Ixodes Tick-borne Borreliosis Research Articles

Clinical and laboratory prognostic factors in patients with mixed infection of erythema form of ixodic tick-borne borreliosis and tick-borne encephalitis

Background. Early diagnosis of the mixed infection of ixodic tick-borne borreliosis and tick-borne encephalitis can be difficult without laboratory confirmation of the diagnosis.The aim. To assess clinical and laboratory predictors in patients for building the models of early differential diagnosis between mixed infection of erythema form of ixodic tick-borne borreliosis and febrile form of tick-borne encephalitis and monoinfection of erythema form of ixodic tick-borne borreliosis.Materials and methods. The clinical study included 26 patients with mixed infection of the erythema form of ixodic tick-borne borreliosis with tick-borne encephalitis (mean age – 46.7 years) and 30 patients with monoinfection of the erythema form of ixodic tick-borne borreliosis (mean age – 48.5 years). 59 clinical, epidemiological and laboratory parameters, including 6 leukocyte blood indices, standard and extended hemogram profiles were studied in these patients the first week of the disease. For statistical analysis, we used Pearson and Mann – Whitney goodness-of-fit tests, ROC analysis with calculation of the area under curve (AUC) and logistic regression. Results. Patients with mixed infection, compared to the patients with monoinfection, had increased odds of having febrile fever, weakness, headache and orbital pain; meningism symptoms occurred only in patients with mixed infection. Early predictors of a preliminary diagnosis of mixed infection were elevated values of fever (AUC = 0.87), intoxication syndrome score (AUC = 0.71), leukocyte count (AUC = 0.64) and neutrophils (AUC = 0.71) in the hemogram, levels of leukocyte intoxication index according to V.K. Ostrovsky (AUC = 0.67) and neutrophil-leukocyte index (AUC = 0.65), as well as a decrease in the number of platelets (AUC = 0.77), eosinophils (AUC = 0.72) and basophils (AUC = 0.79) in peripheral blood. Two prognostic models which included clinical and laboratory parameters demonstrated excellent prediction of mixed infection (AUC = 0.90 and AUC = 0.91).Conclusion. Early clinical and laboratory predictors have been established and models have been developed that make it possible, with excellent prognosis quality, to calculate in patients the probability of a preliminary diagnosis of mixed infection of the erythema form of ixodic tick-borne borreliosis with tick-borne encephalitis in comparison with borreliosis monoinfection.

Tick-borne infections in the Leningrad oblast: incidence and seroprevalence

The study’s objective was to reveal trends in infections transmitted by ixodes ticks epidemic processes and the level of seroprevalence of the population to the tick-borne encephalitis virus, Borrelia burgdorferi sensu lato, Coxiella burnetii, Anaplasma phagocytophilum and Ehrlichia chaffeensis/ E. muris in the Leningrad Oblast.Materials and methods. A retrospective epidemiological analysis of the tick-bite incidence rate, the ixodic tick-borne borreliosis, tick-borne encephalitis, Q fever, human granulocytic anaplasmosis and human monocytic ehrlichiosis incidence rates, as well as vaccination against tick-borne encephalitis of the population of the Leningrad Oblast in 20112020. The official data of the tick-bite incidence rate, infections transmitted by ixodes ticks incidence rates and vaccination of the population was taken from the forms of federal statistical observation No. 2 and No. 5. Blood was sampled in 2019-2020 from randomly selected donors. Blood serum samples were examined by enzyme-linked immunosorbent assay for the presence of IgG antibodies to the pathogens of the studied infections using commercial test systems according to the manufacturer’s instructions.Results. In the Leningrad Oblast, in 2011-2020, there was a downward trend in the tick-bite incidence rate, as well as in the incidence rates of infections transmitted by ixodic ticks. The long-term average tick bite incidence rate was 369.0. The long-term average incidence rate of ixodic tick–borne borreliosis was 4.1; tick–borne encephalitis was 1.4; Q fever was 0.02. During the analyzed period, no cases of human granulocytic anaplasmosis and human monocytic ehrlichiosis were reported. The seroprevalence to tick-borne encephalitis virus was 1.7%; to B. burgdorferi s. l. – 3.7%; to C. burnetii – 1.8%; to A. phagocytophilum – 1.0%; to E. chaffeensis/ E.muris – 3.2%.Conclusion. The results obtained indicate the existence of active natural foci of infections transmitted by ixodes ticks, fairly frequent contact of the residents with these foci, and possible significant hypodiagnosis of these infections in the Leningrad Oblast.

