Search

The aim of this work was to clarify the orographic and edaphic parameters of the spatial distribution of epizootic sites in the Central Caucasian high-mountain natural plague focus for electronic certification within the framework of the State Program “Ensuring chemical and biological safety of the Russian Federation, 2021–2024”, R&D “Electronic certification of natural plague and CHF foci in the south of the Russian Federation”. Materials and methods. Data on the spatial and temporal distribution of epizootic sites were obtained from the archive of the Stavropol Anti-Plague Institute of the Rospotrebnadzor. They include 318 points of detection of plague epizootics between 1984 and 2021 with spatial reference in the form of geographical coordinates. The analysis covered four landscape-epizootiological regions (LER): Verkhne-Kubansky, Kubano-Malkinsky, Malko-Baksansky and Baksan-Chegemsky. The Chegem-Chereksky LER was excluded, since no plague strains have been detected from its territory. Edaphic and orographic factors were obtained from the web-sites https://www.fao.org/ (soil data, including names), https://neo.gsfc.nasa.gov/, https://dwtkns.com/srtm30m/ (digital relief model) and from the archive of the Stavropol Anti-Plague Institute of the Rospotrebnadzor. Results and discussion. The epizootic sites have a pronounced confinement to altitudes from 2000 to 2711 meters above sea level. In the mountain-steppe belt, epizootic areas are more often found on the slopes of the North-North-East – South exposures, in the alpine and subalpine belts – the North-North-West exposure. The favorable level of landscape illumination is medium, closer to high; relatively flat or not heavily dissected areas, with soils: dystric and mollic leptosols and dystric cambisols predominate. Epizootic sites are absent on eutric cambisols, although this may be a random phenomenon.

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.

The aim of this work was to rank the territory of the Caspian sandy natural plague focus (43) by the risk of epizooty emergence using the MaxEnt model.Materials and methods. The archival data on epizootic manifestations of plague over the past 35 years, aggregated by the Stavropol Anti-Plague Institute of the Rospotrebnadzor, the Dagestan, Elista, Astrakhan PCSs of the Rospotrebnadzor, were used for model design. 615 archive plague detection points were converted into the coordinate system (1980–2015). 87 publicly available bioclimatic variables BioClim were deployed to construct the MaxEnt model. Applied weather and climatic factors of the BioClim database are averaged over a multiyear period.Results and discussion. The MaxEnt model has a very high degree of reliability (AUC=0.975), with a sufficiently high predictive ability (AUC=0.973). According to the generated model, the Caspian sandy natural plague focus has a heterogeneous structure in terms of the probability of epizooty registration and can be divided into five zones. The most significant factors for the model are the following indicators: the average temperature of the wettest quarter, solar radiation in November, the average temperature of the driest quarter, the amount of precipitation in the coldest quarter, wind speed in May, the amount of precipitation in the wettest quarter, and the average air temperature in September. The data obtained allow for targeted search for plague epizootics and can be used to adjust boundaries of a surveyed natural focus in the future.

Objective: to evaluate the epidemiological and immunological efficacy of tularemia vaccination in the Donbass region from 1991 to the present.Materials and methods: data on the incidence of tularemia, immunization coverage of the population, results of intradermal tests with tularin, agglutination reaction and indirect hemagglutination reaction with tularemia antigen were analyzed.Results: since 2012, immunization against tularemia has not been carried out on the territory of the republic. Since 2015, this approach has resulted in the emergence of foci with multiple cases of human tularemia. Cases were registered on the territory of natural foci of Novoazovsky and Yasinovatsky districts. Since 2017, immunization of the population in enzootic territories has been resumed, planning and selection of contingents to be vaccinated was carried out in a differentiated manner. According to epidemic indications, 400 people were vaccinated from among those at risk of contracting tularemia. In 2020– 2022 vaccination was not carried out. In the five months of 2023, 520 people were vaccinated against tularemia, 80 people were revaccinated.Conclusions: the use of tularemia vaccine in the Donetsk region for 70 years led to the containment of tularemia, demonstrating the epidemiological and immunological effectiveness of specific immunoprophylaxis. The armed conflict and the cessation of vaccination led to an increase in the activity of the epidemic process in natural foci among animals and a significant increase in the incidence of tularemia in humans.

The aim of study was to conduct epizootiological monitoring of natural tularemia foci of the steppe type and investigate epizootic activity in the south-east of the Rostov Region.Materials and methods. An epizootiological survey was carried out on the territory of Remontnensky, Sal’sky and Peschanokopsky districts of the Rostov Region in 2019–2021. To capture and collect mammals, Ixodidae ticks and to study the samples of field material conventional methods were used.Results and discussion. Habitation of 16 species of small mammals, 6 species of Ixodidae ticks has been found. Molecular-genetic analysis of the voles has revealed the presence of the species Microtus arvalis obscurus in the studied area of the region. The circulation of the tularemia agent has been established in the population of common and social voles, forest mouse, hare, rook, Dermacentor marginatus, Hyalomma marginatum, removed from rooks. In May 2020, a high increase in the number of the social vole in the Remontnensky district (up to 21 %), in July 2020 – the common vole in the agrocenoses of the Sal’sky district (up to 33 %) was observed. An extensive epizooty of tularemia was detected in the population of common vole in the south-east of the Rostov Region and in adjacent territories in the Republic of Kalmykia and the Stavropol territory. Two cultures of the pathogen were isolated from the fallen and captured social voles, and four cultures – from the common vole. The isolated strains belong to the Holarctic subspecies of Francisella tularensis EryR. The results obtained attest to the activation of the natural tularemia focus in the south-east of the Rostov Region and its high epizootic activity.

