Introduction: At present, National Healthcare and Demography Projects are being implemented in the Russian Federation and in the Orenburg Region, including the Regional Project for Prevention of Cardiovascular Diseases. Within the National Healthcare Project, the task has been set to reduce the mortality rate from diseases of the circulatory system to 450 per 100,000 population by the year 2024 (from 573.6 per 100,000 population registered in 2018). The regional goal is 477 per 100,000 population in 2024 (against 635.5 per 100,000 population in the year 2018). However, practical implementation of the project shows that in 2019–2020, the targets were not achieved. It is, therefore, important to monitor this indicator and to assess preventable losses associated with diseases of the circulatory system by all possible means including with the use of information technologies. Our objective was to establish regional features of the structure, dynamics, and rates of diseases of the circulatory system among the population of the region and to determine municipalities with high rates of cardiovascular disorders. Materials and methods: We used data of the Russian statistical collections “Medical and Demographic Indicators”, “Morbidity of the Population of Russia”, and annual information and analytical collections of the Orenburg Medical Information and Analytical Center for the years 2009–2018 to conduct a time series analysis.

Results: We observed an increase in the incidence rate of diseases of the circulatory system in the population of the Orenburg Region over the ten­year period. The maximum regional rate of 67.0 ± 1.8 per 1,000 population was registered in 2018 while the minimum rate was observed in 2009 and equaled 27.0 ± 0.27 per 1,000 population.

Conclusion: The study period was characterized by an increase in the incidence of diseases of the circulatory system accompanied by a statistically significant decrease in the prevalence of cardiovascular diseases in the adult population of the Orenburg Region. The diseases related to high blood pressure ranked first.

Background: Dental diseases and their sequelae promote comorbidity and polymorbidity. The objective of the study was to analyze the overall incidence including diseases of the oral cavity among contract military personnel.

Materials: We conducted a retrospective analysis of the overall 5­year morbidity by ICD­10 categories among contract soldiers serving in Dagestan for 2012–2016. We estimated the incidence rate per 1,000 people by disease categories and subcategories (C00–C14, K01–K04 and K05–K14), the structure of morbidity, worktime losses due to sickness absence, and rates of diseases of the digestive system by subcategories K01­K04 and K05­K14.

Results: With account for the diseases of the oral cavity, the proportion of leading diseases (diseases of the digestive system, respiratory system, musculoskeletal system and connective tissue) among the contact soldiers was 41.1 % and differed from the morbidity structure in the general population. The incidence rate of diseases of the digestive system was 1.6 times higher than that of diseases of the respiratory system, which was equal to that in the K01–K04 subcategory. In the category of diseases of the digestive system, the proportion of caries, its complications and other diseases of hard tissues of teeth reached 62.8 % and that of other diseases of the oral cavity – 17.4 %. As for worktime losses, the share of this category reached 8.1 %, of subcategories K01–K04 and K05–K14 – 0.7 % and 2.5 %, respectively. Having excluded the latter subcategories from the analysis, we found that the proportion of diseases of the digestive system became 4,3 times lower and they dropped to the sixth place.

Conclusion: The proportion of diseases of the digestive system, when including and excluding diseases of the oral cavity in the structure of general morbidity, was 18.7 % and 4.7 %, respectively, while diseases of the respiratory system, musculoskeletal system and circulatory system prevailed. It can be assumed that the problem of dental caries is interdisciplinary and its prevention is a common task of both dentists and hygienists.

Introduction: Active introduction of electronic learning tools in educational institutions poses new health risks to school­age children. Creating a modern and secure digital educational environment requires constant monitoring of the conditions and modes of use of new electronic tools, the diversity of which is changing rapidly. The purpose of this work was to assess certain parameters of indoor school environment influenced by the use of interactive panels (IPs), an e­learning tool of the latest generation.

