Natural Focal Infectious Diseases Research Articles

Clinical and Epidemiological Characteristics of Leptospirosis in the Gomel Region

Relevance. Leptospirosis is a zoonotic ubiquitous natural focal infectious disease that has an adverse effect on human and pet health. The territory of the Republic of Belarus in terms of its natural-climatic and soil-geographical conditions is favorable for the existence of both natural and anthropurgical foci of leptospirosis. The purpose of the work is to study the long-term dynamics of the incidence of leptospirosis in the population of the Gomel region and the clinical and epidemiological features of leptospirosis. Materials and methods. The material for the study was the data of the state statistical reporting «Report on individual infectious, parasitic diseases and their carriers» for the period from 2002 to 2022. In this work, epidemiological diagnostic methods and statistical research methods were used. Descriptive retrospective continuous study of these case histories of patients diagnosed with Leptospirosis of the Gomel Regional Infectious Diseases Clinical Hospital institution was conducted to describe clinical data. Results. In the period from 2002 to 2022, 161 cases of leptospirosis were registered in the Gomel region with an average incidence rate of 0.52 per 100 thousand population. Over this period of time, the incidence of leptospirosis was characterized by an uneven distribution and was undulating. Periods with a low incidence of 0.14–0.42 cases per 100 thousand population lasting 5-6 years alternated with periods of rising incidence to 0.99 cases per 100 thousand population lasting 3 years. In 2022, a sharp rise in the incidence of leptospirosis in the Gomel region was registered, and therefore 15.8 times higher than the incidence in 2021, the incidence rate was 1.11 per 100 thousand of the population and exceeded the national average by 4.6 times. Adults predominated among the sick (93.3%). At the same time, 73.0% of the patients were urban residents. The source of infection in 81.2% of cases were rodents, in 7.52% of cases domestic animals. In 7.52% of cases, the disease appeared as a result of professional activity, only in 3.76% of cases the disease occurred after swimming in open water. Thus, the main route of transmission of leptospirosis at present is contact (88.72%), alimentary and water are less important, respectively 7.52% and 3.76%. Results of serological examination for leptospirosis by RMA showed that 5 serogroups of leptospir circulate among rodents: L. Pomona and L. Canicola, L. Grippotyphosa, L. Icterohaemorrhagiae, L. A. Ustralis. 36.4% of the samples showed a positive result at the same time to several serogroups. L. Grippotyphosa, L. Cterohaemorrhagiae and L. Pomona were detected more often, in total, these pathogens accounted for 46.5% of positive samples. The results of the survey of farm animals showed that 60.6% of the sera studied had positive results of RMA with leptospirs of several serogroups. L. Sejroe was also isolated – in 12.3% of samples, L. Hebdomad – in 1.3% of samples, L. Icterohaemorrhagiae – in 1.2%, L. Pomona – in 0.3%, others – 24.2%. In the period from 2002 to 2021, the following serogroups were isolated in patients with leptospirosis: L. Grippotyphosa – 36%, L. Pomona and L. Canicola – 16%, L. Australi – 13%, L. Wolffi – 9%, L. Icterohaemorrhagiae – 7% and L. Tarassovi – 3%. In 2022, there is a change in the polytypage of leptospir: L. Icterohaemorrhagiae (6.7%), L. Tarassovi (6.7%), L. Wolffi (6.7%), L. Pomona (13.3), L. Astralis (13.3), L. Canicola (6.7%), 6.7% – L. Sejroe, L. Grippotyphosa Moskva – 40%. For the period from 2005 to 2022, 49 people diagnosed with leptospirosis were treated at the Gomel Regional Infectious Diseases Hospital, of which men accounted for 69%, the average age of patients was 34.5 ± 3.8 years. Most patients are hospitalized on day 6 [4 – 8] of illness. All patients complained of fever, 86% of patients had muscle pain, headaches were recorded in 56.0%, yellowing of the skin and sclera – 34.0%, abdominal pain – 38%, 25% of patients reported nausea, vomiting, diarrhea syndrome. 28.6% of patients had an icteric form of leptospirosis, Weil's syndrome was diagnosed in 9.3% of patients, hemorrhagic syndrome was observed in 18.7% of patients. All patients had laboratory confirmation of the diagnosis. The duration of hospitalization was 15 [9 – 23] days. 1 case of the disease ended with a detailed outcome for the entire observation period. Conclusion. The incidence of leptospirosis in the Gomel region is undulating and is characterized by a change in periods of rising incidence lasting up to 3 years with periods of low incidence lasting up to 5 years. The results of the study suggest that the emergence and spread of the leptospira serotype in the territory led to a new increase in the incidence. Thus, continuous qualitative monitoring of leptospira serotypes among the population of sources of infection should be carried out.

