ИСТИНА

West Nile Fever (WNF) is a vector-borne natural focal viral disease transmitted mainly by mosquitoes, predominantly among birds. Humans and other mammals are accidentally involved in the circulation of the virus and cannot transmit the infection. This work aims to identify the ecological and geographical prerequisites for the spread of West Nile fever in Russia. The analysis of the epidemiological situation with WNF in Russia was carried out and the contribution of climatic variables to the spread of WNF was estimated. We assessed the suitability of climatic conditions for West Nile virus (WNV) transmission using the degree-day method. Based on the data obtained, we demonstrate the growth of the sums of effective temperatures (ET). At the same time, the increase in the duration of the season of effective infectivity of mosquitoes was not tracked down. The changes in the sums ET coincide with the increase in the average air temperature for the epidemiological season but go at a higher speed. This creates favorable conditions for the development of the virus in the mosquito, as with an increase in ET the circulation of the virus is more efficient. The most favorable situation for the development of West Nile virus (WNF) is in the Caspian region. In this territory, there is a further improvement in the conditions for the circulation of WNF due to an increase in the sums of ET. This research was funded by the Russian Science Foundation (Grant 17-77-20070 «Assessment and Forecast of the Bioclimatic Comfort of Russian Cities under Climate Change in the 21st Century»)