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The review features the situation on Crimean-Congo hemorrhagic fever (CCHF) in the world and the analysis of the epidemiological and epizootiological situation in the Russian Federation in 2023. The number of CCHF cases (26) in Russia was 2.3 times less than in 2022, and 71.6 % lower than the long-term average (in 2013–2022 – an average of 88.8 cases per year, mortality (8 %) is 2.4 times higher than the long-term average (3.3 %). The epidemically significant indicator of the abundance of the main vector of the CCHF virus, ticks Hyalomma marginatum, was 5 times higher than the threshold value (abundance index for cattle – 15.5) at long-term observation points in April. For the first time, one case of CCHF disease was registered in a new epidemically active territory – in the Botlikh and Novolaksky districts of the Republic of Dagestan. For the first time in the Zaporozhye Region, RNA of the CCHF virus was detected in ticks H. marginatum and Rhipicephalus rossicus. Markers of CCHF virus were found in 0.67–18.27 % of samples, CCHF virus variants of the genetic line Europe 1 were circulating on the territory of Russia in 2023. According to the forecast of the epidemic situation for 2024, CCHF morbidity is likely to increase in the south of the European part of Russia. The recommendations for undertaking preventive measures have been provided.

The aim of the study was to assess the current epidemiological situation on Ixodidae tick-borne borreliosis (ITBB) (2017–2022) on the Black Sea coast of the Krasnodar Territory, to study the species composition of Borrelia.Materials and methods. Ixodidae ticks, Ixodes ricinus, Haemaphysalis concinna, H. inermis, Rhipicephalus sanguineus, were examined for infection with tick-borne borreliosis pathogens, followed by DNA sequencing of isolates. Species identification of Borrelia was carried out based on analysis of the nucleotide sequence of the 16S rRNA gene fragment using BLAST algorithm. Additionally, the OspC genotype was determined for isolates of pathogenic genovariants through comparing the obtained sequences with reference ones in the MEGA 5 program. The data were processed applying the cartographic method using the QGIS 2.18 software.Results and discussion. Between 2017 and 2022, 101 cases were registered on the Black Sea coast of the Krasnodar Territory, which accounted for 1.6 % of all ITBB cases in the Krasnodar Territory. The number of complaints with tick bites in Sochi was up to 191.4 per 100 thousand population. During the study, the predominant Borrelia geno-species on the territory of the Black Sea coast of the Krasnodar Territory was determined using sequencing – Borrelia lusitaniae (78.1 %). The circulation of geno-species B. garinii (6.8 %), B. valasiana (5.7 %), B. afzelii (3.6 %), B. miyamotoi (2.6 %), B. tanukii, B. bissettii (1.6 % each) was also observed. For Borrelia pathogenic species, appurtenance to OspC geno-groups was ascertained: four isolates were assigned to invasive OspC geno-groups, of which three B. afzelii isolates were genogroup A8, one B. garinii isolate was G7. High rate of infection of ticks with Borrelia was recorded in the surveyed area (up to 94.5 %). Borrelia of pathogenic species account for only 10.4 % of the total number of isolates studied. Mostly, genovariants that rarely cause diseases in humans (B. lusitaniae, B. valasiana, B. bissettii) and non-pathogenic Borrelia (B. tanukii) were found, which indicates a low risk of infection with ITBB pathogens.

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.

Introduction. With the epidemiological situation for Crimean-Congo hemorrhagic fever (CCHF) remaining tense in many countries worldwide, special attention should be focused on development and improvement of risk-based epidemiological prediction methods.The aim of the study was to build a prediction model for CCHF incidence dynamics (based on the Stavropol Territory) using satellite monitoring (remote sensing) data.Materials and methods. We analyzed the climate data obtained from the Space Research Institute of the Russian Academy of Sciences as well as the data of public statistics reports on CCHF incidence from 2005 to 2021. The prediction model incorporated the Bayes theorem and Wald sequential analysis. The information content of the factors was assessed using the Kullback method.Results. Predictions for each of 26 districts were made stepwise (compared to threshold levels) to predict whether there will be at least one case of CCHF, whether the relative incidence per 100,000 population will exceed the median level (0.9 cases) or the average rate (3.5 cases) or the third quartile rate (4.7 cases). The highest values of information coefficients were obtained for soil temperature and moisture content (at depths of 10 and 40 cm), normalized relative vegetation index, relative humidity, maximum and average air temperature, relative air humidity. During the testing of the model in 2021, false-negative (erroneous) prediction was made for 2 districts.Discussion. The model proved to be most efficient in prediction of occurrence or absence of cases. More accurate quantitative prediction may be difficult due to subjective factors (including misdiagnosing CCHF cases without hemorrhagic manifestations and administering treatment for other conditions with similar symptoms).Conclusion. The tests of the model demonstrate its potential. The practical application of the prediction will make healthcare workers more alert when screening and detecting CCHF cases.