The current epizootic and epidemiological situation of coxiellosis in the territories of the Southern, North Caucasian Federal Districts, Donetsk, Lugansk People's Republics, Zaporizhia and Kherson regions

Objective: to characterize the dynamics and intensity of the incidence of Q fever for the period from 2015 to 2022, to determine the risk areas for human infection in the Southern and North Caucasian Federal districts and in the new subjects of the Russian Federation.Materials and methods: for epidemiological analysis, materials from analytical reviews "The epidemiological situation of natural focal infectious diseases in the Southern and North Caucasus Federal Districts" and state reports "On the state of sanitary and epidemiological welfare of the population" for 2015-2022, reporting data from the Rospotrebnadzor Department for the Rostov region, «Center for Hygiene and Epidemiology in Russia Rostov region» and the Departments of Rospotrebnadzor for the DPR and LPR. From 2022–2023 PCR study was conducted for the presence of Coxiella burnetii DNA in samples of ixodic mites and small mammals in the Rostov region and in 2023 – in the DPR, LPR, Zaporizhia and Kherson regions.Results: the analysis of the territorial distribution of cases of Q fever in the Astrakhan region and Stavropol Territory revealed a cluster of the most disadvantaged areas. An analysis of the conditions of infection of patients with Ku fever in the Rostov region has established that the most likely transmission factors are environmental objects in private farms. The circulation of C. burnetii in natural biotopes of the Rostov region, DNR and LNR regions.Conclusions: the epidemic process of Ku fever is mainly local, limited in the context of municipal districts of Astrakhan and Rostov regions, Stavropol Territory. The sporadic incidence of Ku fever does not reflect its actual level. There is no convincing evidence indicating the leading role of farm animals as a primary link in the formation of the epizootic process of Q fever in anthropurgical foci.

Serological monitoring of actual natural focal infections in the Rostov Region (2020–2022)

Objective: to study the level of the immune layer of the population to pathogens of natural focal infectious diseases in order to establish the epidemic activity of natural foci of particularly dangerous infectious diseases in the Rostov region.Materials and methods: blood serums of healthy donors living in the administrative territories of the region were collected in the period from 2020 to 2022. Specific antibodies in blood sera were determined by the ELISA method. Serum specific IgG class immunoglobulins were used as a serological marker of the transmitted infection.Results: IgG to the Crimean hemorrhagic fever virus was not detected in 2020. In 2021, the share of seropositive results was 0.7%, in 2022 — 2.0%. The proportion of IgG to West Nile virus in 2020 was 8.7%, in 2021 — 9.9%, in 2022 — 12.4%. Serological testing revealed an immune layer to ixodic tick–borne borreliosis in 2020–2022: 3.1%, 2.6% and 2.0%, respectively. Antibodies to hantaviruses, pathogens of hemorrhagic fever with renal syndrome in the blood of residents of the region in 2020 were found in 7.0% of samples, in 2021 — 4.5%, in 2022 — 7.1%. The share of positive samples in the study for Ku fever in 2022 was 2.3%. Conclusion: Seropositive samples were detected for all studied natural focal infections. The greatest variety of natural focal infections confirmed by serological monitoring data was detected in cities (Rostov-on-Don, Taganrog, Zernograd, Kamensk-Shakhtinsky) and districts of RO (Salsky, Neklinovsky, Remontnensky).Conclusion. The results of the serological monitoring made it possible to identify the circulation of pathogens of KGL, LZN, ICB, Ku fever, hantaviruses in the territory of two districts of the region. The detection of specific antibodies in the blood sera of healthy donors indicates the epidemic activity of natural foci. Also, a comprehensive study of healthy donors expanded the understanding of the area of the most relevant natural focal infections such as (KGL, LZN, ICB), and less frequently registered at present (HFRS and Ku fever).

