Epidemiological process, what is epidemiology, structural elements. Mechanism of development of the epidemic process
Sources of the epidemiological process, transmission mechanisms.
The epidemic process is an epidemic in the broad sense of the word. This is the process of the occurrence and spread of infections. A chain of interconnected and resulting from one another infectious conditions of a person L.V. Gromashevsky).
An epidemic process is a chain of epidemic foci interconnected and flowing from one another (I.I. Elkin).
The epidemiological process arises and is maintained only in the presence of three driving forces, three factors, which include: the source of the infectious agent, the implementation of the mechanism of transmission of pathogens and the susceptibility of the population. When at least one of these links is turned off, the epidemic process stops.
A generalization of the accumulated factual material and theoretical developments made it possible to formulate a number of concepts and theories about the essence of the epidemic process:
The doctrine of the epidemic process and the determining role of the pathogen transmission mechanism, developed by the outstanding Soviet epidemiologist L.V. Gromashevsky;
The doctrine of the natural focality of infectious diseases, created by E.N. Pavlovsky and his school;
The socio-ecological concept of the epidemic process, formulated by B.L. Cherkassky.
The modern approach to the study of the epidemic process is distinguished by the integrity of its perception as a system that accumulates biological and social essence and, therefore, is capable of preserving, restoring the original state, or independently choosing a new state in relation to its biological part, like any living system.
In the asymptomatic form of the infectious process, bacteria carriers can be practically healthy people, which creates a particular danger for others due to the difficulty of recognizing them. Bacterial carriage can persist after illness (convalescent carriage). Depending on the duration, it is called acute (up to 3 months after typhoid fever and paratyphoid fever) or chronic (from 3 months to several decades or lifelong, such as carriage of the HBs antigen). The specific manifestation of the infectious process in an infected person depends on the dose of the pathogen entering the body, its virulence, as well as the initial resistance of the body.
As noted, the epidemiological significance of various forms of manifestation of the infectious process is not the same. Thus, specially conducted studies have shown that the massiveness of pathogen excretion is most often directly dependent on the severity of the disease. In accordance with this, the number of pathogens released from the body in mild forms of the disease and in asymptomatic variants of the infectious process is the smallest. However, it is precisely these forms of manifestation of the infectious process that, as a rule, play the most important role in maintaining the epidemic process, since such patients and carriers are usually not hospitalized. These individuals, while remaining socially active, pose the greatest danger as a source of infectious agents.
Thus, a significant epidemiological danger is posed by patients with atypical, difficult to detect forms of infection, as well as bacterial carriers, which in some infections play a leading role in maintaining the epidemic process. At the same time, it should be noted that the infectiousness of patients is not the same during different periods of the infectious process. Infectivity is understood as the time interval during which the pathogen is released from the host organism and its subsequent introduction into another susceptible organism is possible. Some infections have a long period of infectivity, while others have a short period. In some infections, the pathogen begins to be released from the body already during the incubation period, and in others, with the onset of clinical symptoms.
Currently, there are four groups of infectious diseases:
1. Anthroponoses, i.e. peculiar only to humans.
2. Zooanthroponoses, which are common in animals under natural conditions, but which can infect humans.
3. Zoonoses, i.e. characteristic only of animals.
4. Sapronoses, in which the reservoir of infection is abiotic environmental factors.
This division is based on an ecological-biological principle that characterizes the conditions (phenomena) that ensure the preservation of the pathogen as a biological species: with anthroponoses - circulation in the human population, with zoonoses - circulation among animals and only with some infections - in humans, with zoonoses - circulation in the animal world; in sapronoses, the pathogen exists as a species due to objects of inanimate nature. It should be noted that, like all natural phenomena, infectious diseases cannot be placed strictly “on shelves”, since the boundaries between individual groups can be unclear, representing transitional forms.
- Factors of the epidemiological process
- Anti-epidemic measures
The importance of healthy eating
Fortunately, awareness of the need to monitor your diet has become increasingly popular in our country in recent years. Therefore, some of the demands of doctors like Dr. Gay and his...
Its biological basis is the interaction three composite links("triad Gromashevsky" ):
1) the source of the infectious agent,
2) the mechanism of transmission of the pathogen
3) a susceptible organism (collective).
Source of infection - This is a living infected organism, which is the natural environment for the existence of the pathogen, where it multiplies, accumulates and is released into the external environment.
Pathogen transmission mechanism- this is an evolutionarily established natural way of moving a pathogen from the source of infection to a susceptible human or animal organism. (aspiration, fecal-oral, contact, transmissible, vertical,artificial (artificial).