Relevance. According to official data, in 2020 in Russia, Ixodic tick-borne borreliosis took the leading position in the prevalence and registration frequency among tick-borne infections, which amounted to 38.5% of all cases of natural focal transmissible infections. In the Tomsk region for many years, the average long-term incidence of Ixodic tick-borne borreliosis exceeds the Russian one by more than 3 times. Aim. Identify features the features of the clinical and epidemiological manifestations of the Ixodic tick borne borreliosis foci in the Tomsk region; to identify priority areas for carrying out problem-oriented research in the field of ecology, epidemiology and the clinic of borreliosis infection in the Tomsk region. Materials and methods. The material for the study was the data of the federal statistical observation form «Information on infectious and parasitic morbidity» for the 2015-2020. The materials of 713 cases of Ixodic tick-borne borreliosis disease and more than 125 thousand appeals to medical organizations of the region regarding the tick bites, registered in official registration forms, were studied. As part of the annual epidemiological monitoring for a six-year period, 1200 specimens of Ixodid ticks collected in natural biotopes of the Tomsk region were examined for the presence of Borrelia DNA, depending on their genus (Ixodes and Dermacentor). DNA detection of Borrelia burgdorferi sensu lato complex (B. burgdorferi, B. garinii, B. afzelii) and B. miyamotoi was performed by real-time PCR. Results. The high number of ixodid ticks in local areas of natural biotopes (up to 200.0 specimens/km at the height of the epidemiological season), as well as the failure to comply with personal prevention measures, determines a consistently high rate of referral of the population of the Tomsk region to medical organizations due to tick bites. The number of requests annually averages 20.8 thousand. As a result of an annual study using PCR tests of ticks taken from people who applied to emergency prevention centers, Borrelia DNA was detected on average in 40% of samples; blood samples from individuals affected by tick bites were positive on average in 3.7% of cases. In the period 2015-2019 spirochetes B. garinii and B. afzelii were most often found in the tissues of ixodid ticks. Since 2020, the species Borrelia miyamotoi has been included in the list of pathogenic borrelia species to be monitored in the Tomsk region – spontaneous infection of ticks (Ixodes) was 3%. The maximum values both in the number of patients with ixodic tick-borne borreliosis and in the density of infections per 10,000 hectares (90-110 cases) are observed in the south of the Tomsk region (Asinovskyi, Kozhevnikovskyi, Krivosheinskyi, Tomskyi, Shegarskyi districts, the city of Tomsk). In the epidemic season of 2020, the number of laboratory-confirmed cases of non-erythema ixodic tick-borne borreliosis was more than 2.5 times higher than the number of diseases with skin manifestations. Conclusion. The large number of ixode mites in natural biotopes, the high degree of their infection with pathogenic spirochetes indicate the presence of active natural foci of ixodic tick-borne borreliosis in the Tomsk region. The study of the genotypic diversity of pathogenic borrelias in relation to the species diversity of vectors, the analysis of the clinical manifestations of different etiological variants of tick-borne borreliosis (mono- and mixed infections), as well as the development of an algorithm for differential diagnostic search and a model for predicting the outcomes of the infectious process in tick-borne borreliosis and mixed infections are priority directions of problem-oriented scientific research in Tomsk region.

Our research aim was to estimate efficiency of emergency disinsection and deratization that were accomplished to reduce risks of diseases among population in Gorno-Altaiskiy high-mountain natural plague focus. The research was performed in 2016–2021 in Gorno-Altaiskiy high-mountain plague focus which is the northern part of Sailygem cross-border natural focus located both in Russia and Mongolia. Zoological, epizootologic, epidemiological and statistical research procedures as well as GIS-tools were applied to collect and analyze research data. Epidemiologic surveillance over plague in the focus has been accomplished since 1961. Prior to 2011 only rhamnoso-positive strains of the plague microbe with selective virulence were found here, belonging to the Central Asian subspecies Yersinia pestis altaica, circulating mainly in the population of the Ochotona pallassi. Given that, the focus was believed to have low epidemic potential. Since 2012 highly virulent strains of the basic plague microbe Yersinia pestis ssp. pestis started to occur in populations of Marmota baibacina and other carriers. As a result, starting from that period of time, epidemiologic status of the focus changed and it led to 3 cases of bubonic plague among humans in 2014–2016. Disinsection and deratization remained the major components in anti-epidemic activities aimed at non-specific plague prevention. In 2016–2021 fields disinsection covered a total square equal to 162.7 km2; disinsection in settlements, 127.3 thousand m2; deratization in settlements, 461.7 thousand m2. An approach involving disinsection only on land spots that were considered epidemically hazardous was first implemented; such land spots were around livestock breeders’ camps located within boundaries of detected epizooties. Efficiency of fields disinsection amounted to 94.6; disinsection in settlements, 100 %; deratization in settlements, 88.0 %. Population of plague vectors and carriers was controlled bearing in mind environmental aspects in regulating numbers of animals and compliance with environmental protection requirements. Deratization and disinsection, together with other activities aimed at plague prevention, provide epidemiologic welfare in the focus and reduce its epizootic activity.

Relevance. In Russia, the live plague vaccine (LPV) is used for specific prophylaxis of plague. Immunological monitoring of humans vaccinated by LPV in order to search for informative diagnostic markers, as well as to improve the tactics of epidemiological surveillance of plague enzootic territories is an urgent area of research.The aim is to assess the parameters of cellular and humoral immunity in humans revaccinated by LPV who permanently reside on territory of the Tuvinian natural plague focus.Materials and methods. The study involved 76 volunteers from the Republic of Tuva, revaccinated by LPV. Blood sampling was performed before vaccination and 1, 3, and 6 months after revaccination. The study included the determination of cytokine production (IFN-γ, IL-4, TNF-α), specific antibodies, immunoglobulins (IgM, IgG, IgA and IgE) and lymphocyte subpopulation composition (CD3, CD4, CD8, CD16, CD19, immunoregulatory index).Results. A decrease in IgG and IgM and an increase in IgA were found after vaccination with LPV and their increase after revaccination. Correlation relationships were revealed between immunoglobulins, B cells and IL-4. Revaccination leads to an increase seroconversion. The activation of humoral immunity in humans vaccinated against plague is also evidenced by dynamics of changes in the subpopulation composition: an increase in B-lymphocytes and natural killer cells, a decrease in T-helpers and immunoregulatory index, and cellular immunity stimulation is an increase in spontaneous and induced production of pro- and anti-inflammatory cytokines.Conclusion. It has been shown that LPV is capable of causing the body’s immune restructuring and activating the cellular and humoral mechanisms of immunological protection. For a complete understanding of the development and preservation of antiplague immunity, it is necessary to continue the annual immunological monitoring of the population living on the territory of the Tuvinian natural plague focus, using additional modern research methods.

