Peculiarities of the Epidemiological Situation on Tick-Borne Viral Encephalitis in the Russian Federation in 2017 and the Forecast for 2018

The article presents the analysis of tick-borne encephalitis (TBE) epidemiological situation in the Federal Districts of Russia in 2017. Studied has been the effect of causative factors of epidemic process dynamics, such as: rate of people seeking medical help due to tick bites, contamination of ticks with the TBE virus revealed by immune-enzyme analysis and polymerase chain reaction, amount of people who were vaccinated, scope of emergency prophylaxis, the size of treated areas, and amount of funding for TBE-incidence decrease. Authors presented the incidence forecast for the endemic areas as regards TBE, as well as for the whole country for 2018, taking into account the presence or absence of change in its trends during 2008–2017. The values of the confidence interval are 95 % of the indicator fluctuations. Further gradual improvement of the epidemiological situation is expected

Epidemiological Situation on Tick-Borne Viral Encephalitis in the Russian Federation in 2015 and Prognosis for 2016

Analyzed has been epidemiological situation and measures, performed for prophylaxis of tick-borne viral encephalitis in the territory of Russia in 2015. It is shown that the number of humans bitten by ticks increased in the majority of the constituent entities of the country. But specific and nonspecific preventive operations in 2015 were realized to a lesser extent as compared to 2014. Along with the natural factors, it might be the reason for increase in human tick-borne viral encephalitis morbidity rates. In total, 2116 patients with tick-borne viral encephalitis and 24 lethal cases were registered in the country. On the basis of the data regarding tick-borne viral encephalitis (TBVE) incidence rate among the population across the Federal Districts of Russia over a period of 2009-2015, forecasted have been intensive indicators of the clinical forms’ manifestations for 2016. TBVE morbidity rate in RF will amount to (1.90 ± 0.21)о/оооо. With 95 % probability it will be retained within a range of 1.4-2.4о/оооо

Tick-Borne Viral Encephalitis Incidence in the Constituent Entities of the Russian Federation. Communication 2. Verification of Conformity of the Forecast Data and Seasonal Monitoring of Actual Morbidity Rates

Abstract. Despite the decreasing TBE incidence trend in Russia, the disease is considered an ongoing challenge for the state’s public health and economics. Objective of our study was to describe the algorithm of short-term incidence forecast of TBE, to evaluate the conformity of these data to factual incidence and the results of annual strategic seasonal monitoring which takes place across all the entities of Russia. In the paper, we described the procedure for providing short-term extrapolation of TBE incidence forecast onto the Russian territories, depending on the absence or presence of incidence change trends.Materials and methods. Utilized were the State statistics, “The data on infectious and parasitic diseases” (Form No 2), as well as the information on strategic monitoring for a period of 2007–2018. In order to determine the multi-year trend of epidemic process development, regression analysis was applied. If the trend was identified, predictions were made on its basis, if not – through calculating the long-term annual average. In all the cases, 95 % confidence interval for incidence trend deviation was considered. Comparative analysis of actual morbidity rates and predicted ones and the data on strategic monitoring was conducted by Student’s criterion.The commutations were performed using Excel software tools.Results and discussion. The study has demonstrated that the expected rates of TBE incidence are not statistically different from the actual incidence or the data from strategic monitoring. The underestimation of the epidemiological risk is found only in 4 out of 49 entities (8,2 %), and it is of note that in 3 of them it was less than 16 %. The data from operational monitoring are downward biased by reference to actual incidence, which is probably due to inclusion of TBE cases confirmed and/or manifested upon termination of incubation period after expiration of terms of weekly observations. The unified and simple approach that we proposed to TBE-incidence forecasting within the territory of Russia provides for correct information on expected epidemiological risk assessment and timely planning of required preventative measures

TICK-BORNE VIRUS ENCEPHALITIS IN THE RUSSIAN FEDERATION: FEATURES OF EPIDEMIC PROCESS IN STEADY MORBIDITY DECREASE PERIOD. EPIDEMIOLOGICAL CONDITION IN 2016 AND THE FORECAST FOR 2017