Receptive organism (collective). Susceptibility is a specific property of a human or animal body to respond with an infectious process to the introduction of a pathogen. The state of susceptibility depends on a large number of factors that determine both the state of the macroorganism and the virulence and dose of the pathogen.
The possibility of the occurrence and spread of disease among the population depends on 3 factors: biological, natural and social.
Natural factor- these are climatic and landscape conditions that promote or hinder the development of the epidemic process.
14. The doctrine of the epidemic process. The source of infection as a necessary prerequisite for the emergence and maintenance of the continuity of the epidemic process. Characteristics of sources of infection. Reservoir of infection.
Infectious process- interaction between a pathogen and a susceptible organism (human or animal), manifested by disease or carriage of an infectious agent.
Source of infection- this is a living infected organism, which is the natural environment for the existence of the pathogen, where it multiplies, accumulates and is released into the external environment.
Reservoir of infection - a set of biotic (human or animal body) and abiotic (water, soil) objects that are the natural habitat of the pathogen and ensure its existence in nature. Those. This is the habitat without which the pathogen cannot exist as a biological species.
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EPIDEMIOLOGY, EV (department of INFECTIOUS DISEASES WITH EPIDEM)
Epidemiology
Epidemic process
?Epidemiology of infectious diseases as a science studies...
Patterns of occurrence and spread of mass disorders of the public health status, various in nature.
Principles and forms of organizing anti-epidemic work.
Patterns of occurrence and spread of infectious diseases among people and develops methods for the prevention, control and elimination of these diseases.
Patterns of occurrence and spread of infectious diseases among people and develops methods for the prevention, control and elimination of these diseases.
?The epidemic process is...
Spread of infectious diseases among plants
Spread of pathogens among blood-sucking vectors
Spread of infectious diseases in human populations
The state of infection of the human or animal body
?Manifestations of the epidemic process are...
Acute illness
Chronic disease
Carriage
Sporadic type of incidence
Epidemic type of morbidity
?The term “sporadic morbidity” means...
Diseases of people with an infectious disease unusual for a given area
Group diseases of people with infectious disease
Single cases of human infectious disease
The epidemic type of morbidity is...
Single cases of human infectious disease
Group diseases of people with infectious disease
Mass diseases of people with an infectious disease, significantly exceeding the level of sporadic incidence of this disease in a certain territory
Mass diseases of an infectious disease, significantly exceeding the incidence rate characteristic of a given disease, over large areas, including countries, continents, continents
The epidemic process is considered as an “outbreak”, “epidemic”, “pandemic”, “sporadic morbidity” depending on...
Severity of the disease
Disease spread rates
Numbers of sick people
?Manifestations of the infectious process are...
Disease
Carriage
Flu epidemic in the country
Outbreak of infectious disease among rodents
?In what cases can we talk about manifestations of the epidemic process?
In case of mass incidence of influenza in people
When malarial plasmodia are detected in mosquitoes
For single cases of typhoid fever among city residents
For otitis and lymphadenitis in convalescents after scarlet fever
In isolated cases of rabies among wolves and foxes
Among the listed situations, select manifestations of the epidemic process
Outbreak of rubella among children in the younger group of kindergarten
Pseudotuberculosis diagnosed in a milkmaid
Isolated cases of cholera have been reported among residents of the village.
Isolated cases of carriage of toxigenic diphtheria bacteria were identified among primary school children at school
A patient with an initial diagnosis of pneumonia was diagnosed with legionellosis
Several cases of brucellosis have been reported in cows on the farm.
The sick horse was diagnosed with foot and mouth disease.
An outbreak of scarlet fever among primary school children at a boarding school
Leptospirosis was detected among the animals on a pig farm
An outbreak of tularemia was noted among field mice
In what cases can the phenomenon under consideration be interpreted as an infectious process?
Outbreak of yersiniosis among mice and rats
Presence of meningococcal carriers among the plant workers
Damage to the intestinal mucosa due to dysentery
Arthritis in patients with brucellosis
Isolated cases of psittacosis among city residents
?Exotic infections are...
Infectious diseases not native to the area
Infectious diseases specific to the area
Infectious viral diseases spread by arthropods
?The terms “endemic”, “endemicity of a disease” mean...
Long-term preservation of pathogens in soil and water
Infection with pathogens of living vectors
The constant presence in a given territory of an infectious disease characteristic of this area, due to the natural and social conditions present in it, necessary to maintain the epidemic process
Spread of infectious diseases among wild animals in the territory
Enzootic is...
