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Question 27 Infectious process

- a complex multicomponent process of the dynamic interaction of infectious pathogenic agents with macroorganism, characterized by the development of a complex of typical pathological reactions, systemic functional changes, hormonal status disorders, specific immunological defense mechanisms and non-specific resistance factors.

The infectious process is the basis for the development of infectious diseases. The practical importance of knowing the etiology and pathogenesis of infectious diseases, the general laws of their development is due to the fact that infectious diseases for a long time occupy the third place in prevalence after diseases of the cardiovascular system and oncological pathology.

The main stages of the infectious process.

1. Adhesion — attachment of a microorganism to the corresponding host cells.

2. Colonization - fixing microorganisms in the corresponding area.

3. Reproduction (increase in quantity - animation).

4. Penetration - penetration into the underlying layers and the spread of infect.

5. Damage to cells and tissues (associated with the reproduction, penetration and spread of infect).

As is known, the causative agents of infectious diseases include microorganisms of plant and infectious origin - bacteria, spirochetes, lower fungi, protozoa, viruses, and rickettsia. Infectious agents are the primary and indispensable cause of the development of an infectious disease, they determine the "specificity" of an infectious disease, especially the clinical manifestations of pathology. However, not every case of penetration of an infectious pathogen into the body ends with the development of the disease. In response to the action of infectious pathogenic factors, specific immunological defense mechanisms, non-specific resistance factors are activated, and adaptation hormones are released. In the case of the prevalence of adaptation mechanisms, compensation over damage mechanisms, the infectious process does not develop in full, a sufficiently pronounced preimmune and immune response arises, elimination of infectious pathogenic agents from the body, or their transformation into inactive forms. The transition of the pre-immune response to the disease is determined by the degree of pathogenicity, virulence, invasiveness, organotropy, toxigenicity of microorganisms, as well as the initial state of the macroorganism with its reactivity and resistance.

Types of infection

The following types of infectious process are distinguished.

• Sepsis is a severe generalized form of the infectious process, caused by the multiplication of microorganisms in the blood and often in other body fluids.

• Septicopyemia is an infectious process characterized by the secondary development of purulent foci in various tissues and organs in patients with sepsis.

• Bacteremia, viremia - the presence of bacteria and / or viruses in the blood without signs of their reproduction.
It is one of the stages in the development of a number of infP.

• Mixed infection - an infectious process caused simultaneously by two or more pathogens.

• Reinfection - the re-occurrence (after the patient’s recovery) of the infection caused by the same microorganism.

• Superinfection - re-infection of the body with the same pathogen until the recovery period.

• Secondary infection - an infectious process that develops against the background of an existing (primary) infectious disease caused by another microorganism.

Development periods

1. The incubation period - [from lat. incubatio, lie down, sleep somewhere]. Usually, between the penetration of an infectious agent into the body and the manifestation of clinical signs, there is a period of time defined for each disease - an incubation period that is characteristic only of exogenous infections. During this period, the pathogen multiplies, there is an accumulation of both the pathogen and the toxins secreted by it to a certain threshold value, for which the body begins to respond with clinically expressed reactions. The duration of the incubation period can vary from hours and days to several years.

2. The prodromal period - [from Greek prodromos, running ahead, preceding]. As a rule, the initial clinical manifestations do not bear any pathognomonic [from Greek. pathos, disease, + gnomon, indicator, sign] for a specific infection of signs. Common weakness, headache, feeling of weakness. This stage of the infectious disease is called the prodromal period, or the “precursor stage”. Its duration does not exceed 24-48 hours.

3. The period of the development of the disease - At this phase, the personality traits of the disease appear, or signs common to many infectious processes - fever, inflammatory changes, etc. In the clinically pronounced phase, the stages of symptom increase (stadium wcrementum), the flowering of the disease (stadium acme) and fading manifestations (stadium decrementum).

