Effect of the natural and climatic factors on epidemiological situation related to natural focal infections

Abstract

This article is dedicated to the analysis and generalization of the Russian and foreign research results on natural and climatic factors effect on the intensity of epidemic process manifestations and the natural focal infections pathogens vectors vital activity which are the most widespread in the Russian Federation. Over the past seven years tick-borne infections have been accounting for more than 50 per cent in the natural focal diseases general nosological structure. Among the diseases of this group Lyme borreliosis leads in prevalence and frequency of cases identification. Tick-borne viral encephalitis is still a serious danger for national health. Crimean-Congo hemorrhagic fever epidemiological situation remains unfavorable in the south of the European part of Russia. In addition to the annual patients identification, the demonstrable trend of shifting and expansion of the pathogen’s area in a northerly direction was established. It creates a risk for the spread of the Crimean-Congo hemorrhagic fever virus outside the southern regions of the country. High incidence of the dangerous vector-borne infection — West Nile fever — with the involvement of new subjects in the epidemic process and the emergence of local cases of infection in previously non-endemic territories is registered. Expansion of hemorrhagic fever with renal syndrome natural foci borders, which is the most widespread natural focal zoonosis of viral etiology in the Russian Federation and is the second by the frequency of patients identification after tick-borne infections, is noted. Research data for the dependence of the carriers pathogens number and the dynamics of the natural focal infections incidence on the values of climatic factors, confirmed using various methods of mathematical statistics (time-series analysis, autoregression integrated moving average, logistic regression, correlation analysis, one-way analysis of variance and other) were systematized. It was found that the temperature and humidity of the air and soil, the amount of precipitation, the height of the snow cover are the common abiotic factors for all of investigated infections. The values of these factors can be used for the subsequent epidemiological forecast. The further study of relationship between the incidence rate of the population, the number of arthropod vectors and small mammals with indicators of soil moisture and temperature at different depths, hydrothermal coefficient, normalized relative vegetation index, accumulated values of temperature and precipitation, as well as similar studies on other actual natural focal infections in the Russian Federation will be very promising.