Epidemiological situation of natural focal infections in the Volgograd region in 2023

Objective: analysis of epizootiological and epidemiological aspects of natural focal infections, namely plague, tularemia, HFRS, West Nile fever, Crimean hemorrhagic fever, Ixodic tick-borne borreliosis, Cu fever, leptospirosis and rabies, in the Volgograd region over 10 months in 2023.Materials and methods: the article analyzes the epidemiological manifestations of natural focal infections (NFI) in the Volgograd region for 10 months of 2023. The work uses official statistical data from institutions of Rospotrebnadzor of the Volgograd region on NFI for 2023. The main research method is epidemiological analysis.Results: the numbers of small mammals, potential carriers of NFI, on the territory of the Volgograd region in the 2023 season were within the same indicators of the previous year (SIPY), while the number of ticks in the spring-summer period was higher than the SIPY, but in the fall the number of arthropods in stationary points was lower than in previous seasons. The number of mosquitoes carrying arbovirus infections exceeded the long-term average. When studying environmental objects for the presence of markers of NFI pathogens, a slight decrease in the proportion of positive samples was noted compared to SIPY for all nosological forms. Over the 10 months of this year, there has been a deterioration in the epidemiological situation in the Volgograd region for several infections compared to the same period in 2022. There were 18 cases of West Nile fever (WNF), 10 cases of ixodid tick-borne borreliosis (ITB), and 6 cases of hemorrhagic fever with renal syndrome (HFRS). No patients with plague, tularemia, rabies, leptospirosis, Crimean hemorrhagic fever (CHF) and Q fever were identified.Conclusion: the presence of natural foci of dangerous infectious diseases of varying degrees of activity on the territory of the Volgograd region requires constant monitoring and an adequate response to changes in the foci in order to prevent complications of the epidemiological situation due to NFI.

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).

Epizootological situation and epidemiological risks for natural focal infections in the territory of new subjects of the Russian Federation (Donetsk People's Republic, Lugansk People's Republic, Zaporozhye and Kherson regions)

An epizootological inspection of the liberated territories of the Donetsk and Lugansk People's Republics, Zaporozhye and Kherson regions was carried out. It was established that the faunal complex of small mammals, hare-like and ectoparasites, as well as their number, make it possible to ensure the circulation of natural focal infections identified by the results of laboratory studies: tularemia, Crimean hemorrhagic fever (CHF), West Nile fever (WNF), ixodic tick-borne borreliosis (ITB), rickettsiosis, human granulocytic anaplasmosis (HGA), leptospirosis, hemorrhagic fever with renal syndrome (HFRS), Q fever, intestinal yersiniosis, Batai, Inco, Sindbis, Tyaginya fevers. For the first time, the PCR method in field material from the Zaporozhye region (Berdyansk and Melitopol regions) detected the Crimean-Congo hemorrhagic fever virus, on the territory of the Donetsk and Lugansk People's Republics in the populations of small mammals (rodents and insectivores), the circulation of viruses Inco, Sindbis, Tyagin, Batai was established. In the territories of Kherson and Zaporozhye regions, the presence of combined and conjugated natural foci of ixodic tick-borne borreliosis, rickettsiosis and human granulocytic anaplasmosis is determined. According to the results of molecular genetic analysis, it was shown that the causative agents of natural focal infections (Crimean hemorrhagic fever, West Nile fever, ixodic tick-borne borreliosis, rickettsiosis) identified in 2023 are genetically close to strains circulating in the regions of the south European part of Russia.