The aim of the work was to rank statistical models for assessing the contribution of a number of factors that determine the epizootic situation on natural-focal infectious diseases in the communities of non-synanthropic small mammals (SM) in the forests of Ekaterinburg.Materials and methods. The SM survey was carried out for three years in the summer-autumn period. The animals were caught with snap tpaps on a standard bread bait, 9705 trap-nights were worked out. To identify infections (hemorrhagic fever with renal syndrome, tularemia, leptospirosis, yersiniosis, pseudotuberculosis), 333 SM specimens (rodents and shrews of six species) were used, randomly taken from the general sample. To determine the pathogens, the methods of enzyme immunoassay and polymerase chain reaction were used. The cumulative infection rate of small mammals with all studied natural-focal infections was evaluated. Statistical data processing was carried out from the standpoint of a multi-model approach. The selection of models was performed using the Akaike information criterion with the calculation of the sum of the weights of the models based on their full spectrum (SW).Results and discussion. Carriers of all of the mentioned above infections, except for pseudotuberculosis, have been identified in the forest parks of Ekaterinburg. According to the ranking, the model with three predictors received the highest weight: species, year, and the abundance of SM of the previous year in a particular habitat. The most significant predictors for the full spectrum of models are the year (SW=1), species (SW=0.6), abundance of animals in the current and previous year (SW=0.48). The distribution of positive samples by species of small mammals corresponded to their ranking by abundance in the community. The influence of the factors “season” (summer or autumn) and “area” (place of capture of animals) turned out to be insignificant on the scale of the studies (SW = 0.3 and 0.16, respectively). The percentage of infected samples in total for all infections varied significantly by location and year (0–60%). The possible significance of unaccounted factors is discussed: landscape features and the mode of using forest parks, dispersal of small mammals. The conclusion is made about the usefulness of the multi-model approach in the analysis of the data from epizootiological studies.

Background. Dirofilariasis is a vector-borne helminthiasis that tends to expand spatial boundaries in areas with temperate and cold climates. In the Voronezh oblast, located in the Central Black Earth Region of the Russian Federation there were previously isolated reports of cases of dirofilariasis in humans and dogs, but this issue was not specifically studied.Aims. To determine the degree of infection of dogs with Dirofilaria immitis and Dirofilaria repens in the Voronezh oblast in order to determine the level of epidemiological risk.Materials and methods. For seven years, targeted work was carried out to study the spread of different types of dirofilariae in dogs in the Voronezh region. Blood from 3 498 dogs of different breeds, ages, conditions of keeping and household use was examined. Dirofilaria larvae were counted using the Fuchs-Rosenthal camera. The type of dirofilaria larvae isolated from the blood of dogs was determined by the histochemical method. The antigen of the imaginal form of D. immitis was detected using a chromatographic test system the ImmunoRun Antigen Detection Kit Caninae Heartworm Biogal chromatographic test system (Israel). Statistical processing of the material was carried out in the Microsoft Excel 2010 program. Studies were carried out with the consent of animal owners and in accordance with the European Convention for the Protection of Vertebral Animals used for experimental and other scientific purposes (Strasbourg, 1986).Results. As a result of the conducted studies, it was found that in the Voronezh oblast, the average infection of domestic dogs (Canis familiaris) with dirofilariasis is 14.14 ± 0.31 %. The indicator depends on the conditions of keeping animals and makes 27.15 % in stray dogs, 25.26 % – in service dogs and 10.54 % – in apartment dogs. In service dogs, the species D. repens occurs in 52.39 % of cases, D. immitis – in 42.95 %, mixtinvasia – in 4.80 % of cases. In stray dogs, the species D. repens prevails (80.10 %). The second type of D. immitis was established in 10.0 % of cases. At the same time, both types were also established in 10.0 % of cases. The maximum number of cases of dirofilariasis occurs in urban dogs (65.87 %), which is due to the high density of their population and close contact with the vector of transmission in urbanized areas. The seasonal dynamics of infestation is determined by the year-round detection of cases with a peak in October (46.77 %). The number of cases of dirofilariasis increases with age, in dogs from one to six years old it reaches maximum of 63.26 %. There is an epidemiological risk of dirofilariasis in the Voronezh oblast. This is due to the existence and active functioning of synanthropic and natural foci of invasion on the territory of the Voronezh oblast.

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.

