolated strain of the pathogen. Epidemiologists also welcome vaccination against “seasonal” flu, which contains antibodies against damaging agents (proteins) of three types of virus that differ from the “swine” strain.

The WHO advisory on highly pathogenic influenza states the need to avoid close contact with people who “appear unwell, have a fever and a cough.” It is recommended to wash your hands thoroughly and frequently with soap. “Adopt a healthy lifestyle, including getting enough sleep, eating healthy foods, and being physically active.” With proper heat treatment, the virus dies. Primary non-specific prevention is aimed at preventing the virus from entering the body, and at strengthening the non-specific immune response to prevent the development of the disease.

Treatment

Treatment of a disease caused by strains of the swine flu virus is essentially no different from the treatment of the so-called “seasonal” flu. In case of severe symptoms of intoxication and disturbances of the acid-base balance, detoxification and corrective therapy is carried out. Of the drugs that act on the virus itself and its reproduction, the effectiveness of Oseltamivir (Tami-Flu) has been proven. In its absence, WHO experts recommend the drug Zanamivir (Relenza); in case of a relatively mild course of the disease, doctors in post-Soviet countries recommend Arbidol, despite the fact that it is a drug with unproven effectiveness, and the WHO does not consider it at all as an antiviral drug. Treatment of severe and moderate cases is aimed at preventing primary viral pneumonia, which is usually severe and causes hemorrhage and severe respiratory failure, and at preventing the addition of a secondary bacterial infection, which also often causes the development of pneumonia.

Symptomatic therapy is also indicated. Among antipyretic drugs, most experts recommend drugs containing ibuprofen and paracetamol (it is not recommended to use drugs containing aspirin due to the risk of developing Reye's syndrome.

Urgent contact with medical institutions (calling an ambulance) is necessary for signs of severe respiratory failure, depression of brain activity and dysfunction of the cardiovascular system: shortness of breath, shortness of breath, cyanosis (blue skin), fainting, the appearance of colored sputum, low blood pressure, chest pain.

A mandatory visit to a doctor (usually to a local clinic) is necessary in case of a high temperature that does not decrease on the 4th day, or a marked deterioration of the condition after a temporary improvement.

A number of new antiviral drugs are currently being studied, incl. Peramivir.

Recommendations for the prevention and treatment of influenza from the Ministry of Health and Social Development of the Russian Federation.

The Ministry of Health and Social Development of the Russian Federation has released “Temporary guidelines for the treatment and prevention of influenza A/H1N1.”

Temporary guidelines for the treatment and prevention of influenza caused by the A/H1N1 virus for adults and children were prepared jointly with leading research institutes of the Russian Academy of Medical Sciences, the Influenza Research Institute, the Institute of Epidemiology and Microbiology named after. N.F. Gamaleya and the Federal State Institution “Research Institute of Childhood Infections” and the Research Institute of Pulmonology of the Federal Medical and Biological Agency of Russia.

Epidemics caused by the H1N1 influenza virus

Pandemic in 1918 - “Spanish Flu”

Main article: Spanish flu

The Spanish flu or "Spanish flu" (French: La Grippe Espagnole, or Spanish: La Pesadilla) was most likely the worst influenza pandemic in the history of mankind. In 1918-1919, approximately 50-100 million people died from the Spanish flu worldwide. About 400 million people, or 21.5% of the world's population, were infected. The epidemic began in the last months of the First World War and quickly eclipsed this largest bloodshed in terms of casualties.

1976 influenza outbreak

1988 flu outbreak

2007 influenza outbreak

On August 20, 2007, the Philippine Department of Agriculture reported an outbreak of H1N1 influenza in swine farms in Nueva Ecija province and central Luzon.

Influenza A/H1N1 pandemic 2009. Outbreak of the H1N1 influenza virus in 2009.

In April-May 2009, an outbreak of a new strain of influenza virus was observed in Mexico and the United States. The World Health Organization (WHO) and the US Centers for Disease Control and Prevention (CDC) have expressed serious concern about this new strain due to the potential for human-to-human transmission, the high mortality rate in Mexico, and because this strain could develop into a flu pandemic. On April 29, at an emergency meeting, WHO increased the level of pandemic threat from 4 to 5 points (out of 6 possible).

As of August 27, 2009, there have been approximately 255,716 cases of influenza A/H1N1 infections and 2,627 deaths reported in more than 140 regions around the world. In general, the disease with this flu proceeds according to the classical scenario, the frequency of complications and deaths (usually due to pneumonia) does not exceed the average for seasonal flu.

At the moment, there is debate around what to call this strain of influenza. So, on April 27, 2009, “swine flu” was called “California 04/2009”; on April 30, pork producers advocated renaming “swine flu” to “Mexican”; a clear non-scientific name has not yet been invented.

The fifth threat level was announced at the end of April 2009: in accordance with the WHO classification, this level is characterized by the spread of the virus from person to person in at least two countries in the same region.

On June 11, 2009, WHO declared a swine flu pandemic, the first pandemic in 40 years. On the same day, he was assigned the sixth degree of threat (out of six). The WHO threat level does not characterize the pathogenicity of the virus (that is, the danger of the disease to human life), but indicates its ability to spread. Thus, any flu transmitted from person to person reaches the sixth degree of threat.

However, WHO's concerns are related to the genetic novelty of the California strain and its potential for further reassortment, which could result in the emergence of more aggressive variants of the infection. Then, by analogy with the most destructive pandemics of the last century, this virus will lead to serious human losses after a certain (usually six-month) period, accompanied by relatively moderate mortality.

Spanish flu or "Spanish flu"

(French: La Grippe Espagnole, or Spanish: La Pesadilla) was most likely the worst influenza pandemic in human history. In 1918-1919 (18 months), approximately 50-100 million people, or 2.7-5.3% of the world's population, died from the Spanish flu worldwide. About 500 million people, or 21.5% of the world's population, were infected. The epidemic began in the last months of the First World War and quickly eclipsed this largest bloodshed in terms of casualties.

Picture of the disease, name “Spanish flu”

The Spanish flu virus is similar to the H1N1 virus that caused the 2009 pandemic. In May 1918, 8 million people or 39% of its population were infected in Spain (King Alfonso XIII also suffered from the Spanish flu). Many flu victims were young and healthy people in the 20-40 age group (usually only children, the elderly, pregnant women and people with certain medical conditions are at high risk).

Symptoms of the disease: blue complexion - cyanosis, pneumonia, bloody cough. In later stages of the disease, the virus caused intrapulmonary hemorrhage, which resulted in the patient choking on his own blood. But mostly the disease passed without any symptoms. Some infected people died the day after infection.

The flu got its name because Spain was the first to experience a severe outbreak of the disease. According to other sources, it is not yet possible to determine exactly where it appeared, but, most likely, Spain was not the primary epidemic focus. The name "Spanish flu" appeared by accident. Since the military censorship of the fighting parties during the First World War did not allow reports of the epidemic that had begun in the army and among the population, the first news about it appeared in the press in May-June 1918 in neutral Spain. The participants in the World War began to call her the Spanish Flu. The name of the disease stuck mainly due to newspaper hype in Spain, since Spain did not participate in hostilities and was not subject to military censorship.

Flu and its ghosts

Picture copied: http://holimed.lviv.ua/rus/rozsylka/kakbolet/010.html

The influenza virus that is rampant this year is A/California/09/2009 (H1N1), where A is the type of virus (the one that, unlike types B and C, mutates very easily and affects people and animals), California is the place origin, 09 – strain number, 2009 – year of appearance, H1N1 – serotype (that is, a certain subtype of influenza A virus, which differs from others in a set of antigens that determine its toxicity, ability to overcome the body’s defense systems, “infectiousness”, etc.) . This is precisely the influenza virus that is now causing massive morbidity.

Not every cold is worth looking for the flu. Malaise and runny nose can be caused by any of the viruses that are “responsible” for the occurrence of ARVI (acute respiratory viral infections).

Symptoms of the flu (any kind!) are as follows:

very abrupt onset of the disease,

a sharp increase in body temperature - up to 39°C and above,

severe headaches, joint and muscle pain,

nasal congestion, sore throat, dry cough.

Usually, after 3-4 days the temperature drops and, if the disease proceeds without complications (which, in fact, are dangerous for the flu), recovery occurs after 7-10 days.

Complications of influenza:

lesions of the respiratory tract (bronchitis and pneumonia);

diseases of the ENT organs (sinusitis, otitis, tonsillitis);

damage to the cardiovascular system (myocarditis, myocardial dystrophy);

damage to the central nervous system (meningitis, encephalitis); kidney damage (pyelonephritis, glomerulonephritis).

In people with chronic diseases (for example, bronchial asthma, arterial hypertension), their exacerbation due to influenza is very likely.

At-risk groups (according to severe course and consequences!):

pregnant women, young children, elderly people, adults and children with serious chronic diseases, as well as in the presence of immunodeficiency (meaning pathological conditions).

Flu prevention .

The general rules that are important for absolutely everyone are the following:

Wash your hands frequently with soap and water for 20 seconds.

Cough and sneeze into a tissue or hand.

Do not approach patients closer than one and a half to two meters.

Sick children should stay at home (not attend preschools and schools),

and also keep a distance from other people until their condition improves.

Refrain from visiting stores, cinemas or other crowded places.

What to do if a child gets sick?

Leave a sick child at home unless he or she needs medical attention.

Give your child plenty of fluids (juice, water, etc.).

Create a comfortable environment for the sick child. Rest is extremely important.

Give your child the medications the doctor prescribes.

Keep tissues and a trash can for used tissues within the patient's reach.

Avoid contact of a sick child with healthy family members.

If your child has been exposed to someone who has H1N1 influenza, ask your doctor about taking medications to prevent illness from H1N1 influenza.

Olga Zorina

Medical Editorial Studio MedCorr.

http://holimed.lviv.ua/rus/rozsylka/kakbolet/010.html

Alexander Zadorozhny

How to get the flu correctly

Doctor, I have the flu, what do you advise me?
- Stay away from me.

There is probably no person in the world who has not had the flu at least once. And this is not surprising - every year up to 15% of the world's population falls ill with this disease. The attitude of different people towards the flu varies: from absolutely indifferent to panic. Those who do not distinguish the flu from a banal ARVI (acute respiratory viral infection) treat it with disdain and self-confidence, and those who have already had a negative experience with the real flu treat it with caution and prefer to avoid getting sick again.

What is the flu really like? According to the WHO (World Health Organization), influenza is a potentially fatal disease, and this assessment is not unfounded.

Influenza is an acute infectious disease that affects the respiratory, nervous, cardiovascular and other systems. ^ The causative agent of influenza is a virus that multiplies in the mucous membrane of the respiratory tract. It spreads in the air with tiny droplets of saliva, mucus and sputum secreted by sick people and carriers when sneezing, coughing, or talking. The main difference between influenza from other acute respiratory viral infections (ARVI), which it begins acutely, that is, suddenly. After a latent (incubation) period lasting no more than two days, flu symptoms appear.

^ The characteristic features of influenza are a sharp increase in body temperature (up to 40°C), intense headache, pain and aches throughout the body and muscles, photophobia (painful or unpleasant to look at light), pain when moving the eyes. The rise in temperature is accompanied by severe chills. The flu is literally shocking with its symptoms - high fever, terrible weakness. All this may be accompanied by signs of incipient respiratory damage: nasal congestion, sore throat and a typical flu-like sensation of rawness in the chest. On the 2nd day of the disease, a painful cough and pain behind the sternum along the trachea often occur, resulting from damage to the tracheal mucosa. But most often, cough and runny nose come later or do not appear at all.

Other ARVIs, unlike the flu, gain momentum gradually, starting with a sore throat, runny nose, sneezing and general lethargy. On the third or fourth day, the temperature begins to rise. And with the flu, complications already begin by this day. It is the complications that pose the greatest danger to the health and life of a flu patient. As a rule, they develop during the flu and/or during the first two weeks after the illness.

^ The most common complications of influenza:

Secondary bacterial respiratory diseases (pneumonia, bronchitis, meningitis, laryngotracheobronchitis, ear infections, otitis media, etc.);
Exacerbation of chronic lung diseases (asthma, bronchitis, etc.);
Decompensation of cardiovascular diseases (myocarditis, pericarditis);
Inflammation of the kidneys, exacerbation of renal failure;
Exacerbation of endocrine disorders (diabetes mellitus);
Pathologies of pregnancy.
Exacerbation of neurological disorders, radiculitis.

Complications of influenza require hospital treatment. Complications of influenza can be deadly - almost all deaths from influenza are caused by a developed complication. Most complications of influenza are the result of improper treatment and improper behavior of patients.

How to properly get the flu in order to get out of it safely and avoid complications? Let's try together to understand what exactly happens in the body during the flu. To do this, first we will get acquainted with the main culprit of the problems - the causative agent of influenza. This pathogen is a virus.

Viruses, unlike other representatives of the living world, are not, strictly speaking, independent living organisms. Outside living objects, they have the appearance of an organic substance with a crystalline structure, without signs of life, but when they enter a cell they “come to life”.

Hemagglutinin is a surface protein of the influenza virus that ensures the ability of the virus to attach to the host cell.

Neuraminidase is a surface protein of the influenza virus that responds

Firstly, for the ability of a viral particle to penetrate a cell, and,

Secondly, for the ability of viral particles to leave the cell after reproduction.

Nucleocapsid is the genetic material (RNA) of the virus enclosed in a protein shell (capsule).

Infection with the influenza virus, as well as other acute respiratory viral infections, occurs through the upper respiratory tract. If inhaled, Viruses attach to cells using hemagglutinin. The enzyme neuraminidase destroys the cell membrane of mucosal cells, and the virus penetrates into the cell. This process is possible only at pH 5-6, that is, in an acidic environment. The viral RNA then penetrates the cell nucleus and causes it to produce new viral particles according to its program. As they accumulate in the cell, new viruses are released (at the same time the cell is destroyed and lysed) and infect other cells.

Reproduction of viruses can occur at an exceptionally high speed: if one viral particle enters the upper respiratory tract, after 8 hours the number of infectious offspring can reach 10³, and by the end of the first day - 10²³. The high rate of reproduction of the influenza virus explains such a short incubation period (the time elapsed from the moment of infection to the appearance of signs of the disease) - 1-2 days. One infected cell produces many hundreds of virions.

The viruses then enter the bloodstream and spread throughout the body. Exactly the release of viruses into the blood and their spread throughout the body is one of the main causes of severe intoxication during influenza. Unlike most other viruses that cause colds, acute respiratory viral infections, the influenza virus has an envelope consisting of lipids, which are the main factor causing severe intoxication. The process of virus reproduction occurs at a temperature of 32-37°C, and at temperatures above 38°C this process slows down and stops with a further increase. At the same time, with an increase in body temperature, processes develop in the body that contribute to the death of viruses.

An indispensable condition for the penetration of the virus into the cell is the presence of an acidic environment with a pH of 5-6. Normally, the reaction of the blood, as well as the mucous secretions of the respiratory tract, is slightly alkaline: pH greater than 7, which in itself represents a natural obstacle to the penetration of the virus. But when the mucous membrane cools, the vessels narrow, blood flow worsens and acid accumulates in the tissue - the pH decreases and, accordingly, favorable conditions arise for the virus to penetrate into the cell.

Therefore, the first rule of flu prevention : breathe exclusively through your nose. Nasal breathing, firstly, helps to warm the air entering the bronchi and lungs, and this protects the airways from cooling. Secondly, when passing through the nasal passages, the air is cleared of all foreign particles contained in it, including viruses, which are deposited on the nasal mucosa and then, together with the mucus, with the help of special villi, are removed through the esophagus into the stomach, where they are neutralized .

Second rule: Make sure your feet and hands are always warm. There is a reflex connection between them and the upper respiratory tract (URT): a decrease in the temperature of the feet and hands leads to a deterioration in blood circulation in the mucous membrane of the URT and a decrease in their temperature. And, conversely, warming the legs and arms, accordingly, helps improve blood circulation and increase the temperature of the mucous membrane of the upper respiratory tract. Unfortunately, very often there is a situation when a person’s feet are constantly cold, but he doesn’t even notice it. In this case, regular contrast baths on the feet and hands are usually recommended. It is best to do them as needed, but at least 1-2 times a day, especially at night.

The procedure is carried out as follows. Warm water is poured into a basin or bathtub. The initial temperature of the water should be slightly higher than the temperature of the feet, so that the water subjectively feels warm. Then, as the feet warm, hot water is gradually added. The maximum water temperature is 41-42°C. The duration of the procedure is at least 15 minutes, or up to an hour, until the feet become red and a feeling of warmth appears throughout the body. If you have a runny or stuffy nose, then the disappearance of these symptoms may also be a criterion for completing the procedure.

After warming up your feet, you must immediately dip them in cold water or pour cold water over them from a jug. The colder the water, the stronger the effect. If this is not done, then after a short time the legs will cool down and the procedure will be ineffective.

Many people are afraid to pour cold water on their feet, but if you warm up well, then in addition to the benefits, you will also get pleasure. After pouring cold water over your feet, you need to rub them dry and put on socks. After this, it is advisable to walk for 10-15 minutes. This contrast dousing stimulates blood circulation in the legs and, if you perform this procedure regularly, you will feel that your legs are no longer cold. And this is important for the prevention of flu and colds.

The same procedure can be carried out simultaneously, if necessary, for the hands. But it often happens that warming the feet helps warm the hands and this is a criterion for completing the procedure. If this does not happen, it is advisable to warm your hands separately. It is very important to do the contrast bath exactly as described.

It is important to constantly ensure that your feet do not freeze.

If you have a stuffy nose or runny nose, it is advisable to limit your fluid intake; it is better to drink fluids in the evening, when you no longer plan to go out into the cold.

Third rule - drink less fluid, especially if you are often exposed to cold conditions.

The fourth rule for preventing influenza infection - if possible, avoid unnecessary contacts, especially in public places and transport, use protective masks.

During a flu epidemic, it is necessary to limit the consumption of protein foods, which acidify the body, and increase the content of raw (live) foods (apples, cabbage, parsley, celery, Jerusalem artichoke, oranges, tangerines, lemons, etc.). Raw potatoes have good preventive and therapeutic properties against influenza. It contains a large amount of vitamin C, as well as substances with anti-influenza activity. Raw foods should be consumed at every meal. It's better to start with them. This contributes to a high content of leukocytes in the peripheral blood, and, accordingly, maintaining a high level of immunity. It is also good to use live, freshly squeezed juices (fresh) as drinks.

To prevent influenza, you can use 0.25% oxolin ointment. During the period of rise and maximum outbreak of influenza (usually for 25 days), or upon contact with patients with influenza, for individual prevention of influenza, use 0.25% ointment, which is used to lubricate the nasal mucosa twice a day (morning and evening). Oxolin prevents the virus from reproducing.

All of these above rules for preventing influenza help before infection with the influenza virus - before it enters the mucous membrane of the respiratory tract and penetrates the cells of the mucous membrane. After this, as you already know, viruses multiply in the cells of the mucosa. And then the second stage of the influenza process begins - the release of the virus into the bloodstream (this condition is called viremia). Here, all preventive measures aimed at preventing influenza infection are no longer useless and measures related to the development of influenza disease are necessary.

Alexander Zadorozhny

The flu is not as bad as the complications after it, says one woman to another.

- I know this from my own experience. Just after the flu, I married a local doctor.

Last time, we examined in detail the process of infection (infection) of the body with the influenza virus and the conditions under which this infection occurs. I hope that you have taken into account and taken advantage of the recommendations for preventing influenza disease given in the last issue.

Today I will talk about how to behave if you do get the flu: how to get the flu correctly. Correct behavior at the stage of manifestation of the influenza process in the event of infection will help not only prevent the development of complications, but also, as paradoxical as it sounds, achieve a healing effect. This means that if you treat the flu correctly, you can come out of the disease healthier than before.

Every year, usually during the cold season, influenza epidemics occur and affect up to 15% of the world's population: both people and animals and birds.

The influenza virus is characterized by antigenic variability, which is a fundamental feature of influenza viruses types A and B. As a rule, every year changes occur in the structure of the surface antigens of the virus - hemagglutinin and neuraminidase. As a result of this variability, new types (strains) of the influenza virus arise, to which people who have previously had the flu lack immunity.

To carry out its life cycle (reproduction), the influenza virus penetrates into the cell. This process is possible only at pH 5-6, that is, in an acidic environment.

Viral RNA, the genetic code of the virus, penetrates the cell nucleus and causes it to produce new viral particles according to its program. As they accumulate in the cell, new viruses are released (at the same time the cell is destroyed and lysed) and infect other cells. One infected cell produces many hundreds of virions.

During the process of reproduction, viruses enter the blood and spread throughout the body. The release of influenza viruses into the blood is accompanied by chills and a subsequent rise in temperature. It is the release of viruses into the blood and their distribution throughout the body that marks the beginning of the period of acute clinical manifestations of influenza.

The course of the disease depends on the specific immunity of the body - the presence of antibodies to the type of influenza virus that has entered the blood, as well as on the level of nonspecific resistance (resistance) of the body, which depends on one or another combination of many factors that determine the general level of human health.

With a sufficiently high level of body resistance, after the first release of viral bodies into the blood, their further reproduction in the body does not occur and the disease gradually declines.

If there are places in the body where there are conditions favorable for the penetration of viruses into cells, a new cycle of their reproduction occurs, followed by the death of infected cells and the repeated release of viral particles into the blood, the course of the disease becomes more severe and the likelihood of developing complications and the transition of the disease to a hypertoxic form increases.

