Omsk Research Institute of Natural Focal Infections

Omsk hemorrhagic fever virus (OHFV) is a member of the tick-borne encephalitis virus (TBEV) complex of the Flaviviridae family. Currently, there are no data on the cross-reactivity of antibodies to the NS1 proteins of OHFV and TBEV. Such data are of major interest for monitoring viral encephalitis of unknown etiology due to the increasing geographical distribution of OHFV. In this study, a recombinant OHFV NS1 protein was produced using the Escherichia coli expression system and purified. The recombinant OHFV NS1 protein was recognized by specific mice immune ascetic fluids to the native OHFV NS1 protein. A Western blot analysis and ELISA of the recombinant NS1 proteins of OHFV and TBEV were used to study the cross-reactivity of antibodies from immune ascites fluid obtained from OHFV-infected mice and mAbs against TBEV NS1. Anti-TBEV NS1 mouse monoclonal antibodies (mAbs) have been shown to not be cross-reactive to the OHFV NS1 protein. Sera from patients with confirmed tick-borne encephalitis (TBE) were examined by ELISA using recombinant OHFV NS1 and TBEV NS1 proteins as antigens. It was shown for the first time that cross-reactive antibodies to the OHFV NS1 protein were not detected in the sera of TBE patients, whereas the sera contained antibodies to the TBEV NS1 protein.

Aim. To provide data on the diagnostic and prognostic value of questionnaire survey for post-COVID-19 syndrome during screening and regular medical check-ups of employees, as well as preventive medical examinations.Material and methods. This single-center cross-sectional comparative study involved 1120 people (92,1% of the general population — all employees of the organization), including 195 men (67,3% of the general population) and 925 women (79,5% of the general population). All participants filled out the post-COVID-19 syndrome (PS) detection questionnaire, the Hospital Anxiety and Depression Scale and the QAA-25p Adherence Assessment Questionnaire. Potential adherence to treatment was calculated using the SCOPA software. Statistical processing was performed using tools adapted for medical and biomedical research (Python language; Sklearn, NumPy, Pandas libraries) and Statistica 6.13 (StatSoft Inc., USA).Results. As a result, 47% of respondents noted at least one symptom that reduces the quality of life and/or performance efficacy. In all subsamples, women reported symptoms more frequently than men. The most informative indicators associated with post-COVID-19 syndrome are age (Mann-Whitney U test, p=0,042), number of PS symptoms (Mann-Whitney U test, p=0,001), severity of PS symptom (Mann-Whitney U test, p= 0,004) and adherence to health care (Kruskal-Wallis H test, p=0,021). An increased level of anxiety is associated with all the analyzed symptoms, depression level with 6 symptoms, age with 5 symptoms, insufficient compliance with 3 symptoms.Conclusion. PS questionnaire should be included in a comprehensive survey program of persons undergoing medical examinations. It is necessary to develop algorithms for the treatment and diagnosis of patients that take into account the number and severity of individual symptoms separately for men and women with consideration to their COVID-19 epidemiological status, as well as age and markers of anxiety, depression, and adherence to treatment.

Aim. To assess the impact of HIV infection and tuberculosis on life expectancy in Siberian Federal District regions for improving the allocation of health resources.Materials and Methods. We investigated the data on the number of population and mortality (stratified into 5-year age groups) in Siberian Federal District regions. The data have been extracted from the Russian database of fertility and mortality (RosBRiS). Among the indicators, we calculated total mortality, mortality from HIV infection, and mortality from active tuberculosis. Further, we estimated the contribution of deaths from HIV infection and tuberculosis to the reduction of life expectancy.Results. Regions within the Siberian Federal District were characterised by an unacceptably high incidence of HIV infection and tuberculosis. Life expectancy showed a downward trend from 1991 to 2006 (Irkutsk Region, Krasnoyarsk Region, Republic of Khakassia, and Tomsk Region), 2007 (Novosibirsk Region, Republic of Altai, Republic of Tyva), or 2008 (Altai Territory, Kemerovo Region, and Omsk region). In 2020, the average life expectancy in the Siberian Federal District was 70.9 years, with a minimum registered in the Republic of Tyva (66.25 years), and the maximum documented in the Tomsk region (71.17 years). The contribution of HIV infection and tuberculosis to the decrease in the life expectancy in Siberian Federal District during the study period was estimated as 0.52 years, including 0.12 years due to HIV infection and 0.40 years related to tuberculosis.Conclusion. The existing volume of preventive measures is insufficient to achieve the target life expectancy (78 years) in the Siberian Federal District to 2030, limiting the expected life expectancy to 75 years at that time point. As the target life expectancy is attainable by 2038 at best, additional resources are required to reduce age-related mortality rates.

