Scientific-Methodological Approach to the Epidemiological Analysis and Laboratory Diagnostics of the Diseases Caused by Marburg and Ebola Viruses

Analysis of the current epidemiological situation has revealed that epidemic manifestations of infectious diseases, caused by Marburg and Ebola viruses, have been undergoing significant changes over the recent years. Globalization of epidemic process seems obvious due to the scale of the outbreaks, extension of nosoarea, increase in the morbidity rate, short-cut of the intervals between epidemic outbreaks, and increase of the probability of infection export outside the foci of endemic territories. Normative documents regulating the process of diagnostic investigations aimed at detection of Marburg/ Ebola virus agents are missing. In this connection, put forward is the scientific-methodological approach to epidemiological analysis and laboratory diagnostics of the diseases caused by these viruses

Dynamics of the Epidemic Process of Tick-Borne Encephalitis in Irkutsk Region in 2001–2021

The aim of this work was to analyze the spatial and temporal features of the epidemic process dynamics of tick-borne encephalitis (TBE) in Irkutsk Region in 2001–2021.Materials and methods. The data of the Rospotrebnadzor Administration for the Irkutsk Region, the Reference Center of the Irkutsk Research Anti-Plague Institute, the materials of the state statistical reporting form No. 2 “Information on infectious and parasitic diseases”, and scientific publications were analyzed. The chronological and chorological features of the change in the incidence of TVE have been traced. In the latter case, the administrative-territorial formations (ATF) of the subject were differentiated by epidemiological risk groups over two ten-year periods: 2001–2010 and 2011–2020. At each time interval, the grouping of areas according to the level of TBE incidence was carried out using the calculation of 95% confidence interval. Time sequences of observations were analyzed using the construction of regression equations. Standard methods of variation statistics in the Microsoft Excel were deployed.Results and discussion. Over the course of the 21st century, the incidence of TBE in Irkutsk Region has been declining. Based on 2001–2010 data, there were no cases of TBE in six ATF, and endemic areas were divided into three groups: with low (15 districts), medium (6) and high (8) incidence of TBE. A separate assessment of morbidity rates was conducted in the administrative center of the entity, the city of Irkutsk. In 2011–2020, the structure of ATF with varying epidemiological risk of TBE underwent a change. Six non-endemic areas, groups of low (12 ATFs), medium (9), high (6) and very high (2) epidemiological risk were identified. The spatial arrangement of high epidemiological risk zones changed, and their area increased. Each ATF cluster with different TBE incidence in 2011–2020 is characterized by the number of TBE cases and the volume of measures to prevent the infection. It is concluded that preventive measures were insufficient in ATF groups of high and very high epidemiological risk

PECULIARITIES OF TERRITORIAL DISTRIBUTION OF TICK-BORNE ENCEPHALITIS MORBIDITY WITHIN IRKUTSK RESIDENTS

Irkutsk residents are infected, with, tick-borne encephalitis (TBE) mainly in Pribaykalie (Irkutsk region and Buryat Republic). TBE foci are rather various on this territory. Differences in some parameters of morbidity structure at the infection in different areas of this territory are reviewed, in this article

Morbidity Rate Forecasting for 2014 as Regards Tick-Borne Viral Encephalitis in the Territory of the Russian Federation Based on Multi-Factor Regression Models

Morbidity forecasting as regards tick-borne viral encephalitis has been carried out using three various methods. Demonstrated is the fact that variability consistency among the actual values accounting the numbers of seeking medical aid because of tick bites and estimated values within the current quasi-cycle is 31.4 %. Developed have been multi-factor regression models for medical aid encounters on the occasion of tick bites and for tick-borne viral encephalitis morbidity. Identified are the most significant factors which characterize specific prophylaxis, acaricide treatment, and abundance of infected ticks; estimated is the impact of the factors on the forecasting. Maximum level of interdependency has reached 78 %: in case with seroprevention it has come up to 64 %, vaccination - 11.5 %, acaricide treatments - 4 %, and abundance of infected ticks - 3%. It has been outlined that a 20 % extension of areas for acaricide treatments leads to a 5% decrement in medical aid encounters, while a 20% reduction - to an almost 7 % rise, respectively. Thus evaluation of the significance of the preventive and curative interventions is of a crucial importance while developing Territorial prevention programmes if undertaken along with consistent application of acaricide treatments

The Current State of Natural Foci of Tick-Borne Encephalitis near Irkutsk City

Among main factors that influence intensity of tick-borne encephalitis foci one can distinguish the numbers of core vector (here, taiga tick Ixodes persulcatus) and the percentage of infected ticks. This paper shows the results of five-year monitoring of the tick-borne encephalitis focus, which is situated near Irkutsk city. Detected are the variations in numbers and infestation of the core vector of tick-borne encephalitis, both spatial and temporal. Cause-effect connection between these factors and human TBE morbidity is not found. However, morbidity rates of the Irkutsk population, observed on the annual basis, bear evidence of high activity and intensity of the foci. In this regard, a number of preventive measures is put forward, but further observations concerning all the parameters that influence foci activity are required

SPECIFIC TRAITS OF TICK-BORNE ENCEPHALITIS IN ZABAYKALSKY KRAI

We conducted regionalization of Zabaykalsky Krai by the quantity of epidemic manifestations of tick-borne viral encephalitis over a period of 10years. The most adverse territories in the context of tick-borne viral encephalitis were determined. Maximum duration of seasonal incidence rate was 112 days -from the end of April to the mid-August. The categories of population included in infection contamination risk group were revealed. The researches promote forehanded development of the complex of preventive measures aimed at the decrease of tick- borne viral encephalitis incidence rate in Zabaykalsky Krai

