цель-определение геновидового состава боррелий в иксодовых клещах различных видов в природных очагах иксодовых клещевых боррелиозов (икб) юга западной сибири. материалы и методы. исследовано бактериологическим (посев на питательную среду BSK-H, SIGMA, сШа) и молекулярно-генетическим (пцр в режиме реального времени) методами 1148 экз. иксодовых клещей, собранных с растительности, и 2183 экз. клещей, снятых с людей. генотипирование боррелий проводили путем секвенирования. результаты и обсуждение. инфицированность клещей боррелиями варьировала от 22,4 % в республике алтай до 56,9 % в новосибирской области. существенных различий в уровнях инфицированности боррелиями клещей I. persulcatus и I. pavlovskiy не установлено (средний уровень зараженности 40,0 и 38,8 % соответственно). изучение геновидового состава боррелий, циркулирующих в природных очагах западной сибири, показало наличие как минимум четырех геновидов патогенных боррелий (B. garinii, B. afzelii, B. bavariensis и B. miyamotoi). в базу данных GenBank депонировано 30 нуклеотидных последовательностей межгенного спейсера rrf (5S)-rrl (23S). частота выявления геновидов B. garinii и B. afzelii у клещей различных видов (I. persulcatus и I. pavlovskiy) не имеет значимых отличий. отмечена более частая встречаемость B. garinii по сравнению с B. afzelii. уровни инфицированности клещей I. persulcatus боррелиями B. miyamotoi существенно ниже (в 3,5 раза), чем геновидами B. garinii и B. afzelii. в клещах D. reticulatus выявлена днк B. spielmanii и B. miyamotoi. необходимо продолжение исследований по оценке роли луговых клещей D. reticulatus в циркуляции боррелий различных геновидов в природных очагах на территории российской Федерации.

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.

Objective: to analyze the epidemiological situation on Ixodidae tick-borne borreliosis in the Russian Federation in 2019 in comparison with the period of 2002–2018.Materials and methods. The paper uses the data contained in Form No. 2 of the state statistical reporting for 2002–2019 and information obtained by the Reference Center for Monitoring Borreliosis of the Omsk Research Institute of Natural Focal Infections from 74 constituent entities of Russia in 2019. The main research method is epidemiological one with the use of modern information technologies.Results and discussion. In Russia, 8048 cases of tick-borne borreliosis (Lyme disease – LD) were recorded (5.48 0/0000) in 2019. The actual indicators of the LD incidence for the whole country and federal districts (FD) in 2019 were within the confidence limits predicted with linear regression based on the study of the dynamics of the epidemic process in 2002–2018 in the vast majority of cases. A steady upward trend in the LD incidence was observed during 2002–2019 in the Central Federal District due to 10 out of 18 entities (Moscow, Belgorod, Lipetsk, Moscow, Bryansk, Voronezh, Kursk, Ryazan, Tambov, Tula regions); in the Southern Federal District because of the Krasnodar Territory and the Volgograd Region; in the North Caucasus Federal District – because of the Stavropol Territory. Despite the fact that a downward trend in the incidence of LD has been established over the past 18 years in the North-West, Volga and Ural Federal Districts, in some subjects of these regions a trend towards an aggravation of the epidemiological situation is observed (the Komi Republic and Chuvashia, Penza Region). In the absence of a pronounced tendency to change in the incidence rate of LD in the Siberian and Far Eastern Federal Districts, Kemerovo Region-Kuzbass, the Republic of Tuva and the Trans-Baikal Territory where a growing trend has been identified require special attention. In the Ural and Siberian Federal Districts, the share of non-erythema forms among laboratory-confirmed cases of LD was higher than in other regions, which merits further study of the genome-specific features of borrelia populations and their carriers. Effective control of the LD epidemiological situation in Russia is possible provided that the control is improved and maintained, and the capacity of preventive measures and zoological-entomological monitoring of the activity and structure of the natural foci of LD is enhanced in the entities with the long-term tendency towards increase in the incidence of the disease.

Aim. To study the gene-specific composition of Borrelia spp. in ixodid ticks inhabiting the foci of ixodid tick-borne borreliosis (ITBB) in the south of Western Siberia.Materials and Methods. The gene-specific composition of Borrelia spp. in ixodid ticks was determined by inoculation on a BSK-H nutrient medium, real-time polymerase chain reaction, and sequencing (1148 specimens of ixodid ticks collected from vegetation and 2183 specimens withdrawn from humans).Results. Infection of ticks with borrelia ranged from 22.4% in the Altai Republic to 56.9% in the Novosibirsk Region. There were no significant differences in the levels of Borrelia infection between two major ixodides, I. persulcatus and I. pavlovskiy (average infection levels 40.0% and 38.8%, respectively). At least five gene species of pathogenic Borrelia (B. garinii, B. afzelii, B. bavariensis, B. miyamotoi, and B. spielmanii) have been identified. The GenBank database contains 45 nucleotide sequences of the intergenic spacer rrf (5S)-rrl (23S). Prevalence of gene species B. garinii and B. afzelii in different ticks (I. persulcatus and I. pavlovskiy) did not differ significantly, yet B. garinii was found to be more frequent than B. afzelii. The frequency of infection of I. persulcatus ticks with B. miyamotoi was significantly (3.5-fold) as compared to those of B. garinii and B. afzelii. In D. reticulatus ticks, the DNA of B. spielmanii and B. miyamotoi was detected.Conclusion. It is necessary to continue studies to assess the role of the meadow ticks D. reticulatus in the circulation of different Borrelia spp. in various natural foci within the Russian Federation.