Infectious diseases: list, ways of transmission, symptoms, treatment and prevention. Infectious diseases
| Major infectious diseases. Classification, transmission routes and prevention
Fundamentals of life safety
Grade 10
Lesson 21
Major infectious diseases. Classification, transmission routes and prevention
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Man is surrounded by microorganisms throughout his life.. They are in the air, water, soil, deposited on all objects, including food. Microbes live and multiply on the skin, in the mouth and nose, on the mucosa of the upper respiratory tract, in the intestines, especially in its thick section.
Microorganisms play an important role in life not only man, but the entire organic world of the Earth. They, for example, purify the soil and water from dead bodies through putrefaction, fermentation, decomposition. At the same time, getting into the wounds, they can cause suppuration, and penetrating into the internal environment of the human body, they can cause an infectious disease.
Classification of microorganisms and infectious diseases
The whole variety of microorganisms known to modern science, in terms of their effect on the human body, is divided into three types, shown in Scheme 25.
In our country, a classification of infectious diseases has been adopted, which is based on the mechanism of transmission of the infectious principle and its localization in the body. According to this classification, all infectious diseases are divided into five groups (Table 3).
This or that infectious disease is associated with the penetration of a certain microorganism into the body. For example, pertussis bacillus causes only whooping cough, dysentery bacillus - dysentery, diphtheria bacillus - diphtheria, cholera vibrio - cholera.
The emergence and spread of infectious diseases Infectious diseases differ from all others in that they spread quite quickly among people. The mass spread of an infectious disease, far exceeding the usual level of incidence, is called an epidemic. If it covers the territory of an entire state or several countries, it is called a pandemic.
To prevent an infectious disease, you need to know how it occurs and how it spreads among people.
All infectious diseases are contagious and are transmitted from a sick person or a sick animal to a healthy one. But a healthy person can also serve as a source of an infectious disease. After an illness, for reasons that are still unclear, a paradoxical situation arises. A person recovers, feels good, but a pathogenic microbe continues to be present in his body. An amazing union arises when one organism does not notice the other. This can go on for as long as you like. For the body itself, this is not dangerous, but it is extremely dangerous for others, since the pathogenic microbe remains unharmed for a long time and is released into the external environment. This phenomenon is called bacillus carrier, and a person is called a bacillus carrier.
At present, at least five ways of transmission(Fig. 44):
All intestinal infections are transmitted by the fecal-oral route (“diseases of dirty hands”); a pathogenic microbe with feces, vomit of a sick person or a bacillus carrier enters food, water, dishes, and then enters the gastrointestinal tract of a healthy person through the mouth, causing a disease (in particular, dysentery spreads);
all viral diseases of the upper respiratory tract, primarily influenza, spread by airborne droplets: the virus with mucus, when sneezing or talking, enters the mucous membranes of the upper respiratory tract of a healthy person, who becomes infected and falls ill;
the liquid route of transmission is characteristic of the so-called blood infections; carriers of this group of diseases are blood-sucking insects: fleas, lice, ticks, mosquitoes (thus plague, typhus are transmitted);
carriers of zoonotic infections are wild and domestic animals; infection occurs through bites or through close contact with a sick animal (a typical representative of such diseases is rabies);
Most of the sexually transmitted diseases are infected by contact or household contact, with close contact between a healthy person and a sick person (fungal diseases on the skin and nails are also transmitted in the same way).
Immunity
The difference between infectious diseases and all others lies in the fact that the human body after recovery acquires immunity to the re-introduction of the microorganism that caused the disease. This immunity is called immunity.
From a biological point of view, immunity is a way to protect the internal constancy of an organism from living bodies or substances that carry signs of genetically alien information. These bodies and substances are called antigens. These include pathogenic microorganisms, cells and tissues of the body that have become alien, pollen, some plants, some food products. In response to their introduction, the body begins to produce specific substances of a protein nature - antibodies.
Immunity is a set of protective and adaptive reactions of the human body that occur in response to a strictly defined antigenic stimulus in the form of an infectious disease agent or an artificially introduced antigen (vaccine or toxoid).
The body's immune response is the interaction of an antigen with an antibody. An important feature of immunity is the recognition and difference between self and alien.
Immunity is closely related to the functional state of the body and largely depends on environmental factors. Starvation, deficiency or lack of vitamins (avitaminosis), prolonged illness, serious injuries, frequent stressful situations can contribute to a decrease in the body's resistance and the development of an infectious disease.
As a result of an infectious disease or artificial immunization (when an artificially weakened pathogen is introduced into the body), antibodies appear in the human blood directed against a specific antigenic stimulus. The number of antibodies is extremely high.
The organs of the human immune system include the bone marrow, liver, spleen, and lymphatic system.
Nature provides several varieties of immunity. Hereditary immunity is associated with the species of a person. It is inherited from parents to their child.
Further distinguish naturally and artificially acquired immunity. The first is formed as a result of the transferred disease. The second is formed actively or passively. With the active formation of artificial immunity, a vaccine is introduced into the body. This is a pathogenic microorganism weakened in any way, but retaining all its harmful properties. Its introduction into the human body causes an infectious disease that occurs in a mild form, but with a very pronounced immune response. With the passive formation of artificial immunity, ready-made antibodies (serum or gamma globulin) are introduced into the body.
Immunity formed in one way or another has a certain duration. In passive immunity, it ranges from several weeks to two to three months. Active immunity lasts longer. For example, smallpox vaccination (inoculation) gives a full guarantee that a person will never get smallpox. A vaccine against diphtheria or tetanus (with three vaccinations) provides protection for 10 years. Then a second vaccination (revaccination) is required. We must always remember that a single vaccination for certain types of infectious diseases does not give a lifetime guarantee.
Prevention of infectious diseases
In order to prevent the spread of infectious diseases, it is necessary to break the links connecting the elements of the general epidemiological chain, and at the same time act on each of its elements.
First element- a sick person or animal. A sick person with suspected infectious disease is isolated and treated. A sick animal is treated differently: if it is an animal valuable to a person, it is treated, in all other cases it is euthanized. The situation is more complicated with bacillus carriers. These are quite healthy people who would never think of going to the doctors. Therefore, bacillus carriers must be actively identified. It is almost impossible to examine all people for bacillus carrying. Therefore, the survey is carried out randomly. It is subjected to those groups of people who are employed in catering units (buffets, canteens, restaurants) and in children's institutions.
Second element epidemiological chain - the mechanisms of its transmission. To prevent the spread of infection, it is necessary to put a barrier on the ways of its transmission and destroy the mechanisms of its spread. To do this, in everyday life, you must follow the following rules:
All food products must be cooked; plates, cups, forks, knives must be washed with household chemicals, then rinsed with plenty of water; fruits and vegetables must be thoroughly washed in running water; we must not forget about washing hands before eating and after using the toilet;
for colds, a simple and reliable way to prevent the disease is the usual three-layer gauze bandage, which can be used both at work and at home; for the patient, it is necessary to allocate individual dishes and wash them using disinfectants; the patient's handkerchiefs should be boiled and thoroughly ironed;
an effective way to prevent the spread of blood infections is to destroy or repel insects;
zoonotic infections should be prevented in several ways: valuable animals in fur farms should regularly undergo veterinary control; sick animals need to be treated; with a significant increase in the number of carriers and keepers of many infectious zoonotic diseases (these are mice, rats, etc.), they are deratized (destroyed);
reduction of diseases transmitted by household contact can be achieved by increasing the hygiene culture of people, strengthening morality and morality, stimulating public intolerance towards all manifestations of anticulture, violation of ethical norms and rules (an important element in this process is the education and upbringing of children and adolescents, instilling in them culture of health and healthy lifestyle).
Third element in the general epidemiological chain is directly related to you and me. Currently, the only reliable way to protect yourself from an infectious disease is known: to follow the recommendations of doctors for vaccination and revaccination in a timely and accurate manner.
Good nutrition, a reasonable motor regimen, a healthy lifestyle also reduce the risk and likelihood of disease.
In all cases of the occurrence of an infectious disease in the team, a system of measures aimed at preventing the spread of the disease, the so-called quarantine, is mandatory. In a simplified form, this is a strict restriction of the movement and contacts of people among whom the disease was detected. The duration of quarantine depends on the latent (incubation) period of the detected disease and is calculated from the moment the last patient is isolated (the incubation period for cholera is 5 days, for dysentery - 7 days, for typhus - 21 days, etc.).
The complex impact on all parts of the epidemiological process of any infectious disease prevents its spread. This requires the efforts of not only medical specialists, but also of us. Getting vaccinated on time, observing a hygienic culture, a culture of health, cultivating a hygienic worldview is in the interests of each of us.
External signs of an infectious disease
Most infectious diseases are accompanied by a rise in temperature, chills, weakness throughout the body, and headache. Often there are coughing, sneezing, copious discharge from the nose, sometimes vomiting, repeated loose stools, pain in the abdomen. A distinctive feature of many infectious diseases is the appearance of a rash in the form of small reddish spots on the skin in various parts of the body. Sometimes a small bubble filled with a clear liquid is seen in the center of the spot. As a rule, the diagnosis of an infectious disease is made on the basis of a bacteriological examination of the natural functions of the patient (smear from the pharynx, secretions of the genital organs, scrapings from the skin, a smear from the rectum).
External signs of an infectious disease appear not immediately from the moment the pathogenic microbe enters the body, but only after a while. The time from the introduction of the microorganism to the manifestation of the disease is called the incubation period. The duration of the incubation period for each infectious disease is different: from several hours to several weeks and even years.
Incubation or latent period does not mean that nothing happens in the body during this period. On the contrary, there is a fierce struggle between the pathogenic microbe and the organism.
In the development of an infectious disease, several successively changing periods can be traced: a latent (incubation) period, the onset of the disease, the active manifestation of the disease, and recovery. The duration of the periods is different and depends on the nature of the infection.
14.10.2013 30120 0Lesson goals. To acquaint students with the signs of infectious diseases, the conditions and mechanisms of transmission of infection. To acquaint students with the most common infections and the mechanisms of their transmission. Explain the obligatory rules of personal hygiene to prevent infectious diseases.
Checking homework.
1. Answer the questions.
Define your definition of health. What is the WHO definition of health?
What are the components of the concept of "health"?
List the main functions of health.
What is individual health and what does it depend on?
-What is public health and what factors affect it?
Name the main types of environmental pollution.
Give examples of chemical pollution.
Briefly describe physical pollution
Briefly describe biological pollution.
What is immunity?
What types of "social pollution" of society do you know? Briefly describe them.
Learning new material. Introduction by the teacher.
In the last lesson, we talked about biological pollution of the environment, about biological pollutants. Human infectious diseases are one of the manifestations of such pollution.
Questions to activate knowledge.
What is an infection?
What is an infectious disease?
What are the characteristic signs of infectious diseases?
How are infectious diseases transmitted?
What is an epidemic?