Animal morbidity typical for the area
Spread of infectious diseases among animals
Morbidity of people characteristic of a given area
?The links of the epidemic process are...
Causative agents of infectious diseases
Source of infectious agent
Pathogen transmission mechanism
Water, air, soil, food, household and industrial items, living vectors
Receptive organism (collective)
?The source of the infectious agent is...
Any objects on which a pathogen is detected
Living infected human or animal organism
Any environment in which the pathogen persists for a long period of time
Vectors in which the pathogen persists and multiplies
?The source of infection in anthroponoses is...
Infected people
Infected animals
Infected vectors
Contaminated environmental objects
The reservoir of the infectious agent is...
Infected biotic and abiotic objects (living and non-living), which are the natural habitat of the pathogen and ensure its existence in nature
An infected human or animal organism that is in its natural habitat
Pathogen and ensuring its existence in nature
Select potential sources of infection from the list provided
Sick people
Bacteria carriers
?Who poses the greatest danger as a source of infection?
Patients with severe disease
Patients with mild illness
Transient bacteria carriers
Chronic bacteria carriers
?During what periods of an infectious disease is a sick person dangerous to others?
During the entire incubation period
During the last days of the incubation period
During the prodromal period
During the height of the illness
The real danger of infection sources depends on...
Clinical form of the disease
Age
Professions
?Sources of infection for humans can be...
Pets (cats, dogs, etc.)
Farm animals (cattle, goats, sheep, horses, pigs, etc.)
Wild animals (wolves, foxes, hares, mouse-like rodents, etc.)
Synanthropic rodents (rats, mice)
Everything is true
Select zoonoses from the list provided...
Salmonellosis
Legionellosis
Pseudotuberculosis
Shigillosis
Zoonoses, in which humans can become a source of infectious agents...
Brucellosis
Yersiniosis
Tick-borne encephalitis
Salmonellosis
Zoonoses in which only animals can be the source of infection (obligate zoonoses)…
Lyme disease (tick-borne systemic borreliosis)
Tularemia
Brucellosis
Pseudotuberculosis
Campylobacteriosis
You clarify the patient's epidemiological history. For which infections should the possibility of contact with animals be investigated?
Paratyphoid A
Leptospirosis
Tularemia
Diseases in which birds can be sources of infection...
Salmonellosis
Psittacosis
Escherichiosis
Tick-borne encephalitis
Rabies
Infectious diseases in which synanthropic rodents can be sources of infection...
Yersiniosis
Legionellosis
Salmonellosis
Tick-borne encephalitis
Tularemia
Sapronoses are diseases in which...
The source of infection has not been determined
Pathogens form spores
The pathogens are unpretentious and reproduce in water, soil, and on the surface of various objects
Pathogens are stored in vectors
Select sapronoses from the list provided...
Escherichiosis
Pseudomonas infection (pseudomonosis)
Legionellosis
Foodborne illness caused by staphylococci
Foodborne illness caused by Bacillus cereus
?The uniqueness of the pathogen transmission mechanism is determined...
The severity of the infectious disease
Localization of the pathogen in the infected organism
Behavior and living conditions of infection sources
From the proposed list, select natural variants of the pathogen transmission mechanism
Transmissible
Fecal-oral
Everything is true
Aspiration (airborne, aerosol)
Vertical
?The aspiration transmission mechanism is realized in the following ways:
Airborne
Airborne dust
Through living carriers
Specify infectious diseases with aspiration mechanism of transmission
Toxoplasmosis
Viral hepatitis A
Scarlet fever
Chicken pox
The transmission mechanism of pathogen transmission means their spread...
By air
Live carriers
Environmental items
The following infectious diseases have a vector-borne mechanism of transmission:
Rabies (hydrophobia)
Leptospirosis
Tick-borne encephalitis
Tularemia
Specify infections that have a contact mechanism of pathogen transmission
Chicken pox
Meningococcal infection
Rabies (hydrophobia)
Viral hepatitis E
?The fecal-oral transmission mechanism is realized...
Through the water
Through food
Through environmental objects
The fecal-oral transmission mechanism is realized in the following infectious diseases
Dysentery
Viral hepatitis A
Trichophytosis
Salmonellosis
Typhus
The vertical mechanism means that the pathogen is transmitted...
From contaminated soil
Through contaminated vegetables
Through the dust in the home
From mother to fetus
The vertical transmission mechanism is characteristic of the following infectious diseases...
Rubella
Malaria
HIV infection
Chicken pox
An artificial (artificial) method of infection of the pathogen is possible...