Epidemic status in Russia’s Northwestern Federal District: tick-borne encephalitis and ixodes tick-borne borreliosis (lyme disease), 2002–2021

The study's objective was to reveal trends in tick-borne encephalitis (TBE) and Ixodes tick-borne borreliosis (ITBB) epidemic processes in Russia's Northwestern Federal District (NWFD) in 2002–2021. In the NWFD during the analyzed period, more than 1.1 million patients sought medical help following tick bites (14% of all cases registered nationwide). The long-term average tick bite incidence rate in the NWFD exceeded the nation-wide value: 409.5 and 280.7, respectively. In the NWFD, the highest long-term average tick bite incidence rates were recorded in Vologda Oblast, Pskov Oblast, and Novgorod Oblast. The tick bite incidence rate tended to grow in the NWFD, as well as nationally. The growth in tick bite incidence was statistically significant in the Republic of Komi, Kaliningrad Oblast, and Arkhangelsk Oblast. In 2002–2021, more than 6000 TBE cases were registered in the NWFD (11% of all cases registered nationwide), and the TBE long-term average incidence rate in the NWFD exceeded the national value: 2.3 and 2.0, respectively. The Republic of Karelia, Arkhangelsk Oblast, and Vologda Oblast were three NWFD subjects with high TBE epidemical hazard. TBE incidence in the analyzed period tended to decrease, both in the NWFD and nationwide. A statistically significant decrease in TBE incidence was revealed in St. Petersburg, in the Republic of Karelia, in Novgorod Oblast, and in Leningrad Oblast. About 22 000 ITBB cases were reported in the NWFD during the analyzed period (15% of all ITBB cases in Russia). The ITBB long-term average incidence rate in the NWFD exceeded the national value: 7.9 and 4.9, respectively. Vologda Oblast, Kaliningrad Oblast, and Pskov Oblast were three NWFD subjects with high epidemical hazard in terms of ITBB. ITBB incidence during the analyzed period tended to decrease, both in the NWFD and nationwide. The decrease in ITBB incidence was statistically significant in Vologda, Kaliningrad, Novgorod, Leningrad and Pskov Oblasts, as well as in St. Petersburg. In the Republic of Komi, in contrast to other NWFD subjects or national data, there was an uptrend in both TBE and ITBB incidence.

Review of the Epidemiological Situation on Ixodic Tick-Borne Borrelioses in the Russian Federation in 2013–2022 and Forecast for 2023

The aim of the review was to characterize the epidemiological situation on ixodic tick-borne borreliosis (ITBB) in the constituent entities of the Russian Federation in 2022, to forecast the development of the ITBB epidemic process in 2023 based on the analysis of its trends in the period of 2013–2022. In total, 7 264 cases of ITBB were registered in the Russian Federation in 2022, which is 1.9 times higher than the 2021-value. In all regions in 2022, after a sharp decrease in the level of registered morbidity during the “covid” phase of 2020–2021, there was an incidence raise to the pre-pandemic level. During 2013–2022, distinctive features of the trends in the development of the ITBB epidemic process in the territories of varying degree of epidemic hazard were retained. A downward tendency in the incidence rates was revealed in 14 out of 18 entities with a long-term average annual incidence (LTAA) of ITBB above 6.2 0 /0000, with the exception of Moscow and the Kaluga Region, where a further increase in the incidence of ITBB is possible. In 6 out of 16 regions with LTAA 2013–2022 between 3.31 and 6.2 0 /0000, an upward trend was observed, and in 8 – a decrease in morbidity. The trend towards an increase in morbidity was detected in 7 out of 21 entities with LTAA of ITBB from 1.21 to 3.3 0 /0000 and in 15 out of 26 regions with a low LTAA 2013–2022 (below 1.2 0 /0000). The analysis of trends in the development of the ITBB epidemic process against the trends in changes in the frequency of contacts of the population with ticks, as well as calculations of the probable incidence rate allowed us to conclude that the incidence rate of ITBB in 2023 will range within the confidence intervals of long-term average annual values for the majority of the federal districts, with the exception of the Central Federal District, where an increase in the number of cases of ixodic tick-borne borreliosis is likely to occur, provided that the existing volumes of preventive measures are maintained and abnormal climatic phenomena absent. Effective control of the epidemic situation on the ITBB is attainable through preservation, and for such areas as Moscow, the Moscow Region, Voronezh, Kaluga, Orel, Ryazan, Penza and Rostov Regions, the Republic of Buryatia – increase in the volume of preventive measures, strengthening zoological and entomological monitoring of activity and structure of natural foci. There is an obvious need to develop algorithms for molecular-genetic monitoring of pathogens circulating in natural foci, and to focus attention onto the problems of diagnosis and prophylaxis of tick-borne transmissible infections.