What is hygiene?
How does compliance with hygiene rules affect the likelihood of a person contracting an infectious disease?
You can start studying new material with the definition of the term - infection.
Infection(from the medieval Latin word infectio - infection), the introduction and reproduction in the human or animal body of pathogens, accompanied by a complex of reactive processes; ends with an infectious disease, bacteriocarrier or death of microbes. The source of the infectious agent infects healthy people upon contact, through the mouth (with water and food), air (with droplets of saliva and mucus), and arthropod vectors.
Infection, or rather, the process denoted by this term, underlies the existence of a special kind of disease - infectious.
infectious diseases - diseases caused by pathogensmicro-organisms that are transmitted from an infected person to rovy. Each infectious disease is caused by a specific pathogen.
The causative agents of infectious diseases have a number of features:
1. The ability to be transmitted from the sick to the healthy and thus spread among people, causing epidemics.
2. The presence of an incubation period of reproduction in the body.
3. Complexity of detection in the external environment.
4. The ability of some pathogens to persist for a long time outside the body of a person or animal.
Epidemic (Greek epidemia) - the massive spread of a human infectious disease in any locality, country, significantly exceeding the usual incidence rate.
Transmission conditions, as mentioned above, is a set.
Scientists identify three main groups conditions:
Natural - climate, landscape, flora and fauna, presence of natural (endemic for the area) foci of infectious diseases, hydrography, wind rose, natural disasters.
Social- population density, housing conditions, sanitary and communal arrangement of settlements, material well-being, the state of the health care system, migration processes, the state of the transport system, the general development of the sanitary culture of the population, working conditions, food structure and others.|
Personal- the ability of the body to respond to the introduction, reproduction and vital activity of pathogenic microorganisms, to the development of the infectious process with a complex of protective and adaptive reactions. Personal transmission conditions are usually referred to as "susceptibility".
The causative agents of infectious diseases have different resistance in the environment: some are able to live outside the human body for only a few hours, others can live in the environment from several days to several years. For others, the environment is a natural habitat. For others, other organisms, such as wild animals, are a place of conservation and reproduction.
These features depend transmission mechanisms of infectious diseases.
Under transmission mechanism pathogenic microbes understand the totality of evolutionarily established ways of moving pathogens from an infected organism to a healthy one. It includes: removal of the pathogen from the infected organism; his stay in the external environment; the introduction of the pathogen into a healthy organism. There are several approaches to classify the mechanisms of transmission of infectious diseases. They differ only in details. At home, you will familiarize yourself with the classification given in the textbook (see pp. 132-133). The teacher asks to write in a notebook one of the classifications of modes of transmission of infection.
Fecal-oral (for intestinal infections).
Airborne (with respiratory tract infections).
Liquid (for blood infections).
Contact (for infections of the external integument).
Zoonotic (carrier - animals).
Thus, infectious diseases occur under unfavorable conditions for a person and society. Usually, infectious diseases spread from their natural habitat through transport routes and during mass migrations of disease-carrying animals. When the percentage of cases is much higher than usual, they talk about an epidemic. Their scale depends on natural and social conditions. The disease of a particular person depends on his susceptibility, i.e. the body's ability to resist infection. There are various mechanisms of infection transmission, on the basis of which infectious diseases are classified.
Infectious diseases are a great danger to mankind. In the Middle Ages, epidemics carried away the populations of entire states, leaving behind deserted cities and throwing back entire civilizations. Such a thing cannot be allowed. Epidemics arise and spread in different ways, the diseases that generate them have a different transmission mechanism. It is necessary to know this mechanism, because the rules for the safe behavior of each person in an epidemic are determined precisely by the infection transmission mechanism.
Currently, all over the world, including our country, infectious diseases of “dirty hands” are quite widespread. The mechanism of their transmission is fecal-oral. They usually occur in the summer, spread very quickly and sometimes lead to epidemics. These diseases include:
Cholera (Greek cholera, from chole bile + rheo to flow, expire) - an acute infectious disease, characterized by damage to the gastrointestinal tract, impaired water-salt metabolism and dehydration of the body; refers to quarantine infections. In the history of mankind, cholera periodically spread to many countries of the world and entire continents, claiming millions of human lives. The last, seventh, pandemic of the disease began in 1961. The epidemic situation of cholera in the world remains tense, several thousand people fall ill every year. In the countries of South and Southeast Asia and in a number of African countries (more than half of the cases of diseases are recorded on the African continent), there are endemic foci of cholera and epidemics periodically occur.
The causative agent is Vibrio cholerae Vibriocholerae- similar to a comma, very mobile, grows well on nutrient media with an alkaline reaction. Vibrio cholerae tolerate low temperatures, can overwinter in frozen water bodies, and persist for a long time in coastal waters of the seas. Boiling kills vibrios instantly. They are sensitive to drying, exposure to sunlight, disinfectants. In the water of surface reservoirs in the warm season, even the reproduction of cholera vibrios is possible, which is facilitated by water pollution with alkaline waste, especially bath and laundry drains.
The source of the causative agent of infection is only a person - a patient or a carrier of cholera vibrios. Cholera is transmitted only by the fecal-oral route. The main route of transmission is waterborne - when drinking contaminated water, washing dishes, vegetables, fruits, bathing, etc., as well as through contaminated food and household contacts. Human susceptibility to the disease is high.
In the event of an outbreak of cholera, sanitary control points are created on railway, water and air transport, on highways to identify and hospitalize patients with gastrointestinal disorders in order to prevent the importation of cholera. Repeated disinfection is carried out in the hearth. In some cases, according to epidemic indications, emergency prophylaxis of the entire population with antibiotics is carried out in the outbreak. Within a year after the elimination of the outbreak of cholera, constant monitoring of compliance with sanitary and preventive measures in the area is carried out. At least once every 10 days, a bacteriological examination of water from sources of drinking water supply, open reservoirs and domestic wastewater for the presence of cholera vibrios is carried out.
Dysentery. The causative agent is a dysenteric bacillus. It retains its properties: in feces, in linen, in moist soil, in milk, on the surface of fruits, berries, vegetables, paper and metal money. Dies in the spring environment under the influence of high and low temperatures, sunlight, disinfectants. A temperature of 60 ° C and a 1% solution of carbolic acid kill it in 30 minutes. Sources: sick or recovering people. Infection occurs through dirty hands, contaminated objects and food. The peddlers are flies. The disease is recorded throughout the year, peaking in July-August.
Prevention of dysentery consists in strict observance of the rules of personal hygiene, food hygiene andtimely detection of bacillus carriers
Infectious (epidemic) hepatitis- Botkin's disease. The causative agent is a special type of filterable virus (a virus that passes through a bacterial filter). It affects primarily the liver and is found in the blood, bile and feces of a sick person. It is stable in the environment and therefore very dangerous.
Infection of a healthy person can occur in two ways: through the gastrointestinal tract (with water and food), as well as through the blood (when using a poorly sterilized syringe, when transfusing blood that has not passed control, during an operation, through a drug addict's needle). The incubation period is up to 50 days, and when infected through the blood - up to 200 days. A healthy person who has had Botkin's disease is dangerous, because. the virus is still in his blood after recovery. The main means of prevention is the obligatory fulfillment of the requirements of personal hygiene and food hygiene.
Diphtheria . The causative agent is a stick, which is highly resistant in the external environment and releases a very strong toxic substance. Sources - a sick or convalescent person. Infection most often occurs by airborne droplets when sneezing and talking, but infection through books, toys, and food is not excluded. The entrance gate of the pathogen is the mucous membrane of the nose, throat, eyes, damaged skin. The incubation period lasts from 2 to 7 days. Depending on the localization, diphtheria of the pharynx, throat, nose, eyes, ear, skin and even the external genital organs are distinguished. When wounded, diphtheria of wounds is possible. The disease begins acutely. The temperature can rise to 38-39 ° C, which is accompanied by headache, weakness.
Prevention of diphtheria consists, first of all, in the immunization of children, revaccination of adults and the identification of bacillus carriers. In case of an outbreak of diphtheria, quarantine is organized for 7 days from the moment of the last disease. These days, those in contact with the patient are monitored for body temperature and carefully monitored for their condition. Disinfection is carried out in the room, dishes and children's toys are treated with a disinfectant solution and boiling water.
Sexually transmitted infections. Venereal diseases are infectious diseases, the causative agents of which are transmitted from a sick person or a carrier to a healthy one. They can be transmitted not only sexually, but also through close household contact (through common utensils, etc.), in utero. The diseases transmitted not only sexually include: ureaplasmosis, trichomoniasis, genital herpes. This group also includes HIV infection.
HIV infection. AIDS, acquired immunodeficiency syndrome. This is a disease of the immune system of the human body, leading to its destruction.
Symptoms of this disease were first reported in 1978 in several patients in the United States and Sweden (in homosexual men), as well as in Tanzania and Haiti (in heterosexuals of both sexes). And in 1983, Luc Montagnier of the Pasteur Institute (France) discovered the human immunodeficiency virus (HIV), which is the cause of AIDS. To date, it is known that this virus comes from West Africa, its nature and structure have been determined, the ways of transmission and viability of the virus have been studied, but so far all this has not led scientists to create a drug for the treatment of HIV. The statistics on the spread of HIV infection are horrifying: at the moment, 40 million people in the world are already infected with HIV or have AIDS.
There are several ways to get HIV infection:
1. Unprotected (without a condom) sexual intercourse (70-80%);
2. Sharing of syringes, needles and other injection equipment (5-10%);
3. Use of non-sterile instruments for tattoos and piercings;
4. Use of other people's shaving accessories, toothbrushes with visible blood residues;
5. Transfusion of infected blood (5-10%);
6. Transmission of the virus from an HIV-positive mother to her child - during pregnancy, childbirth and breastfeeding (5-10%).
A person living with HIV may look and feel good for many years and not even know they are infected. However, over time, the virus continues to destroy the cells of the immune system, and when the number of cells drops below a critical level, the person becomes vulnerable to diseases, many of which are usually avoidable. AIDS (Acquired Immune Deficiency Syndrome) is usually diagnosed several years after HIV infection, when a person develops one or more serious illnesses. For example, early signs of HIV infection progression include oral thrush, unexplained fever, night sweats, diarrhea, weight loss, frequent acute respiratory infections, shingles (herpes), etc.
A blood test for HIV can be done in any hospital, including anonymously. For questions about HIV infection and the results of the analysis, you can consult with an immunologist or venereologist, who, if necessary, will prescribe treatment. To avoid the risk of contracting HIV, you must follow some rules of personal safety, and especially in the intimate area.
Of the diseases transmitted by zoonotic transmission mechanism, the greatest danger in our country is malaria, encephalitis and rabies.
Malaria, also known as swamp fever, intermittent fever, paroxysmal malaria, an acute infectious disease caused by several species of protozoa of the genus Plasmodium and transmitted by the bite of a mosquito of the genus Anopheles.