Genetic Marker Detection of Natural-Focal Infectious Disease Pathogens in Samples of Ixodidae Ticks, Collected on the Territory of the Republic of Guinea

The circulation of a rather wide range of pathogens of natural-focal infectious diseases transmitted by ticks was detected in West Africa at different points of time: Borrelia, Rickettsia, Coxiella, Crimean-Congo hemorrhagic fever (CCHF), Bhanja, and bluetongue viruses, etc. Current epidemiological and epizootiological situation on natural-focal infectious diseases on the territory of the Republic of Guinea is not entirely clarified.The aim of this work was to identify genetic markers (RNA/DNA) of natural-focal infectious disease agents in samples of Ixodidae ticks collected in the Republic of Guinea, and to determine the spectrum of pathogens circulating in various landscape-geographical zones of the country.Materials and methods. To conduct research on the territory of all landscape-geographical zones of the Republic of Guinea, 4695 specimens of Ixodidae ticks of 11 species were collected. Taking into account the species appurtenance, gender, phase of development, as well as the site of collection, a panel of 1645 samples was compiled. Genetic markers of Crimean-Congo hemorrhagic fever and tick-borne encephalitis viruses, as well as Borrelia burgdorferi s.l., Ehrlichia chaffeensis, Ehrlichia muris, Anaplasma phagocytophilum, Coxiella burnetii, Rickettsia of the tick-borne spotted fever (TBSF) group, and Francisella tularensis were detected using polymerase chain reaction (PCR) and reverse transcription polymerase chain reaction (RT-PCR).Results and discussion. The following markers of natural-focal disease agents were found in the Ixodidae tick suspensions: DNA of Rickettsia of the TBSF group (25.6 % of all samples studied), DNA of C. burnetii (6.2 %), cDNA of B. burgdorferi s.l. (9.1 %), and RNA of the CCHF virus (2.5 %). The listed spectrum of pathogens has been registered in all landscape-geographical zones of Guinea. Genetic markers of tularemia, anaplasmosis, ehrlichiosis and tick-borne encephalitis pathogens have not been identified in this study. The results obtained made it possible to clarify the probable spectrum of tick-borne diseases in the territory of the Republic of Guinea, determined the need for further study of the circulation of natural-focal infectious disease agents in West Africa and conducting regular epizootiological monitoring.

Results of a Joint Epizootiological Survey of Transboundary Natural Plague Foci of the Russian Federation and Potentially Focal Territories of the Republic of Kazakhstan in 2019–2022

Consolidation of the efforts in implementation of epidemiological surveillance and control over plague and other dangerous natural-focal infections is an essential aspect in ensuring epidemiological well-being as regards particularly dangerous infectious diseases in the territory of natural plague foci and potentially focal territories located within the borders of the Russian Federation and the Republic of Kazakhstan. The aim of the work was to carry out a joint epizootiological survey of the transboundary territories of the Volga-Ural sandy natural plague focus and the territory of the East Kazakhstan region of the Republic of Kazakhstan (RK) potentially focal for plague over the period of 2019–2022. Materials and methods. Samples of field materials, collected during the epizootiological survey of the territory of Kazakhstan, were studied using bacteriological, molecular-genetic, and immune-serological methods. Results and discussion. We have obtained the current evidence on the spatial-biocenotic structure, the circulation of pathogens of dangerous natural-focal infectious diseases in the transboundary territories of Eastern and Western Kazakhstan. It has been established that the conditions that contribute to the possibility of human infection with plague and other dangerous infectious diseases in case of the aggravation of epizootic situation in the foci or importation of the pathogens into the territory are in place.

