Tick-borne Viral Encephalitis Research Articles

Assessment of the Current State of the Hissar High-Mountain Natural Plague Focus in the Republic of Tajikistan

The review is devoted to discussing the results of survey in the Hissar high-mountain natural plague focus on the territory of the Republic of Tajikistan in 2015–2023. Regular examination of the focus was carried out in 1970–1991. According to its results, the main carrier of the plague pathogen was the juniper vole, in the population of which a strain of the non-main subspecies central asiatica (0.PE4) of Hissar biovar (0.PE4h) was steadily circulating, the strain considered avirulent for humans. During that period, 853 strains were isolated in the focus, of which 799 (93.7%) were from the juniper vole and its fleas. Secondary carriers – the silver vole, the pygmy wood mouse, and the gray hamster – were rarely involved in epizootics. The red marmot, which has epidemiological significance due to its hunting by the local population, occupies a special position in the focus. Socio-political phenomena at the end of the 20th – early 21st century caused a long break in the work of the Tajik Plague Control Station. In 2008, the Station was transformed into the Republican Center for Combating Quarantine Diseases under the Ministry of Health and Social Protection of the Population of the Republic of Tajikistan. In 2015, studies were resumed, but carried out on a small scale. In 2021–2023, epizootiological monitoring in the Hissar focus was performed jointly with Russian specialists with the testing of field material samples for plague and other natural-focal infections. Currently, against the background of low numbers and population density of small mammals and their blood-sucking ectoparasites – potential carriers and vectors of zoonoses – the circulation of agents of plague, tularemia, pseudotuberculosis, tick-borne viral encephalitis, Ixodidae tick-borne borreliosis, human granulocytic anaplasmosis, human monocytic ehrlichiosis has not been registered. Markers (DNA) of causative agents of leptospirosis and intestinal yersiniosis have been identified. Joint Tajik-Russian cooperation on issues of ensuring the epidemiological well-being of the population of the Republic of Tajikistan must be continued.

Socio-Demographic and Eco-Epidemiological Parameters of Tick-Borne Infections Morbidity in Baikal Region

The aim of the work was to compare the main socio-demographic and eco-epidemiological parameters of tick-borne viral encephalitis, tick-borne borrelioses and tick-borne rickettsiosis.Materials and methods. The authors’ databases based on epidemiological investigation records were used for the study. All in all, 2974 cases (Irkutsk and the Irkutsk district) were analyzed during the periods of 1995–2022 for tick-borne viral encephalitis and tick-borne borrelioses, and 2001–2022 for tick-borne rickettsiosis.Results and discussion. The following parameters were assessed: the timing of epidemic season; the geography of prevalence; localization of tick bite on the human body; incubation time; gender and age structure of patients; social composition and exposure conditions. It was shown, that the parameters had their own features for each disease, and part of them are common to all Eurasian area of these infections. The shared characteristics include: the early epidemic season onset for tick-borne rickettsiosis; the shorter incubation time for tickborne rickettsiosis as compared to tick-borne viral encephalitis and tick-borne borrelioses; the increased frequency of tick-borne rickettsiosis vectors’ bites near the head and neck, and tick-borne borrelioses vectors – on the torso; large percentage of older persons among patients with tick-borne borrelioses and children under 14 years of age among patients with tick-borne rickettsiosis; prevalence of male population over female one as regards all surveyed pathogens. Low incidence of tick-borne diseases among professional contingent (the work associated with staying in natural foci of infection), an increased risk of tick-borne encephalitis and rickettsiosis among social group “unemployed”, and tick-borne borrelioses – among retirees, can be attributed to regional specificity.

Analysis of the Dynamics of Tick-Borne Encephalitis Incidence and the Number of People who Appealed to Medical Organizations about Tick Bites in the European North of Russia