Malaria is characterized by recurrent bouts of severe chills, high fever, and profuse sweating. It is widespread in warm and humid regions with an average annual temperature of 16 ° C and above, it is also found in zones of a more temperate climate and is completely absent in the polar regions. The disease causes serious economic damage to countries with a tropical and subtropical climate, leading among all diseases as the main cause of disability and mortality.
Malaria remains fairly common in many other regions as well. It is found in the West Indies, Mexico, Central America, in the northern regions of South America, especially in the Amazon Valley. Malaria poses a constant threat to many parts of Africa. It is also common on the coast of the Red and Mediterranean Seas, in the Balkans and Ukraine. Numerous cases of malaria are reported each year in Southeast Asia, India and northern Australia. In the United States, the highest incidence of malaria was in the South, especially in Florida.
Only female mosquitoes carry the pathogen; in males, the piercing and sucking parts of the oral apparatus are reduced. Mosquitoes are the main host of the malarial Plasmodium, while humans are the intermediate host.
Measures to limit the number of mosquito vectors are aimed at the destruction of their larvae, which live in the subsurface layer of quiet water bodies. For this purpose, wetlands are drained, an oil film is applied to the surface of reservoirs, insecticides are sprayed, and small fish that feed on mosquito larvae are bred.
In places where such activities are not carried out, insect repellents should be used. However, repellents provide incomplete and short-term protection.
Tick-borne encephalitis (spring-summer, taiga, Far East, Russian encephalitis). In 1935, a filterable virus, the causative agent of encephalitis, was isolated and the route of transmission was shown: from rodents, through ixodid ticks, the main carriers of spring-summer encephalitis. In addition to the bite of a tick, infection is also possible through the consumption of milk from infected animals. In addition to rodents, birds, wild and domestic animals, as well as ticks themselves, can be a reservoir of the virus.
The incubation period lasts from 1 to 30 days. The disease begins suddenly with chills, a rapid increase in body temperature to 38-39 ° C, severe headache, pain throughout the body, fatigue, weakness, sleep disturbance, nausea, and sometimes vomiting. From 3-5 days of illness, damage to the nervous system begins.
Tick-borne encephalitis mainly affects people living or working in wooded, taiga regions (lumberjacks, hunters, geologists, oil workers, etc.), and visitors get sick more often than indigenous people.
When a tick bites, the virus enters directly into the patient's blood and then spreads through the bloodstream, reaching a maximum concentration in the brain 3-4 days after the bite. The severity of tick-borne encephalitis depends to a certain extent on the number of bites and the number of viruses that enter the body during each bite.
After the disease, persistent immunity arises, in the blood of those who have been ill in those for a long time, specific antibodies are determined.
Rabies - a viral disease that occurs with severe damage to the nervous system and ends, as a rule, with a fatal outcome.
The disease has been known to mankind for several millennia. First described by K. Celsus in the 1st century. n. e. In 1885, L. Pasteur received and used a vaccine to save people bitten by rabid animals. The viral nature of the disease was proved in 1903 by P. Remlenzhe.
The virus is resistant to phenol, freezing, antibiotics. Destroyed by acids, alkalis, heating.
The virus is dangerous for most warm-blooded animals (mammals and birds).
The source of infection are infected animals: foxes, wolves, dogs, cats, bats, rodents, horses, small and large cattle. Human infection occurs when an animal bites or saliva on damaged skin or mucous membranes. The virus is released into the environment with the saliva of an infected animal or person. Cases of human disease as a result of bites by apparently healthy animals are described. Person-to-person transmission of the virus cannot be ruled out.
Rules of personal and public hygiene.
Speaking of infectious diseases, we often mentioned the word "immunity". Immunity - the ability of the human and animal body to specifically respond to the presence of a foreign substance in it. This reaction of the body provides its resistance and is therefore important for its survival. The reaction is based on the synthesis of special proteins, the so-called. antibodies that can combine with foreign substances - antigens. The science that studies the mechanisms of immunity is called immunology.
Thus, immunity determines the ability of a living organism, including humans, to resist all harmful external influences, such as pathogens. But we are often faced with the fact that one person practically does not get sick, while the other becomes a victim of any infection. This is because the level of immunity in people is different. Many factors influence the level of immunity.
Vaccination. We also talked about it when we studied infectious diseases. However, under this concept, too, you need to bring a scientific basis. Currently, the concept of vaccination has been revised and the term is used "vaccination And immunization".
artificial active immunization- stimulation of the immune system by introducing a vaccine or toxoid (a neutralized bacterial toxin that retains its antigenic properties); with artificial passive immunization, ready-made antibodies, immunoglobulins, are introduced into the body. natural active immunization of the body occurs as a result of its infection, and natural passive immunization - when maternal antibodies are transferred to the fetus through the placenta or into the body of a newborn with colostrum.
As a result of artificial immunization, highly specific immunity is produced, i.e. a vaccine, toxoid or ready-made antibodies give the body partial or complete resistance to a given disease. Vaccines and toxoids protect the body for a long time, sometimes until the end of life. Ready-made antibodies provide only temporary protection; in case of re-infection, they must be administered again. Two ways of artificial active immunization are possible: 1) the introduction of live but weakened microorganisms and 2) the introduction of killed microorganisms, their toxins or antigens. In both cases, a person is injected with a vaccine or toxin that does not in itself cause disease, but stimulates the immune system, making it able to recognize and neutralize a specific microorganism.
Many childhood diseases are now vaccinated against whooping cough, polio, measles, mumps, rubella, and influenza B (the main cause of meningitis in childhood). Immunoglobulins have been obtained that can quickly protect the body from snake bites, tetanus, botulism and diphtheria.
Sanitary and hygienic measures - a set of organizational, technical, economic, medical and other measures aimed at preserving the health of the population. The methods of carrying out these activities take into account the nature and conditions of work and life of people, their physical development, the degree of exposure to occupational and infectious diseases.
The basis of sanitary and hygienic measures is the implementation of preventive and current state sanitary supervision: control over the implementation of nationwide measures aimed at eliminating and preventing environmental pollution, improving the working and living conditions of the population, as well as the implementation by departments, enterprises, organizations and individual citizens of sanitary -hygienic and sanitary-anti-epidemic rules.
Preventive sanitary supervision implies a preliminary hygienic assessment of new industrial enterprises, new consumer goods, new building materials, etc.
Current sanitary supervision provides for regular planned monitoring of compliance with the established sanitary and epidemic regime for the operation of enterprises, institutions and structures, the sanitary condition of populated areas, working conditions, etc.
A special place among sanitary and hygienic measures is occupied by prevention infectious diseases - a set of measures aimed at preventing diseases.
It is carried out mainly by the forces of the sanitary-epidemiological service and includes the following main activities: disinsection, disinfection, deratization, quarantine, observation.
Summing up the lesson.
Questions to consolidate knowledge.
What is an infection?
Define an infectious disease.
What are the characteristics of pathogens of infectious diseases?
Define an epidemic and give examples from the history of our country and world history.
List the conditions for an outbreak.
What is susceptibility?
Name and briefly describe the mechanisms of infection transmission.
Name the most dangerous diseases transmitted by the fecal-oral route.
What preventive measures are taken to prevent these infections?
What are the symptoms of dysentery in humans? Viral hepatitis? cholera?
What is the peculiarity of botulism infection?
Name the most dangerous diseases transmitted by airborne droplets.
Name the preventive measures in case of the threat of an influenza epidemic.
– What is the zoonotic mode of infection transmission?
How does a person become infected with encephalitis?
What measures are usually taken to control the spread of malaria?
Summing up the lesson.
Homework.
Determine the mechanism of transmission of the most widely known infectious diseases:
The flu is airborne.
Dysentery - fecal-oral.
Viral hepatitis (Botkin's disease) - fecal-oral.
Human immunodeficiency virus (HIV) - liquid.
Leprosy (leprosy) - contact.
Malaria is zoonotic.
Typhoid fever - fecal-oral.
Typhus relapsing - zoonotic.
Infectious diseases
caused by pathogenic microorganisms that, due to suboptimal functionality of the immune system, enter the body. These microorganisms have a certain degree of virulence (toxicity), which manifests itself in different ways:
- in the process of their vital activity in the body;
- with its own destruction.
Infectious diseases are characterized by the incubation period of pathogens - this is the time before the first signs of a particular pathology appear and the duration of this period depends on the type of pathogen, method of infection. The incubation period of an infectious disease can last from a few hours to several years.
Classification of infectious diseases
Infectious diseases are distinguished by many "parameters".
A. According to the location of the infection, these diseases are:
- intestinal (typhoid fever, salmonellosis, escherichiosis, dysentery, cholera, food poisoning ...);
- pulmonary (infectious diseases of the respiratory tract: influenza, SARS, chicken pox, respiratory infections, measles ...);
- transmissible (infectious blood diseases: HIV, typhoid, plague, malaria...);
- diseases of the external integument (anthrax, tetanus).
B. According to the type of pathogen, infectious diseases of people are:
- viral (cytomegalovirus infection, viral hepatitis, HIV, influenza, measles, meningitis...);
- prions (caused by protein infectious agents: Creutzfeldt-Jakob disease, kuru ...);
- protozoan (caused by the simplest infectious agents: amoebiosis, balantidiasis, malaria, isosporiasis ...);
- bacterial (meningitis, dysentery, salmonellosis, plague, cholera...);
- mycoses (caused by fungal infectious agents: chromomycosis, candidiasis, epidermophytosis, cryptococcosis ...).
D. Particularly dangerous diseases, which are called quarantine, are classified as a separate group of infectious diseases.
This group is characterized by a short incubation period, a high spread rate, a severe course, and a high percentage of death. The World Health Organization classified this group of infectious diseases as: cholera, Ebola, plague, smallpox, some types of influenza, yellow fever.
Causes of infectious diseases
The cause of all infectious diseases is a pathogenic microorganism, which, when it enters the body, excites infectious processes. As a rule, each disease of this nature has its own pathogen, although there are exceptions, for example, sepsis occurs as a result of exposure to several pathogens, and streptococcus can cause several diseases (scarlet fever, tonsillitis, erysipelas).
The organisms of different people react differently to the invasion of foreign agents: some are practically immune to them, while others, on the contrary, immediately begin to react sharply to this, showing various symptoms of an infectious disease.
This is due to the fact that the defenses of the body in people are different. Protective forces characterize the state of the immune system. And so we can say that the main cause of infectious diseases is the suboptimal functionality of the immune system.
If the immune system is weak, then the body does not "have enough strength" to fight pathogenic microorganisms - this human condition is called immunodeficiency.
It happens that the immune system is inadequately active and begins to perceive the tissues of its own body as foreign, and attacks them - this condition is called autoimmune.
Causative agents of infectious diseases
Viruses.
It means "poison" in Latin. They are able to multiply only inside living cells, where they seek to penetrate.
bacteria.