Babesiosis in humans (lecture)

Babesiosis is a natural focal infectious disease caused by protozoa of the genus Babesia, transmitted transmissibly and characterized by fever, intoxication, progressive hemolytic anemia, and often severe course in immunocompromised patients. The clinical picture of babesiosis is nonspecific. The disease should be suspected in patients with unexplained fever who have been in endemic areas for 2 months or have received a blood transfusion within 6 months. Diagnosis of babesiosis is difficult; depends on the qualifications of the doctor and the number of parasites in the blood. The aim of the work is to summarize the available information about the etiology, epidemiology, pathogenesis, clinic, diagnosis, etiotropic therapy and prevention of babesiosis in humans. A review of domestic and foreign literature over the past 30 years, including Internet resources, has been carried out.

Results of Field and Laboratory Studies of Carriers and Vectors of Natural-Focal Infections on the Territory of the Republic of Armenia

The purpose of the study was to assess the current epizootic potential of the Transcaucasian high-mountain and Pre-Araks low-mountain natural plague foci on the territory of the Republic of Armenia using GIS technologies. Materials and methods. We used the data from an epizootiological survey, records of the abundance and species composition, spatial distribution of rodents and ectoparasites in the plague-enzootic territories of the Republic of Armenia in 2021. Results and discussion. Based on the results of the research, an electronic database of carriers and vectors of pathogens of natural-focal zoonotic infections in the plague-enzootic territories of the Republic of Armenia has been created. Applying GIS technologies, an assessment of the spatial distribution of carriers and vectors of plague has been made and areas of circulation of tularemia and leptospirosis pathogens identified. The results obtained serve as the basis for improving the efficiency of planning and carrying out preventive measures aimed at ensuring the epidemiological welfare as regards natural-focal infectious diseases in the territory of the Republic of Armenia.

International Cooperation of Kazakhstan in the Prevention of Particularly Dangerous Infections

The dependence of the incidence of various nosologies on the epidemic situation in neighboring countries has been a feature of the epidemic process in recent years. In this regard, it is of particular importance to carry out joint anti-epidemic and preventive measures in border areas in order to prevent the importation of dangerous infections into the territory of neighboring states. The aim of the work was to analyze the results of international cooperation in the prevention of particularly dangerous infections. Presented are the areas of cooperation and outcomes of joint research activities. Measures for cooperation between the relevant institutions of the Ministry of Health of the Republic of Kazakhstan and the Rospotrebnadzor on the operational exchange of information in case of emergencies, joint research work on the monitoring of particularly dangerous and other natural-focal infectious diseases in the border areas, joint seminars, scientific and practical conferences on the introduction of modern methods of laboratory diagnostics into practice, internships on the exchange of experience in epizootiological survey in foci of particularly dangerous infections are described in the paper. Examples of Russian-Kazakh cooperation are provided. The results of a joint epizootiological survey of the territory of the Kazakh part of the Altai Mountains are presented. On a global scale, cases of plague and other particularly dangerous infections in any geographic region can constitute international public health emergencies and this type of threat requires international cooperation.

Development of a method for detection of specific antibodies to E protein of yellow fever virus (Flaviviridae: Flavivirus) by enzyme immunoassay

