Epidemiological Situation of Tick-Borne Encephalitis in the Kurgan Region (1983–2017)

Abstract

Relevance.Тhe Ural Federal district (Ural Federal district) is a highly endemic tick-borne viral encephalitis (TBEV) territories in the Russian Federation. The epidemiological situation on the TBEV is studied in Sverdlovsk and Chelyabinsk regions and slightly shown in the Kurgan region. There is no information about the evolution TBEV, the structure of immunity population, vaccine prevention in the Kurgan region. The article presents the dynamics epidemiological situation on TBEV in the Kurgan region over a 30-year period.Materials and methods: Used expedition reports, viral encephalitis named after the Academy of medical Sciences of the USSR for 1983–2007, as well as materials of medical institutions of the Kurgan region 2007–2017. For population immunity used: hemagglutination test (HAI-test), neutralization test (NT). To identify specific antibodies – IgG, IgM, antigen of TBEV, sets of reagents of ELISA from «Vector-Best» were used. To immunotypicalli and genotypically Strains and isolates RNA of TBEV isolated in 1983–2007, used precipitation in agar (RDPA) and by RT-PCR technique in real time with genotypespecific probes.Results and discussions: Kurgan region is a highly TBEV endemic area. the morbidity rate – 18,3 per 100 thousand people 1983. Maximum elevation – 44.1 in 1996 to and decrease to 13.5 in 2000–2012. The immune part of the population according hemagglutination tests, on epidemiologically significant territories is 15–20%, (66% NT), in the regions with sporadic incidence is 8%, (21–50% NT), in non-endemic territories – 3%. At the present stage, the region marked the expansion of nosoareal TBEV due to the previously less significant Eastern regions. In Kurgan region vaccination coverage against TBE 39.3%. The clinical efficacy of vaccination was manifested in an increase in fever forms of TBE disease and a decrease in meningeal and focal forms of the disease. In the period 2004–2012 the number of vaccinated patients was 20.3% of the total number of patients.Сonclusions. Evolution of tick-borne encephalitis manifested the expansion of nosoareal TBEV, increase seasonal activity of ticks, the TBEV Siberian subtype is absolutely dominating.

Keywords

• tick-borne encephalitis
• morbidity dynamics
• population immunity
• vaccine prevention
• siberian subtype