The vast majority of unicellular microorganisms.
Protozoa.
Unicellular microorganisms that can perform some of the functions inherent in individual tissues and organs of more highly developed forms.
Mycoplasmas (fungi).
They differ from other unicellular organisms in that they do not have a membrane and can initiate infectious processes while outside the cells.
Spirochetes.
At their core, they are bacteria that have a characteristic spiral shape.
Chlamydia, rickettsia.
Intracellularly functioning microorganisms, inherently occupying an intermediate position between viruses and bacteria.
The degree of possibility of an infectious disease in a person depends on the ability of his immune system to give an adequate response to the invasion of any of these foreign elements, recognize it and neutralize it.
Infectious diseases: symptoms
The symptomatology of these diseases is so diverse that, despite its pronounced severity, it is often very difficult to determine its type, and this is due to the choice of treatment method.
Modern medicine knows more than 5,000 infectious diseases and about 1,500 of their symptoms. This suggests that the same symptoms appear in many diseases - such symptoms are called general or non-specific. Here they are:
- elevated body temperature;
- general weakness of the body;
- loss of appetite;
- chills;
- sleep disturbance ;
- muscle pain;
- ache in the joints;
- nausea and vomiting;
- increased sweating;
- dizziness;
- severe headaches;
- apathy...
But of particular value in the diagnosis of infectious diseases are pathognomonic symptoms - signs characteristic of only one form of infectious pathology. Here are some examples of such symptoms:
- Volsky-Filatov-Koplik spots on the oral mucosa are characteristic only of measles;
- whooping cough is characterized by a special cough - convulsive with reprisals;
- opisthotonus (arching of the back) is a characteristic symptom of tetanus;
- rabies is a hallmark of rabies;
- meningococcal infection can be diagnosed with 100% certainty by the presence of a vesicular rash along the nerve trunks ...
Pathognomonic symptoms are known for most infectious diseases, and every infectious disease doctor must know the most common of them.
Among other things, there is a group of symptoms that occupies, as it were, an intermediate position between general and pathognomonic symptoms. These symptoms can occur not only in infectious diseases, but in others too. For example, an enlarged liver is characteristic of both viral hepatitis and cirrhosis of the liver, heart failure, malaria, typhoid fever ..., an enlarged spleen occurs in typhoid fever, sepsis, malaria, viral hepatitis ...
That is why any infectious diseases people are diagnosed when a combination of many signs using a variety of methods of analysis and instrumental diagnostics, because, we repeat, the choice of a method for treating a disease depends on this, and, accordingly, success depends on it.
Diagnosis of infectious diseases in humans
After questioning the patient and preliminary conclusions, the material is taken for analysis, which is determined by the doctor. This material can be: blood (most often), urine, feces, cerebrospinal fluid, sputum, smears from the mucous membranes, vomit, biopsy specimens and organ punctures ...
Recently, for the diagnosis of infectious diseases, enzyme immunoassay has become widespread.
Most diagnostic methods are aimed at determining the type of pathogen, or the presence and belonging of antibodies to certain classes of immune components, which makes it possible to differentiate various infectious diseases.
Also, skin tests with allergens introduced into them are often used to diagnose these diseases to provoke appropriate reactions.
Treatment of human infectious diseases
Currently, there is a huge number of different drugs that are designed to treat various infectious diseases in humans, and it is impossible to list them all ... and there is no need for this. Many well-known scientists, at present, have a very ambiguous attitude, for example, to antibiotics, others to other drugs.
Firstly, any drug has certain contraindications and causes some side effects, and this is their main drawback.
Secondly, drugs, the action of which is aimed at neutralizing foreign agents, in fact, do a disservice to the immune system, which develops and grows stronger only in collisions with infections, and therefore excessive drug intake actually weakens the body. . It turns out a paradox: we treat one and immediately "catch" another disease, or even a whole "bouquet" of them.
Thirdly, taking medications (especially antibiotics) gradually destroys the microflora of the stomach - the most important link in the human immune system, and this has very unpredictable consequences. That is why treatment of infectious diseases must be carried out simultaneously with the intake of probiotics and prebiotics, which are 100% natural.
Treatment of infectious diseases in humans consists in the use of the following drugs:
- antibacterial (chemo- and antibiotic therapy);
- gamma or immunoglobulins (serotherapy);
- interferons;
- bacteriophages (phage therapy);
- Vaccines (vaccination therapy);
- blood products (hemotherapy)
Today, a new paradigm is ripe in the treatment of infectious diseases: scientists have come to the conclusion that it is more important to support the immune system (IS) in its fight against foreign agents, and not directly influence these agents, although in severe cases, of course, there is no time for restoring the optimal functionality of the IS.
It is for this reason that complex therapy of these pathologies is necessary, in which, along with traditional medicines, it is necessary to use immunomodulators and immunostimulants. Many of these drugs:
- neutralize the side effects caused by drugs;
- strengthens the body's immunity;
- enhances the therapeutic effect of the applied medicinal preparations;
- quickly restores the body.
Infectious diseases: prevention
Preventive measures to prevent infectious diseases have been known for a long time and in the Soviet period they were called: "Healthy lifestyle". Since then, they have not lost their relevance, and we will recall them here.
1. First of all, infectious diseases depend on the normal functionality of the immune system, which, in turn, depends on normal nutrition. Therefore, rule number 1 - eat right: do not overeat, eat less animal fats, include more fresh fruits and vegetables in the diet, eat fried foods as little as possible, eat more often, but in smaller quantities ...
2. Infectious diseases can be prevented by the systematic use of immune preparations: immunomodulators and immunostimulants (this is the second most important rule).
3. Strengthen your immune system by regularly eating herbal products such as onion, garlic, honey, lemon juice (not pure), raspberries, sea buckthorn, ginger...
4. Lead an active lifestyle: exercise in the morning, go to the gym or pool, run in the evenings...
5. Infectious diseases not afraid of a hardened body, so get hardened (a bath and a contrast shower are the best way for these purposes).
6. Give up bad habits: stop smoking and abusing alcohol.
7. Avoid stressful situations and do not succumb to depressive states, nothing suppresses the immune system as much as our nervous breakdowns, so become an optimist and understand that there is nothing more important in this life than your health.
8. Learn to rest properly. Constantly watching television and "resting" on the couch is not a vacation. Real rest should be active and necessarily provide for the alternation of physical and mental stress.
These are simple rules that should become a way of life for every person, and then we guarantee you: no infectious diseases will pose absolutely no danger to you.
Topic: INFECTIOUS DISEASES AND THEIR PREVENTION
infectious process.
epidemic process.
Federal Law "On Immunoprophylaxis of Infectious Diseases".
The concept of immunity and its types.
General principles for the prevention of infectious diseases.
INFECTIOUS PROCESS
Infectious diseases include those that develop as a response of the body to the introduction and reproduction of pathogens. A characteristic and distinctive feature of an infectious disease is the ability of the pathogen to spread in the environment of the sick person and cause new cases of diseases. Therefore, infectious diseases are called contagious.
The nature of an infectious disease is the infectious process is the result of the confrontation between the patient's body and the invading microorganisms. During the development of the infectious process, there are violations of the structure and function of the affected organs and systems of the body, which leads to disorders in the normal functioning of a person. The nature of the development of the infectious process, the characteristics of the course of the disease and the outcome of the disease are determined by the following factors:
1. Pathogenic properties (pathogenicity) of the pathogen: a) its virulence (the ability to penetrate the protective barriers of the human body); b) its reproduction (the ability to multiply intensively in the tissues of an infected organism); c) its toxigenicity (the ability to release bacterial poisons or toxins).
2. The protective potential of the human body or its susceptibility to an infectious onset, which depends on: a) resistance or immunity to infection as a result of innate or acquired immunity; b) reactivity, the state of the body's defense system.
3. Habitat conditions, determining the possibility of interaction between macro- and microorganism. Pathogens that can cause an infectious process are called pathogenic, and this property is called pathogenicity. The degree of pathogenicity of a particular pathogen is estimated as virulence. They talk about high or low virulence of pathogenic microbes. The causative agents of infectious diseases are bacteria, viruses, rickettsia (typhus), microscopic fungi, and protozoa.
To indicate the state of infection of the body with protozoa, the term " invasion"(from lat. Invasion - invasion, invasion).
entrance gate causative agent (the place of penetration of the infectious principle into the human body):
Leather,
- mucous membranes,
Tonsils.
infectious dose. For a person to fall ill, that is, for an infectious process to occur, an appropriate infectious dose is needed, which is different for different pathogens and different for each person. For example, the minimum doses for tularemia are 15 live sticks, anthrax - 6000, dysentery - 500 million microbial cells. .
The specificity of the infectious process. The infectious process is always specific, that is, it depends on the type of pathogen. Vibrio cholerae can only lead to the development of cholera, the influenza virus causes influenza, the dysentery bacillus causes dysentery, the measles virus causes measles, etc.
In the process of dynamic development of almost any infectious disease, characteristic periods:
1. Incubation or latent (hidden) period of the disease, which lasts from the moment of infection until the first signs of the disease appear (flu - from several hours to 3 days, AIDS - years);
2. Prodromal period of the disease (harbingers). During this period, symptoms common to all diseases predominate: general malaise, fever, headache, general weakness, and a state of discomfort. At the end of the prodromal period, in some infectious diseases, specific symptoms appear (rash with bark or scarlet fever);
3. Clinical period of the disease (height of the disease), when the symptoms of the disease are most fully deployed, and the specific signs of the disease appear most clearly ; the apogee of the infectious process;
4. The outcome of an infectious disease: a) recovery, b) death, c) chronic form, d) recovery with residual effects of the disease or its complications, e) bacteriocarrier.
Forms of the course of the infectious process. According to the severity of the course, infectious diseases are divided into 1) acute: flu, measles, scarlet fever, chickenpox, etc.; 2) chronic: malaria, tuberculosis, etc. Many infections have acute and chronic forms: dysentery, brucellosis, etc. There are also latent (hidden) flow , when the pathogen, multiplying, is in the body for a long time and does not cause clinical symptoms of the disease. Sometimes this form of the disease is called an asymptomatic infection.
Bacteriocarrier- a special form of relationship between a microorganism and a person. It is most often observed in the period after recovery from infection. It is characteristic that there is a microbe in the body, but there are no signs of the disease. A healthy bacteriocarrier is when no signs of the disease develop at all, despite the introduction of a pathogen.
mixed infection- this is an infection with several pathogens (measles and scarlet fever, dysentery and typhoid fever).
secondary infection- this is when, for example, after a viral infection (influenza), inflammation of the lungs caused by the bacterial flora develops.
Focal infection- for example, a furuncle, a syphilitic ulcer, tuberculosis can be localized. If the infection spreads throughout the body, they talk about process generalization(for example, sepsis occurs from a boil).