Epidemiological situation for tick-borne virus encephalitis (TBVE) in the Russian Federation is analyzed for the last twenty years (1997–2006 and 2007–2016). It is established that the last decade is characterized by decrease of the morbidity indicators in all constituent entities of the country attributed to the groups with high and middle intensity of the epidemic process, except for the Kirov region. Differences in the dynamics of morbidity decrease are revealed in groups of entities with various intensity of epidemic process in European and Asian parts of Russia. It is shown that at current period the epidemic process is the most intensive in the Asian part of nosoarea of TBVE. In short-term prospect the incidence rate is expected to be below average long-term indicators for 2007–2016 or slightly exceed them

Epidemiological Situation on Tick-Borne Viral Encephalitis in the Russian Federation in 2011–2021 and Short-Term Forecast of its Development

The aim of the work was to analyze the epidemiological situation on tick-borne viral encephalitis in the endemic territories of the Russian Federation in 2021 in comparison with the dynamics over 2011–2020 and its shortterm forecast for 2022. In Russia, 48 constituent entities belonging to seven federal districts are endemic for tick-borne viral encephalitis (TBVE). There is a statistically significant downward trend in the incidence of TBVE in the Siberian Federal District (which is characterized by the maximum incidence rate in the country), the Volga and Far Eastern Federal Districts. In the Ural Federal District (the second in terms of TBVE incidence), the decline in the incidence has stalled since 2021. The average long-term incidence of TBVE in the constituent entities of the Russian Federation varies from sporadic (Republic of Crimea)  up to 12.5 per 100 thousand of the population (0/0000) (Krasnoyarsk Territory). In 2021, TBVE cases were detected in 42 endemic regions and in one non-endemic region – Stavropol Territory. At the same time, 1015 cases of TBVE were in the country (0.69 0/0000). In all Federal Districts, the incidence of TBVE is below the long-term average values. Using the Quantum GIS program, the incidence of TBVE in 917 administrative territories of the country has been ranked and grouped according to the level of epidemiological risk. This made it possible to establish that 65 % of the territories form a zone of low epidemiological risk. High and very high epidemiological risk is observed in 13% of the analyzed districts. The structure of TBVE clinical manifestations in 2021 was dominated by febrile (59.7 %) and meningeal (24.3 %) forms. 14 lethal outcomes were reported. In 2021, 2 889 515 people were vaccinated (including 1 433 850 children), of which 14 fell ill. Specific immunoglobulin was used to prevent the overt development of infection in 100 704 individuals, which accounts for 22.6 % of the persons affected by tick bites (30.6 % among children). Acaricidic treatments were carried out on an operational area of 233 125 hectares of territories of socially significant objects. The scope of all TBVE prevention measures in 2021 increased as compared to 2020. In 2022, a decline in the incidence of TBVE in endemic Federal Districts and in the country on the whole is forecasted to (0,64±0,192) 0/0000

Epidemiological Situation on Tick-Borne Viral Encephalitis in the Russian Federation in 2022 and Forecast of its Development for 2023

The aim of this review is to predict the incidence of tick-borne viral encephalitis (TBVE) in the Russian Federation for 2023 based on analysis of the epidemiological situation on TBVE during 2012–2022. Over the decade, the highest incidence of TBVE was registered in the Siberian, Volga and Ural Federal Districts. In 2022, the Ural Federal District took the second place, the share of the North-Western one decreased by almost two times. Ranking of territories according to the rate of TBVE incidence at the level of constituent entities has made it possible to attribute 16 of them to the group of regions with a high epidemic risk, 14 – to medium epidemic risk, and 18 – to a low epidemic risk. In 2022, the incidence of TBVE in Russia increased by 1.9 times compared to 2021, and amounted to 1.34 0/0000. Despite the increase in the incidence of TBVE in 2022, a significant downward trend has been retained. The rate of infection of ticks removed from humans in 2022 was below the long-term average values. PCR and ELISA were applied for tests. Infection rate of ticks from environmental objects when studied by PCR was higher than the multi-year average values, and lower when studied by ELISA. In 2022, 3.5 million people were immunized against TBVE (vaccinated and revaccinated). Emergency immunoprophylaxis with immunoglobulin covered 24.5 % of the people affected by tick bites (children accounted for 34.3 %). The forecast for TBVE incidence in Russia in 2023 remains favorable. It is expected to be reduced to (0.83±0.298) 0/0000. However, there was not only an increase in the number of TBVE cases, but also the proportion of clinical manifestations of the disease, as well as lethal outcomes among those who suffered from tick bites in 2022. If this pattern holds, the incidence of TBVE in 2023 will be higher than predicted, especially in the constituent entities where the share of individuals with manifest forms among those who suffered from tick bites has increased greatly

