Computed dynamics of an epidemic depends on the following modeled processes:
In addition to these processes, the model simulates the corresponding countermeasures (responses).
- Formation of a "contagious tension" (intensity of infection) because of a potential external infection source and/or infectivity of not isolated infected cases at the second and/or third stages of disease;
- Reduction or increase in the activity of the external source of infection;
- Infection of susceptible persons, depending on the "contagious tension" and their immune statuses;
- Formation of the cohort of contacts proportional to the number of newly infected sensitive persons;
- Infection of contacts with a rate exceeding the rates for other persons;
- Transition of infected persons from stage to stage depending on the time they stay in a certain stage;
- Recovery, that is a process accelerating with the course of the final stage; typically, the recovered persons are “discarded” from epidemic; however, the persons recovered from some infections are returned back supplementing the cohort of immune persons; and
- Death of infected persons, mainly in the final stage; the mortality rate decreases if the detected infected persons are subject to treatment, are immune, or have a mild form of disease.