Materials and methods: We studied the parameters of electromagnetic radiation, microclimate (air temperature and relative humidity), artificial lighting levels, chemical composition of indoor air, concentrations of positive and negative air ions during the school day in classrooms with and without interactive panels. The measurements were carried out in accordance with the approved methods of laboratory and instrumental research, and the results were then assessed for compliance with current sanitary rules and regulations. Statistical processing of the results was carried out using parametric methods of statistical analysis.

Results and conclusion: Indices of the microclimate and air ions in IP­equipped classrooms demonstrated a more pronounced negative dynamics during the school day. Our findings indicate the need for hygienists to pay close attention to the problem of using new electronic teaching aids and interactive panels in particular, to continue research in the area under study in order to elaborate hygienic regulations for applying IPs in the classroom and to prevent overwork and health risks to school­age children.

Introduction: Air quality of the premises of a sports university determines comfort and effectiveness of the educational and training processes and can be considered as a risk factor for students’ health.

The purpose of our study was to give a hygienic assessment of changes in the indoor CO₂ concentration at a sports university during the school day.

Materials and methods: Air quality measurements were taken in twelve classrooms, six lecture halls, three sports halls, and a gym. The subjective assessment of air quality in classrooms was analyzed using data of a questionnaire­based survey of 651 students.

Results: We found that differences in the proportion of air samples with elevated CO₂ concentrations between the rooms were insignificant and ranged from 32 ± 4.66 % to 41.33 ± 2.84 % in the cold season (CS) and from 42.33 ± 2.85 % to 49.33 ± 4.08 % in the warm season (WS). Average CO₂ concentrations in non­standard samples were 1,132.11 ± 93.21 ppm and 1,124.98 ± 98.51 ppm in the cold and warm season, respectively. We established that in the cold season, indoor CO₂ concentration exceeded the permissible limit in 100 % of the classrooms, 50 % of the lecture halls and the gym already by 3.40 p.m. (15:40); by the end of the school day, the excess was registered in 100 % of the university rooms. In the warm season, CO₂ concentrations were above the limit in the gym and in 33.3% of the lecture halls by 1 p.m. (13:00), and by 3.40 p.m. the excess was observed in 100 % of the rooms examined. Subjective air quality assessments indicated that most students often complained about stuffiness in classrooms; 25.25 ± 1.2 % of the respondents mentioned a strong odor in sports halls and the gym.

Conclusion: In a significant part of sports university rooms, CO₂ concentrations did not exceed permissible values for more than 80 % of school hours. Yet, after the fourth double lesson, this air quality indicator went beyond the standard value, and by the end of the school day indoor concentrations of carbon dioxide were above the permissible limit in 100 % of the university rooms.

Introduction: Many published data on variability of anthropometric characteristics of newborns related to the influence of adverse environmental factors during their antenatal development have been accumulated by now. The purpose of our work was to study the relationship between certain parameters of antenatal physical development of newborns and varying environmental and climatic conditions.

Materials and methods: Anthropometric measurements were taken in the delivery room immediately after birth and then assessed against environmental and climatic characteristics of the antenatal period.

Results: We established the relationship between the exposure to different environmental and climatic factors, including radiation, during the antenatal period and anthropometric characteristics of the examined newborns. We observed a quantitative variety of signs and found that the body mass was most “sensitive” to the impact of adverse environmental factors. At the same time, the phenogenetic analysis helped establish a significant effect of atmospheric pressure on the body mass. The effects of radiation exposure were, to a greater extent, associated with the signs of influence of both environmental (including the total and ultraviolet radiation – in 57.3 % and 67.8 % of cases, respectively) and genetic factors (in 42.7 % and 32.2 % of cases, respectively).

Conclusion: The established genotype­environment effects of exposures to changing environmental and climatic conditions prove the importance of continuing longitudinal observations of the examined infants using a cytogenetic analysis.

Introduction: Air quality of the premises of a sports university determines comfort and effectiveness of the educational and training processes and can be considered as a risk factor for students’ health.

