Natural Focal Viral Fevers in the South of European Part of Russia. West Nile Fever

Abstract

Aim. Investigation of modern epizootic and epidemic situation on West Nile fever (WNF) in the south of the European part of the Russian Federation. Materials and methods. Data from statistical documentation (epidemiological survey of the infectious disease focus, annual summary reports over the period of 2009–2018) and epizootic monitoring data presented by the Rospotrebnadzor Administrations and the Centers of Hygiene and Epidemiology in the constituent entities of the Southern and the North Caucasian Federal Districts were used. Descriptive, analytical methods and retrospective epidemiological analysis were applied. Results and discusson. The activity of natural WNF focus in the south of the European part of the Russian Federation was confirmed by the results of the annual epizootiological monitoring and the annual epidemic manifestations of the disease. 74.15 per cent of the cases and all major WNF outbreaks in the country between 2009 and 2018 were noted in the territory of the southern region. Most of the patients (97.8 per cent) are registered in the Volgograd, Astrakhan and Rostov Regions. In other southern entities sporadic incidence (this represents 2.2 per cent of all WNF cases in the south of the Russian Federation) was noted. Less serious clinical forms of the disease without the damage of central nervous system were observed in most of WNF patients. Fatal outcomes were registered in 7 WNF patients (this represents 0.58 per cent of all cases) over the past 10 years. The significant expanding of the West Nile virus geographic area and activation of the natural foci of this infection in the south of the Russian Federation in 2009- 2018 has been established. The epizootic and epidemic WNF center is located in the Volgograd, Astrakhan and Rostov Regions. It was confirmed by persistent epizootic and epidemic instability in this territory. The modern epidemic WNF feature in the south of the European part of the Russian Federation during the 10-year survey period is the relatively low mortality (0.58 per cent).