Present-Day Peculiarities of Epidemiology and Prophylaxis Results of Tick-Borne Encephalitis in the Republic of Khakassia

Abstract

A retrospective descriptive epidemiological study of an incidence rate and prophylaxis of tick-borne encephalitis (TBE) was carried out in the Republic of Khakassia over 2007–2016. Also, a relative risk (RR) of the incidence rate was assessed in the cohorts of vaccinated and unvaccinated population. Over the decade, 569 TBE cases were registered. There is a distinct tendency of TBE rate reduction (slope coefficient of the regression line b = –1.1 per annum, P < 0.05) as well as an expressed irregularity in the territorial distribution of longterm average annual rates in various towns and rural districts (from 0.9 up to 44.2 cases per 100 thousand people). In the vaccinated population cohort the TBE was registered 22.8 times less than in the unvaccinated one: χ2 = 23.78 (P < 0.001); RR = 3.1 (1.9–4.9). As the extend of mass-vaccination (b = 0.06 per annum, P < 0.05) and the area of acaricide treatments (b = 0.09 per annum, P < 0.05) were increasing, the number of virus-carrying ticks was reducing (b = –0.09 per annum, P < 0.001). The results of the comparison analysis of affect to the incidence of TBEcontrollable and uncontrollable factors in the territories with various rates of incidence prove the practicability of a risk-based approach to the prophylaxis of tick-borne encephalitis.

Influence exerted by biological and social risk factors on morbidity with tick-borne en-cephalitis in some regins in the Urals Federal District

“…Nevertheless, it is well known that it is rather difficult to estimate contribution made by these prevention activities into a fall in morbidity with TBE. Squares exposed to acaricide treatments are substantially smaller that the square of a whole region; besides, such treatments are usually accomplished in places specifically designed for people's rest (forest camps, for example) and people usually get infected beyond such places [17].…”

Influence Exerted by Biological and Social Risk Factors on Morbidity With Tick-Borne E Ncephalitis in Some Regins in the Urals Federal District

“…Тем не менее известно, что существует проблема оценки вклада этого профилактического мероприятия в снижение заболеваемости КЭ. Площади акарицидных обработок во много раз меньше, чем площадь всего региона, кроме того, в основном обработки проводятся в местах организованного отдыха, а случаи заражения, как правило, происходят за пределами таких мест [17]. Исходя из данных литературы и многолетних наблюдений, в Тюменской области отмечены одни из самых высоких уровней серопрофилактики против КВЭ среди субъектов РФ, что, по-видимому, указывает на отсутствие учета результатов лабораторного исследования присосавшихся клещей при назначении иммуноглобулина [18].…”