Y. pestis MLVA typing is used both to seek for similarities and differences between individual isolates upon conducting epidemiological investigations as well as for clonal clustering of intraspecies phylogenetic groups while analyzing microevolution and taxonomy issues. It cannot be ruled out that the most variable loci may be indicators allowing to approximate the unique strain-related properties circulating in certain natural plague foci. The Central Caucasian Highland Natural Plague Focus distinguished by heterogeneity of the circulating strains therein, including proline pro- and auxo-trophy, may represent a convenient model for testing this hypothesis. The purpose of our work was to assess the frequencies of the VNTR alleles associated with proline dependence among the Y. pestis strain VNTR loci, determined during previous MLVA-25 typing in the Central Caucasian Highland Natural Plague Focus. The main task was to identify the most informative sets of VNTR loci suitable for predicting proline pro— and auxotrophy (pro+, pro—). It was found that the loci ms45, ms56, ms46, ms07, ms69, ms62 displayed peak variability by allele frequencies and/or exhibited significant differences of mean allele frequencies in the pro— and pro+ strains. In particular, it was showed that the alleles of the ms45 locus contained 6 tandem repeats suggesting probability for pro+ reaching 0.944, whereas the alleles of the ms45 locus contained 7 tandem repeats with expected probability for pro— reaching 0.783. Moreover, the ms56 and ms46 contained 9 and more than 18 tandem repeats, respectively, thereby pointing at probability for pro+ equal to 0.933 and 0.818, respectively. Diagnostics for pro+/pro— phenotype by using specific statistical methods demonstrated statistical error 13.33% and 26.67% for the pro— and pro+ strains, respectively. All pro+ strains bearing a 6 tandem repeat complex from the ms45 locus, 9 tandem repeats derived from the ms56 locus and ms46 locus-derived 29—30 tandem repeats were accurately diagnosed solely based on these 3 loci. Thus, it is possible to predict some properties of Y. pestis strains based on determining the allele frequencies. While the number of MLVA typed plaque strains isolated in such natural focus has been progressively increased, it may be expected that opportunities for prognosing their properties based on determining locus tandem repeat composition having diagnostic value would be elevated.

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.

Objective of the study was an assessment of the current epizootiological situation on tularemia in the Stavropol Region. Materials and methods. Processed were the data of laboratory investigations of the field material over the period of 2010-2017. All field samples were studied in the laboratories of the Stavropol Anti-Plague Institute using PCR and bioassay. Results and discussion. This paper presents the analysis of the epizootiological situation for the period of 2010-2017 in the Stavropol Region. The species composition and the number of the main carriers of tularemia have been established. Epizootic activity of the focus is defined by mice of the genus Sylvaemus. Data on the isolation of strains from ticks, small mammals and environmental objects are presented and processed. According to our studies, over the past seven years, infection with tularemia agent has been detected in seven species of mammals: S. uralensis, Microtus arvalis, M. socialis, Mus musculus, Crocidura suaveolens, Erinaceus roumanicus, Lepus europaeus. For the period of epizootic monitoring between 2010 and 2017 37 strains of the causative agent were isolated from small mammals - 12 (32.4 %), ectoparasites - 9 (24.3 %), and environmental objects - 16 (43.2 %). All isolated strains have been identified as Francisella tularensis holarctica biovar II, eryR.

Background. Plague is an especially dangerous natural focal infectious disease belonging to a group of quarantine infections. There are eleven natural plague foci in Russian Federation. In Republic Tyva plague endemic territories include Ovyur, Mongun-Taigin and Tes-Hem areas where Y. pestis strains are intermittently isolated from Citellus undulates. Population living at the territory of the natural foci get immunoprophylaxis against plague at complication of epizootic and epidemic conditions.This paper presents the results of monitoring indicators of the immune status of people vaccinated with the plague vaccine living in the territory of the Tuva natural focus.Materials and methods. The study involved 76 volunteers who had not previously been vaccinated. The study included the determination of production IFN-γ, IL-4, TNF-α by blood cells, titers of specific IgG antibodies to the capsule F1 antigen of the Yersinia pestis, and concentrations of immunoglobulins in serum blood, as well as immunophenotyping of blood lymphocytes.Results. In the course of a comprehensive immunological study, features of the development of cellular and humoral reactions in people living in the territory of the Tuva natural plague focus were established in the first months after vaccination. Changes in the concentration dynamics of the main classes of immunoglobulins were accompanied by an increase in the level of specific IgGs to the F1 within 6 months after immunization. In the same period, a significant increase in the production of cytokines, as well as significant changes in terms of the subpopulation composition of the vaccinated blood.Conclusion. It is necessary to note the importance of studying of the human immune status in 1–3 months after plague vaccination as this period coincides with potentially dangerous season from epidemiological point of view. Nevertheless, much important role for improvement of tactics of the specific prevention measures plays the data received after the revaccination.

Revealed by morphological characters, physiological status, and genetic diversity of populations of the main plague host Rhombomys opimus Licht., 1823 in Central Asia desert natural focus is described.Differences in the skull parameters of R. opimus from different populations were revealed. It’s shown that gerbils from Moyunkum are separate autonomous populations group. Samples from Moyunkum and Mangyshlak differed from other samples. In Balkhash-Alakol depression found two regional complexes: Pre-Balkhash and Dzungarian.Study results of free amino acids level in R. opimus blood serum obtained by gas-liquid chromatography of blood sera from animals captured in different zones of Central Asian focus gave statistically significant differences. To determine genetic variability in ecological and geographical isolation of R. opimus populations the DNA was genotyped.DNA samples analysis combined the studied gerbil from the desert focus into four clusters with eighteen haplotypes. R. opimus sequence analysis taking into account data from territories of Iran, Kazakhstan and China, clustered into three large clusters. First cluster combined the sequences of Kazakhstan and China samples, while great gerbil captured in Kazakhstan is located in a separate treasure. Second and third clusters include sequences of a great gerbil captured in Iran.

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. To compare by flow cytometry the cellular immune status indicators in persons, living on the territory of the Caspian sandy natural plague focus for epidemic indications. Materials and methods. Whole blood leukocytes of 120 people were examined by flow cytometry with using the two four-color labeled monoclonal antibody reagents (Cyto-Stat CD45-FITC, CD4-PE, CD8-ECD, CD3-PC5 и Cyto-Stat CD45-FITC, CD56-PE, CD19-ECD, CD3-PC5) and by means of CD95-FITC reagent. The results were taken into account before and in a month and 6 months after vaccination. We were determined in the blood the relative content of lymphocytes, monocytes, granulocytes, leukocytes carrying an early apoptosis marker (CD95), T and B- lymphocytes, NK cells as well T – lymphocyte helpers (Th) and cytotoxic T-lymphocytes (Tcyt) for immunoregulatory index (IRI) calculation. Results. Before anti-plague vaccination in 14 people (11,7%) were found abnormally low immunoregulatory index values characterized the immunodeficiency state (IRI