Depending on the general state of health, age, and whether the patient has previously been in contact with this type of virus, he may develop one of 4 forms of influenza: mild, moderate, severe and hypertoxic. In severe cases of influenza, irreversible damage to the cardiovascular system, respiratory organs, and central nervous system often occurs, causing heart and vascular diseases, pneumonia, tracheobronchitis, and meningoencephalitis. With the hypertoxic form of influenza, there is a serious risk of death (death). After suffering from the flu, symptoms of post-infectious asthenia may persist for 2-3 weeks: fatigue, weakness, headache, irritability, insomnia, etc.

The development of a viral process in the human body requires significant expenditure of energy and material resources; this is accompanied by blocking of natural physiological processes, which leads to the accumulation of toxic products which, in turn, also contribute to a significant deterioration in the general condition of the flu patient.

Why do mutations of the influenza virus constantly occur, as a result of which, unlike other viral infections, it is impossible to develop stable immunity to the influenza virus?

What is the influenza virus for, what function does it perform in nature?

Why does a person need to get the flu?

The answers to these questions will help us understand how to properly get sick with the flu. Therefore, I ask you to accept the information presented below as a working hypothesis necessary for understanding the algorithm of behavior during influenza.

Today, there is very strong evidence that viruses, including the influenza virus, play a very important role in the exchange of genetic information between various living organisms. Such an exchange is necessary for better adaptation of living organisms to a changing external environment. Are viruses the carriers of “best practices in the biosphere” in relation to highly organized organisms? And the most important role in this belongs to the influenza virus.

At the cellular level, we are all mutants, and we cannot be different, since evolutionary progress is nothing more than a process of changing the genetic structure of populations towards increasing the diversity of forms and their better adaptation to environmental conditions.

Medical valeology - a science that studies the processes of individual health - notes one important pattern: the more energy accumulated in each individual cell and, accordingly, in the body as a whole, the greater the range of external influences it can withstand, and the higher the level of human health. At a high level of health, the processes of energy supply to cells occur in an aerobic mode (with good access to oxygen). The lower the level of health, the lower the level of aerobic oxidation and the higher the level of anaerobic processes. This produces a large amount of lactic acid, which creates an acidic environment around the cells.

A high level of health guarantees reliable protection against infection with the virus. In a healthy body there are no conditions for infection. The weaker the body, the lower its level of health, the more acidified the tissues are with the waste products of cells. The most productive in this regard are cancer cells, which, unlike healthy cells, provide themselves with energy primarily anaerobically (without access to oxygen).

Thus, the lower the level of human health, the more cells working in anaerobic mode. In such an organism, favorable conditions are created for infection with the virus. We can say that with a low level of health, the body seems to need infection with a virus. Sounds paradoxical, doesn't it? But if you think about it, it turns out that cancer cells are most susceptible to infection by the influenza virus. And the virus itself is the magic bullet that can kill a cancer cell. It can be assumed that infection with the influenza virus helps rid the body of cancer and other weakened, non-viable cells.

So, your task during the process of suffering from the flu is “the birth of a new harmonious world”: increasing the level of your health. To do this, you will need to mobilize your forces as much as possible, combine them with the forces of the enemy (flu) and direct this combined energy to improve the health of your loved one. Therefore, all our actions during influenza should be aimed not at fighting the virus, but at optimizing the processes occurring in the body during the flu and using the body’s reaction to the influenza virus for health purposes. In practice, this means that we, as it were, use the influenza virus that has entered our body as a medicine. We give it the opportunity to “walk” a little through our body, identify all the diseased cells and destroy them. At the same time, we use the ability of the influenza virus to mobilize the body’s defenses and processes and launch healing and cleansing reactions. Correct behavior during flu is like a controlled nuclear reaction at a nuclear power plant: if we do everything correctly, we will benefit, if control is lost, we will suffer.

What should be the sequence of your actions? There are many processes in the human body that require energy. With the flu, the need for energy increases sharply, so the body takes emergency measures to increase metabolic processes, which is accompanied by severe chills. To help yourself in this situation, you need to take measures to saturate your body with warmth: steam your feet, take a bath, cover yourself with heating pads, wrap yourself in a blanket, drink hot tea with lemon. Warming should continue until the chills stop. Further, to reduce energy consumption and mobilize strength, firstly, bed rest is necessary. Digesting food is very costly from the point of view of the body's energy, therefore, secondly, it is best to stop eating food, especially protein and thermally processed food - it requires very high energy costs. Thirdly, it is necessary to ensure the neutralization and removal of “waste” and toxins from the body.

With influenza, there are two main sources of intoxication. The first is influenza viruses circulating in the blood, and the second is the large intestine. In any disease accompanied by a deterioration in the general condition (well-being) of a person, especially with influenza, there is an increase in the permeability of the intestinal barrier, resulting in an increase in the absorption of intestinal toxins into the blood, which further aggravate the patient’s condition. Therefore, at the first signs of malaise, it is best to first cleanse the intestines. This can be done in various ways:

1. Using an enema.

2. Taking laxatives.

3. A combination of the first and second methods.

I will dwell in detail on the administration of an enema. Its purpose is to empty the intestines of feces, which are a source of intoxication. We need to prepare a pear for performing an enema, with a volume of 200-500 ml, and also, as a working fluid, an aqueous solution of salt, since the enema should be slightly hypertonic - 1.5-2%. To do this, dissolve one teaspoon (with top) of kitchen salt in 500 ml of water. Before performing an enema, be sure to make sure that your feet are warm - then the procedure will be effective. If necessary, you can make a foot bath, as was described in the last issue of the newsletter. If you are chilling, the water temperature should be about 39-40°C, but if you are hot - 30-35°. After introducing the liquid into the rectum, you need to hold it until the urge appears. If emptying was insufficient, the procedure can be repeated.

In addition to an enema, activated charcoal is very helpful for quick detoxification. To carry out detoxification, you need to take 25-30 g of activated carbon (100-120 tablets!). Coal must be ground in a coffee grinder or ground into a fine powder in a mortar or other container. If you use an electric coffee grinder, do not open the lid immediately, let the coal dust settle. Then carefully pour the coal powder into a glass with 100 ml of water, stir gently until the coal is wetted with water, then shake and quickly drink the coal suspension. What is left should be eaten with a spoon, then rinse your mouth with water. Attention! Under no circumstances should you try to swallow dry charcoal powder and be careful that the powder does not get into your respiratory tract! More comfortable for oral administration are the modern preparations of activated carbon that exist today, soluble in water, with a large surface area and, accordingly, a lower dosage.

To cleanse the intestines, only osmotic laxatives can be taken as a laxative for influenza. These include saline laxatives such as Carlsbad salt, Truskavets "Barbara" salt, magnesium sulfate (magnesia). A 20-25% saline laxative solution is taken: 1-2 tablespoons per 150-250 ml of alkaline mineral water of the Borjomi type. Sodium thiosulfate is used as an antitoxic agent in the form of a 10-15% solution - 2 teaspoons per 100-150 ml of water. Ready-made Morshyn ropa and Hungarian mineral water “Hunyadi Janos” are used in the amount of 100-150 ml per dose. You can also use a food substitute for sugar, sorbitol: 1-2 tablespoons per 150-250 ml of water. Sorbitol can be added to tea with lemon. This procedure is called intestinal lavage.

Before taking a laxative solution, you also need to make sure that your feet are warm. It is better to take a laxative on an empty stomach, then it will work faster. In case of cholelithiasis, this procedure must be carried out carefully, the concentration of solutions should be 2-3 times less, and if there are attacks, it is better to abandon it. After taking a laxative, you need to lie on your right side on a warm heating pad for about an hour until you feel thirsty, after which you can drink some liquid. It is better not to use medicinal laxatives for the flu. These procedures: cleansing the intestines and taking activated charcoal significantly improves the condition of a patient with influenza, headaches and body aches decrease or disappear completely, and the temperature decreases. You need to repeat such cleansing every day until complete recovery.

When the influenza process manifests itself, an increase in body temperature occurs - this is an adaptive reaction that contributes to a sharp acceleration of all physiological processes in the body, including the synthesis of interferon, which blocks the biosynthesis of viral particles in the infected cell and thereby reduces the development of the viral process. In addition, as I mentioned earlier, when body temperature rises above 38°C, the process of virus reproduction slows down and with a further increase, it stops. At the same time, due to an increase in body temperature, processes develop in the body that contribute to the improvement of impaired metabolism (metabolism), the elimination of metabolic and oxygen debt in cells and tissues, the death of non-viable and diseased cells and the removal of toxic products from the body.

Many people are afraid of high temperatures, especially in children. In fact, the rise in temperature is not that bad and is quite manageable. The only organ that is “afraid” of a temperature rise to 40°C is the brain. He really can't stand overheating. The rest of the body only benefits from such a rise in temperature. Therefore, never try to lower your temperature at any cost, especially if you are sick with the flu. If the temperature is brought down with antipyretic drugs, the virus continues to multiply and its quantity in the body will increase catastrophically, accordingly its toxic damaging effect will increase, that is, the disease will worsen - there will be more damaged cells, organs and tissues - the recovery period will be longer and the risk of developing complications due to viral damage to the body.

A child’s high temperature, of course, must be controlled. But it is better to do this using natural methods. An antipyretic drug, as a last resort, can be given once (this is for faint-hearted parents, for self-soothing) - if the temperature drops and then rises again, then it is not worth giving again - there may be complications and the disease may progress to a protracted course.

The brain suffers the most from temperature, so everything must be done to ensure the outflow of heat from the head. This includes compresses on the head, undressing the child, and wiping him with a damp towel. You need to pay attention to the child’s condition: if he is chilly, it is better to wipe him with warm water, if he is warm, you can wipe him with cool water. In any case, pay attention to how the child reacts to wiping - if he does not like it, change the temperature regime to the opposite.

Pay attention to the child's limbs - hands and feet, as well as to the skin. If they are cold, you need to warm them in warm water (bath) or in another way (a heating pad, rubbing or warming with warm hands), as soon as they warm up, the blood flow to them will increase and, accordingly, heat transfer will increase and the temperature will definitely drop by 0.5- 1 degree. At the same time, apply a damp compress to the forehead (cloth moistened with water). This is often enough to make the child feel more comfortable and, perhaps, fall asleep.

The cause of spasms in children at elevated temperatures is overheating of the brain and a large temperature difference between the brain and extremities. Conclusion: if the child has warm hands and feet and the head is sufficiently cooled (through removable compresses) everything will be fine. Of course, these procedures require patience and time (it’s easier to give a pill), but the child will come out of the disease not only not weakened, but on the contrary, will gain useful life experience and immunity. Pay attention to the child’s psychological state: if he is in a good mood and playing, you don’t have to worry too much about the elevated temperature. If he cries, is capricious, or weakened, lethargic, he requires increased attention and observation. The most important thing that is required from parents is patience and perseverance. Of course, it’s easier to give a fever pill and go to sleep, but this temporary relief can later lead to unpleasant consequences and prolong the process

I hope you now know how to control the temperature. I just want to warn you that a high temperature with the flu can last for 3-4 days, especially if you haven’t cleansed your intestines enough, continue to eat, don’t keep bed rest, or your body is heavily polluted. Therefore, following the recommendations on the regimen and detoxification of the body will contribute to a faster recovery from the disease. My observations indicate that if all recommendations are followed correctly and accurately, the illness lasts no more than 4-5 days.

There are times when the body is not able to respond to illness by increasing body temperature. And such a rise in the flu is extremely necessary. One of the fathers of medicine said something like this about this: “Give me a remedy to raise the temperature and I will cure any disease.” This is why thermal procedures in the form of a bath are so popular among all nations as a means of treatment and healing. Therefore, if you do not have a fever with the flu, you will have to take all measures to increase it.

If the intoxication is not very pronounced and you have the strength, you can take a warm bath, gradually increasing its temperature, but not too zealously, so as not to weaken completely. You can do an enema right in the bath, if the appropriate conditions exist. Having warmed up in this way, you need to put on cotton underwear or a tracksuit, go to bed, wrapped in a blanket and covered with heating pads. It is necessary to place a thermometer in the armpit area to monitor body temperature and lie there without opening until the temperature rises to 38.5°C-39°C. The head should be open and, if necessary, it can be cooled with compresses. If you don’t have the strength for a bath, then you can immediately start by warming up in bed - it will be a little slower. For better warming, it’s very good to drink 150-200 ml of hot tea with honey and lemon.

So, you've cleaned yourself, warmed up, what's next? And then you need to start drinking diaphoretic tea little by little. It can be raspberry, linden tea, tea with elderflowers... You need to drink in small portions - 1-2 sips every 10-15 minutes, so it is better to keep the tea in a thermos or in a water bath so that it does not cool down. The diaphoretic tea should not be very hot. When you start to sweat, try to stay open for as long as possible to avoid cooling down. If you try really hard, this state of sweating can last 3-4 hours. If you feel weak or hungry, you can add honey to your tea. If you are weak, you can also drink alkaline mineral water such as “Borjomi” or cucumber or cabbage brine, diluting it by half or two-thirds with water.

When you have the flu, it is very important to stay in bed and get as much sleep as possible. This is necessary to reduce the load on the heart, which works very intensely during flu. Sleep promotes less blood flow to the head and thereby protects the brain from the effects of toxins. When the temperature returns to normal, the signs of intoxication disappear and a feeling of hunger appears - do not rush to eat up - for a day or two it will be enough to drink fruit juices or eat raw fruits or vegetables until you are completely sure of your recovery. And if you follow the recommendations given here correctly, it will come within 4-5 days. After this, you will need to take a bath or shower to wash off all the sweat and dirt that has accumulated on your body during your illness. If you have the strength, you can take a bath every day. After the bath you will feel how refreshed your body is. If you have ever tried to fast for at least 10 days in your life, then you will be able to evaluate your condition after 3-5 days of proper flu illness - it can be compared to the condition that occurs after cleansing the body with hunger. Confirmation of this may be another pleasant for many, but there may be a somewhat unexpected consequence of correct behavior during the flu: a decrease in body weight to 2-5 kg.

Finally, I would like to say that the basic principles described here are applicable to any acute illness. I will briefly list them again: fasting, cleansing through the intestines (enemas, intestinal lavage) and skin (sweating), detoxification (with activated carbon), bed rest, maintaining, and not knocking down, high body temperature, drinking regime that ensures sufficient sweating, but drinking should not be excessive and too abundant.

Municipal state educational institution

"Secondary school No. 3"

Stavropol region, Stepnovsky district,
Bogdanovka village

MKOU secondary school No. 3, 10th grade student
Scientific adviser:

Toboeva Natalya Konstantinovna
teacher of geography, biology, MKOU secondary school No. 3

I .Introduction

II.Main part:

1. Discovery of viruses

2.Origin of viruses

3. Structure

4.Penetration into the cell

5.Flu

6. Chicken pox 7. Tick-borne encephalitis 8. The future of virology

III.Conclusion

IV. Bibliography

V.Appendix

Object of study:

Non-cellular life forms are viruses.

Subject of study:

The present and future of virology.

Goal of the work:

Find out the significance of virology at the present time and determine its future. The set goal could be achieved as a result of solving the following tasks:

1) study of literature covering the structure of viruses as non-cellular life forms;

2) research into the causes of viral diseases, as well as their prevention.

This determined the topic of my research.

I. Introduction.

The action-packed and fascinating history of virology is characterized by triumphant victories, but, unfortunately, also defeats. The development of virology is associated with the brilliant successes of molecular genetics.

The study of viruses has led to an understanding of the fine structure of genes, deciphering the genetic code, and identifying the mechanisms of mutations.

Viruses are widely used in genetic engineering and research.

But their cunning and ability to adapt know no bounds, their behavior in each case is unpredictable. The victims of viruses are millions of people who died from smallpox, yellow fever, AIDS and other diseases. Much remains to be discovered and learned. And yet, the main successes in virology have been achieved in the fight against specific diseases. That is why scientists say that virology will take a leading place in the third millennium.

What has virology given to humanity in the fight against its formidable enemy - the virus? What is its structure, where and how does it live, how does it reproduce, what other “surprises” does it prepare? I considered these questions in my work.

II.Main part:

1. Discovery of viruses.

The discoverer of the world of viruses was the Russian botanist D.I. Ivanovsky. In 1891-1892 he persistently searched for the causative agent of tobacco mosaic disease. The scientist examined the liquid obtained by rubbing diseased tobacco leaves. I filtered it through filters that were not supposed to let a single bacteria through. Patiently, he pumped liters of juice taken from mosaic tobacco leaves into hollow bacterial filters made of finely porous porcelain, reminiscent of long candles. The walls of the filter sweated with transparent droplets that flowed into a pre-sterilized vessel. By lightly rubbing, the scientist applied a drop of this filtered juice to the surface of the tobacco leaf. After 7-10 days, undoubted signs of mosaic disease appeared in previously healthy plants. A drop of filtered juice from an infected plant affected any other tobacco bush with a mosaic disease. The infestation could pass from plant to plant endlessly, like a flame of fire from one thatched roof to another.

Subsequently, it was possible to establish that many other viral pathogens of infectious diseases in humans, animals and plants are capable of passing through, which could be seen through the most advanced light microscopes. Particles of various viruses could only be seen through the window of an all-seeing device - an electron microscope, which provides a magnification of hundreds of thousands of times.

D.I. himself Ivanovsky did not attach much importance to this fact, although he described his experience in detail.

His work gained fame after the Dutch botanist and microbiologist Martin Beijerinck confirmed the results of D. I. Ivanovsky’s research in 1899. M. Beyerinck proved that the mosaic of tobacco can be transferred from one plant to another using filtrates. These studies marked the beginning of the study of viruses and the emergence of virology as a science.

2. Origin of viruses.

3. Structure.

Being completely primitive creatures, viruses have all the basic properties of living organisms. They reproduce offspring similar to the original parental forms, although their method of reproduction is peculiar and differs in many respects from what is known about the reproduction of other creatures. Their metabolism is closely related to the metabolism of host cells. They have heredity characteristic of all living organisms. Finally, they, like all other living beings, are characterized by variability and adaptability to changing environmental conditions.

The largest viruses (for example, smallpox viruses) reach a size of 400-700 nm and are close in size to small bacteria, the smallest (causative agents of polio, encephalitis, foot-and-mouth disease) measure only tens of nanometers, i.e. are close to large protein molecules, in particular blood hemoglobin molecules.

Viruses come in a variety of shapes, from spherical to filamentous. Electron microscopy allows not only to see viruses, determine their shapes and sizes, but also to study their spatial structure - molecular architectonics.

A relatively simple composition is typical for viruses: nucleic acid (RNA or DNA), protein; more complex structures contain carbohydrates and lipids, and sometimes have a number of their own enzymes.

As a rule, the nucleic acid is located in the center of the viral particle and is protected from adverse effects by a protein shell - capsomers. Electron microscope observations showed that the virus particle

(or virions) come in several basic types in shape.

Some viruses (usually the simplest ones) resemble regular geometric bodies. Their protein shell almost always approaches the shape of an icosahedron (regular twenty-sided structure) with faces of equilateral triangles. These virions are called cubic (such as the polio virus). The nucleic acid of such a virus is often twisted into a ball. Particles of other viruses are shaped like oblong rods. In this case, their nucleic acid is surrounded by a cylindrical capsid. Such virions are called helical virions (for example, tobacco mosaic virus).

Viruses of a more complex structure, in addition to the icosahedral or helical capsid, also have an outer shell, which consists of a variety of proteins (many of them enzymes), as well as lipids and carbons.

The physical structure of the outer shell is very varied and is not as compact as that of the capsid. For example, the herpes virus is an enveloped helical virion. There are viruses with an even more complex structure. Thus, the smallpox virus does not have a visible capsid (protein shell), but its nucleic acid is surrounded by several shells.

4.Penetration into the cell.

As a rule, the penetration of the virus into the cytoplasm of the cell is preceded by its binding to a special receptor protein located on the cell surface. Binding to the receptor occurs due to the presence of special proteins on the surface of the viral cell. The area of the cell surface to which the virus has attached is immersed in the cytoplasm and turns into a vacuole. A vacuole is a wall that consists of a cytoplasmic membrane that can merge with other vacuoles or the nucleus. This way the virus is delivered to any part of the cell.

The receptor mechanism for virus penetration into the cell ensures the specificity of the infectious process. The infectious process begins when viruses that have entered the cell begin to multiply, i.e. The viral genome is reduplicated and the capsid self-assembles. For reduplication to occur, the nucleic acid must be freed from the capsid. After the synthesis of a new nucleic acid molecule, it is dressed with viral proteins synthesized in the cytoplasm of the host cell - a capsid is formed.

The accumulation of viral particles leads to elimination from the cell. For some viruses, this occurs through an “explosion,” in which the integrity of the cell is disrupted and it dies. Other viruses are released in a manner reminiscent of budding. In this case, the cells can maintain their viability.

Bacteriophage viruses have a different way of entering cells. The bacteriophage inserts a full rod into the cell and pushes out the DNA (or RNA) found in its head through it. The bacteriophage genome enters

cytoplasm, and the capsid remains outside. In the bacterial cytoplasm, the reduplication of the bacteriophage genome, the synthesis of its proteins and the formation of the capsid begin. After a certain period of time, the bacterial cell dies and mature particles enter the environment.

5.Flu.

Influenza is an acute infectious disease, the causative agent of which is a filter virus, causing general intoxication and damage to the mucous membrane of the upper respiratory tract.

It has now been established that the influenza virus has several serological types, differing in their antigenic structure.

There are the following types of influenza virus: A, B, C, D. Virus A has 2 subtypes, designated:A 1 and A2.

The influenza virus outside the human body is unstable and dies quickly. The virus dried in a vacuum can persist for a long time.