The review presents an analysis of the epidemiological and epizootiological situation on Crimean-Congo hemorrhagic fever (CCHF) in the Russian Federation in 2021. 49 cases of CCHF were detected in 2021, which is 1.53 times higher than in 2020. The mortality rate was 6.1 %. Sporadic cases of CCHF were registered in the Stavropol Territory, Rostov, Volgograd Regions, the Republics of Dagestan and Kalmykia. The incidence rates of CCHF were below the long-term average annual values in the majority of the constituent entities. Epizootiological survey of stationary observation points has revealed that the number of Hyalomma marginatum imago corresponded to the average long-term indicators in 2021, the peak of H. marginatum activity was noted in the II–III decades of May. The proportion of Ixodidae tick pools positive for Crimean-Congo hemorrhagic fever (CCHF) virus markers exceeded the long-term average indexes in a number of regions. On the territory of the natural focus of CCHF, the circulation of the CCHF virus of the genetic lineages “Europe-1” and “Europe-3” was detected in 2021. Based on the analysis of the epidemiological data of the previous year and natural and climatic factors affecting the abundance and vital activity of H. marginatum ticks, risk-based quantitative forecast for the incidence of CCHF in the Stavropol Territory for 2022 has been compiled.

The aim of this study was to investigate the current state of vertebrates populations and to determine their role in maintaining natural foci of zoonoses in the Stavropol Territory in 2015–2019. Material and methods. Organ suspensions and blood samples from small mammals and birds were studied using certified diagnostic test-systems for the markers of Crimean hemorrhagic fever, West Nile fever, hemorrhagic fever with renal syndrome, tularemia, and leptospirosis pathogens. The data were statistically processed using Wilson’s method. Results and discussion. Identified have been the main reservoirs of natural-focal infections in the Stavropol Territory at the present stage: birds – for the West Nile fever virus, mammals and birds inhabiting the areas of semi-desert landscape-geographical zone – for Crimean hemorrhagic fever agent. The main natural reservoir of orthohantaviruses in the Stavropol Territory is the common vole Microtus arvalis, which lives in all landscape-geographical zones. The circulation of tularemia and leptospirosis pathogens has been established throughout the whole territory of the region, the small wood mouse Sylvaemus uralensis is of the greatest epizootic significance. Findings indicate the need for further epizootiologic monitoring of Stavropol Territory in order to identify the biocenotic patterns of the pathogens’ existence and the reasons that determine the dynamics of the epizootic process and epidemic manifestations of natural foci. It is advisable to determine the sites of long-term monitoring over the number of carriers and vectors of natural-focal infections and strengthen the epizootiological control over the territory, especially during periods of seasonal activity in carriers and vectors of 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.

The review presents an analysis of the epidemiological and epizootiological situation on Crimean hemorrhagic fever in the Russian Federation in 2020. During the stated period, 32 CHF cases were registered, which is the minimum indicator since the activation of the natural focus of CHF in 1999. The mortality rate was 3.1 %. The incidence was recorded in the Rostov, Astrakhan Regions, Stavropol Territory, the Republics of Dagestan and Kalmykia. A significant decrease in the incidence of CHF was noted in all entities of the Southern Federal District and the North-Caucasian Federal District. An imported from the Republic of Crimea case of CHF was detected in Moscow. The seasonality of morbidity, occupational, and age composition of CHF patients, modes of transmission, features of the clinical course of the disease in 2020 corresponded to the data of long-term observations. Epizootiological monitoring of the territory of the CHF natural focus showed that the abundance of Hyalomma marginatum adults and the percentage of Ixodidae tick pools positive for the presence of CCHF virus markers corresponded to the average long-term indicators at stationary observation points in 2020 , which indicates the persisting epizootiological disadvantage of the territory of the natural CHF focus in the Russian Federation. The persisting high numbers and infection rate of H. marginatum ticks can contribute to the development of an unfavorable epidemiological situation in the south of the country with a possible increase in the incidence of CHF in the Russian Federation in 2021.