Yellow fever (YF) remains one of the most common natural focal infectious diseases in the world. In connection with the increasing tourist flow to countries endemic for YF, the discovery of stable populations of Aedes aegypti and Ae. albopictus which are the main vectors of the yellow fever virus (YFV), in the southern regions of Russia, and the fact that in medical institutions in our country it is possible to obtain a live attenuated vaccine against YF, but there is no way to evaluate the effectiveness of vaccination, the question arises of the development and implementation of diagnostic kits for detecting antibodies (AB) to the pathogen by enzyme immunoassay (ELISA).The aim of this study was to develop a method for detecting specific IgG antibodies to the E protein of YFV by ELISA and assessing its diagnostic characteristics. A specific cDNA was synthesized by reverse transcription on an RNA template of YFV isolated on a cell culture of Aedes albopictus clone C6/36, and a fragment of the genome coding the YFV E protein was amplified and subsequently cloned into the plasmid pET160 (Thermo Fisher Scientific, USA). The resulting gene fragment was used as a DNA template to obtain a recombinant analog of the third domain of the YFV E protein in Escherichia coli cells (BL-21(DE3)). Next, the immunogenicity of the obtained antigen was evaluated and the analysis conditions were optimized. The optimal conditions for the production of the obtained recombinant E protein of YFV were determined, its specificity was confirmed by immunological methods (Western blot and ELISA), sorption buffers and blocking solutions were selected, and sensitivity and specificity of detection of antibodies to YFV using the recombinant antigen were assessed. A method for the detection of specific IgG antibodies to the YFV E protein by ELISA was developed. This diagnostic kit can be used both to study the protective properties of the YF vaccine and to detect imported cases of infection in non-endemic areas.

Experience in Using Mobile Laboratory for Monitoring and Diagnostics in the Socialist Republic of Vietnam

The aim was to present the experience of using mobile laboratory for monitoring and diagnostics (MLMD) during the epizootiological monitoring of the northern provinces of Vietnam. MLMD was transferred by Federal Service for Surveillance in the Sphere of Consumers Rights Protection and Human Welfare to the Socialist Republic of Vietnam as part of implementation of cooperation programs on combating infectious diseases. The use of MLMD made it possible to obtain new information on the circulation of pathogens of natural-focal infectious diseases on the territory of Vietnam. It also provided the necessary conditions for conducting research using methods of express diagnostics, bacteriological analysis, performing a full cycle of work – from the receipt of samples to the disinfection and destruction of infected material in compliance with the requirements of biological safety in the field. The effectiveness of using mobile laboratories in response to the emergencies of sanitary and epidemiological nature, both to strengthen stationary laboratory bases and to organize diagnostic studies in remote regions, has been shown. The use of MLMD for the diagnosis of COVID‑19 has been an effective component of countering the new coronavirus infection in Vietnam and significantly increased the volume of testing in the country.

Распространение, патогенез и комплексная терапия лептоспироза собак

Leptospirosis is a natural focal infectious disease of domestic and wild animals of many species, including humans. This disease in the conditions of the Bezhitsky veterinary hospital in Bryansk tends to increase over the past three years. In 2019, 9 dogs suffering from leptospirosis were registered, in 2020 – 12, in 2021 – 16 dogs. The change in biochemical parameters with varying degrees of severity of the course of leptospirosis was profound. The total protein content throughout the experiment was lower than the control by 29.6, 25.4 and 32.7 %, respectively. Indicators of nitrogenous products in the blood – urea and creatinine had a tendency to increase. Glucose on days 1-9-18 of the experiment was lower than in control individuals in 1,6–2,9–2,4 three times. Cholesterol increased throughout the study, but the peak of its rise was observed on day 9 – 39.2 %. The highest concentration of bilirubin was 4.4 times at the initial stage. Calcium and phosphorus tended to decrease in comparison with the control only at the end of the experiment by 41,4 and 46,1 %, respectively. The indicators of enzyme metabolism were strained and were high compared to the control analogues. On days 1–9–18 of the study, the ALT and AST levels were higher, respectively, in 2,0–2,1–2,2 and 2,6–2,7–2,8 three times. The content of alkaline phosphatase was the most significant on the 18th day of the experiment. The most effective result from complex treatment was obtained in the experimental group, where the chemotherapeutic agent enrofloxacin, hepatotropic – heptral, hormonal – dexamethasone and others were used. In the control group, where traditional therapy was used, the clinical status of the animals was normalized on day 17, in the experimental group – on day 12.