Background. The epidemiological situation in the Astrakhan region indicates the activation of the natural foci of the Crimean-Congo hemorrhagic fever (CCHF), due to a sharp increase in carriers and guardians of the CCHF pathogen, Hyalomma marginatum, on both farm animals and in open biotopes. Natural conditions in combination with human activities (animal husbandry, crop production) and the lack of anti-tick measures create a favorable environment for the population of vectors and, therefore, for the circulation of the CCHF virus.Aim - identification of features of ecological and epidemiological manifestations of the CCHF in the Astrakhan region in 2000-2016.Results. The state of the natural foci of CCHF was monitored, which is endemic and the most severely occurring natural focal disease of arbovirus etiology in the Astrakhan region, preserving the tendency to expand the range. For the analyzed period from 2000 to 2016.151 cases of CCHF were registered in the Astrakhan region, the average long-term incidence rate of the population was 0.88 ± 0.2 per 100 ths of the population. The disease is registered in all districts of the region and the city of Astrakhan, but the largest number is noted in the floodplain-delta regions, where there are favorable conditions for grazing cattle. There is a clear connection between the infection and certain landscapes, where the necessary set of conditions for the circulation of the pathogen is provided.

Studying of immune interlayer value to tick-borne encephalitis virus in human population of the Transbaikalia Territory resulted from natural immunization of the healthy population in 31 Municipal areas in 2011–2016 is presented. Human selections were formed proportionally to the population size in the concrete human settlement among persons of the various age and professional groups living at this territory not less than 10 years and unvaccinated against tick-borne encephalitis virus. Total 4367 blood sera were investigated. Laboratory testing for antibodies of G class to tick-borne encephalitis virus in blood sera of the human population was performed by immune-enzyme analysis using a set of reagents “VektoVKE-IgG” of Joint-Stock Company “Vektor-Best” (Novosibirsk city). The monitoring data indicated the presence of natural immunity to tick-borne encephalitis virus in the human population. Mean annual level of immune interlayer in Municipal areas varied from 3.1 to 52.7% (in Transbaikalian Territory — 13.1±0.51%). High level (from 20 to 52.7%) was characteristic for mountain-taiga-forest-steppe zone (Krasnochikoisky — 23.8±3.36%; Uletovsky — 52.4±4.48%; Gazimuro-Zavodsky — 29.4±4.94% districts) and mountain-tundra-taiga zone (Tungokochensky district — 20.0±3.58%). In steppe zone the level of immune interlayer was lower and observed in districts with elements of south-taiga larch and pine forests. It was established that levels of the immune interlayer in human population living in mountain-taiga-foreststeppe and mountain-tundra-taiga zones authentically higher than in steppe area — t = 3.8; Р < 0.001 and t = 2.27; Р < 0.05, respectively. Distinctions in the value of the immune interlayer between mountain-tundra-taiga and mountain-taigaforest-steppe zones were non-authentic: t = 0.1; P > 0.05. Active circulation of tick-borne encephalitis virus was accompanied by authentic (Р < 0.01) increase of the interlayer in persons with the virus antibodies in 2014–2016 (15.8±0.69%) in comparison with 2011–2013 (9.7±0.78%). Also it was noted in all landscape zones: in steppe zone the increase was to 42.8% (P > 0.05); in mountain-taiga-forest-steppe — to 61.3% (P > 0.05); in mountain-tundra-taiga — to 150.0% (Р < 0.01). It was not possible to reveal correlation between the recourse for medical aid and the value of immune interlayer in the population formed as a result of latent immunization. Results of the population immunity studying essentially expand our knowledge about the condition of the natural foci and dynamics of development of the epidemic processes in it, and can be used at planning of the preventive actions.

Aim. Assessment of the epidemiological and epizootic situation and the degree of danger of the territory of Vladimir region in terms of a complex of natural focal zoonotic infections. Materials and methods. In the work, a retrospective analysis of statistical data on the incidence of zooanthroponosis in the population, obtained from Reporting Form No. 2 «Information on Infectious and Parasitic Diseases» of Center for Hygiene and Epidemiology in the Vladimir Region for the period 1958 - 2016 was conducted. Studies of biological material for the presence of pathogens of natural focal infections were conducted in the laboratory of natural focal and especially dangerous infections of Center of Hygiene and Epidemiology in the Vladimir Region. Results. It is established that the following natural focal diseases are registered in the territory of the Vladimir region: rabies, heemorrhagic fever with renal syndrome (HFRS), tick-borne borreliosis (ТВВ), leptospirosis, pseudotuberculosis and tularemia. The largest share in the structure of morbidity falls on HFRS and ТВВ. Annual laboratory studies of biological material for the presence of pathogens of natural focal infections indicate the presence of epizootics among rodent mice, the dominant species among which is the red vole. The ratio of men to women with HFRS is about 3 to 1, the main risk factors for transmission are harvesting in summer cottages and visiting forest areas. As for the ТВВ, in the region there are persistent natural foci of this infection. It was established that there is no territorial dependence between the incidence and «riches» of the territory, and the main epidemiological significance is the iksodid mites I.ricinus and I.persulcatus. Conclusion. The cartographic mapping of the registered incidence allowed to show the territories with different degree of epidemic manifestation for individual natural-focal diseases and for a complex of morbidity in general. Positive laboratory results indicate epizootic activity and a constant risk of exacerbation of the epidemic situation of zooanthroponous infections, and the absence of human morbidity over a number of years is not evidence of the attenuation of the natural focus of infection and the basis for the curtailment of preventive measures.