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.

Objective of the study was to determine the modern epidemiological peculiarities of Crimean-Congo hemorrhagic fever in the south of the Russian Federation.Materials and methods. Data of statistical documentation (epidemiological survey of the infectious disease focus, annual summary reports dated 2010–2019) and epizootiologic monitoring data submitted by the Rospotrebnadzor Administrations and the Centers of Hygiene and Epidemiology in the constituent entities of the Southern and the North Caucasian Federal Districts were used. Descriptive, genetic, analytical methods and retrospective epidemiological analysis were applied.Results and discussion. The СCHF natural focus in the European south of Russia has an area of 815 thousand square kilometers and it is characterized by persistence, expansion of the territory, and circulation of CCHF virus European genotypes. CCHF virus genetic variants form the local overlapping populations. Over the period of 2010–2019 997 CCHF cases were registered. Moderate forms of the disease clinically prevailed (74.2 per cent). Hemorrhagic symptoms were noted in 29.3 % of patients. The lethal outcome of the disease was registered in 31 CCHF patients (3 %). Two cases of nosocomial infection were identified, nine health workers were infected by CCHF pathogen. The expansion of epizootically active territory of the CCHF natural focus is associated with the expansion of the Hyalomma marginatum ticks area northward due to the aridization of the steppes, in part because of global climate change. The stability of the CCHF virus population was noted. The epidemic core of the CCHF natural focus remains on the adjacent territory of the Rostov Region, Stavropol Territory and the Republic of Kalmykia. The higher efficiency of CCHF prevention measures on the territory of the core is stemming from the targetness and intensity of measures, contributing to the early seeking of medical care by patients, their early hospitalization which in its turn influenced the development of clinical manifestations and outcome of the disease, and also made it possible to minimize the CCHF nosocomial infections number, including those among the medical personnel.

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.

Aim. Investigation of modern epizootic and epidemic situation on West Nile fever (WNF) in the south of the European part of the Russian Federation. Materials and methods. Data from statistical documentation (epidemiological survey of the infectious disease focus, annual summary reports over the period of 2009–2018) and epizootic monitoring data presented by the Rospotrebnadzor Administrations and the Centers of Hygiene and Epidemiology in the constituent entities of the Southern and the North Caucasian Federal Districts were used. Descriptive, analytical methods and retrospective epidemiological analysis were applied. Results and discusson. The activity of natural WNF focus in the south of the European part of the Russian Federation was confirmed by the results of the annual epizootiological monitoring and the annual epidemic manifestations of the disease. 74.15 per cent of the cases and all major WNF outbreaks in the country between 2009 and 2018 were noted in the territory of the southern region. Most of the patients (97.8 per cent) are registered in the Volgograd, Astrakhan and Rostov Regions. In other southern entities sporadic incidence (this represents 2.2 per cent of all WNF cases in the south of the Russian Federation) was noted. Less serious clinical forms of the disease without the damage of central nervous system were observed in most of WNF patients. Fatal outcomes were registered in 7 WNF patients (this represents 0.58 per cent of all cases) over the past 10 years. The significant expanding of the West Nile virus geographic area and activation of the natural foci of this infection in the south of the Russian Federation in 2009- 2018 has been established. The epizootic and epidemic WNF center is located in the Volgograd, Astrakhan and Rostov Regions. It was confirmed by persistent epizootic and epidemic instability in this territory. The modern epidemic WNF feature in the south of the European part of the Russian Federation during the 10-year survey period is the relatively low mortality (0.58 per cent).

