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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 constituent elements (links), namely:

1. The source of infectious disease pathogens;

2. the mechanism of transmission of pathogens;

3. The susceptibility of the population.

Switching off any of these links rigorously eliminates the epidemic process as a whole. This is one of the factors of transmission of infection formulated by L. V. Gromashevsky. The epidemic process proceeds continuously in time and space. At the same time, biological factors (the interaction of genotypically and phenotypically heterogeneous parasite and host populations) form the causes of the development of the epidemic process, while social and natural factors regulate the conditions for the development of the epidemic process. The epidemic process exists only with the simultaneous presence of causes and conditions.

The biological factor is the parasitic host-parasitic system, in which both interacting parties exhibit certain properties (the parasite is parasitism and pathogenicity, the host is susceptibility).

Social factors are a set of social conditions that contribute (or hinder) the manifestation of the epidemic process. Social factors include: social development;

social activity of the population; sanitary improvement of settlements.

Natural factors - a combination of natural conditions that contribute to or hinder the manifestation of the epidemic process. Natural factors include: biotic elements;

abiotic elements.

Biotic elements are components of wildlife. An example of the regulatory influence of biotic elements in zoonoses is a change in the intensity of the course of the epidemic process with a change in the number of rodents (intensity of the episodic process) with natural focal infections. In transmissible zoonoses, the number and migration of arthropod vectors has a regulatory effect on the intensity of the epidemic process.

Abiotic elements are climate and landscape-geographical conditions. For example, the closer to the equator, the higher the diversity of nosological forms of infectious diseases.

The mechanism of development of the epidemic process

In accordance with the first law of L.V. Gromashevsky, the epidemic process develops according to the triad:

source of pathogen;

transmission mechanism of the pathogen;

susceptible organism.

The source of the pathogen is an infected (infected) organism of a person, animal or plant, from which infection of susceptible people can occur ..

The transmission mechanism of an infectious agent is a way of moving a parasite from a sick organism to a healthy one, ensuring its existence as a biological species.

Transmission mechanism

External integument (skin, some open mucous membranes - conjunctiva, external genitalia) Contact (direct and indirect contact)

Airways Aerosol

Gastrointestinal tract Fecal-oral

Circulatory system (blood, endothelium of blood vessels) Transmissible (vector) - due to ectoparasites-arthropods

A transmission path is a specific set and sequence of transmission factors by which a transmission mechanism is implemented.

The aerosol pathogen transmission mechanism includes transmission paths:

airborne (meningococcal infection, acute respiratory viral infections; lifetime - minutes)

airborne dust (scarlet fever, tuberculosis; lifetime - day, week, month)

The fecal-oral transmission mechanism of the pathogen includes transmission routes:

water (transmission factor - water)

food (transmission factor - food)

contact-household (transmission factor - household items)

The transmission mechanism of the pathogen includes the transmission paths:

natural (contamination - the pathogen is excreted with the feces of the carrier; inoculation - the pathogen is introduced with saliva)

artificial (associated with medical manipulations: injection, associated with surgery, associated with diagnostic manipulation, transfusion, transplant)

Transmission factor is an environmental object by which the pathogen moves from a sick organism to a healthy one.
Transmission factors include: air, water, food, soil, household items, carriers (arthropods).

Transmission factors are divided into:




In addition, transmission factors can be divided into main and additional.

Phases of movement of the parasite:

discharge from an infected organism,

stay in the environment

incorporation into a susceptible organism.

Susceptibility - the ability of the host to suffer from diseases caused by pathogens, which is manifested by pathological and responsive protective specific (immunity) and non-specific (resistance) reactions.

Susceptibility is divided into:


individual (genotypic and phenotypic).

Manifestations of the epidemic process

The epidemic process is manifested by infection of the host with a pathogen followed by disease of the host or latent carriage of the parasite by the host, and at the population-species level - sporadic incidence, the presence of a natural or epidemic (epizootic, epiphytotic) foci of infection, outbreak, epidemic (epizootic, epiphytotism) or pandemic ( , panfithotia).
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Question 28 The epidemic process

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  2. Features of the epidemic process
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  5. Questions that arise - at the first stage of the breastfeeding process
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  6. Questions to identify the initial level of knowledge on the topic "Nursing process in diseases of the skin, navel, sepsis."
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  8. Parotitis
    Training target: using diagnostic algorithms, be able to establish a diagnosis of mumps, determine the clinical form of the disease, complications and prescribe adequate treatment. Assignment for independent study of the topic. Using a textbook and lecture material to acquire the necessary basic knowledge, learn the following sections for practical training: 1.
    C. George Ray (C. George Ray) Definition. Mumps (mumps) is an acute highly contagious disease of viral etiology, characterized by an increase in the parotid salivary glands, and sometimes involvement in the process of the sex glands. meninges, pancreas, and other organs. Etiology. The causative agent of mumps belongs to the family
  10. Parotitis
    Mumps (mumps) - refers to acute contagious viral diseases, characterized by fever, general intoxication, an increase and soreness of the salivary glands, mainly the parotid. Etiology. The virus causative agent of mumps infection is unstable, is inactivated by heating (at a temperature of 70 ° C for 10 min), ultraviolet radiation, exposure to formalin solutions
  11. Epidemic lethargic encephalitis Economo
    Economo's epidemic lethargic encephalitis (synonym: epidemic encephalitis type A, "sleeping" disease) was first recorded in 1915 by the troops near Verdun and described in 1917 by the Austrian neuropathologist K. Economo. The disease in those years proceeded in the form of epidemics that swept many countries of the world. In subsequent years, the disease manifested itself sporadically. Current disease in a typical
  12. Parotitis
    Mumps (mumps) is a childhood viral infection characterized by acute inflammation in the salivary glands. The causative agent of mumps belongs to the RNA-containing viruses, the genus Paramyxovirus. Infection occurs by airborne droplets. The susceptibility to this disease is about 50-60% (that is, 50-60% of those who were in contact and did not get sick or not vaccinated get sick). Piggy
    Peter L. Ferine Definition. Epidemic relapsing fever is an acute infection characterized by repeated cycles of a rise in body temperature, which are separated from each other by asymptomatic intervals of apparent recovery. It is caused by spirochetes of the genus Borrelia and is represented by two epidemiological varieties - a disease transmitted by lice and a disease transmitted
  14. Piglet Epidemic Diarrhea
    Epidemic diarrhea of ​​piglets (womiting and wasting disease in piglets) is an acute infectious disease, mainly piglets older than 4-5 weeks of age, manifested by watery diarrhea. Etiology. The causative agent of the disease is an RNA-containing virus whose morphology is typical of the Coronaviridae family. Epizootological data. The source of the causative agent of the disease are sick animals,
  15. Epidemic encephalitis
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  16. Parotitis.
    Mumps (mumps) is an acute infectious disease with a primary lesion of the salivary glands. The causative agent is the Pneumophilis parotidis RNA virus from the genus paramyxoviruses. Infection occurs from a patient with manifest or, more often, erased and asymptomatic forms of the disease. The route of infection is airborne. Transmission of the virus through toys and household items infected
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