Using the example of the clinical strain of R. sibirica «Bayevo 105/87», the possibility of quantitative determination of rickettsias in clinical samples from patients with Siberian tick-borne typhus by real-time polymerase chain reaction (PCR-RT) was evaluated. Cultivation was carried out in the yolk sacs of developing chicken embryos, from which a piece of the yolk sac or chorion was taken. A total of 125 samples were examined. A set of reagents "RealBest DNA Rickettsia species (kit1)" was used for PCR-RT. The obtained values of the threshold amplification cycle (Ct) were compared with the results of microscopy of smear preparations stained by the Zdrodovsky method, the values of which were divided into ranks: the I rank - single rickettsias in individual fields of vision, the II rank - single rickettsias in each field of vision, the III rank - from 10 to 25 rickettsias in each field of vision, the IV rank - from 25 to 50 rickettsias in each field of view. The median Ct value for rank I was 17.6 (16.37; 18.58), for the II - 16.0 (15.0; 16.41), for the III - 15.0 (14.0; 15.1) and for the IV - 15.0 (13.7; 14.64). A significant average correlation was established between the number of rickettsias in the preparation under microscopy and the value of the threshold cycle in PCR RT (r=-0, 4849542; p=9.968e-09). When determining the correlation between the pathomorphological characteristic and the value of the threshold cycle, its absence was established. The detection of rickettsias in the blood vessels of the chorion of developing chicken embryos was of interest. In 10 samples, the yolk sac and chorion were taken for the study, and in parallel they were examined by PCR-RT. The use of modern, more sensitive molecular biological methods allows for quantitative analysis of DNA in the chorion, while preserving the volumes of the most valuable material - the yolk sac.

The Siberian Federal District is among the most affected regions with a high prevalence of HIV-infection and is characterized by high HIV-infection incidence rate and high mortality among the HIV-infected population. HIV drug resistance poses a major threat to public health and is associated with increased mortality, HIV incidence, and cost of epidemic control programs. A total of 1281 samples from HIV-infected patients were sequenced and analyzed with the DEONA and HIVdb Program to assess the prevalence of drug resistance mutations in patients in the Siberian Federal District in 2016–2018. The federal surveillance data obtained from 0.5% of HIV-infected patients during the long-term follow-up care in 2021 were also used. The incidence rate of HIV infection in the Siberian Federal District has declined since 2016: from 135.8 per 100 thousand population to 81.1 per 100 thousand population in 2021. Mutations associated with resistance to NRTI and NNRTI were found in 10.3% of the samples in 2016–2018 and in 28.4% of the samples in 2020. The rising prevalence of drug resistance in HIV-infected patients indicates that it is increasingly important to continuously monitor and improve the approaches to the use of effective treatment regimens.

The aim of the review was to characterize the epidemiological situation on rickettsiosis of the tick-borne spotted fever (TSF) group in the constituent entities of the Russian Federation in 2012–2021 and provide a long-term forecast for 2022–2026. In 2020–2021, indicators of registered incidence of tick-borne rickettsiosis in Russia on the whole decreased relative to the average long-term pre-pandemic level in 2012–2019 by 2 fold for all forms of the TSF group on average (Siberian tick-borne typhus – STT, Astrakhan spotted fever and Mediterranean fever). A comparative analysis of the territories revealed a correlation between the incidence of STT and the number of medical facility visits due to “tick bites” (r=0.67, p=0.015), which, against the background of an increase in the frequency of contacts of the population with vectors in 2020–2021 in most regions and a decrease in the incidence in the same regions indicates the credible nature of the changes. The ranking of territories according to average long-term incidence rates made it possible to classify the Republic of Altai and the Altai Territory as regions of extremely high epidemic hazard as regards STT; high hazard – the Republic of Tuva; above average – the Republic of Khakassia, Khabarovsk Territory and the Jewish Autonomous Region. The established downward trend in the incidence of tick-borne rickettsiosis among the population will be sustained in most entities of the Russian Federation within the next 5 years, excluding the Republic of Altai, the Altai Territory, the Republic of Crimea and the city of Sevastopol, where current incidence or an increase should be expected. The results of the analysis indicate the need to put more emphasis on natural-focal infections at the time of COVID-19 pandemic.

Objectivewas 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.

Introduction. Attempts to assess the prevalence of antibodies (seroprevalence) to the Epstein-Barr virus have been made several times. Still, a complete understanding of this issue has not been reached due to the small samples of the surveyed. The goal is to evaluate seroprevalence in different age groups in Europe and Asia using a systematic review and meta-analysis. Material and methods. The search for publications was carried out on PubMed, Cochrane Reviews/CochraneLibrary, eLibrary, Cyberleninka, Researchgate from May 6 to 30, 2020. A total of 2,364 articles were found, 12 of which were included in the study. Seroprevalence to Epstein-Barr virus was determined in 67,561 individuals aged 0 to 80 years. The research results were distributed by age groups, continents (Europe and Asia), and their implementation (2000-2012 and 2013-2019) and subjected to meta-analysis. Results. Minimal seroprevalence was detected among children under 1 and 1-2 years of age (53.3 and 50.9%). With increasing age, it grew, and people over 18 years of age were more than 90%. In 2013-2019, the index value (68.9%) was significantly higher than in 2000-2012 (89.6%). In Asian countries in 2000-2019, seroprevalence (86.7%) was considerably higher than in Europe (76.3%). The highest growth rate was observed in 7-14 years. In 2000-2012, the maximum growth rate of seroprevalence occurred in 15-17 years and 2013-2019 - 3-6 years. For all age groups, the growth rate was higher in Europe than in Asia and 2013-2019 compared to 2000-2012. Conclusion. The meta-analysis revealed differences in seroprevalence depending on age and territory of residence and the growth of indices in the trend.