Disinfectants quickly destroy the virus; ultraviolet radiation and heat also have a detrimental effect on the virus.

Allow the possibility of infection from a virus carrier. The virus is transmitted from a sick person to a healthy person through airborne droplets. Coughing and sneezing contribute to the spread of infection.

Viral influenza epidemics most often occur during the cold season.

A person with the flu is contagious for 5-7 days. All people who have not had the flu are susceptible to this disease. After suffering from the flu, immunity remains for 2-3 years.

The incubation period is short - from several hours to 3 days. Most often 1-2 days.

Usually there are no prodromes, and a sudden onset is typical. Chills, headache, general weakness appear, and the temperature rises to 39-40 degrees. Patients complain of pain when rotating the eyes, aching muscle joints, disturbed sleep, and sweating. All this indicates general intoxication with the involvement of the nervous system in the process.

The central nervous system is especially sensitive to the toxic effects of the influenza virus, which is clinically expressed in severe adynamia, irritability, and decreased sense of smell and taste.

On the part of the digestive tract, the phenomena of influenza intoxication also differ: decreased appetite, stool retention, and sometimes, more often in young children, diarrhea.

The tongue is coated and slightly swollen, which leads to the appearance of teeth marks along the edges. The temperature remains elevated for 3-5 days and, in the absence of complications, drops to normal gradually or drops critically.

After 1-2 days, a runny nose, laryngitis, and bronchitis may appear. Bleeding from the nose is common. The cough is dry at first and turns into a cough with sputum. Vascular disorders are expressed in the form of low blood pressure, pulse instability and disturbances in its rhythm.

Uncomplicated flu usually ends within 3-5 days, however, full recovery takes 1-2 weeks.

Like any infection, influenza can occur in mild, severe, hypertoxic and fulminant forms.

Along with this, viral flu can be extremely mild and spread on the legs, ending within 1-2 days. These forms of influenza are called erased.

Influenza infection can cause complications in various organ systems. Most often in children, the flu is complicated by pneumonia, otitis media, which is accompanied by fever, anxiety, and sleep disturbances.

Complications from the peripheral nervous system are expressed in the form of neuralgia, neuritis, radiculitis.

Treatment:

The patient must be provided with bed rest and rest. Bed rest must be maintained for some time, even after the temperature drops. Systematic ventilation of the room, daily warm or hot baths, good nutrition - all this increases the body's resistance to fighting the flu.

Specific treatment of viral influenza is carried out using the anti-influenza polyvalent serum proposed by A.A. Smorodintsev.

Among the symptomatic remedies for headache, muscle and joint pain, as well as neurological pain, pyramidon, phenacetin, and aspirin with caffeine are prescribed.

In case of severe toxicosis, intravenous glucose is prescribed. For uncomplicated influenza, antibiotics are not used, because They no longer work on the virus. For a dry cough, hot milk with soda or Borjomi is useful.

Prevention:

Patients should be isolated at home or in hospitals. If the patient is left at home, it is necessary to place him in a separate room or separate his bed with a screen or sheet. Caregivers should wear a gauze mask covering the nose and mouth.

6. Chicken pox.

Chickenpox is an acute infectious disease caused by a virus and characterized by a macular vesicular rash on the skin and mucous membranes.

The causative agent of chickenpox is a filter virus and is found in chickenpox vesicles and in the blood. The virus is unstable and exposed to various environmental influences and dies quickly.

The source of infection is the patient, who is contagious during the period of rash and at the end of incubation. The infection is spread by airborne droplets. The disease is not transmitted through objects.

Immunity after chickenpox remains for life. The incubation period lasts from 11 to 21 days, with an average of 14 days.

In most cases, the disease begins immediately, and only sometimes there are precursors in the form of a moderate increase in temperature with symptoms of general malaise. Prodromes may be accompanied by a rash resembling scarlet fever or measles.

With a moderate rise in temperature, a spotted rash of varying sizes appears on different parts of the body - from a pinhead to a lentil. Over the next few hours, a bubble with transparent contents, surrounded by a red rim, forms in place of the spots. Chickenpox blisters (vesicles) are located on unchanged skin, tender and soft to the touch. The contents of the bubble soon become cloudy, and the bubble itself bursts (2-3 days) and turns into a crust, which disappears after 2-3 weeks, usually leaving no scar. The rash and subsequent formation of blisters can be abundant, affecting the entire scalp, trunk, and limbs, while on the face and distal parts of the limbs they are less abundant.

The course of chickenpox is usually accompanied by a slight disturbance in the general condition of the patient. Each new rash causes an increase in temperature to 38° and above. At the same time, appetite decreases.

In addition to the skin, chicken rash can affect the mucous membranes of the oral cavity, conjunctiva, genitals, larynx, etc.

Treatment:

Bed linen must always be clean. Take warm baths (35°-37°) from weak solutions of potassium permanganate. The patient's hands should be clean with short-cut nails.

Individual bubbles are lubricated with iodine or potassium solution, 1% alcohol solution of brilliant green.

For purulent complications caused by secondary infection, treatment is carried out with antibiotics (penicillin, streptomycin, biomycin)

Prevention:

A person infected with chickenpox must be isolated at home. Disinfection is not carried out, the room is ventilated and subjected to wet cleaning.

7. Tick-borne encephalitis.

An acute viral disease characterized by damage to the gray matter of the brain and spinal cord. The reservoir for sources of infection are wild animals (mainly rodents) and ixodid ticks. Infection is possible not only by sucking on a tick, but also by consuming the milk of infected goats. The causative agent is an arbovirus. The gateway of infection is the skin (if ticks are sucked on) or the mucous membrane of the digestive tract (if there is alimentary infection). The virus hematogenously penetrates the central nervous system and causes the most pronounced changes in the nerve cells of the anterior horns of the cervical spinal cord and in the nuclei of the medulla oblongata.

The incubation period is from 8 to 23 days (usually 7-14 days). The disease begins acutely: chills, severe headache, and weakness appear. After encephalitis, lasting consequences may remain in the form of flaccid paralysis of the muscles of the neck and shoulder girdle.

Treatment:

Strict bed rest:

for mild forms - 7-10 days,

for moderate cases - 2-3 weeks,

for severe ones - even longer.

Prevention:

When a tick bites in an area unfavorable for encephalitis, it is necessary to administer anti-encephalitis gamma globulin. According to indications, preventive vaccination is carried out.

8.The future of virology.

What are the prospects for the development of virology in the 21st century? In the second half of the 20th century, progress in virology was associated with classical discoveries in biochemistry, genetics and molecular biology. Modern virology is intertwined with the successes of fundamental applied sciences, so its further development will follow the path of in-depth study of the molecular basis of the pathogenicity of viruses of new previously unknown pathogens (prions and virions), the nature and mechanisms of persistence of viruses, their ecology, the development of new and improvement of existing diagnostic methods and specific prevention of viral diseases.

There is currently no more important aspect in virology than the prevention of infections. Over the 100 years of the existence of the science of viruses and viral diseases, vaccines have undergone great changes, going from attenuated and killed vaccines from the time of Pasteur to modern genetically engineered and synthetic vaccine preparations. This direction will continue to develop, based on physicochemical genetic engineering and synthetic experiments with the goal of creating polyvalent vaccines that require minimal vaccinations as early as possible after birth. Chemotherapy will develop, an approach relatively new to virology. These drugs are so far useful only in isolated cases.

III. Conclusion.

Humanity faces many complex unsolved virological problems: hidden viral infections, viruses and tumors, etc. The level of development of virology today, however, is such that means of combating infections will definitely be found. It is very important to understand that viruses are not an element alien to living nature; they are a necessary component of the biosphere, without which adaptation, evolution, immune defense and other interactions of living objects with their environment would probably be impossible. Understanding viral diseases as pathologies of adaptation, the fight against them should be aimed at improving the status of the immune system, and not at destroying viruses.

Analysis of various literary sources and statistical data allowed us to draw the following conclusions:

viruses are autonomous genetic compounds of structure that are unable to develop outside the cell;

3) come in a variety of shapes and simple composition.

Bibliography:

1. Great Soviet Encyclopedia: T.8 / Ed. B.A. Vvedensky.

2. Denisov I.N., Ulumbaev E.G. Directory - a guide for a practicing physician. - M.: Medicine, 1999.

3. Zverev I.D. A book for reading on human anatomy, physiology and hygiene. - M.: Education, 1983.

4. Luria S. et al. General virology. - M.: Mir, 1981.

6. Pokrovsky V.I. Popular medical encyclopedia. - M.: Onyx, 1998.

7.Tokarik E.N. Virology: present and future // Biology at school. - 2000. - No. 2-3.

QUESTION No. 1 “HISTORY OF VIRUSOLOGY. ROLE OF VIRUSES IN INFECTIOUS PATHOLOGY OF HUMAN ANIMALS."

In the first period, people did not know the essence of the disease, they only described it. In the 18th century, the doctor Gener developed a vaccine against smallpox, with which it was treated. Further credit goes to Pasteur; rabies existed in his time. He proved that rabies is transmitted by biting. Nothing grew on nutrient media. After Pasteur's work, it was found that infectious diseases are caused by tiny organisms (microbes). Not a single method of bacterial research made it possible to isolate microbes whose presence is associated with smallpox, foot-and-mouth disease, and plague.

In 1931, a method for cultivating chicken embryos was proposed. This method is highly sensitive; infection by spontaneous viruses is excluded. The most rapid development of virology began after 1948. Enders proposed a method of single-layer cell and tissue cultures. This method made it possible to study many viruses and obtain vaccines. The study of viruses was formed into the independent science of virology, which studies viruses and the diseases caused by them. General virology studies the nature and origin of viruses, structure and chemical composition, resistance to physico-chemical factors; its subject is also the interaction of virus and cell, genetics of viruses, features of the formation of immunity against viruses, general principles of diagnosis and prevention. She studies the same issues as general virology. Viruses as objects have units of measurement.

QUESTION No. 2 “SUBJECT AND TASKS OF GENERAL AND PRIVATE VETERINARY VIRUSOLOGY. HISTORY OF THE DISCOVERY OF VIRUSES. ACHIEVEMENTS OF DOMESTIC VIRUSOLOGY".

Virology is a science that studies the nature and origin of viruses and the diseases they cause. General virology studies the nature and origin of viruses, structure and chemical composition, resistance to physico-chemical factors; its subject is also the interaction of virus and cell, genetics of viruses, features of the formation of immunity against viruses, general principles of diagnosis and prevention. She studies the same issues as general virology. Viruses as objects have units of measurement. Period - people did not know the essence of the disease, they only described it. In the 18th century, the doctor Gener developed a vaccine against smallpox, with which it was treated. Further credit goes to Pasteur; rabies existed in his time. He proved that rabies is transmitted by biting. Nothing grew on nutrient media. After Pasteur's work, it was found that infectious diseases are caused by tiny organisms (microbes). Not a single method of bacterial research made it possible to isolate microbes whose presence is associated with smallpox, foot-and-mouth disease, and plague.

The idea of the existence of a pathogen different in nature from microbes did not occur to Pasteur. The first virus discovered affected tobacco plants (tobacco mosaic). At that time, this virus caused great economic damage. Scientists set out to find out the cause of this disease. This work was entrusted to D.I. Ivanovsky.

As a result of observations, D.I. Ivanovsky and V.V. Polovtsev first suggested that the tobacco disease, described in 1886 by A.D. Mayer in Holland under the name mosaic, is not one, but two completely different diseases of the same plant: one of them is hazel grouse, the causative agent of which is a fungus, and the other is of unknown origin. D.I. Ivanovsky continues his study of tobacco mosaic disease in the Nikitin Botanical Garden (near Yalta) and the botanical laboratory of the Academy of Sciences and comes to the conclusion that tobacco mosaic disease is caused by bacteria passing through Chamberlant filters, which, however, are not able to grow on artificial substrates . The causative agent of mosaic disease is called by Ivanovsky either “filterable” bacteria or microorganisms, since it was very difficult to immediately formulate the existence of a special world of viruses. Emphasizing that the causative agent of tobacco mosaic disease could not be detected in the tissues of diseased plants using a microscope and was not cultivated on artificial nutrient media.

He founded virology. Increased interest in virology was caused by the fact that viral diseases are of leading importance. 75% of diseases are caused by viruses. They cause enormous economic damage. After Ivanovsky’s discovery, the Danish scientist Beyering repeated Ivanovsky’s experiments and confirmed that the mosaic pathogen passes through porcelain filters and proved that it is a liquid living contagium. The virus gave it its name. In 1903, the causative agents of swine fever and infectious anemia were discovered. In 1915-1917, bacterial viruses were bacteriophages; by the end of the 40s, more than 40 viruses were discovered, and over the past 40 years, more than 500 viral diseases have become known. Scientists set out to obtain viral agents.

QUESTION No. 3 “PRINCIPLES OF MODERN CLASSIFICATION OF VIRUSES, MAIN GROUPS OF VIRUSES.”

The modern classification of viruses is universal for viruses of vertebrates, invertebrates, plants and protozoa. It is based on the fundamental properties of virions, of which the leading ones are those characterizing nucleic acid, morphology, genome strategy, and AG properties. Fundamental properties are placed in 1st place, since viruses with similar AG properties also have a similar type of nucleic acid, similar morphological and biophysical properties. An important feature for classification, which is taken into account with structural characteristics, is the strategy of the viral genome, which is understood as the method of reproduction used by the virus, determined by the characteristics of its genetic material. AG and other biological properties are characteristics that underlie the formation of a species and have significance within the genus. The modern classification is based on the following main criteria: 1) type of nucleic acid (RNA or DNA), its structure (number of strands); 2) the presence of a lipoprotein membrane; 3) viral genome strategy; 4) size and morphology of the virion, type of symmetry, number of capsomeres; 5) phenomena of genetic interactions; 6) range of susceptible hosts; 7) pathogenicity, including pathological changes in cells and the formation of intracellular inclusions; 8) geographical distribution; 9) method of transmission; 10) AG properties. Based on the listed characteristics, viruses are divided into families, subfamilies, genera and types. A number of rules have been developed to organize the names of viruses. The family names end in "viridae" "virinae" "virus". The name allows the usual Latinized designations, numbers and type designations, abbreviations, letters and their combinations.

QUESTION No. 4 “CHEMICAL COMPOSITION AND PHYSICAL STRUCTURE OF VIRUSES. CONCEPT OF VIRION, CAPSIDS, CAPsomeres. TYPE OF SYMMETRY.

Viruses are made up of a piece of genetic material, either DNA or RNA, that makes up core virus, and a protective protein shell surrounding this core, which is called capsid. A fully formed infectious particle is called virion. Some viruses, such as herpes or influenza viruses, also have an additional lipoprotein shell, which arises from the plasma membrane of the host cell. Unlike all other organisms, viruses do not have a cellular structure. The shell of viruses is often constructed of identical repeating subunits - capsomeres. Capsomeres form structures with a high degree of symmetry that are capable of crystallization. This makes it possible to obtain information about their structure using both crystallographic methods based on the use of X-rays and electron microscopy. As soon as virus subunits appear in the host cell, they immediately exhibit the ability to self-assemble into a whole virus. Self-assembly is also characteristic of many other biological structures and is of fundamental importance in biological phenomena. An indispensable component of the viral particle is one of two nucleic acids, protein and ash elements. These three components are common to all viruses without exception, while the remaining lipids and carbohydrates are not included in all viruses. Viruses, which, in addition to protein and nucleic acid, also contain lipids and carbohydrates, as a rule, belong to the group of complex viruses. In addition to the proteins that make up the nucleoprotein “core,” virions may also contain a virus—specific proteins that have been built into the plasma membranes of infected cells and cover the viral particle when it leaves the cell or “buds off” from its surface. In addition, some enveloped viruses have a submembrane matrix protein between the envelope and the nucleocapsid. The second large group of virus-specific proteins consists of non-capsid viral proteins. They are mainly related to the synthesis of virion nucleic acids. The fourth component sometimes found in purified viral preparations is carbohydrates (in an amount exceeding the sugar content of the nucleic acid). The elementary bodies of the influenza virus and classical fowl plague contain up to 17% carbohydrates.

According to morphological characteristics, all viruses are divided into:

1) Rod-shaped

2) Globular

3)Cuboidal

4) Club-shaped

5) Thread-like

The main ones are the first 4, filamentous in the intermediate form.

The concept of the type of symmetry.

Depending on the location of capsomeres in the protein shell, all viruses are divided into 3 groups:

1) Spiral type

2)Cubic type

3) Combined

1 – have viruses that are large in size and have high polymorphism. Their capsomeres are arranged in the form of a spiral with different diameters and thus most often have a spherical shell, sometimes they are covered with a second shell (peplos). Nucleic acid is twisted like a spring and arranged in coils in the form of protein molecules.

2 – in such viruses, capsomeres are arranged in the form of a regular polyhedron (icosahedron). It is twisted into a ball and is located in the center.

In most viruses, capsomeres have the shape of 5-6 faceted prisms.

3 – this type of symmetry is characteristic of bacteriophages. All varieties of bacteriophages have a head of cubic symmetry, and a tail with a spiral structure. The surface of the head is covered with a protein shell, which consists of homogeneous protein subunits. One of the nucleic acids is located in the cavity of the head. The tail end consists of a hollow rod. It ends with a hexagonal plate at the end. The tail end is surrounded by a collar, to which is attached a sheath covering the entire shaft.

Chemical composition of viruses.

Methods of purification and concentration of viruses by salting out, adsorption, ultrafiltration, and sedimentation made it possible to study the chemical composition. Viruses contain proteins and one of the nucleic acids. Viruses of large and medium sizes also contain lipids, carbohydrates and some other organic and inorganic compounds.

Most of the protein and associated lipids and carbohydrates are the membrane. The substances that make up viruses have characteristics, both chemically and biologically.

Proteins – the main part (20 AA).

The significance of viral proteins is their protective function (capsid formation).

The virus contains enzymes of a protein nature (adsorption, targeting function) and endowed with immune properties (determine antigenic properties).

Features of viral proteins:

1. They have the property of self-assembly (as they accumulate, viral proteins aggregate).

2. They have selective sensitivity in relation to physical and chemical factors.

3.Do not undergo hydrolysis under the influence of proteolytic enzymes.

Proteins make up 50-75% of the mass of virions.

Cells infected with the viral gene encode the synthesis of 2 protein groups:

Structural===, ===non-structural===

1.Structural – the amount in the virion, depending on the complexity of the virion’s organization. Structural proteins of group 2 are divided: a. capsid b. supercapsid (peplomers).

Complex viruses contain both types of proteins. A number of such viruses contain enzymes in their capsids that carry out transcription and replication.

Supercapsid proteins form spines (up to 7-10 nm). The main function of glycoproteins is interaction with specific cell receptors. Another function is participation in the synthesis of cellular and viral membranes.

“Address function” is developed in the process of evolution; it is a search for a sensitive cell.

It is realized through the presence of special proteins that recognize special receptors on the cell.

Non-structural (temporary) viral proteins are precursors of viral proteins, DNA/RNA polymerase synthesis enzymes, ensure transcription and replication of the viral genome, regulatory proteins, polymerases.

Lipids – in complex viruses are found in the supercapsid (from 15 to 35 percent). The lipid component stabilizes the structure of the viral particle.

Carbohydrates – up to 10-13%. They are part of glycoproteins. Play an essential role in protein structure and function.

Nucleic acids are a constant component. Complex polymer compounds. Isolated by Miescher in 1869 from leukocytes. Unlike bacteria, they contain only 1 amino acid. Structurally, nucleic acids are different.

1.Linear double helix with open ends.

2. Linear double helix with closed ends.

3.Linear single-spiral.

4.Ring single-spiral.

1.Linear single-spiral.

2.Linear fragmented.

3.Ring single spiral.

5.Linear double-helix fragmented.

QUESTION No. 5 “RESISTANCE OF VIRUSES TO PHYSICAL AND CHEMICAL FACTORS. PRACTICAL USE OF THESE PROPERTIES."

Different groups of viruses have different resistance in the external environment. The least resistant viruses are those that have lipoprotein membranes; the most resistant are isometric viruses. Thus, orthomyxoviruses and paramyxoviruses are inactivated on surfaces in a few hours, while polioviruses, adenoviruses, and reoviruses remain infectious for several days. However, there are exceptions to this rule. Thus, the smallpox virus is resistant to desiccation and persists in excreta for many weeks and months. The hepatitis B virus is resistant to adverse external factors and retains its activity in serum even after short-term boiling. The sensitivity of viruses to ultraviolet and X-ray irradiation depends primarily on the size of their genome. The sensitivity of viruses to formaldehyde and other chemicals that inactivate genetic material depends on many conditions, including the density of packaging of the nucleic acid in the protein case, the size of the genome, and the presence or absence of outer shells. Viruses with lipoprotein envelopes are sensitive to ether, chloroform and detergents, while simply constructed isometric and rod-shaped viruses are resistant to their action. An important feature of viruses is sensitivity to pH. There are viruses that are resistant to acidic pH values (2.2-3.0), for example, viruses that cause intestinal infections and enter the body through nutrition. However, most viruses are inactivated at acidic and alkaline pH values.

QUESTION No. 6 “VIRAL NUCLEIC ACIDS. THEIR VARIETIES, STRUCTURES, BASIC PROPERTIES.