In laboratories
In treatment rooms
At home
In vehicles
?The susceptibility of the body means...
Obligatory occurrence of the disease in infected people
Mandatory development of some form of infectious process after infection
From the list provided, select factors that influence the body’s susceptibility to infectious agents.
Age
Concomitant somatic diseases
Nutritious food
From the list provided, select the source of the causative agent of diphtheria
Diphtheria patient
Handkerchief of a patient with diphtheria
Culture of toxigenic corynebacteria diphtheria
The air of the ward where patients with diphtheria are
Select the source of infection for typhus
Patient with typhus
Patient's bowel movements
Indicate possible sources of salmonella infection
Cattle
Eggs of chickens, ducks
Chickens, ducks
Specify the transmission factors of the causative agent of tularemia
Water rats
Sick people
Cracodiles
With influenza, the sources of infection are...
Sick people
Handkerchiefs, masks and other things used by the patient
Discharge from the patient's nose
Air chamber
Oxygen cushion
?Sources of infection for typhoid fever
Patient's bowel movements
A pond in which typhoid bacteria were found
Live culture of typhoid bacteria
Patient with typhoid fever
Bacteria carrier S.typhi
Indicate in what cases further development of the epidemic process is possible
A patient with chronic brucellosis is in the therapeutic department
A patient with a mild form of whooping cough attends school
Ascaris eggs were isolated from a child hospitalized in the therapeutic department
Treatment of a patient with tularemia is carried out on an outpatient basis
Meningococcus was found in the nasopharynx of a kindergarten teacher
What is included in the concept of “social factors of the epidemic process”?
Hydrogeological characteristics of the territory
Population migration
Condition of the housing stock
Availability of medical care
“Natural factors” of the epidemic process are...
Flora and fauna
Availability and maintenance of preschool children's institutions
Natural disasters
What circumstances may contribute to an increase in the incidence of anthroponoses?
Transport connections
Mass entertainment events
Automation of industrial processes
What may influence the incidence of zoonotic diseases in humans?
Cleaning cities from household waste
Livestock complexes and poultry farms
Hunting, fishing
Swimming in open water
That's right
What manifestations of scientific and technological progress and civilization can contribute to the growth of sapronoses?
Using computers
Using air conditioners
Interstate and interregional trade and transportation
Construction of underground structures
The frequency of the epidemic process is...
A quantitative indicator reflecting the level (frequency) of disease registration among the population as a whole or in certain age, gender, occupational and other groups
Increases in incidence that occur naturally in certain months (seasons) of the year
Time during which the pathogen can be released from an infected body
Regularly recurring rises and falls in morbidity at certain intervals (a year, several years)
Regularly recurring rises and falls in morbidity at certain intervals (a year, several years)
In the development of the epidemic process, priority is given to...
Social factors
Natural factors
Equally social and natural factors
Anti-epidemic measures
?The epidemic focus includes...
Only a room in the home or ward where the patient is located
The entire territory within which the infectious agent can spread in a given specific environment
?The boundaries of the epidemic focus are determined by...
Any doctor who has diagnosed an infectious disease
Attending physician (local therapist, pediatrician)
Doctor - epidemiologist
?How long does the epidemic focus last?
Until the patient is hospitalized
Before final disinfection of the fireplace
During the period of maximum incubation in persons who communicated with the patient
Until the patient recovers, if he received treatment on an outpatient basis
Work in the epidemic outbreak is organized and performed by the following medical personnel
Clinic therapist
Nurse
Epidemiologist
Disinfection staff
That's right
A doctor who suspects an infectious disease must
Find out the epidemiological history
Organize ongoing disinfection of the outbreak
Send an “Emergency Notice” to the territorial center for sanitary and epidemiological surveillance
Identify contact persons
The epidemiological history is ascertained...
Attending physicians to a patient
Epidemiologists visiting a patient
Epidemiologists among persons who interacted with the patient
Bacteriologists performing bacteriological and serological studies
?An "emergency notice" should be sent...
Only after bacteriological confirmation of the diagnosis
After consultation with an infectious disease specialist
Immediately if an infectious disease is suspected
No later than 12 hours from the moment the patient is identified
The epidemiological survey of the outbreak is aimed at...
Clarifying the patient's diagnosis
Identification of persons who communicated with the patient
Determination of the factor or route of transmission of the infectious agent
Identifying the source of the infectious agent
?Hospitalization of infectious patients is carried out...