Superinfection - re-infection with the same pathogen, when the disease has not yet ended. For example, without recovering from the flu, the patient may receive an additional “portion” of viruses from another source of infection. The course of the disease worsens.
reinfection- re-infection with the same type of microbe, but after complete recovery from the previous infection. The course of the disease is easier, as there is immunity.
relapse- this is a return of the disease, an exacerbation in its chronic course.
Remission- a period of relative well-being in the chronic course of the disease between relapses.
Each of the forms of the infectious process has its own clinical and epidemiological significance. For example, latent (hidden) infection and healthy bacterial carriage are of extremely important epidemiological significance, since in these cases, patients usually do not seek treatment and serve as an active source of infection for healthy people for a long time. A person who has had an infectious disease during the recovery period is called convalescent.
Causes of exacerbations and relapses of the disease:
Violation of the regimen or diet prescribed by the doctor;
Activation of the pathogen that caused the underlying disease (reinfection) due to a decrease in the body's resistance;
New infection with another type of pathogen of this disease (superinfection) when communicating with people infected with this infectious disease;
Layering of extraneous microbial flora (secondary infection) due to violation of hygiene requirements when caring for patients;
Insufficient tension of the formed immunity after a previous infection.
Both the course of the infectious process and the severity of the main manifestations of the disease are influenced by forms of spread of the pathogen in organism:
1. Bacteremia and viremia- the process of spreading the pathogen with blood flow through organs and tissues, or generalization of infection. This process can lead to sepsis;
2. Septicemia (sepsis)- filling with microbes of many organs and tissues (anthrax, pyogenic cocci). Sepsis is characterized by the same clinical picture with different microbes. The septic component during the course of an infectious disease can significantly aggravate the course and prognosis, for example, of salmonella, staphylococcal and meningococcal infections.
3. Septicopyemia- this is sepsis, leading to the formation of purulent foci in various organs and tissues.
4. Toxinemia leads to poisoning of the body with toxins that the pathogen produces, and the development of symptoms of intoxication. Clinical signs of intoxication are caused by toxic damage to the central nervous system (headache, dizziness, nausea, vomiting, convulsions, loss of consciousness, etc.), respiratory system (shortness of breath, suffocation, respiratory arrest), blood circulation (tachycardia, bradycardia, increase or decrease in blood pressure , collapse), discharge (polyuria, anuria, dyspepsia, etc.). The toxic component determines the severity of tetanus, botulism, influenza, diphtheria and other infectious diseases.
The macroorganism has a whole series of protective mechanisms against the effects of harmful agents, which are united by a common term - reactivity and as a consequence - resistance, which is stability.
resistance plays a decisive role in the occurrence, course and outcome of an infectious disease. Resistance decreases from starvation, lack of vitamins, physical and mental overwork, cooling, etc., and increases as a result of the elimination of harmful labor factors, the organization of rest and life, hereditary and acquired immunity.
Thus, the occurrence of an infectious process and the form of its course in each specific case are determined by the result of the confrontation between the pathogenic agent and the human body. The outcomes of this confrontation can be: a) the death of the pathogen, b) the emergence of an infectious process (disease); c) mutual adaptation ("healthy bacteria carrier").
EPIDEMIC PROCESS
1. The source of infection that releases the pathogen into the environment (human, animals),
2. Factors of transmission of the pathogen,
3. A susceptible organism, that is, a person who does not have immunity against this infection.
Sources of infection:
1 person. Infectious diseases that affect only people are called anthroponoses (from the Greek anthropos - a person, noses - a disease). For example, only people get sick with typhoid fever, measles, whooping cough, dysentery, cholera.
2. Animals. A large group of infectious and invasive human diseases are zoonoses (from the Greek zoos - animals), in which various types of domestic and wild animals and birds serve as the source of infection. Zoonoses include brucellosis, anthrax, glanders, foot and mouth disease, etc.
There is also a group of zooatroponous infections, in which both animals and people can serve as a source of infection (plague, tuberculosis, salmonellosis).
Transmission factors. Pathogens are transmitted to healthy people by one or more of the following routes:
1. Air- influenza, measles are transmitted only through the air, for other infections, air is the main factor (diphtheria, scarlet fever), and for others - a possible factor in the transmission of the pathogen (plague, tularemia);
2. Water - typhoid fever, dysentery, cholera, tularemia, brucellosis, glanders, anthrax, etc.;
3. Soil- anaerobes (tetanus, botulism, gas gangrene), anthrax, intestinal infections, worms, etc.;
4. Food products- all intestinal infections. With food, pathogens of diphtheria, scarlet fever, tularemia, plague, etc. can also be transmitted;
5. Items of labor and household items, infected with a sick animal or person, can serve as a factor in the transmission of an infectious beginning to healthy people;
6. Arthropods- are often carriers of pathogens of infectious diseases. Ticks transmit viruses, bacteria and rickettsiae; lice - typhus and relapsing fever; fleas - plague and rat typhus; flies - intestinal infections and worms; mosquitoes - malaria; ticks - encephalitis; midges - tularemia; mosquitoes - leishmaniasis, etc.;
7. Biological fluids ( blood, nasopharyngeal secretions, feces, urine, semen, amniotic fluid) - AIDS, syphilis, hepatitis, intestinal infections, etc.
The main epidemiological characteristics of the emergence and spread of an infectious disease are determined by the speed of spread, the vastness of the territory of the epidemic and the mass coverage of the disease in the population.
Options for the development of the epidemic process:
1. sporadia(sporadic incidence). There are single, unrelated cases of infectious diseases that do not take a noticeable spread among the population. The property of an infectious disease to spread in the environment of the sick person is expressed in a minimal way (for example, Botkin's disease).
2. Endemic- group flash. It occurs, as a rule, in an organized team, in conditions of constant and close communication between people. The disease develops from one, common source of infection and in a short time covers up to 10 or more people (an outbreak of mumps in a kindergarten group).
3. Epidemic outbreak. The mass spread of an infectious disease that occurs from a series of group outbreaks and covers one or more organized groups with a total number of 100 or more sick people (intestinal infections and food poisoning).
4. Epidemic. Mass morbidity of the population, in a short time spreading over a vast territory, covering the city, district, region and a number of regions of the state. An epidemic develops from many epidemic outbreaks. The number of cases is estimated at tens and hundreds of thousands of people (epidemics of influenza, cholera, plague).
5. Pandemic. Global spread of epidemic morbidity among humans. The epidemic covers vast territories of various states on many continents of the globe (pandemics of influenza, HIV infection).
Natural focality of infectious diseases- the spread of the disease within certain territorial zones.
Such a phenomenon, when a disease is recorded with great constancy in a certain area, is called endemic. Typically, this is zoonotic infections that spread in the respective territorial foci among animals, with the help of insects that carry the infectious agent. The doctrine of the natural foci of infectious diseases was formulated in 1939 by Academician E.N. Pavlovsky. Natural foci of infectious diseases are called nosoareals, and infectious diseases characteristic of territories are called natural focal infections (hemorrhagic fevers, tick-borne encephalitis, plague, tularemia, etc.).
They can be called environmentally conditioned diseases, since the cause of endemicity is natural factors that favor the spread of these diseases: the presence of animals - sources of infection and blood-sucking insects that act as carriers of the corresponding infection. The nosoareal of cholera is India and Pakistan. A person is not a factor that can support the existence of a focus of natural infection, since such foci formed long before the appearance of people in these territories. Such foci continue to exist after the departure of people (upon completion of exploration, road and other temporary work). The undoubted priority in the discovery and study of the phenomenon of natural foci of infectious diseases belongs to domestic scientists - Academician E.N. Pavlovsky and Academician A.A. Smorodintsev.
Epidemic focus. The object or territory where the epidemic process unfolds is called the epidemic focus. The epidemic focus may be limited to the apartment where the sick person lives, may cover the territory of a preschool institution, school, university, include the territory of a settlement, region. The number of cases in the focus can vary from one or two to many hundreds and thousands of cases.
Elements of an epidemic focus:
1. Sick people and healthy bacteria carriers are sources of infection for people around them;
2. Persons who have been in contact with sick persons (“contacts”), who, if they develop a disease, become a source of infection;
3. Healthy people who, by the nature of their work, represent a group with an increased risk of spreading the infection - the “declared group of the population” (employees of public catering establishments, water supply, medical workers, teachers, etc.);
4. The room in which there is or was a sick person, including the furnishings and everyday items in it that contribute to the transmission of an infectious principle to susceptible people;
5. Environmental factors, especially in rural areas, that can contribute to the spread of infection (sources of water use and food supply, the presence of rodents and insects, places for collecting waste and sewage);
6. Healthy population on the territory of the focus, who had no contact with patients and bacteria carriers, as a contingent susceptible to infection, not immune from possible infection in an epidemic focus.
All of the listed elements of the epidemic focus reflect the three main links of the epidemic process: the source of infection - the route of transmission (mechanism of infection) - the susceptible contingent.
Appropriate anti-epidemic measures should be directed to all elements of the epidemic focus in order to most quickly and effectively solve two interrelated tasks: 1) strictly localize the focus within its boundaries,
to prevent the "spreading" of the boundaries of the focus; 2) to ensure the speedy elimination of the focus itself in order to prevent a mass disease of the population.
Mechanism of transmission consists of 3 phases:
2) the presence of the pathogen in the external environment,
3) the introduction of the pathogen into a new organism.
With air mechanism infection can be transmitted as by airborne droplets, so air-dust. The causative agents of infectious diseases are released into the air from the nasopharynx of a sick person when breathing, when talking, but especially intensively when sneezing and coughing, spreading with droplets of saliva and nasopharyngeal mucus several meters from the sick person. Thus, acute respiratory viral infections (ARVI), whooping cough, diphtheria, mumps, scarlet fever, etc. are spreading. Air dust path the spread of infection, when pathogens with air currents are able to spread over considerable distances from a sick person, is characteristic of "volatile" viral infections (chickenpox, measles, rubella, etc.). With the airborne route of infection, the pathogen enters the body, mainly through the mucous membranes of the upper respiratory tract (through the respiratory tract), then spreading throughout the body.
Fecal-oral mechanism Infection is characterized by the fact that in this case the causative agents of the infection, being released from the body of a sick person or a bacteriocarrier with its intestinal contents, enter the environment. Then, through contaminated water, food, soil, dirty hands, household items, the pathogen enters the body of a healthy person through the gastrointestinal tract (dysentery, cholera, salmonellosis, etc.).
blood mechanism infection differs in that the main factor in the spread of infection in such cases is infected blood, which penetrates into the bloodstream of a healthy person in various ways. Infection can occur during blood transfusion, as a result of unskilled use of reusable medical instruments, in utero from a pregnant woman to her fetus (HIV infection, viral hepatitis, syphilis). This group of diseases includes transmissive infections spread through the bites of blood-sucking insects (malaria, tick-borne encephalitis, tick-borne boreliosis, plague, tularemia, hemorrhagic fevers, etc.).
contact mechanism infection can be carried out both by direct and indirect (indirect) contact - through infected everyday items (various skin diseases and sexually transmitted diseases - STDs).