Viral DNA molecules can be linear or circular, double-stranded or single-stranded along their entire length, or single-stranded only at the ends. Most nucleotide sequences occur only once in the viral genome, but there may be repeating or redundant regions at the ends. There are also large differences in the size of the genome in the structure of the terminal regions of viral DNA. Animal viruses undergo almost no modifications to their DNA. For example, although the DNA of host cells contains many methylated bases, viruses have, at best, only a few methyl groups per genome. The sizes of RNA virus virions vary greatly - from 7.106 daltons in picornaviruses to >2.108 daltons in retroviruses; however, the size of RNA and, therefore, the amount of information it contains varies to a much lesser extent. The picornavirus RNA is probably the smallest known, containing about 7,500 nucleotides, while the paramyxovirus RNA is perhaps the largest, almost 15,000 nucleotides. Apparently, all independently replicating. Nucleic acids are a constant component. Complex polymer compounds. Isolated by Miescher in 1869 from leukocytes. Unlike bacteria, they contain only 1 amino acid. Structurally, nucleic acids are different.

1. Linear single-helix. 2. Linear fragmented. 3. Ring single-helix. 5. Linear double-helix fragmented.

QUESTION No. 7 “VIRUS PROTEINS, THEIR FEATURES (CHARACTERISTICS OF THE PROPERTIES OF NEURAMINIDASES AND ANTIGENS OF MIXOVIRUSES).”

They represent an extremely heterogeneous class of biological macromolecules. AKs are essential components of proteins. Alpha-AA are relatively simple organic molecules. The molecular weight of AK lies in the range of 90-250D. The polypeptide can contain from 15 to 2000 AA. The most common polypeptides weighing from 20 to 700 kDa, consisting of 100-400 AA. Viral proteins—proteins encoded by the virus genome—are synthesized in the infected cell. Based on the function of localization, structure and regulation of synthesis, viral proteins are divided into structural and non-structural; enzymes, precursors, histone-like capsid proteins; membrane, transmembrane.

Structural proteins– all proteins that are part of mature extracellular virions. They perform a number of functions in the virion: 1) protection of the NK from external damaging influences; 2) interaction with the membrane of sensitive cells during the first stage of their infection; 3) interaction with viral NK during and after its packaging into the capsid; 4) interaction with each other during capsid self-assembly; 5) organizing the penetration of the virus into a sensitive cell. These 5 functions are inherent in the structural proteins of all viruses without exception. All functions can be realized by one protein. 6) ability to be destroyed during the liberation of the NK; 7) organization of exit from the infected cell during the formation of the virion. 8) organization of “melting” and fusion of cell membranes.

Proteins may also have the ability to catalyze certain biochemical reactions: 9) RNA-dependent RNA polymerase activity. This function is performed by the structural proteins of all viruses whose virions contain RNA, which does not play the role of mRNA; 10) RNA-dependent DNA polymerase activity - this function is performed by special retroviral proteins called reversetases; 11) protection and stabilization of the viral NK after its release from the capsid in the infected cell.

Depending on the location of a particular protein in the virion, groups of proteins are distinguished: A) Capsid proteins - in the virions of complexly organized viruses, these proteins can perform only 2-3 functions - protection of the NK, the ability to self-assemble and destroy during the release of the NK. In the virions of simple viruses, their functions are usually more diverse. B) Proteins of the viral supercapsid shell - their role is reduced mainly to organizing the budding of virions, the ability to self-assemble, interacting with the membrane of sensitive cells, organizing penetration into a sensitive cell. C) Matrix proteins are proteins of the intermediate layer of virions, located immediately under the supercapsid shell of some viruses. Their main functions: organizing budding, stabilizing the structure of the virion due to hydrophobic interactions, mediating the connection of supercapsid proteins with capsid proteins. D) Viral core proteins - represented mainly by enzymes. Viruses with multilayer capsids may also have a protective role. E) Proteins associated with NK of the innermost layer of virions.

Non-structural proteins– all proteins encoded by the viral genome, but not included in the virion. They have been studied less well, which is due to the incomparably greater difficulties that arise during their identification and isolation compared to structural proteins. Non-structural proteins, depending on their function, are divided into 5 groups: 1) Regulators of viral genome expression - directly affect the viral NK, preventing the synthesis of other viral proteins, or, conversely, triggering their synthesis. 2) Precursors of viral proteins - are precursors of other viral proteins that are formed from them as a result of complex biochemical processes. 3) Non-functional peptides – are formed in an infected cell. 4) Inhibitors of cellular biosynthesis and inducers of cell destruction - these include proteins that destroy cellular DNA and mRNA, modify cellular enzymes, giving them virus-specific activity. 5) Viral enzymes - enzymes encoded by the viral genome, but not included in the virions.

QUESTION No. 8 “PERIODS AND STAGES OF VIRUS REPRODUCTION. TYPES OF INTERACTION.”

Interaction of viruses with host cells and virus reproduction.

Viruses go through a complex development cycle in a cell. Morphogenesis of viruses represents the main stage of this development and consists of formative processes leading to the formation of a virion as the conclusion of the form of virus development. Ontogenesis and reproduction of the development of the virus are regulated by the genome.

In the 50s it was established that the multiplication of the virus occurs through reproduction, i.e. reproduction of nucleic acids and proteins followed by virion assembly. These processes occur in different parts of the cell, for example in the nucleus and cytoplasm (disjunctive mode of reproduction). Viral reproduction is a unique form of expression of a foreign infection in the cells of humans, animals, insects and bacteria.

Morphogenesis is regulated by morphogenetic genes. There is a directly proportional relationship between the complexity of the virion ultrastructure and its morphogenesis. The more complex the organization of the virion, the longer the development path of the virus. This entire process is carried out with the help of special enzymes. Because Viruses do not have their own metabolism and therefore require enzymes. However, over 10 enzymes, different in origin and functional significance, have been found in viruses.

By origin: virion, virus-induced, cellular, modified by viruses. The former are part of many DNA and RNA viruses. DNA-dependent RNA polymerase, protein kinase, ATPase, ribonuclease, RNA-dependent RNA polymerase, exonuclease and others.

Virion forms include: hemoglutinin and neuraminidase, lysozyme.

Virus-inducing enzymes are enzymes whose structure is encoded in the genome, and synthesis occurs on the host ribosome - early virion proteins.

Cellular - include enzymes of the host cell, are not virus-specific, however, when interacting with viruses, the activity can be modified.

According to their functional significance, enzymes are divided into 2 groups:

— Participating in replication and transcription;

— Neuraminidase, lysozyme and ATPase, which contribute to the penetration of the virus into the cell and the exit of mature virions from the cell.

Reproduction of virions is characterized by a change of stages:

According to modern data, there are 3 main periods in the reproduction cycle:

1. Initial (preparatory) 2. Middle (latent) 3. Final (final)

Each period includes a number of stages:

First stage

1.Adsorption of the virus on the cell.

2. Penetration into the cell.

3.Deproteinization (release of nucleic acid).

Second phase

1.Biosynthesis of early viral proteins

2.Biosynthesis of viral components

Third stage

1.Formation of mature virions

2. Exit of mature virions from the cell.

1.Adsorption is a physical and chemical process that is a consequence of the difference in charges. This stage is reversible; its outcome is influenced by the acidity of the environment, temperature and other processes.

The main role in virus adsorption is played by the interaction of the virus with complementary cell receptors. By chemical nature they belong to mucopolyproteins. The rate of adsorption is influenced by hormones acting on the receptors. Adsorption of the virus may not occur, which is due to the different sensitivity of cells to viruses. Sensitivity, in turn, is determined by:

The presence in the cell membrane and cytoplasm of enzymes that can destroy the membrane and release nucleic acid.

The presence of enzymes, material that ensures the synthesis of viral components.

2.Virus penetration into the cell:

The virus penetrates in 3 ways - by direct injection (typical of phages); by destroying the cell membrane (fusion path - typical for plant viruses); by pinocytosis (characteristic of vertebrate viruses).

3. Reproduction of DNA-containing viruses.

4. Exit of the virion from the cell:

1. They leak through the cell membrane and are covered with a supercapsid, which includes cell components: lipids, polysaccharides. In this case, the cell retains its vital activity and then dies. In some cases, during the process of reproduction, processes can occur over several years, but vital activity is maintained. With this method, mature virions leave the cell gradually and over a relatively long period of time. This path is typical for complex viruses that have a double shell.

Anomalous viruses.

During the reproduction process, various abnormal viruses are formed. Through the efforts of Academician Zhdanov, in recent years pseudoviruses have been discovered, consisting of an RNA virus and cell proteins that form the capsid. They have infectious properties, but due to the peculiarity of the capsid, they are not susceptible to the action of antibodies that form a response to this virus.

The formation of such viruses is explained by prolonged virus carriage in the presence of specific antibodies in the body.

The reasons for the formation of such virions are:

1.High multiplicity, as a result of which the cell is not able to provide all its offspring with energy material.

2. The action of interferon - it affects the synthesis of DNA and RNA viruses.

QUESTION No. 9 “PECULIARITIES OF BIOSYNTHESIS OF DNA-CONTAINING VIRUSES. THE CONCEPT OF TRANSCRIPTION AND BROADCASTING.”

Transcription - the rewriting of DNA into RNA - is carried out using the enzyme RNA polymerase, the products of which are the biosynthesis of mRNA. DNA viruses that reproduce in the nucleus use cellular polymerase for transcription. RNA-containing viruses are produced by the genome itself. In some RNA-containing viruses, the transfer of genetic information is carried out according to the RNA-RNA-protein formula. This group of viruses includes picornoviruses and cornoviruses.

Protein synthesis occurs as a result of translation into RNA.

Under the influence of enzymes in DNA-containing viruses, mRNA is synthesized, and the mRNA is sent to the ribosomes of the sensitive cell. The synthesis of early virion proteins begins on the ribosomes of the cell (endowed with the properties of enzymes, blocking cellular metabolism).

Early virion proteins give rise to the formation of early virion acids.

As early virion proteins accumulate, they block themselves and the process is rearranged on the ribosomal apparatus. Virions are assembled and the newly formed virions leave the mother cell.

QUESTION No. 10 “TYPES OF INTERACTION, MAIN OUTCOMES OF VIRUS INTERACTION WITH A CELL.”

1) Productive interaction - when viruses multiplying in a cell form a new generation 2) Abortive - when reproduction cycles are interrupted at some stage. 3) Lytic reaction - when after the formation of the virus the cell dies. 4) Latent reaction - when an infected cell retains its viability for a long time. 5) Integration - when the genomes of viruses and cells are combined. In this case, reproduction of genomes occurs in cells and is subject to general regulation. Reproduction of viruses causes pathological changes in the affected cells, expressed by functional and morphological disorders of the cells. Possible outcomes of the processes of interaction between various viruses and cells can be divided into 5 types: 1) Degeneration of cells - leads to their death. In this case, the cell acquires an irregular round shape, becomes rounded, becomes denser, granularity appears in the cytoplasm, wrinkling and fragmentation of the nuclei. 2.The formation of symplasts is multinucleated. accumulations outside the cell. substances. 3) Cell transformation – i.e. formation of foci of random three-dimensional growth. Cells in these foci acquire new hereditary properties, continuously piling up on each other (tumors). 4. Arr. extracellular inclusions, which are products of the cell reaction to the viral particle. 5) Latent infection is a kind of condition. equilibrium between the virus and the cell., when the infection does not manifest itself in any way. Insignificant production of the virus is observed, without cell damage.

QUESTION No. 11 “PHASES OF INTERACTION OF RNA CONTAINING VIRUS WITH A CELL.”

See question No. 8

QUESTION No. 12 “PATHOGENESIS OF VIRAL INFECTIONS

Tropism is the tendency of a virus to one or another site of infection. For respiratory infections, the virus is localized in the nasopharynx, trachea and lungs; for enteroviruses - in feces; for neurotropic ones - in the GM or SM; with dermotropic - in the skin.

Pathogenesis of viral infections.

Pathogenesis is understood as a set of processes that cause a disease, its development and outcome.

Pathogenesis is determined by:

1.Tropism of the virus

2.Number of infectious particles

3. Cell response to infection.

4. The body's response to changes in cells and tissues.

5. Speed of reproduction.

The tropism of viruses is based on the sensitivity of certain cells to the virus.

Pathogenesis is determined by the main mechanisms of interaction of viruses with cells:

Atrophy or dystrophy (CPD)

Formation of inclusion bodies

Formation of symplasts and syncytia

Transformation

Latent (chronic) infection.

Pathogenesis at the cellular level - this includes CPD (visible morphological changes in cells under the influence of a particular viral agent). The nature of CPP is different and depends on:

1.Type of cell

2.Biochemical properties of the virus

3. Infectious dose

The nature of CPP is assessed using a 4-point cross system and changes are taken into account when cell cultures are used for titration (i.e.).

Pathogenesis at the organismal level.

The state of infection as any biological process is dynamic; the dynamics of interaction are usually called the infectious process. On the one hand, the infectious process includes: the introduction, reproduction and spread of the pathogen in the body, as well as the pathogenic action, and on the other hand, the body’s reaction to this action.

The pathogenic effect of the pathogen may be different. It manifests itself in the form of an infectious disease of varying severity, in others without pronounced clinical signs, in others it manifests itself only by changes identified by virological, biochemical, and immunological methods. It depends on the:

The quantity and quality of the pathogen that has penetrated into a susceptible organism, the conditions of the internal and external environment that determine the resistance of the animal and are characterized by the interaction of micro and macroorganisms. Based on the nature of the interaction between the pathogen and the organism, there are 3 forms:

1.an infectious disease is an infectious process characterized by certain clinical signs, as well as disorders, functional disorders and morphological tissue damage.

2. Microbial carriage is an immunological subinfection. A differentiated approach to various forms of infection makes it possible to correctly diagnose the infection and identify infected animals in a dysfunctional herd. The pathogenesis of any infectious disease is determined by the special action of the pathogen and the body's responses, depending on the conditions in which the interaction of micro and macroorganism occurs. In this case, the routes of penetration and distribution of the pathogen are of no small importance. Pathogen gates: skin, mucous membranes, genitourinary system, placenta.

Each type of pathogen has evolutionarily adapted to such routes of introduction, which provide favorable conditions for reproduction and spread - the entrance gate for each infection is characterized by specificity. To carry out prevention, it is necessary to take into account the specificity of the infection gate. For example, with INAN, the pathogen penetrates the skin through an insect bite. In case of foot and mouth disease, the main route is nutritional; in case of rabies, it is through a bite.

Classification of viral infections.

There are autonomous and integrated infections. Autonomous - in this case, the viral genome replicates independently of the cellular genome. Autonomous infection is typical for most viruses.

Integrated infections - the viral genome is included in the cellular genome, i.e. integrated into the cellular genome and replicated with it. In this case, the viral genome replicates and functions as an integral part of the cellular genome. It can integrate both the entire genome and a part. In integrated infections, there is no assembly of viral particles or exit.

Autonomous infection - a cell sometimes acquires the ability to divide unlimitedly as a result of disruption of the regulatory mechanisms that control division. This is more often observed in oncogenic infections.

Productive and abortive infections:

1. Productive – ends with the release of infectious offspring.

2. Abortive – infectious offspring are not formed or there are few of them.

Forms of the course - both productive and abortive - can occur in acute and chronic forms. An acute infection is an infection that results in the cell either recovering or dying. Acute infection at the cellular level can be cytolytic (when cell death occurs).

A chronic infection is an infection in which a cell continues to produce viral particles for a long time and transfers this ability to daughter cells. More often, an abortive infection takes on a chronic form because viral material accumulates and is transmitted to the daughter cell.

Mixed infection - a cell is infected with two or more different viruses, as a result of which two or more infectious processes can be combined in the cell. There are several possible options for virus interaction during a mixed infection:

1. Interference - one virus suppresses the action of another.

2. Complementation (exaltation) - one virus enhances the effect of another.

Classification of viral infections at the organismal level.

The classification is based on:

1. Generalization of the virus

2.Duration of infection

3.Manifestation of clinical symptoms

4. Release of viruses into the environment

One of the forms can transform into another (for example, focal to generalized, acute to chronic).

Focal infection.

The virus acts near the entry gate of infection, due to local reproduction. They have a shorter latent period compared to generalized ones.

Generalized infections.

After a limited period of reproduction in primary foci, generalization of infections occurs - viruses penetrate other systems, for example, foot-and-mouth disease, polio, and smallpox.

Acute infection.

It lasts for a short period and is released into the environment. Ends in death or recovery.

Persistent infection.

With prolonged interaction of the virus with the body. It can be latent, chronic, slow.

Latent infection - is not accompanied by the release of the virus into the environment; under certain conditions it can become acute and chronic.

For influenza, sepsis, AIDS, etc.

Chronic infection.

This is a long-term process. Characterized by periods of remission (adenovirus, herpes).

Slow infections are a kind of interaction between a virus and a phage and are characterized by long incubation periods.

Sources of infection.

When studying any infectious disease, it is important to know the source, place of permanent residence and reproduction, routes of spread, place and timing of preservation, occurrence in the external environment, methods of transmission from sick to healthy.

The natural environment is a living organism, here it finds all the conditions for existence. The duration of stay of viruses varies widely and depends on the biological properties and reactivity of the body. From the conditions of pathogenesis. Sources of infection are only infected organisms. They only play a role in the transmission process. Most animals excrete viruses in excreta, secretions, blood, effluent, and sputum. In most viral infections, the pathogenesis is based on viremia (foot-and-mouth disease, plague, etc.). In these diseases, the virus is released in all possible ways. In chronic cases, viral shedding is less intense, but can be prolonged. In case of viral diseases, localization is limited to one way: pneumonia - with drops of sputum. The most intense release of the virus into the external environment is observed during the acute period of the disease, but in a number of diseases it also occurs during the incubation period. Asymptomatic infections occur when vaccinated with live vaccines.

QUESTION No. 13 “RULES FOR COLLECTING PATHMATERIAL FROM SICK AND DEAD ANIMALS IN THE EVENT OF SUSPECTED VIRAL DISEASES. TRANSPORTATION AND PREPARATION OF IT FOR VIRUSOLOGICAL STUDIES.

Material for research from sick, dead or forcedly killed animals should be taken as quickly as possible after the appearance of clear signs of the disease or no later than 2-3 hours after clinical death or slaughter. This is due to the fact that immediately after the disease or in the first 1-2 days, the barrier role of the intestine is significantly weakened, which, along with increased permeability of blood vessels, contributes to the dissemination of intestinal flora. In addition, as the infectious process continues and even deepens, the amount of virus may decrease as a result of the influence of the body's defense mechanisms. When taking material for virus isolation, one should proceed from the pathogenesis of the infection being studied (entry gate, routes of spread of the virus in the body, places of its reproduction and routes of excretion). For respiratory infections, nasopharyngeal swabs, nasal and pharyngeal swabs are taken to isolate viruses; for enterovirus - feces; with dermotropic - fresh skin lesions. Various excreta and secretions, pieces of organs, blood, and lymph can serve as materials for isolating the virus. Blood is taken from the jugular vein; in pigs, from the tip of the tail or ear. Washings from the conjunctiva, from the nasal mucosa, from the posterior wall of the pharynx, rectum and cloaca in birds are taken with sterile cotton swabs and immersed in penicillin vials. When taking material from the nasopharynx, you can use the device designed by Thomas and Scott. Saliva flowing from the mouth can be collected directly into a test tube. Urine is collected using a catheter into a sterile container. Feces are removed from the rectum with a spatula or stick and placed in a sterile tube. Vesicular fluid can be collected with a syringe or Pasteur pipette into a sterile tube. The walls of the canker sores and crusts from the surface of the skin are removed with tweezers. After the death of the animal, it is important to take pieces of organs as quickly as possible, because... With many viral infections, the phenomenon of post-mortem autosterilization is observed, as a result of which the virus may not be detected at all or its amount will be very small. Next, the pathological material is placed in low temperatures (dry ice+alcohol; snow+salt) or glycerin on ICH. Patent material must be provided with a reliable and clear label. You need to write what material was obtained from what animal. A cardboard or plywood tag is hung on the thermos with PM samples, indicating the farm, type of animal, type of material, and date. The thermos must be sealed and delivered by express. It is recommended that samples delivered to the laboratory be used immediately for virus isolation. In the laboratory, the resulting pathological material is freed from preservatives, thawed, washed from glycerin, weighed and measured. Some are taken for research, some in the refrigerator. The preparation of organs and tissues is carried out as follows: the virus is released from the cells of organs and tissues - the material is thoroughly crushed and ground in a mortar with sterile quartz sand. A 10% suspension is usually prepared from the ground material in Hanks or phosphate buffer. The suspension is centrifuged at 1500-3000 rpm, the supernatant is sucked off and freed from microflora by treating with antibiotics (penicillin, nystatin). The suspension is exposed to AB for at least 30-60 minutes at room temperature, then the material is subjected to bacteriological control by inoculation on MPA, MPB, MPPB, Sabouraud's medium. The suspension is stored at minus 20-minus 70 C.

QUESTION No. 14 “METHODS FOR PRESERVATION OF VIRUSES AND THEIR PRACTICAL IMPORTANCE.”

The following methods of virus preservation are used:

1) when storing viral material (pieces of organs or tissues), glycerin (50% solution in ICN) is often used, which has a bacteriostatic effect and at the same time protects viruses. In this case, it can be stored for several months at 4C.

2) viruses are most often stored in refrigerators that provide temperatures of -20, -30, -70C. At this temperature, some viruses lose their infectivity relatively quickly without the addition of protective substances. The addition of inactivated blood serum or skim milk or 0.5-1.5% gelatin has a good protective effect when freezing and storing viruses.

3) Quick freezing to minus 196C with liquid nitrogen. Viruses sensitive to low pH values should be frozen in liquids that do not contain monobasic phosphates.

4) Lyophilization - frozen drying under vacuum conditions - is a very good method of canning. In lyophilized form, viruses can be stored for several years.