In all cases of diagnosis of an infectious disease
According to clinical indications
According to epidemiological indications
Mandatory for exotic and conventional diseases
?Indicate where the infectious patient should be placed
In the box of the infectious diseases department of the hospital
To the ward of the infectious diseases hospital
To a therapeutic hospital
Leave at home at the request of the patient and family
From the list provided, select the measures taken at the outbreak in relation to the sources of infection
Hospitalization of the patient
Sanitation of the bacteria carrier
Destruction of arthropods
Boiling drinking water
Treatment or destruction of sick animals
Select the measures carried out in the outbreak to eliminate the routes of transmission of infectious disease agents
Vaccination of children
Extermination of house mice, rats
Killing flies
Sterilization of medical instruments
Disinfection in the patient’s apartment
Epidemiological surveillance includes...
Registration of emerging infectious diseases
Study of the biological properties of isolated pathogen cultures
Analysis of infectious morbidity by age, gender, profession, territory and other characteristics
Analysis of the effectiveness of preventive and anti-epidemic measures
The epidemic process is the process of transmission of an infectious principle from a source of infection to a susceptible organism (spread of infection from a sick person to a healthy one). It includes 3 links:
1. Source of infection that releases the pathogen into the external environment (humans, animals),
Pathogen transmission factors,
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 - person, noses - disease). For example, only humans suffer from typhoid fever, measles, whooping cough, dysentery, and cholera.
2. Animals. A large group of infectious and invasive human diseases are zoonoses (from the Greek zoos - animals), in which the source of infection is various types of domestic and wild animals and birds. Zoonoses include brucellosis, anthrax, glanders, foot-and-mouth disease, etc.
There is also a group of zooatroponotic infections, in which both animals and people can serve as the source of infection (plague, tuberculosis, salmonellosis).
Pathogen transmission factors. Pathogens are transmitted to healthy people in one or more of the following ways:
1. Air - influenza, measles are transmitted only through the air, for other infections air is the main factor (diphtheria, scarlet fever), and for others it is 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. Causative agents of diphtheria, scarlet fever, tularemia, plague, etc. can also be transmitted with food;
5. Work and household items contaminated by a sick animal or person can serve as a factor in transmitting the infectious principle to healthy people;
6. Arthropods - 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, sperm, amniotic fluid) - AIDS, syphilis, hepatitis, intestinal infections, etc.
The main epidemiological characteristics of the occurrence and spread of an infectious disease are determined by the speed of spread, the vastness of the epidemic territory and the mass coverage of the disease in the population.
Options for the development of the epidemic process:
1. Sporadia (sporadic incidence). Isolated, unrelated cases of infectious diseases occur that do not significantly spread among the population. The ability of an infectious disease to spread in the environment of the sick person is minimally expressed (for example, Botkin's disease).
2. Endemic - group outbreak. It usually occurs in an organized team, in conditions of constant and close communication between people. The disease develops from a single, common source of infection and in a short time affects up to 10 or more people (an outbreak of mumps in a kindergarten group).
3. Epidemic outbreak. Mass spread of an infectious disease that occurs from a number of group outbreaks and covers the entirety of one or several organized groups with a total number of sick people of 100 or more people (intestinal infections and foodborne toxic infections).
4. Epidemic. Mass morbidity of the population, spreading over a vast territory in a short time, covering a city, district, region and a number of regions of the state. The epidemic develops from many epidemic outbreaks. The number of sick people amounts to tens and hundreds of thousands of people (epidemics of influenza, cholera, plague).
5. Pandemic. Global spread of epidemic morbidity among people. The epidemic covers vast territories of various countries on many continents of the globe (influenza pandemics, HIV infections).
Natural focality of infectious diseases is the spread of the disease within certain territorial zones. This phenomenon, when a disease is recorded with great consistency in a certain territory, is called endemic. As a rule, these are zoonotic infections, the latter spreading in the corresponding territorial foci among animals, with the help of insects that carry the infectious agent. The doctrine of the natural focality of infectious diseases was formulated in 1939 by Academician E.N. Pavlovsky. Natural foci of infectious diseases are called nosohabits, and infectious diseases characteristic of territories are called natural focal infections (hemorrhagic fevers, tick-borne encephalitis, plague, tularemia, etc.). We can call them environmentally caused 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. Humans are not a factor that can support the existence of a focus of natural infection, since such centers were formed long before the appearance of people in these territories. Such outbreaks continue to exist after people leave (after completion of geological exploration, road and other temporary work). The undoubted priority in the discovery and study of the phenomenon of natural focality 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 is unfolding is called an epidemic focus. An epidemic outbreak may be limited to the boundaries of the apartment where the sick person lives, may cover the territory of a preschool institution or school, or include the territory of a settlement or region. The number of sick people in an outbreak can vary from one or two to many hundreds and thousands of cases of the disease.