Характеристика эндемичности по инфекциям, возбудители которых переносят иксодовые клещи (клещевой вирусный энцефалит, иксодовые клещевые боррелиозы) в Ульяновской области

The work presents the results of monitoring the incidence of the population and the lesion of ticks with the tick-borne encephalitis virus, borrelias of ixodic tick-borne borrelioses for 2002–2021. in the administrative territories of the Ulyanovsk region endemic to tick-borne encephalitis. The results of monitoring the number of Ixodes and Dermacentor mites, their species composition and their changes are presented. Keywords: monitoring, ticks, tick-borne encephalitis, ixodic tick-borne borreliosis, endemicity, Ulyanovsk region.

Clinical and Epidemiological Manifestations of Ixodic Tick-Borne Borreliosis Foci in the Tomsk region

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.

Distribution of the causative agent of relapsing tick-borne fever Borrelia miyamotoi in natural foci in the Tomsk region

Background: Knowledge about the infectious potential of the causative agent of recurrent tick-borne fever Borrelia miyamotoi and the role of this pathogen in the etiological structure formation of transmissible natural focal infections in a number of regions remains incomplete. Among them is the Tomsk region where in 2021 the incidence of ixodic tick-borne borreliosis was 15.7 per 100 thousand population, which is 3.6 times higher than the all-Russian indicator.
 Aims: to summarize and analyze epidemiological data, as well as the results of our own clinical observations and laboratory studies conducted in 2015-2021 confirming the distribution of the causative agent of relapsing tick-borne fever B. miyamotoi in the Tomsk region.
 Materials and methods: Epidemiological data on the manifestation of natural foci of tick-borne infections were analyzed in the Tomsk region for the period 2015-2021. A clinical case of febrile infection caused by B. miyamotoi infection is described as an example of underdiagnosis of relapsing tick-borne fever. Verification of the etiological variant of borreliosis was carried out using real-time PCR. DNA extraction and detection of B. miyamotoi genetic markers were performed using RealBest series kits (Vector-Best, Novosibirsk), followed by nucleic acid sequencing of B. miyamotoi 23SrRNA, glpQ, and recA gene sequences.
 Ixodid ticks (I. persulcatus, I. pavlovskyi, D. reticulatus) collected in the Tomsk region were studied for infestation with B. miyamotoi. Detection of genetic markers of pathogenic borrelia was carried out in nucleic acid samples isolated from tick homogenates using kits of the RealBest series (Vector-Best, Novosibirsk).
 Results: In 2016, the first clinical case of borreliosis caused by B. miyamotoi confirmed by molecular genetic methods in the Tomsk region was identified. During the period 2015-2021, the infection rate of B. miyamotoi ticks of the genus Ixodes in the Tomsk region was up to 7%; ticks of the genus Dermacentor up to 3%.
 Conclusion. The results of this study demonstrated the distribution the causative agent of relapsing tick-borne fever B. miyamotoi in the natural foci of the Tomsk region, which requires further monitoring of the epizootic situation and study of the role of this pathogen in the formation of the etiological structure of transmission natural focal infections.