QUESTION No. 15 “WORK RULES IN A VIRUSOLOGY LABORATORY. SAFETY PRECAUTIONS WHEN WORKING WITH VIRUS-CONTAINING MATERIAL.”

All laboratory personnel are instructed and trained in safe working methods, provided with overalls, safety footwear, sanitary protection and protective equipment in accordance with current standards. The basic rules of work are as follows: 1) entry of unauthorized persons into the production premises, as well as entry of employees into the laboratory without a gown and spare shoes is strictly prohibited; 2) it is prohibited to leave the laboratory in gowns and special shoes or to put on outerwear over the gown, to smoke, to eat and to store food in the laboratory. In boxing, they wear a sterile gown, mask, cap, and, if necessary, wear rubber gloves and goggles. Be sure to change your shoes. 3) all material entering the laboratory for testing must be considered infected. It must be handled very carefully; when unpacking its jars, the outside should be wiped with a disinfectant solution and placed on a tray or in ditches. The work area on the table is covered with several layers of gauze moistened with a 5% chloramine solution. When working with pipettes, use rubber bulbs. Pipettes, slides and cover glasses and other used glassware are disinfected by immersing them in 5% chloramine, phenol, Lysol, sulfuric acid. 4) upon completion of work, the workplace is tidied up and thoroughly disinfected. Virus-containing material necessary for further work is stored in a refrigerator and sealed. 5) hands are thoroughly washed with 5% chloramine, gloves are removed, disinfected a second time, disinfected and washed. When working in a virology laboratory, employees must strictly adhere to the methods and rules of asepsis and antisepsis. Asepsis is a system of measures and work methods that prevent the entry of microorganisms and viruses from the environment into the human body, as well as the material being studied. It involves the use of sterile instruments and materials, disinfection of employees’ hands, and compliance with special sanitary and hygienic rules and work practices. Antiseptics is a set of measures aimed at destroying microorganisms and viruses that can cause an infectious process when they come into contact with damaged or intact areas of the skin and mucous membranes. Ethyl alcohol (70%), alcohol solution of iodine, brilliant green and others are used as antiseptics. Disinfection is the disinfection of environmental objects by destroying pathogenic microorganisms and viruses for humans and animals by physical means and with the help of chemicals. Sterilization – sterilization, complete destruction of microorganisms and viruses in various materials. It is carried out using physical and chemical methods.

QUESTION No. 16 “SCHEME FOR LABORATORY DIAGNOSTICS OF VIRAL INFECTIONS.”

Laboratory diagnostics is a system of measures to detect and indicate the virus. It includes: receipt of sent pathological material, examination of pathological material using a rapid diagnostic method, research using long-term methods (retrospective diagnosis, examination of paired sera in seroreactions).

Laboratory research. I. Indication of the virus in pathological material. 1. Detection – light microscopy of large viruses (Poxviridae), electron microscopy. 2. Detection of inclusion bodies. (Babes-Chenegri bodies in rabies) 3. Detection of viral antigens: serological reactions. 4. Detection of viral NK (DNA probes and PCR - polymerase chain reaction). 5. Detection of the active form of the virus by bioassay (laboratory animals, chicken embryos, cell culture). 6. Detection of hemagglutinins in hemagglutinating viruses (currently practically not used due to the availability of more accurate methods). II. Isolation (isolation) of the virus from pathological material. At least three blind passages are carried out, and a bioassay is performed. A) Laboratory animals (clinic, death, pathological changes) B) Chicken embryos (death, pathological changes, RGA) C) Cell culture (CPD, RGAd, plaque method) III. Identification of the isolated virus - serological reactions. IV. Evidence of etiological role. Sometimes it is necessary to prove the etiological role of the isolated virus. For this purpose, paired blood sera are used in serological reactions. An isolated virus is used as an AG, and paired sera are used as an AT. An increase in antibody titer in the second serum by 4 or more times indicates the etiological role of the isolated virus.

QUESTION No. 17 “CLINICAL-EPIZOOTOLOGICAL DIAGNOSTICS OF VIRAL DISEASES OF ANIMALS, ESSENCE, SIGNIFICANCE.”

Clinical-epidemiological or pre-laboratory diagnostics - carried out on farms and allows only a preliminary diagnosis to be made; recognition is carried out based on collection, comparison of analysis of sick animals (clinical symptoms of the disease, pathological changes in organs). Collecting epidemiological data is very important; it allows us to obtain data on how the disease progresses and information about farms. If the farms are not prosperous, then this once again confirms the diagnosis. A clinical examination focuses the veterinarian on only a few types of diseases. Laboratory diagnostics are still of primary importance.

QUESTION No. 18 “METHODS FOR DETECTING VIRUSES IN PATTERN MATERIAL.”

I. Indication of the virus in pathological material. 1. Detection – light microscopy of large viruses (Poxviridae), electron microscopy. 2. Detection of inclusion bodies (Babes-Chenegri bodies in rabies) 3. Detection of viral antigens: serological reactions. 4. Detection of viral NK (DNA probes and PCR - polymerase chain reaction). 5. Detection of the active form of the virus by bioassay (laboratory animals, chicken embryos, cell culture). 6. Detection of hemagglutinins in hemagglutinating viruses (currently practically not used due to the availability of more accurate methods). Serological tests are used to identify the isolated virus. 1.RIF – immunofluorescence reaction. AG + AT labeled with fluorochrome. Contact is allowed for 30 minutes at 37 C, then a thorough wash is carried out in the laboratory. Detection method: fluorescent light under a microscope. 2.ELISA – enzyme-linked immunosorbent assay. AG + AT with enzyme. Contact, wash, then add a substrate, which upon contact with the AT-enzyme complex gives a color reaction. 3.RSK – complement fixation reaction. AG + AT + complement. Contact. Then the heme system (hemolysin + sheep red blood cells) is added. Contact. If hemolysis does not occur, then AG and AT have fixed complement. Delayed hemolysis is a positive reaction. If hemolysis occurs, then complement is bound by the heme system - the reaction is negative. 4.RDP – diffuse precipitation reaction. AG + AT (diffusion in agar gel). The detection method is the formation of a precipitation contour. 5.RNHA – indirect hemagglutination reaction. Erythrocytes are loaded with antigen and when the antigen-antigen complex is formed, agglutination of erythrocytes occurs. 6.RTGA – hamagglutination inhibition reaction 7.RTGAd – hemadsorption inhibition reaction 8.RN – neutralization reaction. Virus + AT. Contact. Entering a virus-sensitive system. The detection method is to neutralize the infectious activity of the virus.

QUESTION No. 19 “THE PRINCIPLE OF RETROSPECTIVE DIAGNOSTICS, ITS PROS AND CONS.”

Retrospective diagnostics - the goal is to detect the dynamics of the increase in AT, based on the study of paired sera, which are taken twice, at the beginning of the disease and at the end. They are tested in one of the seroreactions. If the increase in AT is 4-5 times greater, the diagnosis is 100%.

Role - the method allows you to reliably make a diagnosis in most cases.

Role – duration of retrospective diagnosis.

QUESTION No. 20 “AUJESKY’S DISEASE VIRUS.”

Aujeszky's disease (pseudorabies, pruritic plague, rabid scabies, infectious bulbar palsy) is an acute disease of all types of farm animals, fur-bearing animals and rodents. It is characterized by signs of damage to the brain and spinal cord, severe itching and scratching.

AD causes particular damage in pig farming and fur farming. In fur-bearing animals this is an acute food infection. The cause is food, which is often slaughterhouse waste and offal obtained from sick animals or virus-carrying animals.

Clinic. The incubation period is 1.5 days - 10-12 days, depending on the method of infection, the virulence of the virus and the resistance of the animal. The virus is pantropic.

In pigs the clinical course proceeds without signs of itching. Suckers and weanlings are seriously ill. The disease is septic in nature. Piglets usually die within 4-12 hours. In piglets from 10 days to 3 months, the first signs of the disease are fever (40-42), depression, mucous discharge from the nose. Later, signs of central nervous system damage appear: restlessness, maneuvering movements, loss of orientation, convulsions, arching of the back, paralysis of the pharynx, larynx, limbs, pulmonary edema, salivation. The illness lasts from several hours to 3 days. Mortality: 70-100%

In sows it manifests itself as a flu-like syndrome with recovery after 3-4 days.

In cattle, the temperature rises to 42 C, chewing stops, severe itching in the nostrils, lips, cheeks, refusal to feed, lethargy, anxiety, fear, rapid breathing, sweating, cramps of the chewing and neck muscles. Death occurs with increasing lethargy after 1-2 days. Recovery is extremely rare.

Carnivorous animals experience food refusal, fearfulness, restlessness, and severe itching. Sometimes dogs and cats show signs of rabies. Then paralysis of the pharynx occurs. Death in 2-3 days. Animals are not the source of the virus and do not excrete it, being an ecological dead end.

Aujeszky's disease can be suspected based on characteristic clinical symptoms and pathological changes (clinical, epizootological and pathological diagnostics).

Material for research: swabs from the nasal cavity and blood (preferably paired serum), from corpses - pieces of the brain, lungs, liver, spleen.

Express method - detection of viral antigen in RIF. Virological method: a) isolation of the virus on a culture of piglet kidney cells: b) bioassay on rabbits (characteristic itching and scratching at the site of infection).

Identification: RIF, RN.

Retrospective diagnosis: based on the increase in antibody titer in paired serum samples.

It is necessary to differentiate Aujeszky's disease from rabies, swine fever, influenza, erysipelas, and table salt poisoning.

Live VGNKI virus vaccine and inactivated cultural vaccine are used - immunity for 6-10 months. Subunit and recombinant vaccines are used abroad.

QUESTION No. 21 “SIGNIFICANCE AND FEATURES OF VIRAL PROTEINS.”

See question number 7

QUESTION No. 22 “GENERAL PRINCIPLES OF SEROLOGICAL REACTIONS AND THEIR USE IN THE DIAGNOSIS OF VIRAL DISEASES.”

In order to determine the type of a given virus, serological methods are used when studying protective processes in the body of a sick person or infected animal. Serology (from the Latin Serum - serum, liquid component of blood) is a branch of immunology that studies antigen reactions with specific protective substances, antibodies, that are found in blood serum. Antibodies neutralize the effect of the virus. They bind to certain antigenic substances located on the surface of viral particles. As a result of the binding of antibody molecules to the surface structure of the virus, the latter loses its pathogenic properties. To establish the level (quantity) of antibodies in the serum or determine the type of a given virus, a virus neutralization reaction is performed. It can be carried out both in animals and in cell culture.

The minimum concentration of serum containing antibodies sufficient to neutralize the virus and prevent it from developing CPE is called the titer of virus neutralizing serum. This concentration can also be detected using the plaque method.

To detect antibodies, the method of inhibiting hemagglutination (the gluing of red blood cells under the influence of a virus) and the method of complement fixation are used. Among the methods used in virology for various research purposes, we can also mention the methods by which virological material is prepared for physical and chemical analyzes that facilitate the study of the fine structure and composition of viruses. These tests require large quantities of completely pure virus. Virus purification is a process in which all foreign particles that contaminate it are eliminated from a suspension with a virus. These are mainly pieces and “fragments” of host cells. Simultaneously with purification, thickening of the suspension usually occurs, increasing the concentration of the virus. This provides source material for many studies.

Using a serological reaction, you can: determine the antibody titer to the hemagglutinating virus in serum; identify an unknown hemagglutinating virus from known sera; establish the degree of antigen relatedness of 2 viruses, determine the titer of virus-neutralizing antibodies in serum, or the neutralization index, identify an unknown virus by testing it with various known sera.

Serological reactions.

1. RIF – immunofluorescence reaction.

AG + AT labeled with fluorochrome. Contact is allowed for 30 minutes at 37 C, then thoroughly washed in saline solution. Detection method: fluorescent light under a microscope.

2. ELISA – enzyme-linked immunosorbent assay.

AG + AT with enzyme. Contact, wash, then add a substrate, which upon contact with the AT-enzyme complex gives a color reaction.

3. RSK – complement fixation reaction.

AG + AT + complement. Contact. Then the heme system (hemolysin + sheep red blood cells) is added. Contact. If hemolysis does not occur, then AG and AT have fixed complement. Delayed hemolysis is a positive reaction. If hemolysis occurs, then complement is bound by the heme system - the reaction is negative.

4. RDP – diffuse precipitation reaction.

AG + AT (diffusion in agar gel). The detection method is the formation of a precipitation contour.

5. RNHA – indirect hemagglutination reaction.

Erythrocytes are loaded with antigen and when the antigen-antigen complex is formed, agglutination of erythrocytes occurs.

6. RTGA – hamagglutination inhibition reaction

7. RTGAd – hemadsorption inhibition reaction

8. RN – neutralization reaction.

Virus + AT. Contact. Entering a virus-sensitive system. The detection method is to neutralize the infectious activity of the virus.

QUESTION No. 23, 25 “RTGA AND ITS USE IN VIRUSOLOGY. ADVANTAGES AND DISADVANTAGES".

One of the simplest serological reactions is the hemagglutination inhibition reaction. It is based on the fact that antibodies, when encountering a homologous antigen, neutralize not only its infectious, but also hemagglutinating activity, because block virion receptors responsible for hemagglutination, forming an “AG + AT” complex with them. The principle of RTGA is that equal volumes of blood serum and virus suspension are mixed in a test tube and, after exposure, it is determined whether the virus remains in the mixture by adding a suspension of red blood cells. Agglutination of erythrocytes indicates the presence, and the absence of hemagglutination indicates the absence of virus in the mixture. The disappearance of the virus from the virus + serum mixture is regarded as a sign of interaction between serum and virus ATs. RTGA allows you to solve the following problems: determine the titer of antibodies to the hemagglutinating virus in serum; identify an unknown hemagglutinating virus from known sera; establish the degree of AG relationship between the two viruses. Advantages of RTGA: simplicity of technique, speed, no sterile work required, specificity, low cost. Disadvantage of RTGA: only possible with hemagglutinating viruses.

The principle of AT titration in RTGA is as follows: prepare a series of successive (usually 2-fold) dilutions of the test serum in equal volumes (usually 0.25 or 0.2 ml); to each dilution add the same volumes of homologous virus in a titer of 4 HAE; the mixtures are kept for a certain time at a certain temperature, equal volumes of a 1% suspension of washed erythrocytes are added to all mixtures; After exposure, hemagglutination in each mixture is assessed in crosses.

QUESTION No. 26 “RDP. IMMUNOLOGICAL BASIS OF THE METHOD, STATEMENT AND ACCOUNTING OF RESULTS. ADVANTAGES AND DISADVANTAGES".

RDP in the gel is based on the ability to diffusion in gels of AT and soluble AG and the absence of such ability in the “AG + AT” complex. This complex is formed upon contact of homologous AG and AT diffusing towards each other. It is deposited at the site of formation in the thickness of the gel in the form of a precipitation band. Starch, gelatin, agar-agar and more are used as gels. Agar gel is often used in laboratory practice. Serum antibodies are Ig molecules, which, despite their rather large size. Able to diffuse in agar gel. Viral Ags are viral proteins. They can be found in virions, representing so-called corpuscular AGs. Large sizes that do not allow them to diffuse in the agar gel. But viral proteins can also be in the form of free molecules formed as a result of the destruction of virions and (or) the destruction of the cells in which they were formed. These are soluble antigens. They are capable of diffusion in an agar gel. The technique for setting up RDP in a gel is to make several depressions in a layer of agar gel and pour AG and serum into them. So that AG and serum are in adjacent wells. From the wells, AG and serum begin to diffuse into the gel layer. Diffusion is directed in all directions from each hole. In the space between the wells containing AG and serum, the latter diffuse towards each other. If they turn out to be homologous, then an “AG + AT” complex is formed, which is not capable of diffusion due to its larger size. It settles at the site of formation in the form of a whitish precipitation streak. RDP solves the following problems: 1) detection of antibodies homologous to antigens in blood serum; 2) detection in the material of an antigen homologous to known serum antibodies; 3) identification of an unknown virus; 4) titration of serum AT. Here, the highest serum dilution, which still gives precipitation with homologous antigen, serves as an indicator of the antibody titer in the serum. RDP is often used to diagnose bovine leukemia and equine infectious anemia. The reaction can be carried out in Petri dishes, on glass slides, capillaries (rarely). To carry out RDP on glass slides, you need: defatted glass slides, graduated pipettes (2-5 ml), Pasteur pipettes; a tube with a diameter of 5 mm or a stamp, a wet chamber, a tool for extracting gel, agar, AG, serum from the wells. Setting up the RDP: The glass slides are placed on a cold surface. Pour agar from a pipette (layer 1.5-2 mm), allow to cool for 5-10 minutes. Holes are cut out and soldered. The RDP components are poured into the wells and placed in a humid chamber (where they are left at room temperature or placed in a thermostat). The RDP preparation on glass slides can be dried after 48-72 hours and stained with amide black solution. This allows the preparation to be stored indefinitely and improves the ability to photograph precipitation bands. Advantages of RDP: simplicity of the technique, quick response, undemanding to the purity of the components, no sterile work required, minimal need for components, suitability for working with any soluble antigens, the ability to document the result by photographing. Disadvantages of RDP: low sensitivity. The reaction is used to detect rabies viruses, infectious bovine rhinotracheitis, African swine fever, canine fever, and others in pathological material; And also for the identification of equine infectious anemia viruses, adenoviruses, respiratory syncytial virus, bovine diarrhea virus, for the detection in blood serum of antibodies to equine infectious anemia viruses, bovine respiratory syncytial virus and in many other cases.

QUESTION No. 27 “RSK. IMMUNOLOGICAL BASIS AND CHARACTERISTICS OF REACTION COMPONENTS.”

The complement fixation test (FFR) is one of the traditional serological tests used to diagnose many viral diseases. The name itself largely reflects the essence of the method, which consists of two separate stages. The first stage involves an antigen and an antibody (one of these ingredients is known in advance), as well as a certain amount of pre-titrated complement. If the antigen and antibody match, their complex binds complement, which is detected at the second stage using an indicator system (a mixture of sheep red blood cells and antiserum to them - hemolysin). If complement is bound by the interaction of antigen and antibody, then lysis of red blood cells does not occur (positive RBC). With negative RSC, unbound complement promotes hemolysis of erythrocytes (Fig. 80).

RSCs are often used in diagnostic practice for the detection and identification of viruses, detection and titration of antibodies in blood serum.

The main components of RSC are antigens (known or detectable), antibodies (known antisera or test sera), complement, hemolytic serum and sheep erythrocytes; Isotonic sodium chloride solution (pH 7.2-7.4) or various buffer solutions are used as a diluent. Antigens and serums may have anti-complementarity, i.e. the ability to adsorb complement, which delays hemolysis and distorts the results of the reaction. To get rid of anticomplementarity, antigens are purified by various methods: acetone, freon, ether, chloroform, etc., depending on the type of tissue used as the antigen and the virus. Serums are freed from anticomplementarity by heating, treating complement and other methods.

Antigens for CSC are prepared from the organs of infected animals, from the allantoic or amniotic fluid of infected chicken embryos, as well as from the liquid medium of infected cell cultures.

differs significantly from its preparation for bacterial infections. This is due to a number of specific properties of viruses.

First, to release viral antigen from a cell, it is often necessary to further process the infectious material in order to destroy the cells and release the antigen.

Secondly, the greater thermolability of viral antigens compared to bacterial ones. In most viruses, the complement-fixing antigen is associated with the infectious particle, and its destruction occurs in parallel with the loss of the infectious one. Therefore, materials for obtaining the antigen must be taken from dead animals only in the first hours after their death, or better yet, during life. Preservation of virus-containing material with various disinfectants often does not give positive results, since many of them cause the destruction of the viral antigen.

Thirdly, the unevenness of complement fixation when they are worn differently; with an excess of antibodies, complement fixation sharply decreases, since the active antigen + antibody complex is presented mainly in the form of antibodies and the active complement surface is insignificant. The same is observed in the zone of excess antigen, where the suppression of complement fixation occurs even faster. Therefore, to establish the optimal zone of complement fixation, preliminary titration of antigen and antibodies is necessary.

Fourthly, the volume of the antigen + antibody complex is insignificant. The size of the viral particles entering the complex is very small, and therefore the area of complement fixation is insignificant. With an increase in the volume of the antigen + antibody complex by lengthening the period of complement fixation (up to 18 hours at 4 ° C), the sensitivity of the reaction increases, but its specificity decreases, since with a long period of fixation, the fixation of complement by nonspecific antigens (tissue) increases.

And finally, fifthly, the high complementary activity of the viral antigen. To exclude nonspecific complement fixation, more complete purification of the viral antigen from tissue fragments is necessary.

A big obstacle to the use of RSC in the diagnosis of viral diseases of animals and humans is the uneven accumulation of viral antigen during different periods of the disease and especially during different infections.

RSC is used to determine the types and subtypes (variants) of the foot-and-mouth disease virus that cause disease in animals, to test production strains of the foot-and-mouth disease virus in the manufacture of vaccines and laboratory strains in research work.

QUESTION No. 28 “TITER OF VIRUSES AND PRINCIPLES OF ITS DETERMINATION IN UNITS OF 50% INFECTIOUS ACTION.”