Central-Caucasian natural plague focus was permanently epizootically active since its discovering in 1971 till 2007. Inter-epizootic period has been in progress since 2008. It was not possible to isolate agent strains from field material. Therefore a forecast for focus activation is a relevant task, especially against the background of registered plague cases in humans in 2014–2016. Objective of the study was to create a forecasting model for quantitative prediction of possible activation or maintenance of inter-epizootic period. Materials and methods. We used archival data of Kabardino-Balkar Plague Control Station: journals of rodents’ autopsy, annual reports on epizootiological surveillance, meteorological data from meteostation “Kislovodsk” over the period of 1989–2017, and our epidemiological data for the period 2010 to 2017. We applied Spearman nonparametric correlation analysis, regression analysis, including principal component method, quarterly analysis, and inhomogeneous sequential pattern recognition procedures for statistical processing. Results and discussion. We have designed statistical model which provides for forecasting of plague focus epizootic activity proactively, a year in advance and 99 % probability or higher. The model was tested on retrospective data over the course of 7 years. All predictions were correct. The operational forecasts from 2015 to 2017 proved right too. However there is a possibility of fast changes in the ecology system conditions of the Central-Caucasian natural plague focus because of the global warming. Thereby the forecasting model will be annually checked for informative value of the predictors and, if necessary, adjusted accordingly.

The Ebola disease derives its name after a small river, the Ebola River, flowing through the former Zaire (present day DR Congo) and was formally named in 1976. The disease belongs to the category of diseases referred to as “haemorrhagic fever”; the causal agent – a filovirus (from Latin “filo” = thread) belonging to the Filoviridae family. The treatment of Ebola has been only symptomatic, i.e. based on mitigation of the symptoms related to the infection, such as kidneys and liver. An effective vaccine has not been developed yet, even though rigorous attempts have been made and reported. Ebola has been primarily found in the Ivory Coast, DR Congo, Sudan, Gabon and other equatorial African countries. Based on the data obtained during the latest epidemics, people are strongly advised to avoid direct contact with patients, avoid buying bush meat in street markets and not handle dead bats, megabats, monkeys or gorillas. Estimated data suggest that more than 5,000 of these animals have died. The disease was also diagnosed in patients in the USA and Europe. The epidemic afflicted West Africa and had significant implication on their economy in terms of lost production, higher fiscal deficits, rising prices and lower real household incomes, leading to greater poverty.

West Nile virus (WNV) circulation in the territory of Saratov region and its role in the infectious pathology were investigated. For this purpose, in studies conducted in 2013-2015, suspensions of bloodsucking arthropods, organs of birds and small mammals were analyzed for the presence of WNV markers (antigens and/or RNA). The seroprevalence level in live-stock animals and population of the region was evaluated; clinical samples from patients with symptoms compatible with West Nile fever (WNF) were analyzed. As a result of the investigations, WNV markers were detected in field samples gathered in natural biotopes and in the city of Saratov. Immunity to WNV was detected in horses. A stable domain of persons with immunity to this agent was revealed among regional population. Patients with WNF have been annually registered in the region since 2012. The obtained results confirm active circulation of WNF in the Saratov region, as well as formation of stable natural and anthropourgic foci.

The fundamental theoretical and methodological shortcomings of modern organisation and implementation of epidemiological surveillance of natural focal infections are considered. The conclusion is made about the need to prepare a realistic programme of observations of state change in natural focal parasitic systems and contacts of the population with them. Its main goal is to obtain ecologo-epidemiological and socio-demographic data needed for short and medium term forecasting of the epidemiological manifestations of natural foci.

Objective of research: a study on the ecological and biological features of circulation of opisthorchiasis in conditions of Upper Don river (Voronezh region) based on retrospective and modern original materials. Materials and methods: wild carnivores (fox, stone marten, pine marten, American mink), and domestic carnivores (dog and cat) were examined by the method of full helminthological autopsy. Cyprinid fish have been investigated by compression method. The number of Opisthorchis metacercaria in fish muscles were calculated to determine the number values. Taxonomic studies were carried out using the field guides. Processing of whole-mount and terminal preparations from larval and adult trematodes was conducted by standard and laboratory-developed methods. The index of abundance, intensity and extensity of infection were used to evaluate the qualitative and quantitative characteristics of infestation and the prevalence of larval and adult opisthorchids in hosts. Results and discussion: 4 types of opisthorchids were registered in Voronezh region: Opisthorchis felineus, Pseudamphistomum truncatum, Metorchis bilis and M. xanthosomus. It was determined that first of all the opisthorchiasis foci occur at small rivers. Opisthorchis marites were found in 5 types of mammals in natural ecosystems of Voronezh region. Domestic cats play a key role in circulation of opisthorchiasis in anthropogenic ecosystems of Voronezh region. The evaluation of infestation of cyprinid fish with Opisthorchis metacercariae was presented. It was found that with respect to invasion and accumulation of Opisthorchis metacercariae there are 3 dominant types of cyprinid fish: roach, redfin and bleak leading.

Natural tularemia foci in the territory of the Khanty-Mansiisk Autonomous District - Yugra are still active and sustainable ones despite of the extended periods of epidemiological welfare. Agent reservoir is the water vole. However, recently tularemia agent has been detected in the northern red-backed vole and common red-toothed shrew. Khanty-Mansiisk town, Berezovsky, Khanty-Mansiisk, Kondinsky, and Oktyabr’sky Regions are situated in the territory of the most active foci. Serious outbreaks of infection among the population occur with an interval up to 30 years. Their transmissibility preconditions the scale and intensiveness. All cohorts are under the risk of exposure, irrespective of the age and occupation, including the infants. The paper discusses tularemia outbreak impact on the population of Khanty-Mansiisk and the Khanty-Mansiisk Region in July-October, 2013. Casualty toll is 1005 cases. Given is a brief retrospective analysis of epidemiological situation on tularemia since 1930-s up to the onset of the outbreak under investigation. Described is the experience in management of the response activities.

This paper presents a new ecological and epidemiological data on the distribution and the epidemic manifestation of natural foci of tick-borne infections in the Kemerovo region, taking into account the study of their combination with the use of modern molecular biology methods.