Current Status of the Natural Foci of Tick-Borne Diseases in the Stavropol Region

Background: Tick-borne diseases are a serious threat to the epidemiological safety of the population of the Stavropol Region, making up more than 70 per cent of all natural focal infectious diseases registered in this territory annually. A wide range of hosts contributes to high tick abundance, diversity of tick-borne pathogens, and maintenance of the natural foci. Objective: To assess the activity of natural foci of tick-borne infections in the Stavropol Region in 2016–2020. Materials and methods: We used notifications submitted by the Center for Hygiene and Epidemiology in the Stavropol Region to the Scientific and Methodological Center for Monitoring the Pathogens of Infectious and Parasitic Diseases of Pathogenicity Groups II–IV for the subjects of the North Caucasian and Southern Federal Districts and the results of an epizootological survey of the Stavropol territory by specialists of the Stavropol Plague Control Research Institute. Markers of the causative agents of tick-borne diseases were detected by ELISA and PCR methods. Data processing was carried out using Microsoft Excel 2010. Results: Active natural foci of Crimean-Congo hemorrhagic fever, Q fever, a group of tick-borne spotted fevers, Lyme disease, human granulocytic anaplasmosis, and human monocytic ehrlichiosis were established in the region in 2016–2020. Human cases of the Crimean-Congo hemorrhagic fever, Lyme borreliosis and Q fever were also registered annually. The abundance of infected ticks in resort towns of the Caucasian Mineral Waters is of particular concern. Conclusion: We established up-to-date epizootic and epidemic manifestations of tick-borne infections in the Stavropol Region in the modern period, which are an important link in epidemiological surveillance and the basis for improving preventive measures

PRECONDITIONS TO DEEPEN BASIC KNOWLEDGE ON ISSUES OF "NATURAL FOCAL INFECTIONS" IN MEDICAL STUDENTS NOWADAYS

At the stage of forming of fundamental knowledge on focal infectious diseases, three compulsory disciplines are vertically “encountered”: medical biology, microbiology, virology and immunology, and infectious diseases. Microbiology, virology and immunology occupy a central position in the formation of basic knowledge, and as a leading preclinical discipline, it lays the foundations for the application of acquired knowledge, skills and abilities by future healthcare professionals. The article discusses the preconditions to form the fundamental knowledge of natural focal infections in medical students, whose majors are specialty "Medicine», and "Paediatrics", as well as possible ways to boost students’ cognitive activity/ learning interest, taking into account interdisciplinary integration. Medical students gain knowledge on natural focal infectious diseases, the scientifically grounded characteristics of this group of infections and the ways to apply this knowledge during their II and III years being fostered in the educational and cognitive environment of the Department of Microbiology, Virology and Immunology. Students are guided on receiving knowledge on natural focal infections also during independent out-of-class training. Such model is implemented in four stages, each of which assumes its own psychological and didactic goals aimed at the implementation of educational activities, and as the end result, consisting in the formation of basic knowledge on each specific topic of the practical lesson, for each specific thematic block, and at the end of intensive cognitive activity at the department - an expected high-quality educational and effective product from the mastered discipline.

The Problem of Natural Focal Infectious Diseases in the Volgograd Region: A State-of-the-Art Review