Results of Ixodes Tick-Borne Borreliosis Monitoring in Crimea in 2015–2021

Introduction: The studies of borreliosis and the official disease registration in Crimea began in the year 2000. An obvious increase in the number of human cases of Ixodes tick-borne borreliosis has been observed since then: 204 cases of Lyme disease were registered in Crimea in 2000–2014 and already 324 cases in the years 2015–2021. Objective: To specify reservoirs, vectors and boundaries of natural foci of tick-borne borreliosis in Crimea based on the results of research conducted in 2015–2021. Materials and methods: Collection of Ixodes ticks and trapping of small mammals were carried out in all administrative areas in different landscape zones of the Crimea. The field material was delivered to the laboratory, where it was identified, pooled, and investigated using molecular genetic methods. Geoinformation technologies were used to map the results. Results and discussion: The majority of positive markers of tick-borne borreliosis were found in pools of Ixodes ticks in the Mountain and Foothill area while positive samples from small mammals were detected in the Steppe part of the peninsula. The dominant species of reservoirs (gen. Crocidura, Cricetulus, Rattus) and vectors (gen. Ixodes) of tick-borne borreliosis in Crimea in the years 2015–2021 were identified. Conclusion: Lyme borreliosis is distributed almost throughout the whole territory of the Crimean Peninsula. A systematic local monitoring of reservoirs and vectors of tick-borne borreliosis is important to clarify the features of activity of natural foci in different natural zones, to determine the diversity of Borrelia species, and to assess the disease risk for humans.

Epizootiological aspects of natural nidality of Ixodes tick-borne borreliosis in the Moscow region (Russian Federation)

Background and Aim:At present, tick-borne borreliosis is the most common infectious disease transmitted by ticks in Europe, Asia, and North America. This study aimed to examine the epizootiological aspects of the natural nidality of tick-borne borreliosis in Moscow region (the Russian Federation).Materials and Methods:A total of 2,537 ticks representing two species were collected, namely, Ixodes ricinus and Dermacentor reticulatus. The activity, number of ticks, and Borrelia infestation rates were investigated during a high season, that is, from early spring to mid-autumn.Results:In May, amount of I. ricinus spp. was found 2.5 times more than those representing D. reticulatus spp. (p≤0.01). In June, August, and September, the amount of I. ricinus was 9.0 (p≤0.0001), 2.0 (p≤0.05), and 5.0 times higher, respectively, compared to D. reticulatus. In the first 10 days of April, the amount of D. reticulatus was 3 times higher than that of I. ricinus (p≤0.02); in the next 10 days, their amounts were equal (p≥0.05) and in the last 10 days the amount of I. ricinus exceeded that of D. reticulatus (p≤0.05) by 1.5 times. In general, Borrelia afzelii, and Borrelia garinii, were detected. In addition, the naturally occurring tick-borne borreliosis pesthole was revealed in the Moscow region.Conclusion:Borrelia infection rates for ticks comprise 30%. An increase in Borrelia tick infestation was detected within the vicinity of populated areas. The amount of ticks directly depends on the temperature (20°C-25°C) and moisture (from 50%) values.

Early neuroborreliosis in children, Bannwart syndrome (clinical observations)

The problem of ixodic tick-borne borreliosis remains relevant due to its ubiquity, high incidence, especially in the Northwestern Federal District, a variety of clinical manifestations, as well as the possibility of chronization, including in children.Purpose: to describe our own clinical observations of Bannwart syndrome, which developed during the dissemination of the pathogen.Results. Bannwart syndrome is pathognomonic for borreliosis symptoms, including a triad of clinical manifestations: serous meningitis, single- or bilateral lesion of facial nerves, polyneuropathy. Timely clinical and adequate laboratory diagnostics determine the favorable course of the disease.

Results of epizootic monitoring of natural foci of particularly dangerous infections common to humans and animals in Rostov Oblast