The titer is the amount of virus contained in a unit volume of material. Of the local damage caused by viruses, the most famous are plaques and pockmarks on the XAO EC. If there is evidence to the contrary, the infectious activity of the virus can be measured in plaque-forming units (PFU) or pox-forming units (PFU) 1 PFU = dose of virus capable of causing the formation of one plaque, and one PFU - one pock. Methods: several CCs or ECs are infected at KhAO. The arithmetic mean number of pockmarks or plaques is calculated. It = PFU or OFU of the virus. Calculate how many PFU or TFU are per unit volume of virus-containing material. This is the title. T=n/Va, where n is the arithmetic mean of plaques or pockmarks, and is the dilution of the material, V is the administered dose. Method of 50% infectious action. One unit of the amount of virus is a dose that can cause an infectious effect in 50% of those infected. The number of such doses per unit of material will express the titer of the virus in this material. A 10-fold dilution of the test material is prepared, then equal groups of living test objects are infected with equal doses. They take into account the result of the action and find in what dilution the virus showed its effect by 50%. If such a dilution is not immediately found, then it is calculated using the formula T=lgB – (b-50)/(b-a) *lgd, where B is the dilution giving an infectious effect of more than 50%, b is the percentage giving an infectious effect of more than 50%, a – less than 50% d – dilution factor. 1HAE is taken to be a dose of the virus that is capable of agglutinating approximately 50% of the red blood cells contained in the same volume as the virus, 1% of a suspension of washed red blood cells. A series of successive multiple dilutions of the material are prepared and a 1% suspension is added to each dilution. The reaction is scored in crosses. The 2-cross reaction contains 1GAE, which is multiplied by the dilution factor.

QUESTION No. 29 “BIOLOGICAL CHARACTERISTICS OF FOOT-AND-MOUTH VIRUS. DIAGNOSTIC PRINCIPLE"

Foot-and-mouth disease is an acute, highly contagious disease of artiodactyls, manifested by fever, vesicular lesions of the mucous membranes of the mouth, skin of the corolla and udder, in young animals by lesions of the mucous membranes of the mouth, skin of the corolla and udder, and in young animals by damage to the myocardium and skeletal muscles. Foot and mouth disease is recorded in many countries around the world. The incubation period lasts 1-3 days. Sometimes up to 7-10 days. The most characteristic sign of this disease in animals is vesicular lesions of the mucous membranes of the mouth and the skin of the corolla and udder. In cattle - it is acute, benign in adults. Initially, a deterioration in appetite, increased salivation, and an increase in body temperature are noted. On the 2-3 day, aphthae appear on the inner surface of the lips and tongue (in some, in the area of the interhoof gap, on the udder). After a day, erosions form. After 2-3 weeks, the erosions heal and the animal recovers. The virus belongs to the Picornaviridae family, genus Aphthovirus, RNA-containing, does not have a supercapsid shell. Virions are small particles of icosahedral shape. The virus is quite resistant to environmental influences. Domestic and wild artiodactyls are susceptible. The virus can be isolated already during the incubation period. Relapse may be accompanied by prolonged viral carriage. About 50% of recovered cattle can shed the virus for 8 months, and some for up to 2 years. The virus is cultivated on naturally susceptible and laboratory animals: newborn mice, rabbits and guinea pigs. Proliferates well in bud cells. It does not have hemagglutinating properties. There are 7 known types of FMD: A, O, C, Sat-1, Sat-2, Sat-3, Asia-1. In the body of naturally susceptible animals, the virus induces the formation of virus-neutralizing, complement-binding and precipitating antibodies.

Foot and mouth disease virus is usually determined in the RSC. The main components of RSC are AG, AT, complement, hemolytic serum and sheep erythrocytes; ICN or various buffer solutions are used as a diluent. AG and serum may have anticomplementarity - the ability to adsorb complement, which delays hemolysis and distorts the results of the reaction. To get rid of anticomplementarity, AG is purified using various methods: acetone, freon, ether, chloroform, depending on the type of tissue used as AG and virus. AG for RSC is prepared from the organs of infected animals, from the allantoic and amniotic fluid of infected EC, as well as from the liquid medium of infected EC. RSC is used to determine the types and subtypes of foot-and-mouth disease virus that cause disease in animals, to test production strains of foot-and-mouth disease virus in the manufacture of vaccines and laboratory strains in research work.

QUESTION No. 30 “LUMINESTENCE MICROSCOPY. BASICS OF IMMUNOFLUORESCENCE".

The method is based on the phenomenon of luminescence, the essence of which is that by absorbing various types of energy (light, electrical), atoms of certain substances go into an excited state, and then, returning to their original state, release the absorbed energy in the form of light radiation. Luminescence is observed in the form of fluorescence - a glow that occurs at the moment of irradiation with exciting light and stops immediately after its completion. Phosphorescence is a glow that continues for a long time even after the end of the excitation process.

QUESTION No. 31 “RABIS VIRUS, ITS PROPERTIES. PATHOGENICITY. PRINCIPLES OF DIAGNOSTICS".

Rabies is an acute infectious disease that occurs with severe damage to the nervous system, usually with a fatal outcome. Humans and all mammals are susceptible. Rabies is widespread. The pathogen is transmitted by dogs, cats, wild rodents and predators, as well as blood-sucking vampire bats. The duration of the incubation period depends on the location, strength of the bite, the amount and virulence of the virus that has entered the wound, and the resistance of the bitten animal. The incubation period lasts from 1-3 weeks to a year or more. The disease is acute. Clinical signs of an atypical course are loss of appetite, rumen atony, pharyngeal paralysis, drooling. There can also be a violent and quiet course of the disease. The rabies virus (RV) has pronounced neuroprobasia. Penetrating from the periphery along the nerve trunks into the central nervous system centripetally, it spreads in the body centrifugally along the peripheral nerves and enters various organs, including the salivary glands.

The virus belongs to the family Rhabdoviridae, genus Lyssavirus. Virions have the shape of a rod with a chopped end. The virus virion is RNA-containing with a helical type of symmetry and has a lipoprotein envelope. Low temperatures preserve the virus. The VB virion contains glycoprotein and nucleocapsid Ag. The first induces the formation of virus-neutralizing antibodies, and the second – complement-fixing and precipitating antibodies. In the body, the virus is localized mainly in the central nervous system, in the salivary glands, and saliva. Cultivated in mice, rabbits, guinea pigs, and in primary cell cultures. Reproduction of the virus in CC does not always manifest itself as CPE. The sources of infection are sick animals. They transmit the virus through a bite. The diagnosis of rabies is made on the basis of epidemiological, clinical data and laboratory test results, which are of critical importance. For research, fresh corpses of small animals are sent to the laboratory as a whole, and from large and medium-sized animals - the head with 2 cervical vertebrae. The corpses of small animals are treated with insecticides before being sent for research. Laboratory diagnostics include: detection of viral hypertension in RIF and RDP, Babes-Negri bodies and bioassays on white mice. RIF - for this reaction, the bioindustry produces fluorescent anti-rabies gamma globulin. Principle – 1) Make prints or smears from various sections of the left and right side of the GM on glass slides (at least 2 preparations from each section); 2) They are dried and fixed in chilled acetone; 3) Dry, apply fluorescent gamma globulin; 4) Place in a humid chamber; 5) I thoroughly wash the ICN, rinse it with water, air dry it, apply non-fluorescent immersion oil and view it under a fluorescent microscope. In preparations containing WB AG, yellow-green fluorescent granules of different sizes and shapes are observed in neurons, but more often outside cells. RDP – 1) Agar gel is poured onto glass slides 2) Wells are made (D = 4-5 mm); 3) The wells are filled with a paste-like mass from the GM sections. 4) Controls with “+” and “-“ AG are placed on a separate glass using the same stencil; 5) After filling the wells, the preparations are placed in a humid chamber and placed in a thermostat at 37C for 6 hours, then at room temperature for 18 hours. The reaction is considered positive when one or 2-3 lines of precipitation of any intensity appear between the wells containing the brain suspension and rabies gamma globulin. DETECTION OF BODIES - thin smears or imprints are made on glass slides from all parts of the GM and stained according to Sellers or Muromtsev or Mann or Lenz. BIOPEST - white mice (16-20 grams) are selected, the nervous tissue from all parts of the GM is ground in a mortar with sterile sand, ICN is added to a 10% suspension, left for 30-40 minutes and the supernatant is used for infection to infect the pups. Infect 10-12 pieces: half intracerebrally with 0.03 ml, half subcutaneously in the area of the nose or in the upper lip with 0.1-0.2 ml. Observed for 30 days. In the presence of VD in the pathological material, from 7-10 days after infection, mice exhibit symptoms: ruffled fur, a peculiar hunchback of the back, impaired coordination of movements, paralysis of the hind, then forelimbs and death. In dead mice, the GM is examined in the RIF for the detection of Babes-Negri bodies and a RDP is diagnosed. A bioassay for rabies is considered positive if Babes-Negri bodies are found in preparations from the brains of infected mice or if AG is detected by RIF or RDP methods. A negative diagnosis is the absence of death of mice within 30 days.

QUESTION No. 32 “MODERN CLASSIFICATION OF IMMUNITY. AT STRUCTURE CHARACTERISTICS OF DIFFERENT CLASSES OF IMMUNOGLOBULINS AND THEIR STRUCTURE.”

Immunity is a state of the body's immunity to the effects of pathogenic microbes, their toxins and other foreign substances of biological nature.

The body's immune system is a system of organs and cells that responds against foreign substances.

Innate immunity is immunity to infectious agents, located in the genome and manifested by the number and order of arrangement of gangliosides of a certain type on the surface of cell membranes. It is very durable, but not absolute.

Acquired immunity is the body's resistance only to a specific pathogen. This immunity is divided into natural and artificial. Natural is divided into 1. active - it is formed after the animal has naturally recovered from the disease, sometimes after exposure to repeated small doses of the pathogen (immunizing subinfection). 2.passive – immunity of newborns acquired due to the receipt of antibodies to the fetus from the mother through the placenta or after birth through the intestines with colostrum. There are natural and artificial colostral immunity; in the first case, immunity arises due to antibodies naturally produced in the mother's body under the influence of various environmental antigens. In the second case, through targeted immunization of the mother’s body. Naturally acquired active immunity can last 2 years, sometimes for life; artificially acquired immunity can provide a state of immunity from several weeks to several months.

Artificially acquired immunity is also divided into 1.active - occurs as a result of immunization of animals with vaccines (develops after 7-14 days and lasts up to several months to 1 year or more) and passive - is created when immune serum containing specific antibodies against a specific pathogen.

There are also types of immunities: 1. Antibacterial immunity - protective mechanisms are directed against the pathogenic microbe. 2. Antiviral - the body produces antiviral antibodies. 3. Antitoxic immunity - during the formation of which bacteria are not destroyed, but antibodies are produced that effectively neutralize toxins in the patient’s body.

4.Local immunity. 5. Sterile immunity - if after an illness the body is freed from the pathogen, while maintaining a state of immunity. 6. Non-sterile - when immunity is maintained only as long as the pathogen is in the body. 7. Humoral immunity - the production of specific antibodies in the infected body. 8. Cellular – ensured by the formation of T-lymphocytes that specifically react with the pathogen.

Nonspecific factors of the body's defense.

They act as the first protective barrier and do not need to be rebuilt.

The skin is a powerful barrier to the penetration of microorganisms, and mechanical factors are important.

Mucous membranes - in the respiratory tract with the help of ciliated epithelium (moves a film of mucus along with microorganisms towards natural openings), in the mouth to the nasal passages (coughing and sneezing). These membranes secrete secretions that have bactericidal properties, in particular due to lysozyme and IgA. The secretions of the digestive tract have the ability to neutralize many pathogenic microbes. Saliva contains lysozyme, amylase, and phosphatase. Bile causes the death of pasteurella. The intestinal mucosa contains powerful antimicrobial factors.

Lymph nodes - inflammation develops in them, in its zone microbes are fixed by fibrin threads. The complement system and endogenous mediators are involved in inflammation.

Phagocytosis is the process of active absorption by the cells of the body of pathogenic living or killed microbes and other foreign particles entering it, followed by digestion with the help of enzymes.

Antibodies can exist in millions of varieties, each with its own unique antigen binding site. Collectively called immunoglobulin (Ig), AT proteins form one of the major classes of blood proteins, accounting by weight for approximately 20% of total plasma protein. When antigen binds to the membrane antigen-specific receptors of the B cell, cell proliferation and differentiation occurs to form antigen-secreting cells. ATs have 2 identical Ag-binding sites. The simplest AT molecules are schematically shaped like the letter gamma with two identical Ag-binding sites, one at the end of each of the two “branches.” Since there are 2 such sites, these ATs are called bivalent. The protective effect of antigens is not simply explained by their ability to bind antigens. They also perform a number of other functions in which the “tail” is involved; they are called effector functions and are determined not by the participation of the “tail” in them, but by the structure of the Fc fragment. This region of the molecule determines what happens to the AG if it is bound. Antibodies with the same antigen-binding regions can have very different “tail” regions, and therefore different functional properties. The Ig G, D, E and serum IgA molecule consists of 4 polypeptide chains - 2 light and 2 heavy. In higher vertebrates, there are 5 different classes of antibodies - IgA, IgD, IgE, IgG, IgM, each with its own class of heavy chains. IgG antibodies constitute the main class of Ig found in the blood. They are produced in large quantities during the secondary response and are the only antibodies that can pass from mother to fetus. This is the predominant class of antibodies produced in most secondary immune responses; in the early stages of the primary immune response, mainly IgM antibodies enter the blood - they are also the first class of antibodies produced by developing B cells. IgA is the main class of antibodies in milk secretions, saliva, tears, secretions of the respiratory tract and intestinal tract. ATs protect vertebrates from infections by inactivating viruses, mobilizing complement and various cells that kill and engulf invading MOs.

QUESTION No. 33 “PECULIARITIES OF ANTI-VIRAL IMMUNITY.”

1. Antiviral immunity is associated with unique protective mechanisms, because Viruses are unable to develop and reproduce in a non-living cell. The body's protective adaptation is aimed at 2 forms of existence of the virus. On the extracellular viral nonspecific and specific immunity factors, on the intracellular form - the process of phagocytosis. During viral infections, it is always incomplete, interferon has an exogenous effect on the extracellular form, viruses lose their ability to adsorb, endogenous interferon is synthesized in cells in response to viral Ag.

2.Means and methods of influencing viruses can be effective only at certain stages of the virus’s existence, which is most clearly manifested when treating patients with immune drugs, because Abs are not able to penetrate into cells.

3. Antiviral immunity is longer lasting than bacterial immunity, and in some viral infections it is lifelong (rinder, canine, bluetongue, smallpox).

QUESTION No. 34 “ROLE OF LYMPHOID CELLS IN ANTI-VIRAL IMMUNITY (CHARACTERISTICS OF T AND B LYMPHOCYTES).”

T lymphocytes. Thymus-dependent lymphocytes are formed from stem cells of hematopoietic tissue. The precursors of T-lymphocytes enter the thymus, undergo differentiation in it and emerge as cells with various functions, bearing characteristic markers. There are several subpopulations of T lymphocytes depending on their biological properties.

T helper cells (helpers) belong to the category of regulatory support cells. Stimulate the proliferation of B lymphocytes and differentiation into antibody-forming cells (plasma cells). It has been established that the response of B lymphocytes to the influence of most protein antigens is completely dependent on the help of T helper cells, which is carried out in two ways. The first requires direct action of a helper T cell and a responding B cell. It is believed that the T cell recognizes the determinants of the antigenic molecule that is already fixed on the B cell by cell receptors: In the second case, the helper function of T cells in activating B lymphocytes can also be carried out through the formation of soluble nonspecific helper factors - lymphokines (cytokines).

T-killers (killers) perform effector functions, carrying out cellular forms of the immune response. They recognize and lyse cells on the surface of which there are antigens foreign to a given organism (tumor, viral and histocompatibility). Proliferation and differentiation of T-killers occurs with the participation of T-helpers, the action of which is carried out mainly with the help of soluble factors, in particular interleikin. It has been established that killer T cells carry out a delayed-type hypersensitivity reaction.

T-y s i l and t e l and activate the immune response within the T-subsystem of immunity, and T-helpers provide the opportunity for its development in the B-link of immunity in response to thymus-dependent antigens.

T-suppressors (suppressors) provide internal self-regulation of the immune system in two ways: suppressor cells limit the immune response to antigens; prevent the development of autoimmune reactions. T-suppressors inhibit the production of antibodies and the development of delayed-type hypersensitivity; the formation of T-killers ensures the formation and maintenance of immunological tolerance.

Immune memory T cells provide a secondary type of immune response in the event of repeated contact of the body with this antigen. Antigen-binding receptors and Fe receptors, IgA or IgM are found on the membranes of T cells. Null lymphocytes do not have distinctive markers of T and B lymphocytes. They are capable of carrying out antibody-dependent, complement-free, lysis of target cells in the presence of antibodies specific against these cells. K lymphocytes are a type of null lymphocyte. For them, the target cells are tumor cells, T- and B-lymphocytes modified by viruses, monocytes, fibroblasts, and erythrocytes.

B lymphocytes. Like T-lymphocytes, they are formed from stem cells of hematopoietic tissue. The precursors of B lymphocytes in the bursa of Fabricius undergo differentiation and then migrate to the lymph nodes and spleen, where they perform their specific functions.

The presence of two classes of B cells has been established: B-effectors and B-regulators. The effector cells of B-lymphocytes are antibody-forming cells (plasma), synthesizing antibodies of one specificity, i.e., against one antigenic determinant. B-regulators, in turn, are divided into suppressors and amplifiers (amplifiers). The function of the regulators is to release mediators that inhibit DNA production in T and B lymphocytes only within the bone marrow, as well as to enhance B effectors. B lymphocytes are larger than T lymphocytes (8 and 5 µm, respectively). Thanks to electron microscopy, it was found that the surface of B lymphocytes is covered with numerous villi and folded, while the surface of T lymphocytes is smooth.

QUESTION No. 35 “ROLE OF CELLULAR FACTORS IN ANTI-VIRAL IMMUNITY.”

It differs from humoral in that the effector elements of cellular immunity are T-lymphocytes, and humoral - plasma cells. It is of particular importance for infections caused by many viruses, bacteria, and fungi.

Formation of cytotoxic T cells (TCC) - among cell surface Ags that can cause the formation of the TTC cycle - MHC products (mononuclear system), viruses, tumor-specific Ags. TCA cycles have receptors through which antigen binds and processes that trigger cell lysis are triggered. The lytic activity of T cells begins with a close interaction between the killer cell and the target cell, a change in the membrane permeability of the target cell occurs, ending with the rupture of the cell membrane.

PCs have the ability to directly lyse a wide range of target cells, especially tumor cells; they can lyse cells regardless of MHC products (interferon and IL-2 enhance the lytic activity of PCs).

HRT is a T-cell dependent immunological response that manifests itself as inflammation at the site of Ag entry into the body, usually the skin. Lymphocytes that can tolerate HRT are T cells and are called TGRT lymphocytes (they can become activated and respond to protein Ags, alloantigens, tumor antigens, to Ags of viruses, bacteria, fungi, protozoa.

Macrophages play a major role in cellular immunity. When pathogens multiply inside phagocytes, intracellular destruction occurs only after macrophages receive a stimulus from specially sensitized T lymphocytes. T lymphocytes activate macrophages by releasing lymphokines.

QUESTION No. 36 “ROLE OF HUMORAL FACTORS IN ANTI-VIRAL IMMUNITY”

In addition to AT - a specific factor of antiviral immunity - the body produces special virus-tropic substances - inhibitors that can interact with viruses and suppress their activity. Serum inhibitors have a wide range of action: some suppress the hemagglutinating properties of viruses, others suppress their cytopathogenic effect, and others suppress their infectious activity. Heat-labile inhibitors are found in normal human and animal sera. They have a wide range of virus-neutralizing effects, are able to block the hemagglutinating activity of influenza viruses, New Castle disease, measles, arboviruses and others and neutralize the infectious and immunogenic properties of inhibitor-sensitive viruses. Heat-stable gamma inhibitors are highly active against modern variants of the influenza virus. Heat-stable alpha inhibitors block the hemagglutinating, but not the infectious, activity of the virus.

QUESTION No. 37 “ANTIVIRAL AT, THEIR PROPERTIES, BIOLOGICAL ROLE, DETECTION AND TITRATION METHODS.”

AT are proteins formed in the body upon parenteral administration of high-molecular substances with signs of genetic foreignness for the given organism. Antibodies are capable of interacting with antigen in response to which it was formed and neutralizing its biological activity. The usual source of AT is blood serum. When encountering an antigen, AT neutralizes not only its infectious, but also its hemagglutinating activity, because blocks virion receptors responsible for hemagglutination, resulting in the formation of the “AG + AT” complex.

implemented MOs.

QUESTION No. 38 “INTERFERON AND ITS ROLE IN ANTI-VIRAL IMMUNITY.”