Differentiation of Transbaikal Territory by Tick-Borne Viral Encephalitis Incidence

Objective of the study was to differentiate the Administrative Districts of theTransbaikalTerritory at the time of Tick-borne viral encephalitis (TBVE) incidence recession by epidemiological risk groups and to characterize them by volume of specific and nonspecific preventive measures.Materials and methods. Retrospective analysis of TBVE epidemiological situation is based on the statistical reporting data “Information on infectious and parasitic diseases” in 2009–2019 and other materials of the Rospotrebnadzor Administration in the Transbaikal Territory. The clustering of areas with various levels of epidemiological risk was conducted by calculation of 95 % confidential interval for long-term annual average of TBVE cases in municipal units of the Territory over a decade and assessment of appurtenance of the deviating values to the aggregate under study.Results and discussion. Twenty four out of 32 districts of the Transbaikal Territory are endemic for TBVE. These areas are divided into five groups: with very high epidemiological risk (2 districts), high (5), medium (8), and low (8) risk respectively, as well as the administrative center of the constituent entity which by the whole complex of indicators (disease manifestation, population density, factors of targeted TBVE decrease, social-and-living and economical conditions) cannot be considered together with the rest of municipalities. Each group of the districts was characterized by the number of cases and TBVE incidence rates, medical aid seeking by persons who suffered from tick bites, vaccination volumes, seroprevention, areas of acaricide treatments. Recommendations are presented for the essential complex and scope of measures to prevent TBVE in the groups of administrative districts that differ by the level of epidemiological risk

Classification of Municipalities in the Republic of Buryatia by the Level of Tick-Borne Viral Encephalitis Incidence

Tick-borne viral encephalitis (TBVE) is one of the most significant natural-focal infections in the Russian Federation.The aim of the study was to analyze the current epidemiological situation on TBVE in the Buryat Republic in 2010–2020 with a subsequent differentiation of municipalities by epidemiological risk groups in order to elaborate proposals for optimization of preventive measures.Materials and methods. A retrospective analysis of the epidemiological situation on TBVE in the Buryat Republic was carried out using forms of federal statistical surveillance No. 2 “Information on infectious and parasitic diseases” over 2010–2020 and the data from the Reference Center of the Irkutsk Research Anti-Plague Institute of Siberia and Far East of the Rospotrebnadzor on the epidemiological situation and preventive measures in the municipalities of the constituent entity. Statistical processing was performed applying conventional methods of variation statistics. Based on calculated 95 % parametric confidence interval for the data on variability of the long-term average TBVE incidence in the municipalities of the Republic of Buryatia over a 10-year period, the entities were differentiated by epidemiological risk groups. QGis 2.18.28 and a set of open geodata OpenStreetMap were used for mapping.Results and discussion. All municipalities have been classified into five groups by the level of epidemiological risk: with zero TBVE incidence – 2 districts, with a low level – 4, medium – 8, high – 5, very high – 2. In addition, the administrative center has been placed into a separate group. Each individual group of municipalities is characterized by the number of TBVE cases, the level of morbidity, the frequency of seeking medical aid because of tick bites, the scope of specific and non-specific prevention measures. Recommendations for optimizing the tactics of TBVE prevention in certain municipal districts have been provided

Algorithm classification of municipal unions of the russian federation region based on a confidential interval estimation of tick-borne encephalitis virus incidence (transbaikalian krai as an example)

The algorithm of classification of municipal unions (MU is based on definition of a confidential interval of average long-term tick-borne encephalitis virus (TBE) sickness rate, as a quantitative integrated indicator of an epidemiological situation at the territory. It is proved that a decade is a sufficient period to reveal the patters that can be transferred to general totality and facilitate realization of MU classification. Distribution by MU groups is a steady characteristic of TBE morbidity at MU territories by decades in 95 % a confidential interval

Epidemiological situation on Tick-Borne Rickettsiosis in the Siberian Federal District

Siberian tick-borne typhus (STBT) is a disease caused by Rickettsia sibirica, characterized by high indicators and degree of localization of manifestations in separate territories. Between 2009–2016, the total of 10190 STBT human cases was registered in the Siberian Federal District; it makes 80.4 % of the case numbers across the country. Objective of the study was retrospective estimation of dynamics of epidemic STBT manifestations in Siberian Federal District in 2009–2016 for forecasting epidemiological situation development and working out proposals for its stabilization. Materials and methods. Analysis of epidemic status of all the entities of the Siberian Federal District was performed on the basis of the State Statistical Reporting form No 2. Results and conclusions. Through calculation of the confidence interval for long-term annual average STBT values the entities were united in three groups which differ in the morbidity rate level. In territories with high intensity of epidemic process the tendency to further deterioration of epidemic status was observed (Altai and Tuva Republics, Altai Territory) which will negatively affect the incidence rate indicators across the country. To stabilize the situation with STBT manifestation, wider use of nonspecific preventive methods is required, as well as organization of etiotropic antibiotic therapy for persons who had been exposed to tick bites, on the basis of introduction of the test-systems for rickettsia detection at the emergency aid stations. In Altai and Tuva Republics, Altai Territory it is necessary to analyze the tactics of acaricide measures (sites, periods, frequency rate of treatments, acaricide dosages) taking into account the leading role of Dermacentor and Haemaphysalis genera representatives in rickettsia transmission