Objective of the study was to determine the modem epizootic and epidemic peculiarities of hemorrhagic fever with renal syndrome in the south of the European part of Russia. Materials and methods. Data of statistical documentation (epidemiological survey of the infectious disease focus, annual summary reports dated 2009-2018) and epizootic monitoring data submitted by the Rospotrebnadzor Administrations and the Centers of Hygiene and Epidemiology in the constituent entities of the Southern and the North Caucasian Federal Districts were used. Descriptive, analytical methods and retrospective epidemiological analysis were applied. Results and discussion. The circulation of hantavirus in the Volgograd and Astrakhan Regions, Stavropol and Krasnodar Territories, Republics of Adygeya, Kalmykia and Crimea was confirmed. However, two geographically and genetically isolated groups of hantaviruses circulating in the Volgograd Region and in the mountain-foothill zone of the Krasnodar Territory and the Republic of Adygeya were the most epidemiologically significant. Over the period of 2009-2018, 152 HFRS cases with annual fluctuations from 4 to 25 cases were registered. Almost all patients lived in the Volgograd Region (44 cases), where the incidence is caused by the HFRS-Puumala virus, or in the Krasnodar Territory (98 cases), where the HFRS Hantavirus Dobrava-Ap circulates. In HFRS patients with the HFRS-Dobrava-Ap virus severe clinical forms were noted at twice the rate, a fatal outcome in one patient with HFRS-Puumala was recorded. The correct preliminary diagnosis was made for 56.3 per cent of patients in the Volgograd Region and only for 31.7 per cent of patients in the Krasnodar Territory and in the Republic of Adygeya. There are different types of natural HFRS foci in the European south of Russia, they vary by the type of hosts and hantaviruses circulating in them - Puumala, Dobrava, Tula, and Dobrava-Ap. Natural foci where of HFRS-PUU and HFRS-DOB-Ap viruses circulate have high epidemic potential. Severe forms of the HFRS are more often observed in patients with the HFRS-DOB-Ap virus.

Aim. To determine the boundaries of the Crimean-Congo haemorrhagic fever (CCHF) natural focus in the Russian Federation at the current stage, to clarify the range of the main reservoirs and vectors of CCHF pathogen, to assess the epidemiological capacity of the natural focus. Materials and methods. The materials of epidemiological and epizootological monitoring of the CCHF natural focus, methods of epidemiological and epizootological analysis, molecular-genetic and cartographic methods were used in the work. The findings have been treated using by software package Microsoft Office Excel 2010. Results. The unified integrity of the CCHF semi-desert-steppe natural focus, which occupies vast territory of the southern part of the Russian Federation of 831 thousand square kilometres, is science-based. Expanding the geographic area of the CCHF agent with the involvement new administrative district can be seen. The trend of shifting of the CCHF natural focus borders in a northerly direction has been established. An increasing of epidemiological capacity of the CCHF natural focus has been noted. Hyalomma marginatum ticks are the main reservoirs and vectors of CCHF virus. The genotype «Europe-1» is predominant genotype in the natural focus. Conclusion. It is necessary to improve the tactics of CCHF epidemiological surveillance using modern science-based approaches. For example, automated forecasting-modeling system, using results of multifactorial risk analysis, which have an impact on the intensity of CCHF epidemic appearances, allows to quantitative forecast epidemiological situation on this infection in the aggregate and for certain subjects of the south of the Russian Federation.

Aim. The analysis of epidemiological situation on natural focal infections in the south of the European part of the Russian Federation in 2017. Materials and methods. Data of statistical documentation of Departments of Rospotrebnadzor, Centers of Hygiene and Epidemiology in subjects of the Russian Federation, Plague Control Research Institutions and Anti-Plague stations from 8 subjects of the Southern and 7 subjects of the North-Caucasian Federal Districts were used. The findings have been treated using by Microsoft Excel 2010 program. Results. On the territory of the south of the European part of the Russian Federation 962 cases of natural focal infectious diseases (of which 89 per cent were bacterial etiology and 11 per cent were viral etiology) were identified in 2017. Compared with 2016 the rate of bacterial natural focal infections increased by 2,3 per cent, the rate of viral natural focal infections decreased by 50,7 per cent. The number of natural focal infections patients decreased by 8 per cent compared to the previous year. The most of epidemiological complications were observed on the «tick-borne» infections, the rate of which in the general structure of the reported natural focal infections cases amounted to 78,6 per cent (756 patients). Also 6 dengue fever cases were registered, but all of the patients might have acquired the disease after travelling to other areas. Conclusion. The analysis of natural focal infections morbidity in the south of the European part of the Russian Federation in 2017 demonstrates the retention of activity of the natural foci of bacterial and viral infections, therefore questions of prevention of natural focal infectious diseases and constant monitoring of their natural foci in subjects of the Southern and North-Caucasian Federal Districts had the particular relevance.