Some infectious diseases are characterized by pronounced seasonality (intestinal infections during the hot season).
A number of infectious diseases are age-specific, for example, childhood infections (whooping cough).
The main directions of anti-epidemic measures
As mentioned, the epidemic process arises and is maintained only in the presence of three links: the source of infection, the mechanism of transmission of the pathogen, and the susceptible population. Consequently, the elimination of one of the links will inevitably lead to the termination of the epidemic process.
The main anti-epidemic measures include:
1. Measures aimed at eliminating the source of infection: identification of patients, bacteria carriers, their isolation and treatment; detection of persons who have been in contact with the sick, for subsequent monitoring of their health, in order to timely identify new cases of diseases and isolate sick people in a timely manner.
2. Measures aimed at preventing the spread of infection and to prevent the expansion of the boundaries of the outbreak:
A) regime restrictive measures- observation and quarantine. Observation- specially organized medical monitoring of the population in the focus of infection, including a number of measures aimed at the timely detection and isolation of patients in order to prevent the spread of the epidemic. At the same time, with the help of antibiotics, they carry out emergency prophylaxis, make the necessary vaccinations, monitor the strict implementation of the rules of personal and public hygiene. The period of observation is determined by the duration of the maximum incubation period for a given disease and is calculated from the moment of isolation of the last patient and the end of disinfection in the outbreak. Quarantine- this is a system of the most stringent isolation and restrictive anti-epidemic measures taken to prevent the spread of infectious diseases;
b) disinfection measures, including not only disinfection, but also disinsection, deratization (destruction of insects and rodents);
3. Measures aimed at increasing the resistance of the population to infection, among which the most important are the methods of emergency prevention of the onset of the disease:
A) population immunization according to epidemic indications;
b) preventive use of antimicrobials(bacteriophages, interferons, antibiotics).
These anti-epidemic measures in the conditions of an epidemic focus are necessarily supplemented by a number of organizational measures aimed at limiting contacts among the population. In organized groups, sanitary-educational and educational work is carried out, the media are involved. The educational and sanitary-educational work of teachers with students is of great importance.
Disinfection methods in an epidemic outbreak. Disinfection is a set of measures aimed at destroying pathogens and eliminating sources of infection, as well as preventing further spread. Disinfection measures include:
1) disinfection(methods for the destruction of pathogens),
2) pest control(methods of destruction of insects - carriers of pathogens of infectious diseases),
3) deratization(methods of destruction of rodents - sources and spreaders of infection).
In addition to disinfection, there are other ways to destroy microorganisms: 1) sterilization(boiling instruments for 45 minutes prevents infection with epidemic hepatitis), 2) pasteurization- heating liquids to 50-60 degrees in order to disinfect them (for example, milk). Within 15-30 minutes, the vegetative forms of Escherichia coli die.
Disinfection methods. Physical and chemical disinfection methods are used for disinfection. TO physical methods include boiling, autoclaving, heat treatment in dry ovens, in disinfection chambers, ultraviolet irradiation. Chemical Methods disinfection is carried out using chemicals with high bactericidal activity (chlorine, chloramine, calcium and sodium hypochlorites, lysol, formalin, carbolic acid). Soaps and synthetic detergents also have a disinfecting effect. biological methods disinfection is the destruction of microorganisms by means of a biological nature (for example, with the help of antagonist microbes). It is used for disinfection of sewage, garbage and garbage.
For focal current and final disinfection in foci of intestinal infections, a 0.5% solution of chlorine-containing disinfectants is used, for airborne infections - 1.0%, in foci of active tuberculosis - 5.0%. When working with disinfectants, care must be taken (use protective clothing, goggles, mask, gloves).
FEDERAL LAW "ON IMMUNOPROPHYLAXIS OF INFECTIOUS DISEASES" dated September 17, 1998 No. 157-FZ.
Immunoprophylaxis of infectious diseases- a system of measures taken to prevent, limit the spread and eliminate infectious diseases through preventive vaccinations.
Preventive vaccinations- the introduction of medical immunobiological preparations into the human body to create specific immunity to infectious diseases.
Medical immunobiological preparations- vaccines, toxoids, immunoglobulins and other drugs designed to create specific immunity to infectious diseases.
- a normative act establishing the terms and procedure for carrying out preventive vaccinations for citizens.
Post-vaccination complications caused by preventive vaccinations included in the national calendar of preventive vaccinations, and preventive vaccinations according to epidemic indications - severe and persistent health disorders due to preventive vaccinations.
Certificate of preventive vaccinations- a document in which preventive vaccinations of citizens are registered.
State policy in the field of immunoprophylaxis(extracts from article 4).
1. The state policy in the field of immunoprophylaxis is aimed at preventing, limiting the spread and eliminating infectious diseases.
In the field of immunoprophylaxis, the state guarantees:
availability of preventive vaccinations for citizens;
free provision of preventive vaccinations included in the National calendar of preventive vaccinations, and preventive vaccinations according to epidemic indications in organizations of the state and municipal health systems;
social protection of citizens in the event of post-vaccination complications;
use for the implementation of immunoprophylaxis of effective medical immunobiological preparations.
1. Citizens in the implementation of immunoprophylaxis have the right to:
obtaining complete and objective information from medical workers about the need for preventive vaccinations, the consequences of refusing them, and possible post-vaccination complications;
choice of state, municipal or private healthcare organizations or citizens engaged in private practice;
free preventive vaccinations included in the National calendar of preventive vaccinations, and preventive vaccinations according to epidemic indications in organizations of the state and municipal health systems;
free medical examination, and, if necessary, a medical examination before preventive vaccinations in state and municipal healthcare organizations;
free treatment in state and municipal healthcare organizations in case of post-vaccination complications;
social protection in the event of post-vaccination complications;
refusal of preventive vaccinations.
prohibition for citizens to travel to countries where stay in accordance with international health regulations or international treaties of the Russian Federation requires specific preventive vaccinations;
temporary refusal to admit citizens to educational and health-improving institutions in the event of mass infectious diseases or the threat of epidemics;
refusal to hire citizens for work or suspension from work, the performance of which is associated with a high risk of contracting infectious diseases.
comply with the instructions of medical workers;
confirm in writing the refusal of preventive vaccinations.
These preventive vaccinations are carried out for all citizens of the Russian Federation within the time limits established by the National Calendar of Preventive Immunizations. (Extract from article 9).
Immunization calendar(Compiled in accordance with the order of the Ministry of Health of the Russian Federation dated December 18, 1997 No. 375 “On the vaccination calendar”
CONCEPT ABOUT IMMUNITY AND ITS TYPES
Organs of the immune system:
· central: bone marrow and thymus (thymus gland);
· peripheral: accumulations of lymphoid tissue in the intestines, lungs, genitourinary system (tonsils, Peyer's patches), lymph nodes, spleen. Peripheral organs of the immune system, like watchtowers, are located on the path of possible advancement of genetically alien substances.
Protection factors are divided into non-specific and specific.
Nonspecific mechanisms of immunity These are general factors and protective adaptations of the body. These include: impermeability of healthy skin and mucous membranes;
impermeability of histo-hematological barriers; the presence of bactericidal substances in biological fluids (saliva, tears, blood, cerebrospinal fluid); excretion of viruses by the kidneys; phagocytic system; barrier function of lymphoid tissue; hydrolytic enzymes; interferons; lymphokines; complement system, etc.
Intact skin and mucous membranes of the eyes, respiratory tract, gastrointestinal tract, and genital organs are impervious to most microbes. The secrets of the sebaceous and sweat glands have a bactericidal effect against many infections (except for pyogenic cocci).
Peeling of the skin - the constant renewal of the upper layer - is an important mechanism for its self-purification from microbes and other contaminants. Saliva contains lysozyme, which has an antimicrobial effect. The blink reflex of the eyes, the movement of the cilia of the epithelium of the respiratory tract in combination with the cough reflex, intestinal motility - all this helps to remove microbes and toxins. Thus, intact skin and mucous membranes are first protective barrier for microorganisms.
If an infection breakthrough occurs (trauma, burns, frostbite), then the next line of defense comes out - second barrier - an inflammatory reaction at the site of the introduction of microorganisms.
The leading role in this process belongs to phagocytosis (factors of cellular immunity). Phagocytosis, first studied by I.I. Mechnikov, is the absorption and enzymatic digestion by macro- and microphages - cells of mesodermal origin - microbes or other particles, resulting in the release of the body from harmful foreign substances. Reticular and endothelial cells of lymph nodes, spleen, bone marrow, Kupffer cells of the liver, histiocytes, monocytes, polyblasts, neutrophils, eosinophils, basophils have phagocytic activity.
Each of these factors and adaptations is directed against all microbes. Nonspecific protective factors neutralize even those substances that the body has not encountered before. The body's defense system is very vulnerable. The main factors that reduce the body's defenses include: alcoholism, smoking, drugs, psycho-emotional stress, physical inactivity, lack of sleep, overweight. A person's susceptibility to infection depends on his individual biological characteristics, on the influence of heredity, on the characteristics of the human constitution, on the state of his metabolism, on the neuroendocrine regulation of life support functions and their functional reserves; on the nature of nutrition, vitamin supply of the body, on climatic factors and the season of the year, on environmental pollution, the conditions of his life and activity, on the lifestyle that a person leads.
Specific mechanisms of immunity- this is antibody formation in the lymph nodes, spleen, liver and bone marrow. Specific antibodies are produced by the body in response to an artificial introduction of an antigen (vaccination) or as a result of a natural encounter with a microorganism (infectious disease).
Antigens- substances that carry a sign of foreignness (proteins, bacteria, toxins, viruses, cellular elements). These substances are able to: a) cause the formation of antibodies, b) interact with them.
Antibodies- proteins that can bind to antigens and neutralize them. They are strictly specific, that is, they act only against those microorganisms or toxins, in response to the introduction of which they have been developed. Among the antibodies, there are: antitoxins (neutralize microbial toxins), agglutinins (stick together microbial cells), precipitins (precipitate protein molecules), opsonins (dissolve microbial cells), virus-neutralizing antibodies, etc. All antibodies are altered globulins or immunoglobulins (Ig), protective substances, elements of humoral immunity. 80-90% of antibodies are in gamma globulins. So IgG and IgM protect against viruses and bacteria, IgA protects the mucous membranes of the digestive, respiratory, urinary and reproductive systems, IgE is involved in allergic reactions. The concentration of Ig M increases during acute inflammatory processes, Ig G - during exacerbation of chronic diseases. Humoral immunity factors include interferons and interleukins, which are secreted by a lymphocyte when a viral infection enters the body.
The human body is able to respond with antibody formation simultaneously to 30 or more antigens. This property is used to make combination vaccines.