The first time was identified by PCR in real time in Ixodes ticks and leukocyte blood fractions of persons tested after a tick bite, the existence of a number of pathogens of tick-borne infections (B. burgdorferi s.l., B. miyamotoi, A. phagocytophilum, E. chaffeensis/E. muris, tick-borne encephalitis virus) on two focal areas adjacent to Vladivostok. The infection of I. persulcatus B. burgdorferi s.l. reached 31%, and for the first time identified B. miyamotoi, Anaplasma, Ehrlichia - 4%. Detection of RNA of TBE virus in 2 cases in epidemiological season in 2014, indicating a low potential epizootological natural focuses of TBE in the southern Far East.

In connection with the 75th anniversary of the theory of academician E.N. Pavlovsky about the natural focality of diseases presents the General results of the development of its fundamental theoretical positions. Planned most promising areas for further research, which can immeasurably increase when the combination of modern molecular biology and traditional population-ecological methods for the study of natural foci.

Epizootiological monitoring of the forest-steppe area of the natural tularemia focus in the Stavropol region has revealed that the role of particular species of small mammals in the persistence of natural tularemia focality is unequal. Epizootic activity of the focus in 1959-1970 was determined by the numerous species of rodents: Microtus arvalis , mice of Syvaemus genus and Mus musculus . In 1972-2010 there occurred significant changes in the grouping of the main tularemia agent carriers under the influence of strong anthropogenic pressure. Nowadays the leading role is played by the widely-spread and subsistent mice of Sylvaemus genus and C. suaveolens , the latter ones being responsible for 31.2 % of overall, isolated from small mammals, tularemia agent strains. In addition to this, epizootic significance of M. arvalis has greatly changed. Index of strains isolated from field vole has lowered from 55.3 up to 28.4. Numbers of M. arvalis and Mus musculus are continuously on the low level, which is due to the absence of favorable breeding conditions. It reduces their impact on the persistence of natural focality in the territory under surveillance significantly.

The plague natural foci of Kazakhstan are a complicated system of relations between the plague microbe, warm-blood host and vector. The complex approaches used for study of the processes of the plague epizooty and prognosis it. Use of computerized programs with the classic methods of study helps to process the data in time and space. For epidemiological and epizootological analysis the passport data of the strains Y. pestis isolated by Zhosaly Anti-plague Station of the Republic of Kazakhstan in 1990-2012 were processed. The Anti-plague Station carries out the epizootic study of the landscape and epizootology regions as the North Qizilqum, East Karakum, and West part of Aryskum-Dariyalyktakyr. From 1990 to 2012 there were 295 plague strains isolated, 57 % of them were isolated from rodents, and 49,3 % of them were isolated from vectors (ticks and fleas). The passport data for 1990-2011 of three mentioned above landscape and epizootology regions were processed by STATA 12 program; and the regression models of the North Qizilqum and East Karakum were created. The model shows that the plague epizooty activity has been declining by the years. The second model shows that the plague activity in the North Qizilqum has been increasing by the years. Also the passport data of the strains Y. pestis isolated in two natural plague foci of Central Asia desert plague focus as Qizilqum and Aryskum-Dariyalyktakyr natural foci were processed by ArcGIS 10. The regression analysis and modeling in ArcGIS 10 give the opportunities for carrying out of spatial and temporal characteristics of conditions of epizootic activities of the natural plague foci, for detection more possible regions where people livestock as camels can be infected with plague and for prevention of infection of people during their activities. Application of this analysis in the complex of epizootic and epidemiological analysis gives the possibility to prognosis of possible plague epidemic complications and make remote prognosis for carrying out of the prophylaxis measurements under the influences of anthropogenic transformation of the foci, social and climatic factors and can help to survey the foci and protect the population who live there. Use of the regression analysis in the epidemiological and epizootological monitoring of the plague in the natural plague foci can help to prognosis the dynamics of the plague epizooty in the foci and detect a correlation between the microbe, vector, and host of the plague.

On the model of the Saratov and West-Kazakhstan regions carried out is the analysis of the current epidemiological and epizootiological situations in the cross-border territories of the two states: the Russian Federation and the Republic of Kazakhstan. Depicted is not only the common area of natural-focal territories of old-established infections, such as tularemia, but an intense outspread and formation of natural foci of the emerging infectious diseases too: Crimean hemorrhagic and West Nile fevers. This phenomenon assumes a great deal of importance due to dissemination and circulation of previously unknown to these areas infections concurrently in the two neighboring regions. Specified uniformity of epidemiological public risks in the bordering regions testifies to the need for development and implementation of the integrated system for prevention and response to the emergency situations in the sphere of sanitary-epidemiological welfare of the population in the territory of both of them.

Microbiological monitoring of the six districts of the Krasnoyarsk Territory was conducted in order to prove the existence of natural foci of human granulocytic anaplasmosis (HGA) and monocytic ehrlichiosis (HME) on its territory. Two-round PCR method was used for the detection of Anaplasma and Ehrlichia DNA. 374 samples from mites were analyzed with two-round PCR for the presence of Anaplasma and Ehrlichia DNA: 341 specimens of Ixodes persulcatus and 33 specimens of Haemaphysalis concinna. Ticks were collected from vegetation on the flag in the 6 districts of the Krasnoyarsk Territory: Yeniseisky, Achynsky, Sharypovsky, Ilansky, Minusinsky and Ermakovsky, belonging to different climate zones and have landscaped, geo-botanical and faunal features. The study showed that 5.6 % of taiga ticks infected with E. muris, 2,1 % with A. phagocytophilum. In 0.3 % of carriers we identified mixtinfected E. muris and A. phagocytophilum. These data indicate presence of HGA and HME foci in the central, western and southern parts of the Krasnoyarsk Territory.