In recent decades, a significant increase in the incidence of tick-borne viral encephalitis (TBVE) and the number of people attacked by ticks has been recorded in the European North of Russia.The aim of the study was to analyze the dynamics of the TBVE incidence and the number of people who appealed to medical organizations regarding tick bites in the European North of Russia.Materials and methods. We used the Form No. 2 “Information on infectious and parasitic diseases”, the results of operational seasonal monitoring of TBVE, presented by the Rospotrebnadzor Administrations of the respective territories for our study. Statistical data processing was performed using the Microsoft Excel program. Display of the results on the map was carried out in the geographic information system ESRI ArcMap.Results and discussion. Combined analysis of the data on the number of cases and TBVE incidence, the number of people who appealed to medical organizations about tick bites and the number of people seeking advice about tick bites per 100 thousand population for the Arkhangelsk Region, the Republics of Karelia and Komi and their municipal districts has been performed. The mean values and gradients of the number of cases, incidence (2010–2020), the number of people who appealed to medical organizations regarding tick bites, and the number of people seeking treatment for tick bites per 100 000 population (2002–2020) have been calculated; maps of average values and gradients constructed. The incidence and the number of cases remain at the high level, exceeding the national average, but have been declining in the last decade. The number of people who appealed to medical organizations and the appealability of the population about tick bites per 100 000 of the population remain at a consistently high level and show no downward trend. The incidence and appealability of the population due to tick bites per 100 thousand of the population is spreading in a northerly direction, covering new territories in the Arctic zone. The main driving force behind the observed epidemic situation in the European North of Russia is the natural processes of climate change.

ЭПИДЕМИОЛОГИЧЕСКАЯ ХАРАКТЕРИСТИКА И ПРОФИЛАКТИКА КЛЕЩЕВОГО ВИРУСНОГО ЭНЦЕФАЛИТА НА ПРИАРКТИЧЕСКИХ ТЕРРИТОРИЯХ ЕВРОПЕЙСКОГО СЕВЕРА

Current: In the subarctic territories of the European North, a combination of system-forming factors shaping an increased risk of morbidity has been accumulated: climatogeographic, ecological, ethnic, social. These factors can become triggers for the spread of natural focal infections, including tick-borne viral encephalitis. They require a special approach in the organization of healthcare. The aim of this study was to study of the features of the incidence of tick-borne viral encephalitis among the population of the subarctic territories for the period from 2012 to 2021 and evaluation of measures for the implementation of specific prevention. Materials and methods. The data taken from the federal forms of statistical observation (statistical reporting form No. 2 "Information on infectious and parasitic diseases", statistical reporting form No. 5 "Information on preventive vaccinations") were used in the territories of the Arkhangelsk, Murmansk regions, the Republic of Karelia, the Komi Republic. A comparative study was conducted between them, as well as with the average statistical values for the Russian Federation. The results of the study and their discussion. over the past decade, a decrease in the incidence of tick-borne viral encephalitis has been observed in the studied subarctic territories. At the same time, in the Arkhangelsk region, the Republics of Karelia and Komi, it remained higher in comparison with the average values for the Russian Federation. In the last 2 years, there has also been a decline in cases of infection, but this down-fall is much slower than in the country as a whole. Some positive trends are determined by the results of the implementation of preventive measures. Among them, the main importance was played by full-fledged vaccination of the population in endemic regions (the Arkhangelsk region, partly the Komi Republic and Karelia), thanks to which a sufficient pool of antibodies to the causative agent of tick-borne encephalitis is created in the body. It exceeded the all-Russian indicators in scale. In addition, in areas with a wide spread of vector ticks, powerful nonspecific prevention is carried out, aimed at the destruction of vectors or treatment with repellents.

Modern Means of Personal Protection of People from Bloodsucking Arthropods

The review focuses on the means of personal protection of people from blood-sucking arthropods, mainly from Ixodidae ticks. Individual (personal) protection of humans is an important component of nonspecific prevention of natural-focal vector-borne diseases. The paper considers statistical data describing the level of significance and relevance of the information about the infections transmitted by ticks, for instance, tick-borne viral encephalitis, tick-borne borreliosis etc. Presented are the characteristics of different groups of personal protection means: insectoacaricidal, repellent, and insectoacaricidal-repellent ones. Indicators of their effectiveness are assessed; their practical use, as well as the features of special protective clothing and the necessity of its application is described. The toxicity of protective clothing is reduced through a lining fabric, local inserts of fabric with insectoacaricidal impregnation and the use of underwear. Different interpretation of the term “repellent” in the domestic and foreign literature, and also two different approaches (“Eastern” and “Western”) to the design and manufacture of personal protection means for people against attacks of blood-sucking arthropods, including Ixodidae ticks, in Russia and Western Europe countries and the USA is discussed. The paper highlights the effect of different pyrethroid groups on the behavioral reactions of ticks. It is shown that in the Russian Federation the use of permethrin is prohibited for the treatment of protective clothing against blood-sucking arthropods, in particular against the taiga tick Ixodes persulcatus, which is the main vector of dangerous infections across the major part of the country (in the east of the European part, the Urals, Siberia and the Far East).