Analysis of Crimean Hemorrhagic Fever Morbidity Rates in the Russian Federation in 2017 and Prognosis for 2018

This paper presents the analysis of Crimean hemorrhagic fever (CHF) morbidity rates in Russia in 2017; summarized are the results of epidemiological survey of the territory of the natural CHF focus in the south of the European part of Russia, discussed are the results of genetic typing of CCHF virus isolates. In 2017, the Russian Federation reported 78 cases of CHF. Decrease in the incidence of CHF occurred in the Volgograd Region, Stavropol Territory, Astrakhan Region, Republic of Kalmykia, and Rostov Region. For the first time since 1967, CHF case has been identified in Crimea Republic. It is expected that the level of epizootic activity of CHF natural focus in Russia in 2018 will be at least equal to 2017. In case of favorable for Ixodidae ticks weather and climate conditions of the winter 2017–2018, as well as untimely acaricidal treatments, the number of Ixodidae ticks may increase, which along with the high scale of CCHF virus infection in ticks, will contribute to the increase in CHF incidence

Analysis of Epidemiological Situation on Crimean Hemorrhagic Fever in the Russian Federation in 2013 and Prognosis for 2014

Crimean hemorrhagic fever remains one of the priority infections in the South of Russia. Within the past five years morbidity rates are retained consistently high in a number of regions; mortality rates are on average 4.4 %. In 2013 registered were 79 cases of CHF in the Southern and North-Caucasian Federal Districts. Therewith performed has been analysis of epidemiological situation on CHF in the Russian Federation for 2013, summarized have been the results of epizootiological surveillance of the natural CHF focus area in the South of European Russia, discussed are the results of genetic CCHF virus typing, identified in 2011-2013 in the South of Russia. Based on epizootiological surveillance data made has been the forecast of epidemiological situation development as regards CHF for 2014

Epidemiological Situation on Crimean-Congo Hemorrhagic Fever in the Russian Federation in 2019 and Forecast for 2020

The review presents an analysis of epidemic and epizootic situation of Crimean-Congo hemorrhagic fever in the Russian Federation in 2010–2019, summarizes the results of epizootiological monitoring of the CCHF natural focus territory in the south of European part of Russia. An unfavorable epidemiological situation regarding CCHF is maintained in the Russian Federation. In 2010–2019, 999 CCHF cases were registered in nine regions of Southern and North-Caucasian Federal Districts. In 2019, an increase in the CCHF incidence level in the entities of the SFD and NCFD was observed as compared to 2017–2018. The expansion of the territory with registered epidemic manifestations of CCHF continues. In 2010–2019, the number of imago and pre-imaginal phases of Hyalomma marginatum – the main vector of the CCHF virus in Russia, remained consistently high. High numbers of H. marginatum ticks and their CCHFV infection rates can contribute to the development of an unfavorable epidemiological situation in the south of the Russian Federation with a possible increase in the CCHF incidence in 2020

Crimean-Congo Hemorrhagic Fever: Epidemiological and Epizootiological Situation in the Russian Federation in 2022, Incidence Forecast for 2023

The review presents an analysis of the epidemiological and epizootiological situation on Crimean-Congo hemorrhagic fever (CCHF) in the Russian Federation in 2022. The incidence rate of CCHF registered in 2022 (59 cases) was 1.2 times higher as compared to 2021, however, below the long-term average annual values. The mortality rate was 10.2 %, which exceeds the indicators of long-term observations (in 2012–2021 – 3.2 %). Following epizootiological survey of stationary observation points, it was found that the number of Hyalomma marginatum imago in 2022, in general, corresponded to the average long-term indicators. CCHF virus isolates circulating in Russia in 2017–2022 belonged to the genetic lines “Europe-1” (V), “Europe-2” (VI), and “Europe-3” (VII). The ratio of CCHF virus genovariants in the population on the territory of the Russian Federation in 2017–2022 didn’t change. Based on the analysis of naturalclimatic factors, the forecast for the incidence of CCHF in the Russian Federation for 2023 has been made