4. Reconvalescence - [from lat. re-, repetition of action, + convalescentia, recovery]. The recovery period, or convalescence as the final period of an infectious disease, can be fast (crisis) or slow (lysis), and also be characterized by a transition to a chronic state. In favorable cases, clinical manifestations usually disappear faster than the normalization of morphological disorders of organs and tissues and the complete removal of the pathogen from the body. Recovery can be complete or accompanied by the development of complications (for example, from the central nervous system, musculoskeletal system or cardiovascular system). The period of final removal of the infectious agent can be delayed and for some infections (for example, typhoid fever) can be calculated in weeks.
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Question 27 Infectious process

  1. Infectious process
    All human diseases known to modern medicine, by the nature of their occurrence, can be divided into two groups: somatic (bodily), and infectious. Somatic - even with the closest communication, they are not transmitted from one person to another. The cause of somatic diseases is either inside the person (heredity, failure of adaptive-compensatory mechanisms), or outside
    Subject: The concept of "infectious process" and its main characteristics. The definition of "infectious process" (infection), "infectious disease". Conditions for the occurrence of an infectious process. Topic: The role of microorganisms in the infectious process. Forms of the interaction of micro- and macroorganisms: mutualism, commensalism, parasitism. Infection as a form of parasitism. Evolution
  3. Question 28 The epidemic process
    —A chain of continuous, consecutive, infectious conditions, from asymptomatic carriage to manifest diseases caused by a pathogen circulating in the collective. The epidemic process manifests itself in the form of epidemic foci, with one or more cases of illness or carriage. The epidemic process is determined by the continuity of the interaction of its three components
  4. Question 29. Prevention of infectious diseases
    Infectious diseases are a group of diseases caused by the penetration of pathogenic (pathogenic) microorganisms into the body. In order for a pathogenic microbe to cause an infectious disease, it must have virulence (poisonous; Lat. Virus - poison), that is, the ability to overcome the body's resistance and exhibit toxic effects. Some pathogenic agents cause
  5. Subject: The concept of "infectious process" and its main characteristics.
    The definition of "infectious process" (infection), "infectious disease". Infectious conditions
  6. The role of microflora in the infectious process
    The term “infection” is derived from lat. inficio, infectum - nourish, stain, infect, poison, spoil. The discovery by Louis Pasteur of microscopic living creatures that can cause fermentation and, as it soon became clear, a number of human diseases, gave impetus to the development of new areas of knowledge, such as microbiology and immunology. To the most impressive results achieved by microbiology and
  7. Topic: Phases of the development of the infectious process.
    Colonization, invasion, microbial damage to cells and tissues. Genetic control of pathogenicity factors in microorganisms. Heterogeneity of microbial populations based on virulence and pathogenicity factors. The role of plasmids in the expression of pathogenicity factors in microorganisms. Critical doses of microorganisms causing an infectious disease. The penetration of pathogenic microbes into the body.
  9. . Features of the development of the infectious process in the fetus
    Recall that the first trimester of pregnancy is the period of embryogenesis and placentation. In turn, it distinguishes the first 3 weeks - blastogenesis, 4-8 weeks - embryogenesis and 9-12 weeks - the early fetal period of development. The penetration of a bacterial infection through the internal pharynx causes either acute inflammation of the uterus (endomyometritis), increased myometrial tone and spontaneous miscarriage, or does not damage
  10. Topic: The role of microorganisms in the infectious process.
    Forms of interaction of micro- and macroorganisms: mutualism, commensalism, parasitism. Infection as a form of parasitism. The evolution of microbial parasitism. The concept of sapronoses. Pathogenicity of microorganisms, definition. Obligatory pathogenic, conditionally pathogenic, non-pathogenic microorganisms. Virulence, definition, units (Dlm, LD50 and
  11. Clinical manifestations of infectious processes of various localization
    Superficial abscesses. Skin and subcutaneous tissue. Impetigo is a superficial infection caused by hemolytic group A streptococci, sometimes in combination with Staphylococcus aureus. This is primarily a disease of children, common in the warm season, characterized by the presence of multiple erythematous lesions, manifested by intense itching and the formation of purulent vesicles (pustules). At
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