Analysis of the Potential of GIS Technologies in the Assessment of Environmental Factors of Malariogenicity in the Territories of the Volgograd Region

Abstract

In the southern regions of Russia, high risks of the spread of malaria remain. The situation is aggravated by the increase in average annual temperatures in the long-term distribution and the growth of eutrophicated small water bodies, which are favorable for the completion of the life cycle of the disease vectors mosquitoes of the genus Anopheles. In order to establish the relationship between climatic factors and the status of populations of insect vectors of the causative agent of malaria, an analysis of the amount of surface water was carried out using GIS technologies. For the calculation, the MNDWI index was chosen, based on the use of images in the Green and SWIR bands of the Landsat 8 satellite. The indicators of the average and maximum number of larvae and adults of mosquitoes were analyzed on the basis of information presented in the annual reports of the Office of the Federal Service for Supervision of Consumer Rights Protection and human well-being in the Volgograd region. There are three malariogenic zones in the region: northern (Kamyshinsky), central (Volgograd) and southern (Kotelnikovskaya). The overall dynamics of MNDWI for the Kamyshin zone tended to increase the water index from -0.176 to -0.171 in a two-year range. Similar MNDWI indicators for the Volgograd and Kotelnikovsky malariogenic foci also had a positive trend in the period from 2018 to 2020. The modified normalized water index for them increased from -0.152 to -0.126 and from -0.215 to -0.158, respectively. Calculation of the Pearson correlation coefficient for the study area revealed the presence of a high closeness of a direct relationship between the MNDWI index and the maximum number of larvae/adults in the Kamyshin region (0.994/0.833). For Volgograd, the strength of the correlation was in the region of average (noticeable) values, except for the average value for adults, where the relationship was strong (0.904). In Kotelnikovo, the relationship between periods of drought and the number of larvae was inversely proportional, with the exception of the maximum number of adults (0.943), which can be explained by the small value of the sample of the final emergence of insects and the measurement error due to the logic of the methodology for studying the number of larval forms in natural water bodies. The results obtained can be used to improve the system for monitoring the dynamics of malariogenicity by supervisory authorities in the field of population welfare. Further research prospects are associated with a change in approaches to assessing the average values of the number of malaria vector insects, as well as with our own field work on the study of the composition of the mosquito entemofauna of the river. Anopheles for the purpose of calibrating data reported by government agencies.