Objective – analysis of epizootiological manifestations of natural focal infections in the territory of the south of the European part of the Russian Federation in 2017.Materials and methods. Statistical documentation data from the Rospotrebnadzor Administrations, Centers of Hygiene and Epidemiology in the constituent entities of the Russian Federation, and Plague Control Research Institutes and Stations were used. The information was processed using Microsoft Excel 2010 software.Results and discussion. Epizootiological survey for 19 nosological forms of natural focal infections in the territory of the south of the European part of the Russian Federation was conducted. The total of 70155 samples of field material was tested; markers of 14 pathogens of natural focal infections were identified. The circulation of Crimean-Congo hemorrhagic fever virus was revealed in 11 constituent entities, tularemia and Lyme borreliosis pathogens – in 8 entities, West Nile virus – in 7. Markers of leptospirosis, Q fever, human granulocytic anaplasmosis and human monocytic ehrlichiosis pathogens were detected in 6 constituent entities, markers of the agent of hemorrhagic fever with renal syndrome – in 5 entities; markers of intestinal yersiniosis pathogen – in 3 constituent entities of the Russian Federation, pathogens of tick spotted fevers group, tick-borne viral encephalitis and pseudotuberculosis – in 2. The circulation of the virus Sindbis was identified in the Rostov Region.

Subject of study. Examining an impact of the contemporary climatic changes on the natural CCHF focus as well as CCHF incidence in the South of the European part of the Russian Federation. Materials and methods. Annual Epidemiological Report on CCHF Incidence provided by Departments of the Russian Federal Service for Surveillance on Consumer Rights Protection and Human Wellbeing in the subjects of the Southern and the North-Caucasian Federal Districts, CCHF Epizootologic Monitoring Report on the territory of the Volgograd Region, Rostov Region and Stavropol Region were used in the study. Hydrometeorological data were obtained from the database of the All-Russian Research Institute of Hydrometeorological Information — World Data Center, weather station archives as well as The 2011—2016 National Report on the State of Environment in the Stavropol Region. Results. For the first time, climatic factors affecting each phase of the life cycle of ixodid tick Hyalomma marginatum which is the main CCHF virus vector in the South of the European part of the Russian Federation were identified. A direct correlation between seasonal air temperature fluctuations determining ixodid tick count and CCHF incidence was demonstrated. It was found that the average air temperature and accumulated precipitation collectively affect H. marginatum population (e.g., in Stavropol Region). Peak CCHF incidence was demonstrated to correlate with temperature conditions favorable to developing ixodid ticks. In contrast, air temperature fluctuations were noted to negatively impact in the years preceding decreased CCHF incidence. A relation between CCHF incidence and degree of wetting during preceding spring-and-summer as well as autumn seasons affecting vital activity, metamorphosis in preimaginal stages and count of the next-generation H. marginatum was revealed. Moreover, CCHF virus tended to expand geographic range northwards due to an effects of climatic changes. Virus-carrying Ixodidae found on the territory of the administrative districts of the Volgograd Region adjacent to the Volga Federal District evidence about a risk of CCHF virus spreading outside the Southern Regions of the Russian Federation.

The review presents the analysis of epidemic and epizootic situation on Crimean hemorrhagic fever (CHF)in the Russian Federation in 2009–2018. Over the past decade, 980 CHF cases have been registered in Russia (2,8 %lethal). In 2009–2018, there was a significant expansion of the epidemiologically active area of the natural CHF focus.Epizootiological monitoring of the territory of natural CHF focus showed that in 2009–2018 the number of imago andpreimaginal phases of Hyalomma marginatum – the main vector of the CCHF virus in Russia, remained consistently high.The average long-term rate of Ixodidae ticks infestation by the CCHF virus in 2013–2017 was 3,3 %. In 2009–2018 in the south of the European part of Russia CCHF virus variants belonging to the genetic lines Europe-1 (V), Europe-3 (VII) and Africa-3 (III) were detected. There were no significant changes in the ratio of circulating genetic variants of the virus in the regions of the Russian Federation, which confirms the relative stability of the CCHF virus population. In 2018, CHF morbidity rate in the Russian Federation retained downward trend, however, in some regions of South Federal District the number of CHF cases increased. One of the reasons for CHF morbidity rate decrement in the Russian Federation in 2018 was the well-timed acaricidal treatments of cattle and natural biotopes in most of CHF endemic regions.