Introduction: The importance of the problem of natural focal infections (NFIs) in the world is associated with their wide spread and a severe clinical course. The Volgograd Region, which is part of the Southern Federal District, is endemic for a whole number of NFIs. Regional epizootic and epidemic manifestations in foci of plague, tularemia, Q fever, ixodes tick-borne borreliosis (Lyme disease), hemorrhagic fever with renal syndrome (HFRS), Crimean – Congo hemorrhagic fever (CCHF), and West Nile fever (WNV) have been of varying degrees of activity over a long period of time. Objective: To study the features of epidemic and epizootic manifestations of natural focal diseases (plague, tularemia, Lyme disease, HFRS, WNV, CCHF, Q fever) in the territory of the Volgograd Region. Materials and methods: We analyzed the results of epizootologic and epidemiologic surveillance carried out in natural foci of contagious diseases in the Volgograd Region over the past decade, including data on the incidence of NFIs and the results of laboratory testing of zoological and entomological assays. We did an epidemiologic analysis of the ten-year rate, structure and changes in the incidence of natural focal diseases in the population of the Volgograd Region. Electronic databases were developed and analyzed in Microsoft Excel 2010 (Microsoft, USA). Results and discussion: We established that over the past decade, the number of endemic areas in the Volgograd Region has risen from 18 to 25 for СCHF and from 5 to 11 for Lyme disease. At present, all regional districts are endemic for tularemia, WNV, HFRS, and Q fever, 25 districts – for CCHF, and 11 – for Lyme disease. We observed a general promising tendency towards a decrease in incidence rates for all nosological forms. At the same time, the incidence of Q fever and Lyme disease remains low while that of HFRS and СCHF is somewhat higher. The West Nile fever, epidemic manifestations of which have been registered since 1999, is the main challenge in terms of NFIs in the Volgograd Region today.

A Multi-Model Paradigm in Application to the Analysis of the Factors Defining the Epizootic Situation in the Communities of Non-Synanthropic Small Mammals in Ekaterinburg

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.

Lessons Learned from and Prospects of Using Mobile Laboratories for Epidemiological Surveillance over Plague, Other Particularly Dangerous, Natural-Focal, Zoonotic Infectious Diseases

The review presents the materials on the use of mobile laboratories, developed in the Russian Federation, in the framework of four main areas: monitoring of territories to identify the circulation of pathogens of natural-focal infectious diseases; monitoring of territories during the exacerbation of the epizootic situation; participation in the elimination of outbreaks of infectious diseases; monitoring of territories to control and predict the epidemiological and epizootiologic situation in preparation for mass events. The tactical and technical characteristics and the procedure for organizing the operation of the mobile laboratory for monitoring and diagnostics mounted on the platform of the KamAZ chassis are considered. A distinctive feature of the laboratory from the existing Russian and foreign counterparts is the availability of the necessary conditions for conducting research using bacteriological analysis, rapid and accelerated diagnostic methods, and performing a full cycle of works – from the preparatory stage to the destruction of infected material. Hightech equipment allows the realization of two research schemes: the first – bacteriological analysis alongside the PCR, which ensures high reliability of the results; the second – conducting the PCR at the first stage, and when identifying genetic markers of the pathogen – performing bacteriological analysis of positive samples in order to isolate the culture of the pathogen and identify it subsequently. The second scheme will reduce the volume of bacteriological studies; make changes in the tactics of epizootiological survey. Tests of the mobile laboratory have demonstrated the effectiveness of its use in the epizootiological examination of natural plague foci, including cross-border ones. Owing to the use of a mobile laboratory in the Gorno-Altaisk high-mountain natural focus of plague, a new epizootic site was identified, located in a remote area, used by the population as a summer pasture for grazing domestic animals. The use of mobile laboratories will strengthen the laboratory base of institutions that monitor particularly dangerous, natural-focal and other dangerous infectious diseases; will help to bring the advanced diagnostic technologies directly to the natural focus, reduce the risk of epidemic complications due to plague and other particularly dangerous infections in cross-border natural foci.