The “antigen + antibody” reaction occurs both in a human or animal body and in a test tube if the patient’s blood serum is mixed with a suspension of the corresponding microbes or toxins. These reactions are used to diagnose many infectious diseases: the Vidal reaction in typhoid fever, etc.
Vaccines, serums. Even in ancient times, people, describing the epidemic, pointed out: "who suffered the disease was already safe, because no one fell ill twice." Long before civilization, the Indians rubbed crusts from smallpox patients into the skin of their children for prophylactic purposes. In this case, smallpox was usually mild. The scientific substantiation of this issue was first given by the English physician E. Jenner (1749 - 1823), who prepared the smallpox vaccine on calves. After the publication of his work in 1798, smallpox vaccination quickly began to spread throughout the world. In Russia, Catherine II was the first to be vaccinated against smallpox. Since 1980, compulsory vaccination against smallpox in Russia has been canceled due to the complete elimination of this disease in the country. At present, a large number of vaccines and sera are available to prevent infectious diseases by artificially creating human immunity.
Vaccines- These are preparations from microbial cells or their toxins, the use of which is called vaccination. Antibodies appear in the human body 1-2 weeks after the introduction of vaccines.
Vaccination- the main practical purpose of vaccines. Modern vaccine preparations are divided into 5 groups:
1. Live vaccines with weakened virulence (against smallpox, anthrax, rabies, tuberculosis, plague, measles, mumps, etc.). These are the most effective vaccines. They create a long (for several years) and intense immunity. The introduced weakened live pathogen multiplies in the body, which creates a sufficient amount of antigen for the production of antibodies.
2. Killed germ vaccines prepared against typhoid fever, cholera, whooping cough, poliomyelitis, etc. The duration of immunity is 6-12 months.
3. Chemical vaccines - these are preparations not from whole microbial cells, but from chemical complexes of their surface structures (against typhoid, paratyphoid A and B, tetanus).
4. Anatoxins prepared from exotoxins of the corresponding pathogens (diphtheria, tetanus, staphylococcus, gas gangrene, etc.).
5. Associated vaccines, that is, combined (for example, DTP - associated pertussis-diphtheria-tetanus vaccine).
Serums more often used for treatment (serotherapy) of infectious patients and less often for the prevention (seroprophylaxis) of infectious diseases. The earlier the serum is administered, the more effective its therapeutic and prophylactic effect. The duration of the protective action of serums is 1-2 weeks. Serums are prepared from the blood of people who have recovered from an infectious disease or by artificially infecting animals with microbes (horses, cows, donkeys). Main types:
1. Antitoxic serums neutralize the poisons of microbes (anti-diphtheria, anti-tetanus, anti-snake, etc.).
2. Antimicrobial serums inactivate bacterial cells and viruses, are used against a number of diseases, more often in the form of gamma globulins.
Gamma globulins from human blood are available against measles, poliomyelitis, infectious hepatitis, etc. These are safe drugs, since they do not contain pathogens, unnecessary ballast substances. Gamma globulins are also prepared from the blood of hyperimmunized horses against anthrax, plague, smallpox, rabies, etc. These drugs can cause allergic reactions.
Immune sera contain ready-made antibodies and act from the first minutes after administration.
Interferon occupies an intermediate position between general and specific mechanisms of immunity, since, being formed on the introduction of a virus of one type into the body, it is also active against other viruses.
specific immunity subdivided into congenital (species) and acquired .
innate immunity inherent in a person from birth, inherited from parents. Immune substances pass through the placenta from mother to fetus. A special case of innate immunity can be considered the immunity received by a newborn with mother's milk.
Acquired immunity arises (acquired) in the process of life and is divided into natural and artificial.
Natural acquired immunity occurs after the transfer of an infectious disease: after recovery, antibodies to the causative agent of this disease remain in the blood. Often, people who have been ill in childhood, for example, with measles or chicken pox, later either do not get sick with this disease at all, or fall ill again in a mild, erased form.
Artificial immunity is developed through special medical measures, and it can be active and passive.
Active artificial immunity occurs as a result of protective vaccinations, when a vaccine is introduced into the body - or weakened pathogens of a particular disease ("live" vaccine), or toxins - waste products of pathogenic microorganisms ("dead" vaccine). In response to the introduction of the vaccine, a person, as it were, falls ill with this disease, but in a very mild, almost imperceptible form. His body actively produces protective antibodies. And although active artificial immunity does not appear immediately after the introduction of the vaccine (it takes a certain time to produce antibodies), it is quite strong and lasts for many years, sometimes for life. The closer the vaccine immunopreparation is to the natural causative agent of infection, the higher its immunogenic properties and the stronger the resulting post-vaccination immunity.
Vaccination with a live vaccine, as a rule, provides complete immunity to the corresponding infection for 5-6 years, vaccination with an inactivated vaccine creates immunity for the next 2-3 years, and the introduction of a chemical vaccine and toxoid provides protection for the body for 1-1.5 years. At the same time, the more purified the vaccine, the less likely it is to cause unwanted, adverse reactions to its introduction into the human body. As an example of active immunity, one can name vaccinations against poliomyelitis, diphtheria, whooping cough.
Passive artificial immunity occurs as a result of the introduction into the body of serum - defibrinated blood plasma, already containing antibodies to a particular disease. Serum is prepared either from the blood of people who have recovered from this disease, or, more often, from the blood of animals that are specially vaccinated with this disease and in whose blood specific antibodies are formed. Passive artificial immunity occurs almost immediately after the introduction of serum, but since the introduced antibodies are inherently foreign, i.e. possess antigenic properties, over time, the body suppresses their activity.
Therefore, passive immunity is relatively unstable. Immune serum and immunoglobulin, when introduced into the body, provide artificial passive immunity that retains a protective effect for a short time (4-6 weeks). The most characteristic example of passive immunity is anti-tetanus and anti-rabies serum. The bulk of vaccinations are carried out at preschool age. At school age, revaccination is carried out, aimed at maintaining the proper level of immunity. An immunization schedule is a rule-prescribed sequence of vaccinations with a specific vaccine, when the age of the child to be immunized is indicated, the number of vaccinations against a given infection is prescribed, and certain time intervals between vaccinations are recommended. There is a special, legally approved immunization calendar for children and adolescents (the general schedule of immunization schemes). The administration of sera is used in cases where the likelihood of a disease is high, as well as in the early stages of the disease, to help the body cope with the disease. For example, vaccinations against influenza in case of an epidemic threat, vaccinations against tick-borne encephalitis before leaving for field practice, after being bitten by a rabid animal, etc.
Vaccination reactions. In response to the introduction of a vaccine into the body, a general, local or allergic reaction (anaphylactic shock, serum sickness) may develop. The general reaction is characterized by chills, fever, general weakness, body aches, and headache. A local reaction is usually observed at the site of injection or inoculation of the immunological drug and is manifested by redness of the skin, swelling, and soreness at the site of the vaccine. Often this is accompanied by itching. Usually vaccination reactions are mild and they are short-lived. Severe reactions to the vaccine, requiring hospitalization and special medical supervision, are quite rare. Allergic reactions to vaccinations are manifested by an itchy rash, swelling of the subcutaneous tissue, joint pain, temperature reaction, less often by difficulty breathing. Vaccination of persons who previously had allergic reactions is allowed only under conditions of special medical supervision.
Indications and contraindications for immunization. The main indication for planned, unscheduled and urgently carried out immunoprophylaxis of infectious diseases is the need to create immunity to infection by stimulating the production of specific immunity by the body's immune system.
Contraindications are:
1. Allergic reactions to previous vaccinations. The decision on vaccination in this case is made by the doctor, and it is carried out in an allergological hospital;
2. Other allergic reactions: respiratory allergy, food and insect allergy. Vaccinations are carried out under the supervision of an allergist;
3. Chronic diseases that occur with a violation of the vital functions of the body; respiration, circulation, liver, kidneys, central nervous and endocrine systems;
4. Any acute diseases (flu, tonsillitis, acute respiratory disease in the acute period and within 1 month after recovery).
If contraindications are found in some children, giving rise to a withdrawal from vaccination for health reasons (medical withdrawal), the issue of the possibility of vaccination is decided by specialist doctors collectively. The rest of the children must be vaccinated, otherwise an infectious disease in a children's institution may become widespread.
GENERAL PRINCIPLES FOR THE PREVENTION OF INFECTIOUS DISEASES
Primary prevention includes the following activities: personal hygiene, hardening, preventive and current sanitary supervision, promotion of knowledge about infectious diseases and methods for their prevention, preventive vaccinations, and a healthy lifestyle.
Secondary prevention is the early detection of cases and monitoring of persons who have been in contact with patients (hence, knowledge of the signs of the disease), regime-restrictive measures (quarantine, observation), isolation of patients.
Tertiary prevention measures include timely, adequate and effective treatment.
There is hardly a person who at least once in his life has not encountered such a problem as infectious diseases. The list of these pathologies is large and includes the well-known flu and colds, outbreaks of which are recorded in a particular region every year.
Infections can be dangerous, especially if the person has not been given adequate treatment or has not sought help at all. That is why it is worth learning more about the types of infectious diseases, their features, main symptoms, methods of diagnosis and therapy.
Infectious diseases: list and classification
Infectious diseases have accompanied humanity throughout history. One has only to recall the plague epidemics that destroyed more than 50% of the population of Europe. Today, medicine, of course, has learned to cope with a huge number of infections, many of which were considered fatal even a few centuries ago.
There are several systems for classifying infectious diseases. For example, they distinguish intestinal ailments and blood diseases, lesions of the respiratory tract and skin. But most often pathologies are classified depending on the nature of the pathogen:
- prion (fatal familial insomnia, kuru);
- bacterial (salmonellosis, cholera, anthrax);
- viral (influenza, measles, parotitis, HIV infection, hepatitis);
- fungal, or mycotic (thrush);
- protozoan (malaria, amoebiasis).
Transmission routes and risk factors
Infectious agents can enter the body in different ways. There are such ways of infection:
- The alimentary route, in which pathogens enter the body through the digestive tract (for example, along with unwashed food, contaminated water, dirty hands).
- Airborne transmission, in which pathogens are introduced through the respiratory system. For example, pathogens can be found in dust. In addition, microorganisms are released into the external environment along with mucus during coughing and sneezing.
- Contact infection occurs when sharing household items or toys, direct contact with the skin of a sick person. When it comes to sexually transmitted diseases, the transmission of infection occurs during sexual intercourse.
- Pathogenic microorganisms are often transmitted from person to person along with the blood. Infection can occur during a blood transfusion, as a result of the use of non-sterile instruments, and not only medical ones. For example, you can catch an infection while doing a manicure. Often, pathogenic microorganisms are transmitted from a sick mother to a child during pregnancy or childbirth. Insects can also be carriers.
