The epidemic process is characterized by infectious morbidity. In this case, epidemic foci are formed. What is the meaning of this concept? More will be described in the article below.
There are several definitions of an outbreak. V. D. Belyakov believes that this term denotes a territory on which infection of infectious pathogens is possible in certain spatiotemporal boundaries.
Modern interpretation
The modern characteristic refers to the manifestation of the epidemic process as asymptomatic and manifest forms of diseases, which includes the following components:
- a patient or patients who are evaluated in terms of the spread of the infectious agent;
- healthy people who are evaluated in terms of likelihood of infection;
- An environment that is evaluated in terms of the risk of human infection.
Characteristic of the epidemic outbreak
There are two concepts that characterize such a focus, namely, its boundaries and duration of existence.
Boundaries are determined by the characteristics of the transmission of a specific infectious disease and the specific features of the environment in which the source of infection is located.
The duration of existence is established based on the period of stay of the source and the time of the maximum incubation stage of a particular infection. The epidemic focus after recovery or departure of the patient retains its intrinsic value for the maximum incubation period, as new infected ones may appear.
Focal examination
The method of examination of epidemic foci is a specific set of methods designed to study the causes of the appearance and spread of infectious diseases in this place. This means that the purpose of the epidemiological study of the focus is to determine the source of the infectious pathogen, factors and ways of its transmission, as well as contacts.
Methods for conducting an epidemiological examination
The following techniques for examining epidemic foci are as follows.
1. Determination of the source of infection :
- interrogation of the patient (creation of a hypothesis about the source, factors and routes of transmission, time of possible infection);
- study of documentation (what was the focus before the outbreak of infection);
- laboratory examination of the infected person and those who come in contact with it during the period of infection;
- epidemiological observation.
2. Identification of factors and modes of transmission:
- documentation research;
- sanitary analysis of the outbreak;
- laboratory analysis.
3. Identification of contact persons who have been exposed to the probability of infection:
- laboratory tests;
- survey of contact persons.
Then an act or a map of the examination of the lesion is made.
When is an epidemiological examination ineffective?
Ineffective (or ineffective) examination of the epidemic focus of infection in the following circumstances:
- in a single case of the disease (excluding exotic infections);
- the presence of carriage with this nosoform, especially when it prevails in frequency with respect to manifest infectious forms;
- the likelihood of communication in different places (shops, vehicles, etc.);
- the likelihood of infection at a great distance from the localization of the infectious source (for example, product contamination at the enterprise - home infection).
The work of an epidemiologist
The epidemiologist begins work even before visiting the epidemic outbreak. It consists in the fact that documents are being studied in an anti-epidemic institution that characterize the epidemic situation in this outbreak. The specialist also prepares the laboratory for future sampling from the patient, contact persons, and alleged transmission sources.
Then the activity of the epidemiologist is carried out directly in the outbreak. An epidemiological examination begins with a survey of the patient (if he does not lie in the infectious diseases hospital), as well as of persons in contact with him.
The survey is conducted in order to collect such information that would enable the epidemiologist to put forward a hypothesis about the infectious source, factors and routes of transmission, that is, the causes of the outbreak. For this, the epidemiologist first of all sets the time period (framework) of the alleged infection. To determine the period of infection, you need to know the exact start date of the disease of the person who formed such a focus. The time of infection corresponds to the time between the minimum and maximum incubation periods. After that, the patient’s stay is established.
A major role is played by preventive measures - the implementation of preventive therapy, training of patients and contact persons with hygienic skills and a healthy lifestyle.
Instrumental and laboratory studies in the outbreak are needed to clarify and confirm the clinical diagnosis, determine the factors and sources of infectious transmission, evaluate the effectiveness of therapy, rehabilitation, etc. In the outbreak observation is carried out over the course of its existence.
Outbreak Activities
The following activities are available:
- Registration. Patients and persons suspected of having an infectious disease are put on a special register at the sanitary-epidemiological institution, and therefore the dynamics of the infection is transmitted to the headquarters of the SEC (sanitary-anti-epidemic commission) at least twice a day, and in case of quarantine infections - generally every two hours.
- Hospitalization and isolation of the infected. Active determination of patients with manifest forms of infection, carriers (clinical examination, interrogation, microbiological and other laboratory studies). Quarantine and observational measures in the outbreak. Timely hospitalization of a patient with an infection is a cardinal measure that prevents the spread of the disease. What else are the anti-epidemic measures in the epidemic outbreak?
- Stronger general sanitary measures (regarding sewage disposal, water supply, nutrition). Final and ongoing disinfection. There may be sanitization, pest control and pest control. In the room in which the infectious patient stayed before being hospitalized, the current disinfection is carried out. After his hospitalization - the final one, especially carefully in those places where the injured persons are temporarily accommodated (in dugouts, tents). In case of intestinal infections, from the time the patient is determined, disinfection and disinfection of toilets should be systematically carried out. If it is parasitic typhus, along with the disinfection of the premises, sanitary treatment of contact persons who live with the infected is done. Deratization works are carried out in natural foci.
- Prevention of an emergency nature (passive immunization, phage, chemo, antibiotic prophylaxis). Vaccination of people according to epidemic indications.
- Epidemiological examination. Its purpose is to determine the source of infection and methods of transmission of the pathogen, the number of people communicating, establishing the scope of laboratory analysis and indications for antibiotic prophylaxis or the use of immunopreparations.
- Stronger sanitary and epidemiological surveillance: an additional survey of water sources and food supplies is carried out.
- Sanitary and explanatory actions to increase the degree of sanitary culture of people.
The article examined the features of the epidemic outbreak.