Клещевой вирусный энцефалит на территории Архангельской области в период пандемии COVID-19

Tick-borne viral encephalitis (TBE) is one of the common naturally occurring infections in Russia and epidemiologically significant for the North-Western Federal District, Arkhangelsk Region in particular. The purpose of this article was to assess the epidemiological situation for TBE in the Arkhangelsk Region in 2020–2021 (during the novel coronovirus (COVID-19) pandemic) compared to the 2016–2018 period. Materials and methods. We analysed data (according to the forms of the Federal Statistical Survey) on the TBE incidence rate among the population (including children), age and social structure, clinical forms, and immunization against TBE for the period of 2016–2021 in the endemic areas of the Arkhangelsk Region. Results. A higher TBE incidence was revealed for 2016–2019 compared to 2020–2021 both in Russia and in the Arkhangelsk Region. TBE primarily occurs in the south of the region, but over the years the number of cases in the Arctic areas, especially in the region’s northern towns, has been growing. The Arkhangelsk Region has seen a noticeable increase in the number of people, both adults and children, vaccinated against TBE, which contributes to a decrease in incidence. The study confirmed that the epidemiological situation for TBE still requires active prevention. The restrictions due to COVID-19 contributed to curbing the epidemic processes of infectious diseases, including naturally occurring diseases. At the same time, the scaling-down of preventive measures during the pandemic undoubtedly produced a negative effect on the TBE incidence rate.

Evaluation of the efficacy of permethrin- and cypermethrin-based textile against taiga tick, Ixodes persulcatus

A comparison of the efficacy of permethrin- and cypermethrin-based textile against taiga ticks (Ixodes persulcatus) was carried out in a tick-borne viral encephalitis hotspot in the Irkutsk Region (Russia) using model samples of impregnated textiles. We demonstrated that permethrin- and cypermethrin-treated model samples have similar protective parameters in terms of maximum height reached by the tick when climbing up the treated textile (20.9-38.7cm for cypermethrin, 27.6-39.3cm for permethrin, depending on concentration) and knockdown time (i.e., the time until a female tick falls off the treated textile; 3.52-4.31 min for cypermethrin, 5.02-8.25 min for permethrin, depending on concentration). In contrast, when evaluating the 'biting speed' index (which is the ratio of the average attaching time of ticks contacting untreated textiles and ticks contacting treated textiles), it has been shown that permethrin-treated textiles accelerate biting. So, using permethrin-treated protective clothing against the taiga tick could be risky because it increases the likelihood of being bitten and thus getting infected. In contrast, cypermethrin-treated textiles appear to block the ability of ticks to attack warm-blooded animals and humans - after contact with cypermethrin-treated textiles none of the ticks attached to a rabbit. So cypermethrin-based textiles could be an alternative to permethrin for tick-bite protection clothing production if there is no toxic effect on humans of textile materials based on it.

Clinical and Epidemiological Features of Actual Tick-Borne Infections under Conditions of Mass Vaccination against Tick-Borne Viral Encephalitis (by the Example of a Megapolis)

Relevance. The clinical aspects of tick­borne viral encephalitis (TBE) and Lyme borrelliosis (LB) as monoinfections are well known. At the same time, the issues of interaction of pathogens in tick­borne encephalitis – Lyme borrelliosis mixed infection (TBE – LB mixed infection), the effectiveness of specific prophylaxis, their effect on the incidence rate and clinical forms have not been sufficiently studied.Aims. The aim of this work was to study the clinical course of TBE and TBE ­ LB mixed infection in patients with specific prophylaxis of TBE, as well as in its absence.Materials & Methods. Medical history data from 454 patients patients with a confirmed diagnosis of TBE and TBE – LB mixed infection during 2010–2017 were analyzed.Results. The clinical course of the disease in TBE mono­- and mixed infection, as well as the connection of immunization with the clinical forms of the disease are reflected. The dynamics of the registration of clinical forms of TBE and TBE – LB mixed infection for 8 years was shown using regression models. Synchronization of the incidence of focal and meningeal forms in TBE and TBE – LB mixed infection with a statistically significant decrease in the frequency of their occurrence was noted. The incidence of febrile forms in TBE monoinfection, as well as in mixed infections, remained practically unchanged.Сonclusions. It was found that the incidence of severe focal and meningeal forms of the disease in patients with TBE – LB mixed infection was 1.5 times lower, and the proportion of patients with febrile form TBE was statistically significantly higher than in the group of patients with TBE monoinfection, which may indicate a more favorable during TBE ­ LB mixed infection, and overdiagnosis of febrile form TBE in TBE – LB mixed infection. The increase in the rate of vaccination against TBE of the population contributed to a decrease in the number of TBE и TBE – LB mixed infection cases due to severe clinical forms (focal and meningeal).