It is impossible to completely exclude the possibility of infection in the body. But some people are more prone to this type of disease, and such diseases are much more difficult for them. Why? When infectious agents spread throughout the body, the state of the immune system is of great importance. Dysbacteriosis, anemia, beriberi, weakened immunity - all this creates ideal conditions for the rapid reproduction of pathogens.
Risk factors include severe hypothermia, a sedentary lifestyle, unhealthy diet, bad habits, hormonal disruptions, constant stress, and poor personal hygiene.
Varieties of viral diseases
There are a huge number of viral infections. Here are just a few of them:
- All types of flu, colds (in particular, rhinovirus infection), which are accompanied by general weakness, fever, runny nose, cough, sore throat.
- It is worth mentioning the so-called childhood infections. This group includes rubella, accompanied by damage to the skin, respiratory tract, cervical lymph nodes. Mumps (known as mumps) is also a viral disease that affects the salivary glands and lymph nodes. The list of such infections includes measles, chicken pox.
- Hepatitis is a disease that causes inflammation of the liver. In most cases, the virus is transmitted through the blood (types C and D). But there are also strains that spread by household and alimentary routes (hepatitis A and B). In some cases, the disease leads to the development of liver failure.
- Pneumonia is an inflammation of the lungs that can have very serious consequences. The role of the causative agent can be adenoviruses, cytomegaloviruses, influenza and parainfluenza viruses. By the way, the inflammatory process can also be caused by bacteria, but the symptoms in this case are different. Signs of viral pneumonia - fever, runny nose, general weakness, unproductive cough, shortness of breath. Viral forms of inflammation are characterized by a more rapid course.
- Infectious mononucleosis is considered quite common. Symptoms, treatment and consequences of this disease are of interest to many readers. The causative agent is the Epstein-Barr virus, which is transmitted from an infected person by airborne droplets, most often with saliva (by the way, this is why the disease is often called "kissing disease"). The infection affects the tissues of the pharynx, lymph nodes, liver and spleen. Against the background of the disease, a change in the composition of the blood is observed - atypical mononuclear cells appear in it. Currently, there is no specially developed treatment regimen. Doctors provide symptomatic treatment.
Prion diseases and their features
Prions are rather specific infectious agents. In fact, they are a protein with an abnormal tertiary structure. Unlike viruses, prions do not contain nucleic acids. However, they can increase their numbers (reproduce) using living cells of the body.
Most often, prion infectious diseases are diagnosed in animals. Their list is not that big. In cows, against the background of infection, the so-called mad cow disease, or spongiform encephalopathy, can develop. Prions affect the nervous system of cats, antelopes, ostriches and some other animals.
A person is also susceptible to this type of infection. Against the background of prion activity, people develop Creutzfeldt-Jakob disease, Gerstmann syndrome, fatal familial insomnia.
Bacterial infections
The number of bacterial organisms that can lead to the development of a disease when it enters the human body is huge. Let's take a look at some of the infections.
Salmonellosis. This term unites a whole group of acute infectious diseases that affect the human digestive tract. Bacterial microorganisms of the genus Salmonella act as pathogens. The incubation period lasts from 6 hours to 8 days. The first symptoms are abdominal pain. As the disease progresses, pathogenic agents can affect the organs of the central nervous system and the cardiovascular system.
Botulism. Another disease from the group of intestinal infections. The causative agent is the bacterium Clostridium botulinum. This microorganism, penetrating the wall of the digestive tract, begins to release botulinum toxin, which is dangerous for humans. Signs of botulism are severe abdominal pain, weakness, vomiting, diarrhea, and fever. By the way, most often the pathogen enters the body with food.
Dysentery is an acute intestinal infection caused by a bacterium of the genus Shigella. The disease begins with a simple malaise and a slight increase in temperature, but then other disorders appear, in particular severe diarrhea. The disease is dangerous, as it can lead to damage to the intestinal mucosa and dehydration.
anthrax is a very dangerous disease. It starts acutely and develops very quickly. What are the symptoms of the disease? Anthrax is characterized by serous-hemorrhagic inflammation of the skin, serious lesions of internal organs and lymph nodes. The disease often ends in the death of the patient, even with properly administered therapy.
Lyme disease. Symptoms of the disease are fever, fatigue, skin rash, headaches. The causative agents are bacteria of the genus Borrelia. The infection is carried by ixodid ticks. Sometimes, against the background of infection, an inflammatory lesion of the heart, joints and nervous system is observed.
Venereal diseases. Not to mention sexually transmitted infections. Bacterial diseases include gonorrhea, ureaplasmosis, chlamydia, mycoplasmosis. Sexual syphilis is also dangerous. In the initial stages, this disease is easily treatable, but if left untreated, the pathogen affects almost all organs, including the brain.
Quite common are diseases caused by meningococci. These pathogens are spread by airborne droplets. Forms meningococcal infection may be different. Against the background of infection of the body, pneumonia, meningitis, meningoencephalitis develops. Much less frequently, patients are diagnosed with endocarditis and arthritis.
Mycoses: fungal infections of the body
Mycoses are infectious diseases caused by the penetration of pathogenic fungi into the human body.
Perhaps the most common and well-known disease of this group is candidiasis(thrush). The infection affects the mucous membranes of the genital organs, the oral cavity, less often the skin in the natural folds of the body. A characteristic feature is the formation of a white cheesy plaque with a sour smell.
Onychomycosis- a group of common ailments, the causative agents of which are dermatophyte fungi. Microorganisms infect the nails on the hands and feet, gradually destroying the nail plate.
Other fungal diseases include seborrhea, pityriasis versicolor, ringworm, sporotrichosis and many others.
Protozoal diseases
Malaria a disease caused by plasmodium. The disease is accompanied by the development of anemia, repeated bouts of fever, an increase in the size of the spleen. The causative agent of malaria enters the body through the bite of a malarial mosquito. These protozoa are common in some countries of Africa, Asia and South America.
The group of protozoan diseases also includes amoebiasis(pathogen - amoeba), leishmaniasis(the causative agent is leishmania, which enters the human body through the bite of a mosquito), sarcocystosis, toxoplasmosis, trichomoniasis, sleeping sickness, giardiasis(accompanied by damage to the digestive tract and skin).
Common signs of infectious diseases
There are a huge number of symptoms that can accompany infectious diseases. The list of them can be discussed endlessly, because each ailment has its own, unique characteristics. Nevertheless, there are a number of common signs that are present in any infectious disease:
- An increase in body temperature is observed in almost any infectious lesion of the body.
- It is worth mentioning the symptoms of intoxication - these are headaches, body aches, muscle pain, weakness, drowsiness, fatigue.
- Cough, runny nose, sore throat appear when the respiratory tract is infected (for example, a rhinovirus infection can lead to the appearance of such symptoms).
- The appearance of a rash and redness on the skin that does not disappear with the use of antihistamines.
- Gastrointestinal disorders, including abdominal pain, stool disorders, nausea and vomiting. With liver damage, the color of the skin and sclera of the eyes changes (this is how hepatitis A develops).
Of course, each disease has its own characteristics. An example is Lyme disease, the symptoms of which are the appearance of migratory ring redness on the skin, fever, damage to the nervous system with the further development of depressive states.
Diagnosis of infectious diseases
As you can see, infectious diseases are very diverse. Of course, for proper treatment it is extremely important to determine the nature of the pathogen in time. This can be done through laboratory research. They can be divided into three groups:
- Direct diagnostic methods
The purpose of research is to accurately identify the pathogen. Until recently, the only way to conduct such an analysis was to inoculate samples taken from a patient on a special medium. Further cultivation of the culture of microorganisms made it possible to identify the pathogen and even assess the degree of its sensitivity to certain drugs. This technique is used to this day, but it takes a long time (sometimes 10 days).
A faster method is PCR diagnostics, aimed at identifying certain fragments of the pathogen (usually DNA or RNA) in the patient's blood. This technique is especially effective in viral diseases.
- Indirect diagnostic methods
This group includes laboratory studies in which they study not pathogens, but the reaction of the human body to them. When an infection enters, the immune system begins to produce antigens, in particular immunoglobulins. These are specific proteins. Depending on the structure of the antibodies present in the blood, the doctor can judge the development of a particular infectious disease.
- Paraclinical methods
This includes studies that can help determine the symptoms of the disease and the degree of damage to the body. For example, a blood test confirms the presence of an inflammatory process in the body. Infectious damage to the kidneys affects the functioning of the excretory system - any failures can be detected by examining urine samples. The same methods include ultrasound, X-ray, MRI and other instrumental studies.
What does the treatment depend on?
How are infectious diseases treated? The list of them is huge, and the treatment regimens are varied. In this case, it all depends on the nature of the pathogen, the general condition of the patient, the severity of the disease and other factors.
For example, for bacterial infections, broad-spectrum antibiotics are used. These drugs will be useless in viral diseases, because in such cases the patient needs to take antiviral drugs, interferon and immunomodulators. The presence of mycoses is an indication for taking antifungal agents.
Of course, symptomatic therapy is also carried out. Depending on the symptoms, it includes taking anti-inflammatory, antipyretic, painkillers and antihistamines. A rhinovirus infection, for example, will clear up more easily with special nasal drops. With lesions of the respiratory system, accompanied by a cough, specialists prescribe expectorant syrups and antitussive drugs.
It should be understood that self-medication is impossible in any case. For example, if you find signs of botulism in yourself, you should immediately consult a doctor, as this is a serious disease - in the absence of therapy, serious consequences are possible, especially when it comes to the body of a child.
Preventive actions
It is much easier to prevent an infection than to treat it later. Prevention of infectious diseases should be comprehensive. A person is constantly in contact with pathogenic microorganisms - they are present in the air and in water, get into food, settle on door handles and household items. Therefore, it is important to strengthen the body.
A strong immune system is able to suppress the reproduction of pathogenic microbes that have already entered the human body. Proper nutrition, regular physical activity, outdoor walks, hardening, proper sleep and rest, lack of stress - all this helps to increase the body's defenses.
Do not give up vaccinations. Timely vaccination can protect against pathogens such as mumps, polio and hepatitis, etc. The preparations used for vaccinations contain samples of a dead or weakened pathogen of a particular disease - they cannot cause serious harm to the body, but help to develop strong immunity.
Many people turn to doctors after traveling. The fact is that in some regions of the planet various infectious diseases are rampant. For example, the causative agent of malaria (Plasmodium) enters the human blood only when bitten by a malarial mosquito, which lives only in some regions of Africa, Asia and South America. If you are going to spend some time in a particular country (especially if we are talking about countries with a tropical climate), be sure to ask about the level of spread of a particular infection - it is quite possible that it is better to get vaccinated or stock up on medicines before the trip.
Of course, it is very important to observe hygiene standards, buy high-quality food, wash them before use, and cook them properly. During epidemic outbreaks of influenza or other colds, it is worth avoiding crowded places, taking special drugs to strengthen immunity (for example, Aflubin). To protect against sexual infections during intercourse, it is imperative to use a condom.