Elements of an epidemic focus:
1. Sick people and healthy bacteria carriers are sources of infection for surrounding people;
2. Persons who have been in contact with sick people (“contacts”), who, if they develop a disease, become a source of spread of infection;
3. Healthy people who, by the nature of their work activities, represent a group at increased risk of spreading infection - the “decreed group of the population” (workers of public catering, water supply enterprises, medical workers, teachers, etc.);
4. The room in which the sick person is or has been, including furnishings and everyday items located in it that contribute to the transmission of the infectious principle to susceptible people;
5. Environmental factors, especially in suburban conditions, that can contribute to the spread of infection (sources of water use and food supplies, the presence of rodents and insects, waste and sewage collection sites);
6. The healthy population in the outbreak area, which has not had contact with patients and bacteria carriers, as a contingent susceptible to infection, not immune from possible infection in the conditions of an epidemic outbreak.
All of the listed elements of the epidemic focus reflect the three main links of the epidemic process: source of infection - transmission routes (mechanism of infection) - susceptible contingent.
Appropriate anti-epidemic measures should be directed at all elements of the epidemic focus in order to most quickly and effectively solve two interrelated problems: 1) strictly localize the outbreak within its borders, to prevent the “spreading” of the boundaries of the outbreak; 2) ensure the speedy elimination of the outbreak itself in order to prevent mass disease of the population.
The mechanism of transmission of infection consists of 3 phases:
1) removal of the pathogen from the infected body to the outside,
2) presence of the pathogen in the external environment,
3) introduction of the pathogen into a new organism.
With the airborne mechanism of infection, the infection can be transmitted both by airborne droplets and by airborne 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 intensely 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. spread. The airborne dust path of infection, when pathogens with air currents are able to spread over significant distances from a sick person, is characteristic of “volatile” viral infections (chicken pox, measles, rubella, etc.). With airborne infection, the pathogen enters the body mainly through the mucous membranes of the upper respiratory tract (through the respiratory tract) and then spreads throughout the body.
The fecal-oral mechanism of infection differs in that the infectious agents, released from the body of a sick person or a bacteria carrier with its intestinal contents, enter the environment. Then, through contaminated water, food products, soil, dirty hands, and household items, the pathogen enters the body of a healthy person through the gastrointestinal tract (dysentery, cholera, salmonellosis, etc.).
The blood mechanism of infection differs in that the main factor in the spread of infection in such cases is infected blood, which penetrates the bloodstream of a healthy person in various ways. Infection can occur through blood transfusion, as a result of unskilled use of reusable medical instruments, intrauterine transmission from a pregnant woman to her fetus (HIV infection, viral hepatitis, syphilis). This group of diseases also includes vector-borne infections that spread through the bites of blood-sucking insects (malaria, tick-borne encephalitis, tick-borne borreliosis, plague, tularemia, hemorrhagic fevers, etc.).
The contact mechanism of infection can be carried out both through direct and through 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 in the hot season). A number of infectious diseases are age-specific, for example, childhood infections (whooping cough).
Main directions of anti-epidemic measures
As indicated, 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 cessation 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 communicated with sick people for subsequent monitoring of their health status in order to promptly identify new cases of diseases and promptly isolate sick people.
2. Measures aimed at suppressing the spread of infection and preventing the expansion of the outbreak boundaries:
a) regime restrictive measures - observation and quarantine. Observation is a specially organized medical observation of the population in the source of infection, including a number of activities aimed at the timely detection and isolation of sick people in order to prevent the spread of the epidemic. At the same time, emergency prophylaxis is carried out with the help of antibiotics, the necessary vaccinations are given, and strict adherence to the rules of personal and public hygiene is monitored. The observation period is determined by the length 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 is a system of the most stringent isolation and restrictive anti-epidemic measures carried out 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 population’s immunity to infection, among which the most important are methods of emergency prevention of the occurrence of the disease:
a) immunization of the population according to epidemic indications;
b) the use of antimicrobial agents for prophylactic purposes (bacteriophages, interferons, antibiotics).
The indicated anti-epidemic measures in the conditions of an epidemic outbreak are necessarily complemented by a number of organizational measures aimed at limiting contacts among the population. Sanitary, educational and educational work is carried out in organized groups, and the media are involved. The educational and health education work of teachers with school students is becoming important.
Methods of disinfection 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 of destroying pathogens),
2) disinsection (methods of exterminating insects that carry pathogens of infectious diseases),
3) deratization (methods of exterminating 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, vegetative forms of E. coli die.