Human cells have 27 genetic loci for interferons (hereinafter referred to as I) – 14 are functional. And encoded in the genetic apparatus of the cell. There are alpha, beta, gamma - I. Its system does not have a central organ, all cells have the ability to synthesize it. For its formation, inducers are needed (viruses, bacterial toxins, extracts from bacteria and fungi, double-stranded RNA (the most effective) and others). Virus-infected I – alpha and beta; Gamma-I is formed under the influence of phytohemagglutinin with SEA. During induction of I, 2 or more of its types are synthesized. The most actively inducing viruses are myxo- and arboviruses. The interferonogenicity of viruses increases with a decrease in their virulence for the body. Inducers of a non-viral nature stimulate a more rapid and short-term accumulation of “heavy” I (with a high molecular weight) in the body. And can be obtained 4 hours after intravenous administration of Ig. And it does not affect adsorption, viropexis, deproteinization of virions, it suppresses the production of the virus. It does not act on any specific virus, but on many types in general. And it is able to enhance phagocytic activity (macrophages, when exposed to I, have significantly more vacuoles, attach more quickly to glass, and more actively capture bacteria). Interferon drugs inhibit cell growth and suppress the growth of tumor cells. And it inhibits AT formation and has a direct effect on B-lymphocytes. And it helps to increase the killer activity of T cells. Pre-treatment of cells or animals with small doses of And leads to an increase in the production of And in response to the last induction of its synthesis (priming). When processing producers, And increases in quantities of And, blocking is observed (the opposite effect). The production of I is influenced by external conditions (weather, air temperature). Ionizing radiation reduces the production of And. As the body grows, the amount of And inhibitors decreases. And young animals exhibit a reduced antiviral effect compared to And an adult animal, because the production of mononuclear phagocytes is reduced. During the formation of I in the cells of newborns, cathepsin D is activated and released from lysosomes, which leads to proteolytic degradation of I. As growth occurs, the components that contribute to the release of cathepsin D from lysosomes decrease. The most sensitive to I are viruses that have an outer shell and contain lipids (myxoviruses, smallpox group, arboviruses). For medical and veterinary purposes, inducers of endogenous I are mainly used, but exogenous I is also used. Like hormones, I-ins are secreted by some cells and transmit a specific signal through the intercellular space to other cells. And - “protein factor”, which does not have virus specificity and its antiviral activity is carried out with the participation of cellular metabolism, involving the synthesis of RNA and protein.

QUESTION No. 39 “PRINCIPLE OF OBTAINING BACTERIOPHAGES. DETERMINATION OF ACTIVITY AND PRACTICAL USE OF PHAGES."

The phage is obtained by adding a special phage to the MO culture, kept for 24 hours at a temperature of 37 degrees, filtered through bacterial filters, and the filtrate is checked for purity by inoculation; harmlessness and activity, phage titer.

Determination of phage activity.

Use qualitative and quantitative methods. The amount of phage is determined by titration on liquid or solid nutrient media. To do this, the phage is diluted tenfold. The same amount of daily bacterial broth culture is added to each dilution. Then they are placed in a thermostat and the result is taken into account. The titer is determined after separating the mixture on 1 day in a thermostat.

The phage titer is taken to be its highest dilution, which is capable of delaying the growth of MO. Expressed by the degree of its dilution. Only virulent phages cause complete destruction of the cell and the formation of phage particles.

QUESTION No. 40 “PASSIVE SPECIFIC PREVENTION OF VIRAL DISEASES. THE PRINCIPLE OF RECEIVING."

Preparations for passive IP– for parenteral and oral administration of AT or Ig. For the purpose of carrying out IP, immune, hyperimmune sera, convalescent and allogeneic sera are used.

Convalescent serum– serum from donors of recovered or infected animals. It is used when there are no more effective agents at a dose of 1 ml/kg body weight.

Hyperimmune serums– donor serum, which is obtained as a result of a single administration of massive doses of antigen according to a certain scheme. A healthy donor who has not previously suffered from this disease is selected. He is vaccinated and after 2-3 weeks they begin to administer it according to a certain scheme in increasing doses, bringing it to the peak of the increase in AT. The peak is determined by setting a serological reaction to the AT titer (serum is checked for sterility, activity and harmlessness. Dose 2 ml/kg (therapeutic), 1-1.5 ml/kg (prevention). Administered fractionally. First, a sensitized dose is administered, and after 2-3 hours is the permissive dose to avoid anaphylactic shock.

Allogeneic whey– combined whey, which is obtained from different animals in the same farm. It contains a large set of ATs and various AGs.

QUESTION No. 41 “SPECIFIC PREVENTION OF VIRAL DISEASES. TYPES OF VACCINES AND METHODS OF THEIR ADMINISTRATION".

1. In the practice of epizootology, an increase in the size and density of animal populations increases the risk of epizootics. The main principle in the fight against them is to break the infectious chain in all areas or stop the transition of the epizootic process to a latent state. One of the main tools for breaking the chain is timely prevention. For livestock farming, developing on an industrial basis, the fight against all factors, incl. with pathogenic MOs and viruses is one of the most important conditions for a healthy livestock. IP (immunoprevention), when properly included in the strategy to combat infectious diseases, significantly reduces the danger.

The goal of IP is not only the eradication of infectious diseases, but also the preservation of productivity, therefore it is necessary to strive to create vaccines that can provide a high degree of protection for the entire livestock immediately after vaccination, regardless of the age of the animals.

IP has a number of advantages:

1. The principle of action of IP is based on a specific change in the animal’s body in the direction of maximally reducing the possibility for the pathogen to cause an infectious disease.

2. IP acts continuously and for a long time, sometimes throughout life.

3.IP not only changes the reactivity of the animal’s body, but also increases the ability to immune defense in the entire livestock.

4.The effect of IP on the epizootic process can be accurately calculated.

5. With appropriate selection of vaccination moments, PIs provide maximum protection during the most dangerous periods of life for infection.

6.IP can be linked to the technological process in animal husbandry.

7. The drugs used for IP can be dosed, used in different combinations and standardized.

8. Unlike AB and chemical drugs, PI does not cause resistance in MO.

9. IP requires lower economic costs and costs of raw materials.

10. IP does not have any impact on the quality of animal products.

Negative sides:

1.Evaluation of the individual entrepreneur’s capabilities. The owner of the animal is often convinced that everything has already been done for protection with vaccination, which leads to a weakening of sanitary and hygienic measures.

2. Too large an increase in the final cost of production.

3. Post-vaccination reactions, which for a certain time reduce productivity if an insufficiently tested vaccine is used.

4. Too frequent disturbance of animals, leading to a decrease in productivity.

5. The emergence of diagnostic problems and increasing difficulties in the fight against diseases if vaccine and pathogenic strains under normal conditions do not differ or are distinguished with great difficulty.

The inappropriate use of vaccines can cause harm, therefore, for each specific infectious disease and epizootic situation, it is necessary to carefully select a vaccine and the option for its use, taking into account economic costs and effectiveness, in order to ensure the highest result of mass vaccinations.

Immunoprophylaxis was developed on the basis of the long-standing experience of mankind, according to which people who had infectious diseases did not become ill with them a second time. Back when there was human plague in Athens. Thucydides reported that the sick were left without help if they were not cared for by people who were recovering. In China in the 16th century, when dealing with human smallpox, there was a custom: to inhale dried crushed smallpox crusts through the nose. Jenner invented the smallpox vaccine. Pasteur proposed a method of vaccination against rabies.

Prevention of viral diseases is based on the same principles as the prevention of other infectious diseases:

1. Carrying out organizational activities.

3. Chemoprophylaxis.

Specific prevention of viral diseases is ensured by the use of live, inactivated, poly- and monovalent sera.

Classification and characteristics of immunopreparations:

Biological products are products of biological origin used for active and passive IP.

Preparations for passive IP – for parenteral and oral administration of AT or Ig. For the purpose of carrying out IP, immune, hyperimmune sera, convalescent and allogeneic sera are used.

Convalescent serum is serum from donors of recovered or infected animals. It is used when there are no more effective agents at a dose of 1 ml/kg body weight.

Hyperimmune sera are donor sera that are obtained as a result of a single injection of massive doses of antigen according to a certain scheme. A healthy donor who has not previously suffered from this disease is selected. He is vaccinated and after 2-3 weeks they begin to administer it according to a certain scheme in increasing doses, bringing it to the peak of the increase in AT. The peak is determined by setting a serological reaction to the AT titer (serum is checked for sterility, activity and harmlessness. Dose 2 ml/kg (therapeutic), 1-1.5 ml/kg (prevention). Administered fractionally. First, a sensitized dose is administered, and after 2-3 hours is the permissive dose to avoid anaphylactic shock.

Gamma globulins are obtained from hyperimmune sera by releasing ballast proteins. They are administered subcutaneously or intramuscularly at a dose of 0.5-2 ml/kg. First, sensitization is administered, then a resolving dose.

Allogeneic whey is a combined whey that is obtained from different animals in the same farm. It contains a large set of ATs and various AGs.

Preparations for active immunization - vaccines. There are live and inactivated vaccines.

Vaccines are also classified according to: 1) Initial virus-containing material - tissue, embryo-virus vaccines, cultured virus vaccines; 2) by the attenuation method - lapinized (against foot-and-mouth disease, rinderpest and others, using rabbits), caprinized (through the body of a goat, against sheep pox by passing through several goats, against cattle), ovinized (through sheep - against rinderpest, foot-and-mouth disease).

Vaccine administration methods:

1.Subcutaneously

2. Intramuscular

3. Aerosol

4.Rectal method

5.Intranasal

QUESTION No. 42 “INACTIVATED ANTI-VIRAL VACCINES, THEIR OBTAINING, PROPERTIES, APPLICATION, DIFFERENCE FROM LIVE VACCINES.”

Inactivated vaccines are complex preparations. Their production requires a large amount of virus. The main requirement for killed vaccines is complete and irreversible inactivation of the genome with maximum preservation of the antigen determinant and immune protection of vaccinated animals. To obtain inactivated vaccines, formalin, chloroform, thiomersal, hydroxylamine, ethanol, beta-propiolactone, ethyleneimine, UV and gamma irradiation, and temperature are widely used as inactivants. Inactivated vaccines are used only parenterally. They necessarily include adjuvants - nonspecific stimulators of immunogenesis. A larger dosage is required and, as a rule, repeated administration. They create less intense, short-lasting immunity than with live vaccines.

QUESTION No. 43 “FACTORS OF ANTI-VIRAL IMMUNITY, THEIR CHARACTERISTICS.”

Specific

1) Associated with qualitatively unique protective mechanisms, because viruses are not able to develop outside a living cell 2) Protection is aimed at 2 forms of nouns. virus: outside and inside cells. The resting form is affected by specific and nonspecific factors, humoral and cellular protective factors. Vegetative forms – interferon, which prevents the synthesis of viral mRNA. 3) Virus neutralizing antibody does not react with viral information NK. 4)Methods and means of neutralizing the virus are effective only at a certain stage. 5) Special protective factors: the formation of extracellular oxyphilic and basophilic granules and the presence of antiviral inhibitors. 6) This immunity is long-lasting, and sometimes lifelong.

Nonspecific cellular and general physiological reactions.

Temperature

Hormones reduce resistance, but somatotropic hormones increase resistance and enhance the inflammatory response.

A pregnant animal gets sick faster and the disease is more severe.

The physiological state of the excretory system is the rate of virus release from the body.

Humoral factors - the presence of serum inhibitors (heat-stable or heat-labile). Each species has its own predominant type.

QUESTION No. 44 “LIVE ANTI-VIRAL VACCINES, THEIR PROPERTIES, APPLICATION AND DIFFERENCES FROM INACTIVATED VACCINES.”

Live antiviral vaccines are lyophilized suspensions of vaccine strains of viruses grown in various biological systems (EC, CC, laboratory animals) or use naturally weakened strains of the pathogen that are created during a long-term epizootic. The main property is the persistent loss of the ability to cause a typical infectious disease in the body of a vaccinated animal; they also have the ability to “take root” in the animal’s body, that is, to multiply. The residence and reproduction of the vaccine strain usually lasts 5-10 days. up to several weeks and are not accompanied by clinical manifestations characteristic of this disease, lead to the formation of immunity against the infectious disease. Advantages: high intensity and duration of the immunity they create, approaching post-infectious immunity. Possibility for most single administration. Administration is not only subcutaneous, but also orally and internally. Disadvantages: sensitivity to adverse factors. Strict storage and transportation limits - temperature - 4-8C. It is unacceptable to break the vacuum in vaccine ampoules. Strict adherence to asepsis rules. Quality control: 1) comprehensive examination of donors. 2) assessment of the quality of the nutrient medium and QC for sterility. 3)Supervision over the quality of production virus strains. 4) Creation of optimal conditions for the preservation of biomaterials.

Inactivated vaccines create less intense and long-lasting immunity; they must be administered repeatedly.

QUESTION No. 45 “BACTERIOPHAGES, THEIR IMPORTANCE AND BASIC PROPERTIES.”

Bacteriophages (from Lat. Bacteriophaga) – destroying bacteria. These are viruses that have the ability to penetrate bacterial cells, reproduce in them and cause their death.

The history of the discovery of the bacteriophage is associated with Academician Gamaley, who observed the accidental lysis of anthrax bacteria.

Tvort - described the degeneration of staphylococci (1915). D'Herelle (1917) studied in detail the interaction of the phage and bacteria of the dysentery bacillus and gave the agent the name “bacteriophage”. Subsequently, viruses of fungi, mycoplasmas and other microorganisms were isolated. Therefore, to refer to these viruses, the term “phage” is used - eater.

Phage structure and morphology.

Phages consist of DNA/RNA nucleic acid surrounded by a capsid containing strictly oriented capsomers. Large phages have a tadpole-like structure, have a head, a collar and a tail process ending in a hexagonal basal plate to which fibrils are attached. The head has 2 shells: an outer membrane and an inner membrane in which the AK is enclosed. The average size of the head is 60-100 nm, the tail is 100-200 nm. According to morphology, phages are divided into 6 groups:

Phages with a long process, the sheath of which contracts - T-even phages.

Phages with a long process, the sheath of which does not contract.

Phages with a process analogue.

Phages with a short process.

Filamentous phages.

Phages without a process.

Chemical composition of the phage.

The phage head contains one of the nucleic acids. The shell also contains lipids and carbohydrates. Phages can withstand pressure up to 6 thousand atmospheres. They are resistant to environmental influences and retain their activity in spare ampoules for up to 13 years.

They quickly die under the influence of boiling, UV light, and certain chemicals (1% phenol, alcohol, chloroform ether do not change the phage). Some substances: thymol, chloroform, dinitrophenol have no effect on phages, but kill bacteria.

A 1% formaldehyde solution inactivates the phage. There are phages: polyphages (lyse related bacteria), monophages (lyse related bacteria), monophages (lyse bacteria of the same species), phages that cause lysis of a specific serotype of the 1st species. Based on their type-specific properties, phages are divided into serotypes. Special phages can be easily adapted to related bacteria by riding on bacteria of the same species. The phenomenon of bacteriophagy can be easily observed in both liquid and solid nutrient media. If you inoculate a culture in a dish with a nutrient medium and apply a few drops of a high concentration of phage, then there will be no growth at this place - sterile spots. According to the mechanism of interaction with cells, phages are divided into virulent and moderate.

The phenomenon of bacteriophagy caused by temperate phages manifests itself only in the form of phases of adsorption, penetration into cells, reproduction and release of the phage. The entire reproduction process follows the pattern of DNA viruses. Virulent phages ensure the formation of new phages and lysis of bacterial cells. It has been established that 7-8 phage particles appear in phage-infected bacteria within 1 minute.

Reproduction diagram.

1.Adsorption of phage on the MO shell and its dissolution. Phages are adsorbed by their flagella, these flagella firmly connect to the receptors of the cell wall, as a result of which the phage particle contracts and the end of the process sticks into the bacterial cell membrane and at the same time the phage secretes a lysozyme-like enzyme that dissolves the cell membrane.

2. Injection of nucleic acid into the microbial cell. All the nucleic acid and part of the proteins are injected into the microbial cell; the sheath remains on the surface of the bacterial cell.

3.Latent phase – eclipse phase. The phase promotes the development of DNA viruses. At the beginning, mRNA is synthesized, it gives rise to the synthesis of early viral proteins, which stop cellular metabolism and give rise to the formation of daughter nucleic acids.

4. Formation of new phage particles. The connection of two main phage particles by filling the phage protein shell with nucleic phage particles.

5. Dissolution of the bacterial cell membrane and the release of newly formed particles outside the cell. The rupture of the cell wall is facilitated by: a strong increase in intracellular pressure, and on the other hand, the action of enzymatic processes caused by phages. The number of perceived phages varies and ranges from 1 to 1000 or more.

The entire reproduction process takes from 3 to 10 hours.

Lysogeny - along with virulent phages, there are also temperate phages that differ in the nature of their interaction with the bacterial cell. Their main feature is that they are able to transform from a vegetative state into a non-infectious form called a prophage, which is unable to cause bacterial lysis. Bacterial cells containing a prophage on the chromosome are called lysogenic, and the phenomenon is lysogeny. In this phenomenon, bacteria infected with the phage are not lysed. But artificial lysis can release a phage that can infect bacteria of a given species. The transition of a prophage to a vegetative phage does not occur often. When infected with temperate phages, one part of the cells is lysed to form a vegetative phage, and the other part survives and becomes lysogenic.

In lysogenic bacteria, the phage DNA is integrated into the DNA of the cell and the temperate phage is converted into a prophage, which does not have lytic properties.

Lysogenic bacteria formed as a result of lysogenization become carriers of the phage and acquire immunity for a long time. This connection is strong and is disrupted when the bacterium is exposed to inducing agents. These are UV rays, ionizing radiation, chemical mutagens. Under the influence of these factors, the prophage is transferred to an autonomous state and disintegration occurs.

Lysogenization of bacteria is accompanied by a change in their properties (morphological, cultural and biological properties). Non-toxic strains become toxigenic. Changing the properties of bacteria – phage conversion. Lysogenic bacteria are the most convenient models for studying the interaction of viruses and cells.

Currently, temperate phages are widely used to study questions of genetics, with the help of which it is possible to more accurately differentiate the processes of variability. Under the influence of radiation, the number of phage particles produced by the cells of lysogenic bacteria increases.

Practical use of phages - phages are used to titrate bacteria, treat and prevent a number of infectious diseases, and are used to determine the dose of radiation on spacecraft.

QUESTION No. 46 “LABORATORY ANIMALS, OBJECTIVES AND METHODS OF THEIR USE IN VIROLOGY.”

Due to the fact that viruses can reproduce only in living cells, at the earliest stages of the development of virology, the cultivation of viruses in the body of laboratory animals, specially raised for research on them, was widely used.

Used: 1) to detect the virus in PM 2) primary isolation of the virus from PM 3) accumulation of viral mass 4) maintaining the virus in the laboratory in an active state. 5) titration of the virus 6) as a test object in pH 6) obtaining hyperimmune sera. Animals used: white mice (rabies, foot and mouth disease), white rats (swine flu, Aujeszky's disease), guinea pigs (rabies, foot and mouth disease, canine distemper). Rabbits (rabies, rabbit myxomas).

Requirements for laboratory animals - the animal must be sensitive to this virus; its age is of great importance for the cultivation of many viruses. Most viruses reproduce better in the body of young and even newborn animals; standard sensitivity is achieved by selecting animals of a certain age and the same weight. In terms of sensitivity, the so-called linear animals obtained as a result of inbreeding over a number of generations have the greatest standard; laboratory animals must be healthy. Animals entering the vivarium of the virology laboratory must be brought from a farm free of infectious diseases. They are kept in quarantine and undergo clinical observation. If there is a disease, they are destroyed.

Animals are placed in such a way that, on the one hand, the functioning of all body systems within physiological norms is ensured, and on the other hand, mutual reinfection and the spread of infection beyond the vivarium are excluded. Different methods of individual marking are used for animals of different species. For large animals and chickens, metal tags with a stamped number are used. When using a small group of animals in an experiment and for a short period of time, the hair can be trimmed with marks on the back and hips. Marking of white mice and white rats can be carried out by amputation of individual fingers on the front or hind limbs. The method of applying colored spots to unpigmented wool is often used. Infection of laboratory animals.

1. subcutaneously - back.

2. Intradermal – heel

3. Intramuscular – thigh

4. Intravenously - into the tail (preliminarily rubbed with hot water and squeezing)

5. Intranasally - a drop in the nose (a weak ether anesthesia is first given to prevent sneezing)

6. Interocerebral - the skull is carefully drilled with a needle, do not press, the drop goes away on its own.

All surfaces are pre-lubricated with iodized alcohol.

Preparation lab. animals (using the example of a white mouse)

The skin is lubricated with a disinfectant.

An incision is made along linea alba.

Opening the sternum - the lungs are taken and placed in tube No. 1

Opening the abdominal cavity - the liver, spleen, kidney are taken and placed in tube No. 2.

The skull is opened. The brain is taken, sections of 4 layers are made, the pieces are placed on filter paper and prints are made on glass.

QUESTION No. 47 “STRUCTURE OF A DEVELOPING CHICKEN EMBRYO. MAIN PROBLEMS SOLVED BY THE METHOD OF INFECTION BY TBE AND ITS ADVANTAGES OVER CULTIVATION OF VIRUSES IN LABORATORY ANIMALS.

CE is used in virology mainly for the same purposes as LV: detection of active virus by bioassay in pathological material; primary isolation of the virus; maintaining viruses in the laboratory; virus titration; accumulation of the virus for laboratory research and obtaining vaccines; as a test object in the neutralization reaction.

Structure: 1. Shell 2. Subshell membrane 3. Air chamber 4. Allantoic cavity 5. Yolk sac 6. Albumin sac 7. CHAO - chorion-allantoic membrane 8. Amniotic cavity 9. Embryo 10. Cord (connection of the yolk sac with the umbilical cord) . From 5-12 days EC can be used for infection

1) The shell and subshell membrane serve as good protection from environmental factors. 2) EC contain a substrate for growing the virus. 3) CE are resistant to impacts associated with the release of the material under study. 4) ECs are easily accessible, environmentally friendly, do not require care or feeding, and do not form AT.