Objective. The analysis of epidemiological situation on Crimean hemorrhagic fever (CHF) in the Russian Federation at the current stage, identification of ways to improve the epidemiological surveillance and prophylaxis of the disease. Materials and methods. Data from statistical documentation and results of annual epizootiological monitoring of the CHF natural focus provided by the Administrations of the Rospotrebnadzor, Centers of Hygiene and Epidemiology in entities of the Southern and the North-Caucasian Federal Districts, Reference Centre for CHF monitoring, Research Anti-Plague Institutions and Plague Control stations were used for work. Results and conclusions. The CHF epidemio­logical situation remains unstable, the cases of the disease (including fatal) are registered every year. High activity of the CHF natural focus persists. The northward expansion of CHF natural focus boundaries is observed. The main causes of the unfavorable CHF epidemiological situation are associated with increase in the numbers and period of activity of ticks Hyalomma marginatum due to favorable climatic conditions. The list of priority measures to stabilize the CHF epidemiological situation developed by the Rospotrebnadzor has resulted in decrease in CHF cases by 51.9 % in 2017 compared to 2016 across all the territory of the south of the Russian Federation. The CHF morbidity in 2018 was 1.5 times lower than the average multi-year values (72 CHF patients). The number of CHF cases in comparison to 2017 has decreased by 1.3 times in the Stavropol Territory and by 1.4 times in the Rostov Region. The CHF morbidity has increased in the Astrakhan Region (by 3 times) and Volgograd Region (by 2.3 times). Nosocomial CCHF virus infections cases associated with non-compliance to anti-epidemic regime in hospitals while providing treatment of CHF patients were registered in 2011 (in the Rostov Region) and in 2016 (in the Stavropol Territory). This highlights the need to improve the training of health-care staff for admission of patients with this particularly dangerous infection.

Aim.The analysis of causes of deterioration epidemiological situation on Crimean-Congo haemorrhagic fever (CCHF) in the Russian Federation in 2016. Materials and methods. Data of statistical documentation of Departments of Rospotrebnadzor, Centers of Hygiene and Epidemiology in subjects of the Russian Federation, Plague Control Research Institutions and Anti-Plague stations from 8 subjects of the Southern and 7 subjects of the North-Caucasian Federal Districts were used. The findings have been treated using by Excel program. Results. In 2016, epidemiological manifestations of CCHF are identified on the territory of 6 subjects of the south of Russia. An increase in the incidence of CC H F occurred in the Stavropol Territory, the Republic of Kalmykia, Astrakhan and Volgograd Regions. The main cause of the deterioration epidemiological situation on CCHF was increasing of the number and the period of activity of ticks marginatum, in the epidemic season as a result of favorable climatic conditions; incorrect dates of the realization and inadequacy of the acaricide treatments livestock and natural biotopes. Conclusion. For the improvement epidemiological situation on CCHF timely realization of the acaricide treatments in the early spring (March-April) livestock and natural biotopes using effective insecticides and with its further entomological control it is necessary.

Aim. Analyze epizootologic manifestations of natural-focal infections (NFI) in the south of Russia in 2015. Materials and methods. Reports provided by administrations of Federal Service of Surveillance for Protection of Consumers Rights and Human Welfare, Centers of Hygiene and Epidemiology, Research Institutes for Plague Control and Station for Plague Control were used. Data processing was carried out using Excel program. Results. A total of 37 738 samples of field material were studied, most of those - for tularemia (8268), Crimea hemorrhagic fever (6894) and West Nile fever (4875). Causative agents of 15 nosologic forms of NFI were detected during epizootologic examination of the territory of south of Russia, predominating amount of positive samples was obtained during study of material for tick-borne borreliosis (612), Crimea hemorrhagic fever (279) and tularemia (237). Conclusion. Analysis of epizootologic situation on natural-focal infections in the south of Russia gives evidence on the increase of activity of natural foci of bacterial (tularemia, tick-borne borreliosis), rickettsia (tick-borne spotted fevers) and viral infections (Crimea hemorrhagic fever, West Nile fever, tick-borne viral encephalitis), and thus problems of prophylaxis of natural-focal infectious diseases and constant monitoring of natural foci in subjects of Southern, North-Caucasian and Crimea federal districts are of particular importance.