The purpose of our study was to give a hygienic assessment of changes in the indoor CO₂ concentration at a sports university during the school day.

Materials and methods: Air quality measurements were taken in twelve classrooms, six lecture halls, three sports halls, and a gym. The subjective assessment of air quality in classrooms was analyzed using data of a questionnaire­based survey of 651 students.

Results: We found that differences in the proportion of air samples with elevated CO₂ concentrations between the rooms were insignificant and ranged from 32 ± 4.66 % to 41.33 ± 2.84 % in the cold season (CS) and from 42.33 ± 2.85 % to 49.33 ± 4.08 % in the warm season (WS). Average CO₂ concentrations in non­standard samples were 1,132.11 ± 93.21 ppm and 1,124.98 ± 98.51 ppm in the cold and warm season, respectively. We established that in the cold season, indoor CO₂ concentration exceeded the permissible limit in 100 % of the classrooms, 50 % of the lecture halls and the gym already by 3.40 p.m. (15:40); by the end of the school day, the excess was registered in 100 % of the university rooms. In the warm season, CO₂ concentrations were above the limit in the gym and in 33.3% of the lecture halls by 1 p.m. (13:00), and by 3.40 p.m. the excess was observed in 100 % of the rooms examined. Subjective air quality assessments indicated that most students often complained about stuffiness in classrooms; 25.25 ± 1.2 % of the respondents mentioned a strong odor in sports halls and the gym.

Conclusion: In a significant part of sports university rooms, CO₂ concentrations did not exceed permissible values for more than 80 % of school hours. Yet, after the fourth double lesson, this air quality indicator went beyond the standard value, and by the end of the school day indoor concentrations of carbon dioxide were above the permissible limit in 100 % of the university rooms.

Introduction: Drinking water from centralized drinking water supply systems is not always safe due to its natural pollution with various chemicals and microbiological contamination occurring in the distribution system. In this regard, the role of the service exercising governmental water quality surveillance is growing.

The purpose of the study was to assess the quality of drinking water and the associated health risk and to substantiate priority measures aimed at improving the quality of water in the centralized water supply systems of the region.

Materials and methods: We examined the results of drinking water quality testing performed within the implementation of sanitary and epidemiological surveillance and socio-hygienic monitoring and incidence rates in morbidity of population in 27 districts of the Penza Region and the regional center for the years 2014–2019. Health risks from oral exposures to waterborne chemicals were assessed in accordance with Guidelines R 2.1.10.1920–04. The statistical relationship was studied by the correlation method.

Results: We established that water quality in the centralized water supply systems fed by underground sources is determined by the chemical composition of the exploited aquifers that divide the territory of the Penza Region into four zones. The worst water quality was observed in the fourth zone where concentrations of natural iron, fluorides and boron in tap water were many times higher than their maximum permissible levels and the hazard quotient for fluorides exceeded the limit value (HQ = 2.845 for children and 1.219 for adults). In the third zone, iron posed the highest risks of diseases of mucosa and skin (HI = 0.296), the immune system (HI = 0.311), and hematopoietic system (H = 0.473) in children; we also established a strong correlation between the average annual concentration of iron in tap water and the incidence of genitourinary disorders, gastritis and duodenitis in the child population. Although the share of the population supplied with safe drinking water from centralized water supply systems increased from 86.5 % in 2014 to 89.4 % in 2019, the target set within the Regional Clean Water Project for 2019 was not achieved.

Conclusion: The study results were taken into account when making additions to the Regional Clean Water Project in 2020 envisaging construction of iron removal plants and water well drilling in areas with low fluorine levels.

Introduction: The titanium industry continues to build capacity and introduce innovative technologies driven by high demand for the metal and its alloys. High occupational risks of diseases of the respiratory and circulatory systems, diseases of the skin, and changes in hematological indices were established for titanium metal production workers.