Types of disinfection. In practice, there are two main
1. Focal (anti-epidemic) disinfection is carried out with the aim of eliminating the source of infection in a family, hostel, child care facility, on railway and water transport, in a medical institution. In the conditions of an epidemic outbreak, current and final disinfection is carried out. Routine disinfection is carried out in the room where the sick person is located at least 2-3 times a day for the entire period of stay of the source of infection in the family or in the infectious diseases department of the hospital. Final disinfection is carried out after the patient is hospitalized or after his recovery. All items that a sick person has come into contact with (bedding, linen, shoes, dishes, care items), as well as furniture, walls, floors, etc. must be disinfected.
2. Preventive disinfection is carried out once a day or 2-3 times a week in catering units, children's institutions, boarding schools, general medical institutions, and maternity hospitals. This is a routine disinfection.
Disinfection methods. Physical and chemical disinfection methods are used for disinfection. Physical methods include boiling, autoclaving, heat treatment in dry-heat ovens, disinfection chambers, and ultraviolet irradiation. Chemical methods of disinfection are carried out using chemicals with high bactericidal activity (bleach, chloramine, calcium and sodium hypochlorites, Lysol, formaldehyde, carbolic acid). Soap and synthetic detergents also have a disinfecting effect. Biological methods of disinfection are the destruction of microorganisms by means of a biological nature (for example, with the help of antagonistic microbes). Used for disinfection of wastewater, garbage and waste.
To carry out focal current and final disinfection in foci of intestinal infections, use a 0.5% solution of chlorine-containing disinfectants, for airborne infections - 1.0%, in foci of active tuberculosis - 5.0%. When working with disinfectants, you must be careful (use protective clothing, goggles, mask, gloves).
Epidemic process: definition, forms, structure, anti-epidemic measures, prevention of the epidemic process.
Epidemic process – a continuous chain of sequentially occurring and interconnected infectious conditions, manifested in the form of epidemic foci with one or more patients and carriers.
Continuity epidemic process is supported by interaction 3 mandatory factors(links): source of infection, mechanism (factors) of transmission, susceptibility of the population.
Source can act infected person(patient and carriers: contact and non-contact, healthy and transient, early, in those who have recovered and in convalescents) – anthroponotic infections (typhoid fever, measles, whooping cough, cholera, dysentery) or domestic, wild animal, birds – zoonotic infections (brucellosis, anthrax, glanders, foot and mouth disease, etc.). There is also a group zooanthroponotic infections , in which the source of infection can be both animals and people (plague, tuberculosis, salmonellosis)
Role environmental factors in the epidemic process is not the same. Elements of the external environment that ensure the transition of a pathogen from one organism to another are usually called transmission factors (air, water, soil, food products, labor and household items, arthropods, biological fluids), and the spread of the disease through this factor - by transfer .
Population sensitivity – the body’s ability to respond to the introduction of an infectious agent, the development of a disease or carriage.
Options for the development of the epidemic process.
1) Sporadic disease– these are isolated, occurring from time to time, unrelated diseases. For example, Botkin's disease.
2) Endemic– a group outbreak that usually occurs in an organized group, in conditions of constant and close communication between people. It develops from a single, common source of infection and covers up to 10 or more people in a short time.
3) Epidemic outbreak– group diseases that appeared simultaneously, covering a group or part of it, a locality, united by one source of infection
4) Epidemic– a massive spread of an infectious disease in any locality or country, significantly exceeding the normal incidence rate.
5) Pandemic– a global epidemic covering a significant part of the population of a country, group of countries, or continent.
Prevention of infectious diseases provided: A) holding government events, b) carrying out medical activities, V) taking measures to limit the importation of infections, G) participation of the population.
Measures regarding the source of infection: Identification of patients, bacteria carriers, their isolation and treatment; detection of persons who communicated with sick people for subsequent monitoring of their health status in order to promptly identify new cases of diseases and promptly isolate sick people.
Measures to break the transmission mechanism.
1. General hygiene measures. For intestinal infections Compliance with sanitary standards and rules when receiving, processing, releasing, storing and selling food products is of decisive importance; providing the population with good-quality drinking water, protecting water bodies, sanitary cleaning of territories, strict adherence to the rules of personal hygiene in everyday life and at work, in catering, trade, food, children's, adolescent, etc. institutions. For airborne infections The most reliable mechanical protection against the penetration of contaminated air (filters, masks, bandages, etc.), disinfection is less effective. For blood infections infection is prevented by exposure to the carrier (fight against pediculosis, destruction of blood-sucking insects, measures to protect against their attacks). For infections of the external integument effective sanitary measures in everyday life and at work, compliance with regimes in bathhouses and hairdressing salons.