Objective of the study is to analyze epidemiological and epizootiological manifestations of natural-focal infections in the territory of the North-Caucasian Federal District (NCFD) in 2015. Materials and methods. Utilized were the reports of the Rospotrebnadzor Administrations, “Centers of Hygiene and Epidemiology” in the NCFD entities, Stavropol Research Anti-Plague Institute, Dagestan and Kabardino-Balkaria Plague Control Stations. Data processing was conducted using Excel Microsoft ware. Results and conclusions. Identified have been 8 nosological forms of natural-focal infections, including infections of bacterial etiology – 6 (75 %), and viral etiology – 2 (25 %). The majority of patients (164) are identified in the Stavropol Region: 67 (intestinal yersiniosis), 43 (Crimean–Congo hemorrhagic fever), 40 (Lyme borreliosis), 9 (leptospirosis), 2 (pseudotuberculosis), 1 (rabies), 1 (human granulocytic anaplasmosis) and 1 (human monocytic ehrlichiosis). The patients with 2 nosological forms of natural focal infections are identified in the Republic of Dagestan: 2 – Crimean–Congo hemorrhagic fever and one patient – tularemia. Also 2 nosological forms of natural focal infections are revealed in the Republic of Karachay-Cherkessia: one case of leptospirosis and one case of Crimean–Congo hemorrhagic fever (imported from the Stavropol region). 8502 field samples have been tested for the presence of markers of 12 nosological forms of natural-focal infections. Positive results for 10 of them have been obtained. The most comprehensive epizootiological monitoring has been carried out in the Stavropol Territory (10 nosological forms), whereat circulation of 8 pathogenic agents is registered.

Aim. Analysis of results of epidemiologic monitoring of especially dangerous, natural-foci and other infectious diseases, as well as epizootologic activity of natural foci of infection on the territory of city-resort Sochi. Materials and methods. Laboratory studies of 820 samples by PCR, immune- and bacteriologic methods were carried out, among those 344 - clinical material, 12 - water from open bodies and 321 - field material. Molecular-genetic identification of 143 strains of Vibrio cholerae, isolated from open water bodies of city-resort Sochi, was carried out. Results. Circulation of causative agents of Q fever, tularemia and hemorrhagic fever with renal syndrome of Dobrava-Adler genotypes was established, as well as rickettsia of tick spotted fever group. Predomination of rotaviruses (70.9%) was detected during study of samples of clinical material in etiologic structure of sporadically emerging acute intestine infections. Relatively high temperature values of river water during summer months (from 18 to 30°C), exit of sulfide mineral waters into the riverbed, that create alkaline medium, seasonal reduction of river debit and speed of water current facilitated sustenance of contamination of water of Agura river by V. cholerae. Conclusion. Activity of natural foci of the infectious disease and contamination of Agura river by V. cholerae 01 (atoxigenic) gives evidence on the necessity of constant control of epidemiologic situation by dangerous and natural-foci infectious diseases on the territory of city-resort Sochi, as well as study regional features of their causative agents, including using genetic methods.

Aim. Analysis of epidemiologic features of a norovirus outbreak in Alagir city of the Republic of North Ossetia-Alania and effectiveness of measures of its liquidation. Materials and methods. Data from maps-schemes of water supply system of Alagir city and statistical documentation of Centre of Hygiene and Epidemiology in the Republic of North Ossetia-Alania were used in the study. Indication of norovirus in clinical material and water samples was carried out by polymerase chain reaction method. Results. Etiological agent of outbreak disease was established - genotype II norovirus. Realization of fecal-oral mechanisms of water transmission pathway of the causative agent of norovirus infection was detected. Conditions facilitating emergence and development of the indicated outbreak were determined - non-satisfactory sanitary-technical condition of water supply system of the city. Conclusion. The studied water outbreak of norovirus infection was caused by GII.17 genotype virus, that currently gradually displaces GII.IV genotype, and was characterized by an intensive start, involvement of all population age groups into the epidemic process (with primary infection of adults), low family focality, predominance of average severity disease forms in the clinical presentation. The counter-epidemic measures carried out ensured rapid localization and liquidation of the norovirus infection outbreak.