Objective: To analyze the results of epizootic monitoring of natural foci of particularly dangerous infections common to humans and animals in Rostov Oblast to establish their activity.Materials and Methods: The data of epizootic monitoring conducted by zoologists; the results of laboratory research of field material obtained in natural foci of infectious diseases. Descriptive, zoological, genetic, serological methods, and retrospective epidemiological analysis were used.Results: The results of the conducted epizootic monitoring showed the presence in Rostov Oblast of natural foci of particularly dangerous infectious diseases common to humans and animals. While the natural focus of the plague is in a depressed state and does not show activity, in the foci of tularemia, West Nile fever (WNF), Crimean hemorrhagic fever (CHF), ixodic tick-borne borreliosis (ITB), hemorrhagic fever with renal syndrome (HFRS), Q fever, Batai fever, California serogroups, Syndbis revealed the antigens of these pathogens in biological material obtained from small mammals and blood-sucking insects, which indicates the epizootic activity of these foci. In the natural foci of WNF, CHF, ITB, HFRS, cases of these disease among the population were recorded, which confirms the epidemic activity of these foci.Conclusion: The obtained results of epizootic monitoring over the period from 2008 to 2020 emphasize the relevance and necessity of continuing these studies in natural foci in Rostov Oblast.

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.

Lipid peroxidation and oxidative modification of proteins in tick-borne encephalitis and ixodic tick-borne borreliosis

BACKGROUND: In the South Ural region of Russia, the group of ITTB and TBE occupies the leading rank positions in the structure of infections that are ecologically associated with ixodic ticks. At the present stage, studies aimed at studying non-specific pathological biochemical processes that determine the degree of oxidative damage to cell membranes and organelle membranes, the reactivity of the body, its reserve-adaptive potential under the influence of a number of endogenous and exogenous factors are becoming particularly relevant. One of the most significant metabolic processes of this kind is the free radical oxidation of lipids and the oxidative modification of proteins.
 AIMS: To give a clinical and epidemiological characteristic and to study the role of oxidative stress in the pathogenesis of various clinical forms of tick-borne infections in an endemic region (on the example of the Chelyabinsk region).
 MATERIAL AND METHODS: The study was conducted at the clinical base of the Department of Infectious Diseases of the Southern State Medical University in the MAUZ GKB No. 8 in Chelyabinsk. The study randomly included 105 patients with tick-borne encephalitis, ixodic tick-borne borreliosis and mixed infection who were hospitalized in the hospital in the period from May to October 20182019. The diagnosis was verified by standard immunological methods (ELISA). Modern molecular genetic methods (PCR-RV) were used in the etiological diagnosis of ICD. Material for the study: leukocyte fraction and blood serum. The content of carbonyl products of oxidative modification of proteins was estimated by their reaction with 2.4-dinitrophenylhydrazine, followed by spectrophotometric registration of the interaction products-dinitrophenylhydrazones. When determining the content of primary and secondary products of lipid peroxidation, a method based on the phenomenon of rearrangement of double bonds into diene conjugates during the peroxidation of polyunsaturated fatty acids was used. Statistical processing of the obtained results was carried out by standard methods of nonparametric statistics using the Statistica 8.0 for Windows software package.
 RESULTS: In the structure of infections transmitted by ixodic ticks, ixodic tick-borne borreliosis was most often registered (50.5%), tick-borne encephalitis was observed in 44.8% of cases, mixed infection ― in 4.7%. Borrelia miyamotoi DNA was detected by PCR-RV in 8.6% of biological samples (blood serum, leukocyte fraction). When analyzing the results of oxidative modification of proteins and lipid peroxidation, a reliable picture of oxidative stress is observed, which is more pronounced in patients with ixodic tick-borne borreliosis.
 CONCLUSION: The revealed changes in the study of oxidative stress in patients with tick-borne encephalitis and ixodic tick-borne borreliosis not only indicate the prospects of developing new approaches to the pathogenetic therapy of tick-borne infections, providing for the use of antioxidants in complex therapy, but also suggest a greater effectiveness of direct-acting lipophilic antioxidants that limit diene conjugation, and thereby prevent the accumulation of secondary cytotoxic products of lipid peroxidation.

