Management of the incidence of infectious diseases by applying preventive measures in the weakest period in its cyclicity

Existing preventive measures have not been entirely efficient. Mainly they are aimed at solving social and economic issues, which demands both time and money. Considering this, it is necessary to find and sustain additional effective measures, based on patterns of development of infectious diseases, which could be more cost-effective. One of such approaches could be based on the theory of self-regulation of parasitic systems, which directs epidemiologists to conducting preventive measures before the rise of the number of cases to prevent increase in the agents virulence. Yet this theory does not provide the optimum time for preventive measures. Based on the main statements of the theory of self-regulation of parasitic systems and analysis of annual and/or long-term cyclicity, the article provides substantiation of the theory that the lowest level of incidence is the weakest period in its development. Epidemiological experiments, using bacterial dysentery as an example, showed that preventive administration of polyvalent dysenteric bacteriophage in risk groups (children going to preschool institutions) during two months of the lowest incidence level of the disease appeared to be effective. The positive effect took place in the stages of cyclic increase and decrease of long-term trends. The effect appeared in the groups of children and population in general with most marked decline in disease occurrence in its seasonal peak. The hypothesis that the lowest incidence level is directly related to seasonal climbs of the disease was proved by our earlier studies when we investigated influence of technogenic pollution of the environment on annual incidence rate of more than ten most common infectious diseases with different ways of transmission. Thus, the lowest incidence level of infectious diseases defines their future growth and/or decline, and, therefore, it can be used to conduct preventive measures.