This article contains results of reconnaissance studies intended to find foci of babesia in the Irkutsk region. Babesia DNA were founded in two types of ticks (I. persulcatus, H. concinna) in the three districts of the Irkutsk region (Ekhirit-Bulagatsky, Irkutsky, Shelekhovsky). The analysis of 1220 nr length nucleotide sequences of 18S rRNA gene of five Babesia samples was conducted. It was shown that the identified Babesia sequenced differ from previously known, and refer to the two genetic groups. The first group included babesia, genetically most similar to the sheep pathogen Babesia crassa, second contains sample, nucleotide sequence of which is significantly different from all known (less than 95 % homology).

104 cases of Crimean hemorrhagic fever (CHF), including 9 lethal (8.6 %) were registered in the Volgograd Region in 2000-2009. Dynamics of human incidence and its association with the level of infection in the main carrier and vector - H. marginatum tick were demonstrated. The expansion of this species habitat resulted in the natural focus borders extension. The data presented in the article allowed to make a conclusion that persistent actively functioning natural focus of CHF had been formed in the territory of the Volgograd Region. The epicenter of this focus is situated in 2 South-Western regions - Kotelnikovsky and Oktyabrsky, - and with neighboring administrative territories and green belt of the Volgograd Southern regions being actively involved in the epidemic process.

The role of birds in the circulation of the virus of Congo-Crimean hemorrhagic fever (CCHF) is described in the paper. Investigation of 758 samples of birds revealed the virus CCHF antigen to be present in 19 (2.51 % ± 0.57) rooks' samples. Corvidae were shown to be a full-fledged co-member of the Crimean hemorrhagic fever (CHL) natural foci in the territory of Rostov Region. Epidemiologic significance of this bird family consists in dissemination of the CCHL virus, expansion of the existing natural CHL foci, and thereby supporting the formation of new ones. Ecologic and epizootiologic role of Corvidae should be taken into consideration while conducting epidemiologic surveillance in HCL natural foci.

Presented are the data on Crimean hemorrhagic fever epidemiological situation and morbidity in the South and North-Caucasian Federal Districts of the Russian Federation in 2010. Epizootic situation in the Stavropol region has been analyzed. The prognosis as regards CHF for the year of 2011 in the territory of the South and North-Caucasian Federal Districts is presented, based on epizootiological monitoring .

Presented are the results of retrospective analysis of leptospirosis morbidity in the Rrepublic of Mordovia for 2002-2008. Main directions of the epidemiologic surveillance in natural foci of this infection were shown.

Presented are the results of epizootiological and epidemiological monitoring of Crimean hemorrhagic fever (CHF) in the territory of the Republic of Ingushetia. 6 cases of CHF were registered and confirmed during 5 years (2004-2008), 3 (50 %) of them being fatal. 5 species of ixodic ticks were shown to be infected with Crimean hemorrhagic fever virus of which 67,7 % were ticks Boophilus annulatus. CHF virus antigen and specific antibodies were detected in great and small cattle. Specific antibodies in titres 1:800 - 1:1600 were found in blood serum of donors. Data received confirmed the presence of CHF natural focus in the territory of the Republic of Ingushetia.

A tick-borne encephalitis virus focus was identified in a former goat pasture that had been associated with a milk-borne encephalitis outbreak in 2007. Ticks and rodents were sampled monthly from April 2010 to October 2013 on two separate 0.5 ha sampling sites. At site 1, three tick-borne encephalitis virus strains were isolated from a total of 7,247 sampled ticks; 28 of the 539 tested sera (5.19%) were seropositive. At site 2, from the 2,369 sampled ticks, virus was not isolated, tests of 284 rodent sera resulted in 14 positives (4.93%). For survival, the virus needs a territory with continuously dense rodent and tick population, although observed TBEV prevalence was low both in ticks and in rodents. Sampling points of positive ticks and rodents did not coincided exactly, at a certain time only some m territory is dangerous, these hot spots change unpredictably as positive ticks die or move on with their hosts. [ABSTRACT FROM AUTHOR]

A suburban focus of Lyme borrcliosis situated 11 km from the southern border of the city of Lublin (eastern Poland) was characterized. The focus covers an area of circa 100 krn2, surrounding 3 localities inhabited by circa 7,500 people engaged mostly in farming. It was demonstrated that on the area of focus the infection rate of Ixodes ricinus ticks with Borrelici burgdorferi, frequency of serological response of inhabitants to the antigen of Borrelia burgdorferi, and incidence of Lyme borreliosis were significantly (p<0.001) greater compared to the whole territory of Lublin province, and were respec- tively 13.1% vs. 4.7%, 33.0% vs. 13.7%, and 0.002% vs. 0.00075%. [ABSTRACT FROM AUTHOR]

The purpose of the study was to suppress a known natural focus of field fever exerting an influence on animal hosts of leptospires - small terrestrial mammals (s.t.m.) by rodenticide. After repeated application of the zinc phosphide rodenticide, the s.t.m. were regularly live-trapped and checked for leptospirosis by dark-field microscopy and culture of their renal tissue and serological examination. Isolated leptospira strains were typed by help of rabbit factor sera. The deratization influenced the s.t.m, structure considerably: the proportion of the dominant Microtus arvalis subjects - the main reservoirs of Leptospira kirschneri serovar Grippotyphosa - were gradually and substantionally reduced and, contrarily, the percentage of the potetial hosts subjects - Clethrionomys glareolus and Apodemus flavicollis - rose decisively over time. Changes in culture and serological positivity for leptospirosis of s.t.m, have also been enregistered. The highest original infestation of M. arvalis have slowly but strongly decreased while that of C. glareolus and A. flavicollis has increased decisively and reached its maximum within the last years of investigation. It is probable that these two animal species have undertaken the leading role in the maintenance of the natural focus of the field fever. In other animal species analogous trends were not registered. Based on these long-term findings, there exists the possibility to suppress only partially and temporarily the epizootic process of leptospirosis in a natural focus that can be desirable in some circumstances (building or free time activities, etc.). [ABSTRACT FROM AUTHOR]