6 methods of infection with TBE: 1) Infection in the allantoic cavity (influenza, Newcastle disease). The EC is fixed vertically with the blunt end up, and a 1mm hole is made on the side of the embryo 5-6mm above the border of the air chamber. The needle is inserted parallel to the longitudinal axis to a depth of 10-12 mm. 2) for CAO (smallpox, canine plague): a) B/w natural air chamber. FE into a tripod with the blunt end up, a 15-20mm window in the shell against the center of the air chamber. Remove the shell membrane. 0.2 mm of suspension is applied to the XAO. Hole adhesive plaster. b) B/w artificial air chamber. The tripod is horizontal with the bud up. Make 2 holes: above the center of the air chamber, another 0.2-0.5 cm on the side, on the side of the embryo. The air is sucked out of the first embryo, an artificial air chamber is formed, the bottom of which is CAO, an infectious liquid is applied to it, and it is sealed with an adhesive plaster. 3) In the yolk sac (chlamydia, Marek's b.): a) EC is placed vertically in a stand. A hole above the center of the air chamber, a needle 3.5-4 cm at an angle of 45, opposite to the location of the embryo. b) a similar route of infection is carried out on a horizontally reinforced CE stand; in this case, the embryo is at the bottom, and the yolk is above it. 4) Into the amniotic cavity (flu, Newcastle disease): the method is closed - the embryo. up. The needle is inserted with a blunt end towards the embryo of the open. method - a hole of 1.5-2.5 cm above the air cavity. The subshell membrane is removed. Tweezers push the XAO towards the embryo. Then the amniotic membrane along with the CAO is pulled to the window, and the suspension is introduced there. They let you go. Band-Aid. 5) Infection into the body of the embryo. 6) into blood vessels.

QUESTION No. 48 “TYPES OF CELL CULTURES AND THEIR USE IN VIRUSOLOGY. BRIEF CHARACTERISTICS OF EACH SPECIES.”

Cell culture (CC) is the cells of a multicellular organism that live and multiply in artificial conditions outside the body. The cultivation technique began to develop especially successfully after the 40s. This was facilitated by the following events: the discovery of antibiotics that prevent bacterial infection of CC, the discovery by Hang and Enders of the ability of viruses to cause specific cell destruction. Dulbecco and Vogt (1952) proposed a method for trypsinizing tissues and obtaining single-layer CCs. The following CCs are used: 1) PTCC – cells obtained directly from organs or tissues of the body, growing in vitro in one layer. CC can be obtained from almost any human or animal organ or tissue. It is better to do this from embryonic organs, because embryonic cells have a higher growth potential. Most often, they are obtained from the kidneys, lungs, skin, thymus, and testicles. To obtain primary cells from a healthy animal, no later than 2-3 hours after slaughter, the corresponding organs or tissues are taken, crushed, and treated with trypsin, pancreatin, and collagenase. Enzymes destroy intercellular substances, and the resulting individual cells are suspended in a nutrient medium and cultured on the inner surface of test tubes or mattresses in a thermostat at 37C. The cells attach to the glass and begin to divide. A layer one cell thick forms on the glass, usually after 3-5 days. The nutrient medium is changed as it becomes contaminated with cell waste products. The monolayer will remain viable for 7-21 days. When cultivating viruses in CC, it is possible to obtain preparations with a high titer of the virus, which is important when obtaining antigens and vaccines. 2) Subcultures - they are often used and obtained from primary cells grown in mattresses by removing them from the glass with a solution of versene or trypsin, resuspending them in a new nutrient medium and reseeding them on new mattresses or test tubes. After 2-3 days, a monolayer is formed. They are not inferior in sensitivity to PTCA and are more economical. 3) Transplantable CCs are cells capable of multiplying outside the body for an indefinitely long time. They are maintained in the laboratory by subculture from one vessel to another (subject to replacement of the nutrient medium). They are obtained from primary CCs with increased growth activity through long-term subcultures in a certain cultivation mode. The cells of transplanted cultures have the same shape, a heteroploid set of chromosomes, are stable under in vitro growth conditions, and some of them have oncogenic activity. “+” before the primary ones - it’s easier to prepare, you can check in advance for the presence of latent viruses and microflora; clonal lines provide more standard conditions for virus propagation than primary lines. Most transplanted cells have a wider spectrum of sensitivity to viruses than the corresponding primary cultures. But they are prone to malignant degeneration. 4) Diploid CCs are a morphologically homogeneous population of cells, stabilized during in vitro cultivation, having a limited lifespan, characterized by 3 growth phases, preserving the karyotype characteristic of the original tissue during passaging, free from contaminants and not having tumorigenic activity when transplanted into hamsters. They are also obtained from primary cells. In contrast, they have limited passaging capabilities. The maximum number of passages is 50 -\+ 10, then the number of dividing cells sharply decreases and they die. Advantages over transplantable CCs - they can be in a viable state for 10-12 days without changing the nutrient medium; when changing the medium once a week, they remain viable for 4 weeks; They are especially suitable for long-term cultivation of viruses; they retain the sensitivity of the original tissue to viruses. 5) Suspension CCs – continuous cell cultures in suspension.

QUESTION No. 49 “PRIMARY TRYPSINIZED CELL CULTURES. THEIR ADVANTAGES AND DISADVANTAGES. APPLICATION IN VIROLOGICAL RESEARCH".

PTCC are cells obtained directly from organs or tissues of the body, growing in vitro in one layer. CC can be obtained from almost any human or animal organ or tissue. It is better to do this from embryonic organs, because embryonic cells have a higher growth potential. Most often, they are obtained from the kidneys, lungs, skin, thymus, and testicles. To obtain primary cells from a healthy animal, no later than 2-3 hours after slaughter, the corresponding organs or tissues are taken, crushed, and treated with trypsin, pancreatin, and collagenase. Enzymes destroy intercellular substances, and the resulting individual cells are suspended in a nutrient medium and cultured on the inner surface of test tubes or mattresses in a thermostat at 37C. The cells attach to the glass and begin to divide. A layer one cell thick forms on the glass, usually after 3-5 days. The nutrient medium is changed as it becomes contaminated with cell waste products. The monolayer will remain viable for 7-21 days. When cultivating viruses in CC, it is possible to obtain preparations with a high titer of the virus, which is important when obtaining antigens and vaccines. Using the QC method, some theoretical questions were resolved - about the interaction of the virus with the cell, the place of virus reproduction, the mechanism of antiviral immunization. Currently, QC is used for isolating viruses from pathogenic material, their indication, identification, for setting up a neutralization reaction, determining the titer of viruses, for preparing diagnostic Ags and vaccines, and as test objects in a neutralization reaction.

QUESTION No. 50 “NUTRIENT MEDIA AND SOLUTIONS USED IN VIRUSOLOGY. REQUIREMENTS FOR Utensils for CC CULTIVATION, ITS PROCESSING.”

The most widely used solutions when working with CC are Hanks and Earle solutions, which are prepared using bidistilled water with the addition of various salts and glucose. These balanced salt solutions are used to prepare all culture media because... they ensure the preservation of pH, osmotic pressure in cells and the appropriate concentration of essential inorganic substances. They are also used for washing away growth media, virus dilutions, etc. When culturing cells, dispersing solutions of trypsin and versene are used. Trypsin solution is used to separate pieces of tissue into individual cells and to remove the layer of cells from the glass. Versene solution - used to remove cells from glass. Nutrient media (hereinafter referred to as NS) - distinguish: 1) natural media, which consist of a mixture of saline solution, blood serum, tissue extract, bovine amniotic fluid, etc. The number of components varies. They are rarely used. 2) artificial PS - enzymatic hydrolysates of various protein products: lactalbumin hydrolysate, muscle enzymatic hydrolysate, etc. Of the synthetic media, the most widely used are medium 199 and Eagle’s medium. Phenol red indicator is added to all culture media and some saline solutions to determine the concentration of hydrogen ions. To destroy microflora before use, add AB to the media: penicillin and streptomycin, 100 units per ml. All PS are divided into 2 groups: growth – ensure the life and reproduction of cells; supporting - ensuring the vital activity of cells, but not their reproduction (they do not contain blood serum). Glassware – The quality of the glassware is important for the successful cultivation of cells outside the body. It should be sterile, fat-free, and have no toxic effect. For cell cultivation, test tubes, mattresses of 50, 100, 250, 500, 1000, 1500 ml, roller flasks of 500, 1000, 2000 ml, various pipettes, bottles for PS and solutions, and flasks of various capacities are used. Processing glassware consists of several stages: 1) the infected glassware is immersed in a 2-3% NaOH solution for 5-6 hours; 2) rinse in 3-4 changes of tap water; 3) soak in a 0.3-0.5% powder solution; 4) wash thoroughly with a brush in a warm powder solution; 5) rinse in several changes of tap water; 6) rinse in distilled water containing 0.5% HCl; 7) rinse 4-5 times with tap water and 3 changes of distilled water; 8) dried in a drying cabinet; 9) mounted and sterilized in an oven or autoclaved.

QUESTION No. 51 “THE PRINCIPLE OF INFECTION OF CELL CULTURES BY VIRUS-CONTAINING MATERIAL. INDICATION OF VIRUSES IN CELL CULTURE.”

For infection, test tubes (mattresses) with a continuous cell monolayer are selected, viewing them under a low magnification microscope. The growth nutrient medium is drained, the cells are washed 1-2 times with Hanks solution to remove serum antibodies and inhibitors. 0.1-0.2 ml of virus-containing material is added to each tube and distributed evenly over the cell layer by shaking. Leave for 1-2 hours at 22-37C for virus adsorption on the cell surface. The virus-containing material is removed from the containers and the supporting medium is poured. For indication, there are the following main methods for indicating the virus in CC: by cytopathic effect or cytopathic effect; by a positive hemadsorption reaction; by plaque formation; for detection of intracellular inclusions; to detect viruses in immunofluorescence reactions; to detect virus interference; to suppress cell metabolism (color test); electron microscopy. Detection of specific cell degeneration (by CPD) - a simple sign is degenerative changes in cells (manifestation of CPD). Visible changes in the cell are called cytopathic changes. These changes in infected cells depend on the dose and biological properties of the virus being studied; the manifestation of CPE and its features sometimes allows identification of the isolated viruses. When KK is infected with medium doses of the virus, the nature of these changes is specific and can be classified into groups: focal fine-grained degeneration, fine-grained degeneration throughout the entire monolayer, focal cluster-shaped accumulation of round cells, uniform granularity, association of cells into giant multinuclear symplasts and syncytia. The degree of degeneration is assessed using a 4-point system.

Sometimes the absence of CPD is observed, but this is not considered to be the absence of a virus, and therefore 2-3 blind passages are carried out and at the 2-3 passage the viruses can exhibit the desired properties.

QUESTION No. 52 “METHODS FOR DETECTING VIRIONS AND VIRAL INCLUSION BODIES, THEIR PRACTICAL IMPORTANCE.”

It is usually possible to examine virus virions and establish their structure using electron microscopy, which allows one to distinguish objects up to 0.2-0.4 nm in size. Detection of virions in material from sick animals using electron microscopy can serve as evidence of the presence of viruses in this material and in some cases is used to diagnose viral diseases. But this method is technically complex and expensive, and does not allow accurately identifying the detected virus. With a light microscope it is possible to see only the virions of smallpox viruses at the limit of visibility. The ability to be stained with certain dyes, the size, shape, structure, location in the cell of inclusion bodies formed by different viruses are not the same, but specific to each virus. Therefore, the detection of intracellular inclusion bodies with certain characteristics in material from sick animals allows us to judge what kind of virus they were formed, and therefore the presence of this virus in the material under study. To detect inclusion bodies, smears or prints are prepared (posthumously or intravitally), which are subjected to special staining methods followed by microscopy. For inclusion bodies formed by different viruses, staining methods are different. Many coloring recipes have been developed. Among them there are also universal ones, which include hematoxylin-eosin staining.

Part 1

Each question has four possible answers. Choose only one correct one and enter it into the matrix (part 1).

The object of study of virology is:
- a) cat;
- b) the causative agent of influenza;
- c) longhorned beetle;
- d) boletus.
In order to examine the cells of the human body, you need to use:
- a) magnifying glass;
- b) binoculars;
- c) microscope;
- d) telescope.
The mother put a thermometer on her child, looked at the device and determined that the child was sick. This conclusion was reached because the mother used the method:
- a) measurements;
- b) modeling;
- c) experiment;
- d) observations.
The schoolboy took a piece of bread, broke it in half, left one half in the room, and put the other half in the refrigerator. The bread in the room was moldy, but not in the refrigerator. The student concluded that low temperatures slow down the development of mold. This conclusion was made because the student used the method:
- a) measurements;
- b) modeling;
- c) experiment;
- d) observations.
If you heat a piece of boiled egg in a test tube very strongly, smoke and an unpleasant smell will appear, and the piece in the test tube will turn black. This experiment proves that the egg contains:
- a) organic substances;
- b) mineral salts;
- c) water;
- d) carbon dioxide.
Which of the following foods contains the most fat?
- a) cucumber;
- b) boiled egg white;
- c) bread;
- d) walnut.
What does it consist of? Choose the correct answer:
- a) the virus consists of cells;
- b) a cell consists of organisms;
- c) tissue consists of cells;
- d) the body consists of viruses.
The arm may bend at the elbow due to contraction:
- a) integumentary tissue;
- b) nervous tissue;
- c) connective tissue;
- d) muscle tissue.
If a white chrysanthemum is placed in a solution of red dye, then after a while the petals will turn pink. This will happen due to the operation:
- a) conductive tissue;
- b) integumentary tissue;
- c) mechanical fabric;
- d) connective tissue.
On the trunks of large trees you can sometimes see organisms that destroy wood - tinder fungi. Tinder fungi belong to the kingdom:
- a) plants;
- b) mushrooms;
- c) animals;
- d) bacteria.

Part 2

You are offered test tasks with one answer option out of five possible (a–e), but requiring preliminary multiple choice (out of 1–5). Enter the letter of the correct answer into the matrix (part 2).

1. Of the following organisms you can find in the tundra:

Answers:

a) 1, 2, 4
b) 1, 3, 5
c) 1, 2, 5
d) 3, 4, 5
e) 2, 3, 5

2. Select the names of scientists who contributed to the development of biology:

Answers:

a) 1, 2, 4
b) 2, 3, 4
c) 1, 2, 3
d) 3, 4, 5
e) 2, 4, 5

3. Biological sciences may include:

mineralogy;
zoology;
paleontology;
geology;
entomology.

Answers:

a) 2, 3, 4
b) 2, 3, 5
c) 1, 2, 3
d) 3, 4, 5
e) 2, 4, 5

4. Which animals can be classified as vertebrates?

1) earthworm	2) rattlesnake
Earthworm
3) eel	4) python

5) slug

Answers:

a) 2, 3, 4
b) 2, 3, 5
c) 1, 2, 3
d) 3, 4, 5
e) 2, 4, 5

5. The characteristics of living organisms include:

irritability;
nutrition;
the chemical composition includes silicon;
reproduction;
heat release.

Answers:

a) 1, 3, 4
b) 2, 3, 5
c) 1, 2, 4
d) 3, 4, 5
e) 1, 4, 5

Part 3

A task to determine the correctness of judgments. Enter the numbers of the correct judgments on the answer sheet.

1. Some regions of Russia are indicated in numbers on the map.

Which of the natural zones (or vegetation belts) are most typical for the regions indicated in the figure by numbers 1–5?

Taimyr Peninsula (Krasnoyarsk Territory);
Orenburg region;
Republic of Kabardino-Balkaria;
Kaluga region;
Irkutsk region.

In the answer table, enter in the line “ Region» the corresponding number.

What plants grow in these natural areas?

A – oak;
B – Siberian pine (cedar);
B – feather grass;
G – dwarf birch;
D – edelweiss.

Enter in the line " Plants» the corresponding letter.

What animals live in these natural areas?

E – chipmunk;
F – bison;
Z – saiga;
I – tundra partridge;
K – Caucasian leopard.

Enter in the line " Animals» the corresponding letter.

Answer form

Part 1

1	2	3	4	5	6	7	8	9	10

Part 2

Answers

Part 1

1	2	3	4	5	6	7	8	9	10
b	V	A	V	A	G	V	G	A	b

Part 2

Grading system

For each correct answer in Part I - 1 point, in total for Part I - 10 points.
For each correct answer in Part II - 2 points, in total for Part II - 10 points.
For each correct answer (true/false) in Part III - 2 points, in total for Part III - 10 points.
For each correct answer in Part IV - 2 points, in total for Part IV - 30 points.

Maximum score – 60 points.

The object of study of virology is the cat causative agent of influenza. Virology is the science that studies

PERIODS OF DEVELOPMENT OF VIRUSOLOGY

Level of the organism (30-40s of the XX century).

Cell level (40-50s of the XX century).

Molecular level (50-60s of the XX century).

Submolecular level (70-80s of the XX century).

SCIENTIFIC VIROLOGICAL INSTITUTIONS

http://9school.3dn.ru/news/obrashhenie_direktora_shkoly/2009-11-27-159

http://www.bajena.com/ru/articles/1085/flu-2/

Influenza virus

Epidemiology

Etiology

Pathogenesis

Clinic

Diagnostics

Clinically, the course of this disease generally coincides with the course of the disease when infected with other strains of the influenza virus. A reliable diagnosis is established by serotyping the virus

Prevention

Treatment

Symptomatic therapy is also indicated. Among antipyretic drugs, most experts recommend drugs containing ibuprofen and paracetamol (it is not recommended to use drugs containing aspirin due to the risk of developing Reye's syndrome.

A mandatory visit to a doctor (usually to a local clinic) is necessary in case of a high temperature that does not decrease on the 4th day, or a marked deterioration of the condition after a temporary improvement.

A number of new antiviral drugs are currently being studied, incl. Peramivir.

Recommendations for the prevention and treatment of influenza from the Ministry of Health and Social Development of the Russian Federation.

The Ministry of Health and Social Development of the Russian Federation has released “Temporary guidelines for the treatment and prevention of influenza A/H1N1.”

Epidemics caused by the H1N1 influenza virus

Pandemic in 1918 - “Spanish Flu”

Main article: Spanish flu

1976 influenza outbreak

1988 flu outbreak

2007 influenza outbreak

On August 20, 2007, the Philippine Department of Agriculture reported an outbreak of H1N1 influenza in swine farms in Nueva Ecija province and central Luzon.

Influenza A/H1N1 pandemic 2009. Outbreak of the H1N1 influenza virus in 2009.

At the moment, there is debate around what to call this strain of influenza. So, on April 27, 2009, “swine flu” was called “California 04/2009”; on April 30, pork producers advocated renaming “swine flu” to “Mexican”; a clear non-scientific name has not yet been invented.

The fifth threat level was announced at the end of April 2009: in accordance with the WHO classification, this level is characterized by the spread of the virus from person to person in at least two countries in the same region.

Spanish flu or "Spanish flu"

Picture of the disease, name “Spanish flu”

Flu and its ghosts

Picture copied: http://holimed.lviv.ua/rus/rozsylka/kakbolet/010.html

Not every cold is worth looking for the flu. Malaise and runny nose can be caused by any of the viruses that are “responsible” for the occurrence of ARVI (acute respiratory viral infections).

Symptoms of the flu (any kind!) are as follows:

very abrupt onset of the disease,

a sharp increase in body temperature - up to 39°C and above,

severe headaches, joint and muscle pain,

nasal congestion, sore throat, dry cough.

Usually, after 3-4 days the temperature drops and, if the disease proceeds without complications (which, in fact, are dangerous for the flu), recovery occurs after 7-10 days.

Complications of influenza:

lesions of the respiratory tract (bronchitis and pneumonia);

diseases of the ENT organs (sinusitis, otitis, tonsillitis);

damage to the cardiovascular system (myocarditis, myocardial dystrophy);

damage to the central nervous system (meningitis, encephalitis); kidney damage (pyelonephritis, glomerulonephritis).

In people with chronic diseases (for example, bronchial asthma, arterial hypertension), their exacerbation due to influenza is very likely.

At-risk groups (according to severe course and consequences!):

pregnant women, young children, elderly people, adults and children with serious chronic diseases, as well as in the presence of immunodeficiency (meaning pathological conditions).

Flu prevention .

The general rules that are important for absolutely everyone are the following:

Wash your hands frequently with soap and water for 20 seconds.

Cough and sneeze into a tissue or hand.

Do not approach patients closer than one and a half to two meters.

Sick children should stay at home (not attend preschools and schools),

and also keep a distance from other people until their condition improves.

Refrain from visiting stores, cinemas or other crowded places.

What to do if a child gets sick?

Leave a sick child at home unless he or she needs medical attention.

Give your child plenty of fluids (juice, water, etc.).

Create a comfortable environment for the sick child. Rest is extremely important.

Give your child the medications the doctor prescribes.

Keep tissues and a trash can for used tissues within the patient's reach.

Avoid contact of a sick child with healthy family members.

If your child has been exposed to someone who has H1N1 influenza, ask your doctor about taking medications to prevent illness from H1N1 influenza.

Olga Zorina

Medical Editorial Studio MedCorr.

Alexander Zadorozhny

After warming up your feet, you must immediately dip them in cold water or pour cold water over them from a jug. The colder the water, the stronger the effect. If this is not done, then after a short time the legs will cool down and the procedure will be ineffective.

It is important to constantly ensure that your feet do not freeze.

If you have a stuffy nose or runny nose, it is advisable to limit your fluid intake; it is better to drink fluids in the evening, when you no longer plan to go out into the cold.

Third rule - drink less fluid, especially if you are often exposed to cold conditions.

The fourth rule for preventing influenza infection - if possible, avoid unnecessary contacts, especially in public places and transport, use protective masks.

Alexander Zadorozhny

The flu is not as bad as the complications after it, says one woman to another.

- I know this from my own experience. Just after the flu, I married a local doctor.

Every year, usually during the cold season, influenza epidemics occur and affect up to 15% of the world's population: both people and animals and birds.