2. Organization of disinfection measures. They are carried out by disinfection stations or SES and disinfection departments.
3. Regime restrictive measures - observation and quarantine. Observation – specially organized medical surveillance of the population in the source of infection, including a number of activities aimed at timely detection and isolation of sick people in order to prevent the spread of the epidemic. Quarantine is a system of the most stringent isolation and restrictive anti-epidemic measures carried out to prevent the spread of infectious diseases.
Measures to increase the population's immunity to infections.
They provide:
1. accounting of population groups subject to immunization
2. planning preventive vaccinations in accordance with the decrees of the Ministry of Health
3. compliance with immunization deadlines and medical contraindications
4. compliance with storage conditions for bacterial and viral preparations
5. immunization of the population according to epidemic indications
6. use of antimicrobial agents for prophylactic purposes (bacteriophages, interferons, antibiotics).
10. Pharmacological foundations of medicine: tasks of pharmacology, classification of dosage forms, their advantages and disadvantages, routes of administration and elimination of drugs, dose and its types, types of action of drugs.
Pharmacology- This the science of medicinal substances, their interaction with the body and ways of finding new medicinal substances .
All medications by mode and strength of action are divided into lists :
- List A – poisonous and narcotic drugs;
- List B – potent drugs;
- general list - all other medicines.
Classification of dosage forms- see Table 1.
§ Solid dosage forms: tablets, dragees, powders, capsules, granules, collections of medicinal plants, films and plates, glossets (for sublingual and cheek use), caramels, poultices (semi-solid), soluble tablets (externally - furatsilin tablets), etc.
§ Liquid dosage forms: solutions, infusions, decoctions, mixtures, tinctures, extracts, emulsions, suspensions, applications, balms, collodions, creams, lemonades, syrups, etc.
§ Soft dosage forms: ointments, pastes, suppositories, gels, liniments, patches.
§ Dosage forms for injections.
Routes of drug administration into the body:
v Enteral – administration of the drug orally through the gastrointestinal tract: oral (through the mouth), sublingual (under the tongue), rectal (through the rectum);
Advantages: ease of use, the possibility of using the drug without the participation of medical personnel, the possibility of independent dosage of the drug, the possibility of use in pediatric practice, comparative safety, the absence of complications inherent in the parenteral route.
Flaws : slow development of the effect, the presence of individual differences in the speed and completeness of absorption, the influence of food and other drugs on absorption, destruction in the lumen of the stomach and intestines (insulin, oxytocin) or when passing through the liver.
v Parenteral : intramuscular, intravenous, intradermal, subcutaneous, intra-arterial, intra/subarochnoid, inhalation route, electrophoresis.
Advantages: : possibility of use in emergency cases, without the participation of the patient, rapid onset of effect, greater dosage accuracy, because the influence of gastric juice and gastrointestinal enzymes is excluded, and the barrier role of the liver is excluded.
Flaws : causing a certain psychological trauma to the patient (especially children), violation of the integrity of the skin, the possibility of developing complications
Routes of elimination (excretion) of drugs:gastrointestinal tract; kidneys; lungs; skin glands; mammary gland.
Types of action of drugs:
1) According to the place where their effect is applied:
A) local– in direct contact with the site of application of the medicinal substance (ointments, solutions, suppositories, some tablets);
B) resorptive– after the drug is absorbed into the blood.
2) By purpose, by expected effect:
A) The main thing;
B) incidental: medicinal and toxic ( teratogenic effect– adverse effect of the drug on the fetus, causing congenital deformities);
IN) direct– direct effect on the systems and organs of the body;
G) indirect– indirect action.
D) combined– combined enhanced effect of 2 or more drugs.
Dose – this is the smallest amount of a medicinal substance with a pronounced pharmacological effect, intended for 1 dose.
Doses can be: A) one-time, b) daily allowance, V) coursework, G) drums(deliberately overestimated dose, the effect is quickly achieved, then maintenance single doses are prescribed).
When determining a patient's dose medicinal product taken into account: patient’s condition, age, gender, climatic conditions, time of year.
Highest single dose– the largest amount of a medicinal substance for a single use without the onset of a toxic effect.
Highest daily dose– the largest amount of a medicinal substance that can be prescribed to a patient during the day without causing a toxic effect
Minimum toxic dose– the dose of the drug at which toxic effects begin to occur
Lethal dose- lethal dose.