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.

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.

Tick Paralysis Case Series: An 11-Year Institutional Case Series.

The aims of the study were to identify and to describe cases of pediatric tick paralysis presenting to an emergency department in southern Louisiana during an 11-year period. We conducted a retrospective chart review of patients aged 0 to 18 years with a diagnostic code of toxic effect of venom, tick-borne viral encephalitis, Guillain-Barré syndrome, acute infective polyneuritis, or abnormality of gait from July 2005 to June 2016. Data were collected on visit month, patient age, race and sex, tick's attachment site, location of tick removal, symptoms and length of symptoms, initial diagnosis, time to appropriate diagnosis, and hospital length of stay. Nine patients aged 2 to 10 years presented with lower limb weakness and varying degrees of upper extremity ataxia or paralysis, areflexia, dysarthria, diplopia, or petechia. Five cases were accurately and rapidly diagnosed; 4 cases involved a delay in accurate diagnosis. Treatment of the misdiagnosed cases ranged from septic workup to neurologic workup, including magnetic resonance imaging. The tick was discovered by the patients' relative in 4 cases, by a primary care or emergency care physician at another facility in 3 cases, and by 1 of our emergency care physicians in 2 patients. The incidence of tick paralysis in southern Louisiana is unknown. However, our case series indicates that it is likely higher than expected. Although most cases in our facility were quickly diagnosed and treated through tick removal, delayed diagnosis results in unnecessary tests, procedures, and medical costs. All of our cases fully recovered after tick removal.

Time-Limited Venetoclax and Ibrutinib for Patients with Relapsed/Refractory Chronic Lymphocytic Leukemia (R/R CLL) Who Have Undetectable MRD - Primary Analysis from the Randomized Phase II Vision HO141 Trial

Time-Limited Venetoclax and Ibrutinib for Patients with Relapsed/Refractory Chronic Lymphocytic Leukemia (R/R CLL) Who Have Undetectable MRD - Primary Analysis from the Randomized Phase II Vision HO141 Trial

Identification and molecular analysis of ixodid ticks (Acari: Ixodidae) and their pathogens in Yakutia

The purpose of the research is to identify ixodid ticks and their pathogens in the left bank area of Central Yakutia. Materials and methods. The work was carried out in 2019–2020 in the left bank area of Central Yakutia. Nine ticks were collected in 2019, and 27 ticks in 2020. We studied forest shrub stations, steppe stations, meadow field stations, near-water stations and stations of settlements. To determine faunal and ecological characteristics of ectoparasites in the territory, we used standard collection methods. The tick species was determined using morphological keys by N. A. Filippova; the determination correctness was confirmed by the PCR method. The collected ticks were studied for causative agents of babesiosis and tick-borne viral encephalitis using PCR analysis. Results and discussion. One species of ixodid ticks, Ixodes persulcatus, inhabits the left bank area of Central Yakutia. Haemaphysalis concinna was not found in Yakutia. In 2008, a natural focus of blood protozoan disease of domestic reindeer appeared for the first time in Yakutia in its central zone. Recently, an increase in the number of I. persulcatus has been observed. Tick activity is recorded from the second decade of May to the second decade of August. The ground-squirrel Spermophilus parryii is the main host for the preimaginal stages. Pathogens were not detected when ticks were examined for causative agents of babesiosis and tick-borne viral encephalitis using PCR analysisd.

