8.1. INFECTIOUS PROCESS, INFECTIOUS DISEASES
Infectious process - a complex of pathological and protective-compensatory and adaptive reactions of various levels of the organization of the interrelated morphological, metabolic, executive, and regulatory (especially immune) physiological systems which are at the core of specific infectious diseases.
Infectious diseases (from Latin infectio - contagion) - a group of diseases caused by pathogenic microorganisms characterized by contagiousness, presence of an incubation period, responses of the infected organism to the germ, and, as a rule, by a cyclic course and postinfectious immune development.
Infectious disease - a disturbance of the normal life-sustaining activity of the organism caused by the injection and reproduction of pathogenic organisms in it.
Peculiar features of causative agents of infectious diseases:
• ability to be transmitted from an ill person to a healthy one and quickly propagate;
• presence of a latent period of reproduction;
• difficulties in detection in the ambient environment, difficulty and lengthy time for the diagnostics of diseases;
• the ability of some causative agents to survive for a long time in foodstuffs, water, soil, on various objects, clothes, and in the organism of certain animal species.
By prevalence, infectious diseases (together with cardiovascular and oncological diseases) are persistently within a group of the world's most frequently occurring diseases and among them take various periods of ontogenesis for the
leading position. The incidence of tuberculosis, flu, acute and chronic respiratory, intestinal, and skin diseases is growing up.
At any period of infectious diseases, both specific and nonspecific complications may develop (adjoining of various specific and/or nonspecific processes and reactions to the underlying disease).