Priority directions for non-specific prevention of tick-borne infections

Objective. An important role in the prevention of diseases, the causative agents of which are transmitted by ixodic ticks (tick-borne encephalitis, ixodic tick-borne borreliosis, human granulocytic anaplasmosis, human monocytic erlichiosis) is assigned to non-specific measures. To prevent infection by all pathogens of these infections at the same time, nonspecific preventive measures are of paramount importance. They include the extermination of hungry ticks on the vegetation of relatively small areas of natural biotopes, forest parks, health institutions, recreational areas, summer cottages or gardens; individual protection of the population from ticks and awareness-raising work.
 Materials and methods. The data of official statistics and materials of long-term observation of epidemic process were analyzed.
 Results. Despite the fact that since 2016 according to official data, there is observed a phase of decreased activity of the epidemic process of tick-borne infections, statistical analysis shows that in the forthcoming years an activation of epidemic situation is expected.
 Conclusions. In order to prevent tick attacks, specialists of medical organizations, departments of Rospotrebnadzor of the Russian Federation should intensify sanitary and educational work on non-specific protection of the population. In addition to standard activities, it is important to organize schools, courses for the public, schoolchildren, tourists and other population groups for the prevention of tick-borne infections, including the development of skills for correct tick removal using the Tick Removal Trainer and an algorithm for emergency measures in specific situation.

Review of the Epidemiological Situation on Ixodic Tick-Borne Borreliosis in the Russian Federation in 2010–2020 and Prognosis for 2021

Objective was to analyze the epidemiological situation on Ixodidae tick-borne borreliosis (ITBB) in the constituent entities of the Russian Federation in the dynamics over the period of 2010–2020, taking into account the features of the year 2020, associated with the spread of COVID-19, and to forecast the development of the epidemic process for 2021. In 2020, 4180 cases of ITBB were registered in the Russian Federation, which is 1.93 times less than in 2019 and 1.73 times less than the long-term average annual figure for the previous 10 years. A significant decrease was noted in all federal districts (FD), with the exception of the Central FD, where more than half of all cases occurred. Compared to 2019, 75 out of 78 subjects experienced a decrease in the incidence rate in 2020, while in 56 entities that decrease was statistically significant. The multiplicity of the decrease in the incidence of ITBB in 2020 for all FD was significantly greater than the multiplicity of the decrease in the frequency of contacts of the population with ticks. Infection of Ixodidae ticks of various species with borrelia in natural foci in 2020 was statistically significantly higher than in 2019. Probably, the decrease in the registered incidence of ITBB against the background of the COVID-19 pandemic is due not only to a decrease in the intensity of contacts of the population with natural foci, but also to a sharp redistribution of the volume of inpatient and outpatient medical care in favor of COVID-19 patients. Given the high degree of significance of the identified trends in the dynamics of the epidemic ITBB process during 2010–2020, there is reason to expect an increase in the incidence in the Bryansk, Voronezh, Ryazan, Tula and Saratov regions in 2021, which requires special attention in terms of strengthening preventive measures and monitoring of the activity and structure of natural foci. In the rest of the entities of the Russian Federation, provided that the volumes of preventive measures are maintained on the same level and in the absence of abnormal natural and climatic phenomena, preservation or a slight reduction in the incidence of ITBB is likely to occur in the short term. At the same time, despite the tense situation regarding the new coronavirus infection, there is an obvious need to draw close attention to the problems of diagnosis and prevention of natural focal infections.

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

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

Zoonoses as factor of evolution, population dynamics, and speciation

The role of zoonoses in changes of animal populations and communities is considered. The analysis was carried out using examples of population dynamics of small mammals distributed in the Crimean Peninsula, under the influence of the main zoonoses common for this territory, in particular tularaemia, leptospirosis, Marseille fever, viral tick-borne encephalitis, Ixodes tick-borne borreliosis, Crimea-Congo fever, KU fever, HFRS, and many others. Such data were analysed according to databases on the state of small-mammal populations and zoonoses common in these populations, obtained by original studies over the past 40 years. The role of zoonoses as factors of evolutionary changes in populations of small mammals is considered, in particular as a factor of mortality leading to significant reductions in population numbers and fragmentation of species ranges, as well as factors determining co-evolution of pathogens, vectors (arthropods), and small-mammals as hosts. Both groups of factors lead to the formation of population diversity due to changes in character variability and the formation of new characters associated with adaptations to zoonoses.