DYNAMIC CHANGES OF IN INCIDENCE OF IXODES TICK BITE CASES IN ADULT POPULATION OF VINNITSA REGION, UKRAINE

Not all ticks carry dangerous pathogens, but their bites can threaten humans with diseases such as Ixodes tick-borne borreliosis (Lyme disease), Miyamoto disease, tick-borne viral encephalitis and about 150 other nosological entities. The season of life activity of Ixodes ticks begins in March and usually lasts until November and has two pronounced seasonal peaks during the year: over April – May and August – September. The relevance of the investigation is determined by the lack of the information on the incidence of tick bite cases among the population in Ukraine, and there no well elaborated sets of measures in order to prevent this problem. The purpose of this study is to provide a detailed analysis of the incidence of Ixodes tick bite cases among the adult population in the Vinnytsia region and in the city of Vinnytsia, to compare the number of detected cases for the period from 2013 to 2018, and to identify the most reliable and available prevention methods. The research was conducted at the laboratory of the municipal non-profit enterprise "Vinnytsia City Hospital G1" (KNP "VMKL"); statistical data were provided by the State Regional Sanitary and Epidemiological Station. We compared the prevalence of the disease in different districts of the Vinnytsia region and its insidence for the period from 2013 to 2018. During this period, the number of detected cases of tick bites resulted in the occurrence of various dangerous diseases went up from 53 to 317 cases among the entire adult population of the Vinnytsia region. For all years except 2018, the highest incidence rate was consistently observed in the Mogilev-Podilsk district district, even exceeding the level in more densely populated and large areas. Over the period from 2013 to 2018, the number of detected cases of tick bites in the adult population that resulted in various dangerous diseases rapidly and significantly increased. This necessitates to elaborate the set of preventive measures and to educate the population of all ages. Much attention should be paid to promoting vaccination as the only reliable way and the development of sanitary and hygienic recommendations for residents of municipal and rural areas (in the spring and summer).

Effect of the natural and climatic factors on epidemiological situation related to natural focal infections

This article is dedicated to the analysis and generalization of the Russian and foreign research results on natural and climatic factors effect on the intensity of epidemic process manifestations and the natural focal infections pathogens vectors vital activity which are the most widespread in the Russian Federation. Over the past seven years tick-borne infections have been accounting for more than 50 per cent in the natural focal diseases general nosological structure. Among the diseases of this group Lyme borreliosis leads in prevalence and frequency of cases identification. Tick-borne viral encephalitis is still a serious danger for national health. Crimean-Congo hemorrhagic fever epidemiological situation remains unfavorable in the south of the European part of Russia. In addition to the annual patients identification, the demonstrable trend of shifting and expansion of the pathogen’s area in a northerly direction was established. It creates a risk for the spread of the Crimean-Congo hemorrhagic fever virus outside the southern regions of the country. High incidence of the dangerous vector-borne infection — West Nile fever — with the involvement of new subjects in the epidemic process and the emergence of local cases of infection in previously non-endemic territories is registered. Expansion of hemorrhagic fever with renal syndrome natural foci borders, which is the most widespread natural focal zoonosis of viral etiology in the Russian Federation and is the second by the frequency of patients identification after tick-borne infections, is noted. Research data for the dependence of the carriers pathogens number and the dynamics of the natural focal infections incidence on the values of climatic factors, confirmed using various methods of mathematical statistics (time-series analysis, autoregression integrated moving average, logistic regression, correlation analysis, one-way analysis of variance and other) were systematized. It was found that the temperature and humidity of the air and soil, the amount of precipitation, the height of the snow cover are the common abiotic factors for all of investigated infections. The values of these factors can be used for the subsequent epidemiological forecast. The further study of relationship between the incidence rate of the population, the number of arthropod vectors and small mammals with indicators of soil moisture and temperature at different depths, hydrothermal coefficient, normalized relative vegetation index, accumulated values of temperature and precipitation, as well as similar studies on other actual natural focal infections in the Russian Federation will be very promising.

Arbovirus infections incidence in the south of the European part of the Russian Federation

Purpose: analysis of the arbovirus infections incidence in the south of the European part of the Russian Federation in 2015–2019.Materials and methods. Data from statistical documentation (epidemiological examination of the infectious disease cases, reports on the arbovirus infections incidence) reported by Departments of Rospotrebnadzor to Scientific and Methodological Center for monitoring pathogens of infectious and parasitic diseases of 1–3 risk groups for subjects of the North Caucasian and Southern Federal Districts were analyzed. The obtained data were processed using Microsoft Excel 2010 program.Results. In the south of the European part of the Russian Federation Crimean-Congo hemorrhagic fever (CCHF), West Nile fever (WNF), tick-borne viral encephalitis and dengue fever cases are registered annually.An expansion of the territory with registered epidemic manifestations of CCHF and WNF was noted, reflecting an increase in the area of circulation of their pathogens. An expansion of CCHF and WNF epidemic season with the involvement into the epidemic process of people from all age groups including young children was observed. Significant increase in number of imported cases of dengue fever was documented. Markers of tick-borne viral encephalitis, Batai, Inko, Sindbis, and Tyaginya fevers were detected in residents of a number of territories. A high levels of population humoral immunity to West Nile, Batai, Inko, Sindbis Tyaginya, Ukuniemi, Bhanja, Dkhori viruses were identified in the Astrakhan region.Conclusion. The data obtained indicate the need for epidemiological surveillance both for arbovirus infections with a pronounced epidemiological and clinical manifestations, and for infections, the proportion of which in the structure of infectious pathology in southern Russia has not been sufficiently studied, but carrying a potential risk of spreading.