Детекция и генотипирование вируса ККГЛ в популяциях клещей на территории Жамбылской области

The Republic of Kazakhstan has favorable conditions for the development and distribution of many species of ticks, which are carriers of various types of pathogens of especially dangerous infections. In the course of this study, 319 samples (32 pools) of ticks in the Zhambyl region were collected and examined for the presence of arboviruses. In 2021, the circulation of the CCHF virus was detected among ticks living in the Zhambyl region by the method of polymerase chain reaction with reverse transcription. The population of the CCHF virus in the Republic of Kazakhstan has not been studied more widely, there is no information on the genetic affiliation of the new virus isolates circulating in the country. Analysis of new data on the genetic diversity of the CCHF virus will make it possible to assess the current state of the virus population, to determine the boundaries of the distribution areas of genetic variants of the CCHF virus in the territory of the Republic of Kazakhstan. The work was performed using molecular genetic methods (isolation of nucleic acids, RT-PCR, DNA sequencing according to Sanger), the method of phylogenetic analysis using the Mega 7.0 program, the method of geoinformation analysis using the ArcGIS 10.4.1. program. The nucleotide sequences of the S segment fragment of two CCHF virus isolates isolated from ticks inhabiting the Zhambyl region were determined. Analysis of the nucleotide sequences of the S segment of two CCHF virus isolates showed that they belong to the Asia 2 genotype. New isolates are genetically close to the CCHF viruses isolated in South Kazakhstan, Uzbekistan, Tajikistan, and India. The obtained materials will serve as the basis for the development of a strategy for epidemiological surveillance of natural focal infectious diseases in the territory of the Republic of Kazakhstan.

Emerging Natural Focal Infectious Diseases in Russia: A Medical-Geographical Study.

In Russia, as in other countries, the problem of emerging natural focal infectious diseases (EIDs) became more acute toward the end of the 20th century. However, the situation in Russia is unknown to foreign readers, while the prevention and control of these diseases require international collaboration. The aim of the study is to provide a medical–geographical assessment of the distribution of the main natural focal EIDs in Russia, as well as to present the approaches used in the country to create aggregate maps of risk assessment. To consider its current status, we determined the most important natural focal EIDs for Russia (tick-borne encephalitis, ixodid tick-borne borrelioses, hemorrhagic fever with renal syndrome, Crimean–Congo hemorrhagic fever, West Nile fever, Astrakhan spotted fever, leptospiroses, and tularemia) and analyzed the patterns of their epidemic manifestation. As a result, a working classification of such infections and a series of maps showing the current situation of EID morbidity in Russia were created. To design an aggregated risk map, we developed an original mapping methodology and recalculated the model disease incidence by taking data from administrative units and adjusting them for natural geographical boundaries (biomes) for European Russia, and then evaluated the risk of infection for separate model diseases and for a set of them. The highest risk rates are confined to the northwest regions of European Russia, the Cis-Urals and the Volga region, which are naturally related to forest biomes, as well as to the southern steppe regions of the interfluves between the Volga and the Don, and the foothills of the North Caucasus.

Ectoparasite Complex of the East European Vole Microtus rossiaemeridionalis (Arvicolinae, Rodentia) on the Northern Border of the Range in Western Siberia

The purpose of the researchis establishing the composition, infection rates, species and group ratio of ectoparasites of the East European vole on the northern border of the range in Western Siberia (Middle Ob Region).Materials and methods.In 2015–2018, in order to capture the provider of ectoparasites, the East European vole, we used methods of trap lines, trap trenches, and fence-traps; we recorded 173 animals from which we collected 881 specimens of gamasid mites, ixodic ticks, lice and fleas. To assess the quantitative indicators of ectoparasites, the indices generally accepted in parasitology were used.Results and discussion.In 2014, it was established for the first time that there is a sibling species of the common vole, the East European vole in the Middle Ob Region (middle taiga of the forest zone of Western Siberia). In the city of Surgut and its neighborhood, this animal is confined to the most transformed biotopes. The ectoparasite complex of the East European vole includes 26 species of parasitic arthropods. By the number of species (13) and individuals, gamasid mites predominate, and the proportion of ixodic ticks, lice and fleas put together is almost 3 times lower. In a climate of the Middle Ob Region, the list of ectoparasites will no doubt grow as the range of habitats expands and the contacts of the East European vole with other small mammals increase, and its role in maintaining pathogen circulation of natural focal infectious diseases will increase.

Efficiency of Human Plague Vaccination in Tuvinian Natural Plague Focus

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.