Commitment of Parents and Doctors of Irkutsk City to Vaccination against Tick-Borne Encephalitis

Today in Irkutsk region, we face a noticeable increase in the number of cases of ixodid tick sucking to urban residents. Ticks, found in the territory of Irkutsk city, were detected to have all currently known pathogens causing such serious diseases as tick-borne encephalitis, tick-borne borreliosis, monocytic ehrlichiosis, granulocytic anaplasmosis, rickettsiosis and tick-borne recurrent fever. These diseases may develop to severe forms, and lead to disability or even death. The aim of the study was to evaluate the opinion of parents and doctors on vaccination against tick-borne viral encephalitis in Irkutsk based on the data of an anonymous questionnaire survey. Material and methods. The descriptive retrospective epidemiological study was conducted between November 2018 and January 2019. It included 1620 parents and 193 doctors of various specialties in Irkutsk. Statistical processing of the material was carried out using Excel tables (Windows 2010) and the Statistica 6.0 program. Results and discussion. In general, the attitude towards vaccination looks positive – 98 % of the parents vaccinate their children. 11.3 % of parents vaccinate their children from tick-borne encephalitis, 23.3 % of doctors vaccinate themselves. Every fourth doctor vaccinates his child against this infection. Conclusion . Insufficient vaccination coverage against tick-borne encephalitis is noted both among the population and among doctors of Irkutsk. It is important to introduce health education for the population and to adopt new ways for improving the qualifications of doctors in immunization issues.

Evaluation and dynamics of risk of tick-borne viral encephalitis disease in some regions of Ural Federal District

The regions of the Ural Federal District (UFD) are highly endemic for tick-borne encephalitis (ТВE) territories. The dynamics of morbidity of ТВЕ in the population characterized by complex cyclic, depending on many external variables. Retrospective analysis of the long-term dynamics (2007–2019) of the incidence of ТВЕ in regions of the UFD, taking into account the number of tick affected people was presented. The chances of getting sick in tick affected peoples to quantify the effect of predictors on TBE incidence were calculated. Standard apparatus of the theory of generalized linear models – logit-regression was used. It was established that the regions of the UFD characterized by a similar dynamics in the odds ratio indicator, therefore, TBE incidence with alternating ups and downs with a trend towards a decrease in the chance of TBE getting sick in tick affected people from 2007 to 2019. On average, over 13 years, the chances of developing TBE are statistically significantly different in the studied regions of the UFD, which can be explained by the influence of many risk factors and their combinations on the TBE incidence.

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.

Analysis of the epidemic situation of tick-borne viral encephalitis in the Republic of Altai in 2000-2017

Introduction. The Republic of Altai is one of the regions of the Siberian Federal District endemic for tick-borne encephalitis with high altitude mountain belts with characteristic landscape and climatic conditions. The purpose of this study is to analyze the epidemiological situation of tick-borne encephalitis in the Republic of Altai from 2000 to 2017. Material and methods. In conducting a retrospective epidemiological study, data from sanitary-epidemiological and medical services for 2000-2017 were used. Statistical data processing was carried out with the software “Statistica 12.0”, the construction and analysis of cartograms - with the software ArcGIS. Results. The average long-term incidence rate of this infection in the period from 2000 to 2017 amounted to 21.7 ± 0.76 0/0000, which is 2.2 times higher than the similar indexby for the SFO (10.1 ± 0.23 0/0000). The number of persons affected by tick infestation in the period from 2000 to 2017 increased 3.5 times from 517.7 ± 15.95 0/0000 to 1810.5 ± 28.62 0/0000, respectively (p <0.001). Ranking on the level of the average long-term incidence allowed identifying three groups of the potential risk of infection of the population. Discussion. The factor analysis revealed the presence of an inverse correlation between the incidence of tick-borne encephalitis and the levels of seroprophylaxis (r = -0.93), acaricidal treatments (r = -0.95), vaccination (r = -0.10). The calculated levels of these factors were determined according to the results of the construction of spatial models of their mutual influences, capable of reducing the number of cases in the region to 6 per year. Conclusion. An analysis of the epidemic situation based on factor analysis and spatial modeling of the mutual influence of factors made it possible to determine the necessary volumes of preventive measures to reduce the incidence of the population to a given level. Such a calculation may be applicable in an endemic region to ensure the medical and economic effectiveness of preventive measures.