The objective of our study was to assess the occupational risk from exposures to titanium in the composition of industrial aerosols for the health of workers in the modernized areas of metallurgical production.

Materials and methods: Our risk assessment was based on findings of periodic health examinations and doctor’s visits; we estimated the relative risk (RR) and used χ2 criterion to evaluate the statistical significance of the results. Results: We observed significantly higher incidence rates of diseases of the skin, ear, respiratory and musculoskeletal systems with temporary disability and higher rates of chronic diseases of the skin, respiratory and digestive systems in the titanium metal production workers compared to the workers of the same industrial enterprise unexposed to titanium and its alloys. Chronic diseases developed quicker in the exposed workers of all age groups than in the controls. The prevalence of hematologic disorders, such as high hemoglobin levels, thrombocytopenia, leukocytosis, lymphocytosis, and monocytosis was also higher in the exposed group. In the workers exposed to titanium concentrations exceeding the maximum permissible concentration (MPC) of 10 mg/m³ in the workplace air, we noted significantly higher rates of chronic diseases of the skin and digestive system, elevated hemoglobin levels, and a rising trend in the prevalence of chronic diseases of the circulatory system, high blood pressure, overweight, and thrombocytopenia in comparison with those working in permissible conditions.

Conclusions: We revealed a strong correlation between occupational exposures to airborne titanium and chronic skin diseases and a medium correlation for leukocytosis and monocytosis.

Introduction: The Mi-8 helicopter generates high-intensity broadband noises by its turboshaft engines whereas a comprehensive hygienic assessment of the acoustic environment in the helicopter cabin has not been conducted.

The purpose of the study was to assess the acoustic environment in the Mi-8 helicopter cabin.

Materials and methods: Acoustic measurements were carried out on the ground, inside the central cabin of the Mi-8 helicopter in three operating modes of the turboshaft engines: at startup, in the idle mode, and during cruise flight in the “right correction” mode. Measuring microphones were placed during the recording of the signal on a stand at the level of the human ear at six points located next to the reclining seats in the cabin. Acoustic indicators were measured using an SVAN-945A digital sound level meter and a GRAS 40AZ microphone. The collected data were processed in accordance with the requirements of sanitary and epidemiological rules, sanitary standards, and general tactical and technical requirements of the Air Force.

Results: Values of regulated noise indicators at the seats of the Mi-8 helicopter crew, sound pressure levels of the most significant tonal frequencies in its central compartment were measured. To establish the presence of tonal noise, a one-third octave analysis of the recorded acoustic signals was carried out. In the central compartment of the helicopter, the values of the regulated infrasound indices and the general sound pressure level were measured in the entire regulated frequency range. Discussion: It was found that the sound pressure levels in almost all sound octaves and the equivalent sound level in all operating modes of the helicopter engines exceed the permissible exposure limits while in the infrasound region they are within the normal range (except for the frequency of 16 Hz). Thus, the class of working conditions by noise corresponds to hazard class 3.3, and by infrasound – to class 2. According to the sanitary regulations, helicopter crews should use noise suppressors to protect themselves from high noise exposures through air and bone conduction.

Conclusion: The existing risks of developing a noise and infrasound-induced diseases necessitate constant monitoring of working conditions and health of the crews of Mi-8 helicopters.

Introduction: The issue of the influence of external factors such as meteorological conditions on the dynamics of the coronavirus pandemic is extremely relevant, since understanding of physical foundations of any process helps predict its results in specific conditions and, to a certain extent, manage it.

Objective: In order to assess the effect of relative humidity on the incidence of COVID-19, we analyzed opinions of the international scientific community about the nature and degree of the influence of meteorological conditions on COVID-19 incidence rates in humans.

 Materials and methods: We developed an original method of determining the periods of time when the air humidity level influenced disease rates, establishing the lag and the power of influence of the relative air humidity on the infection process and course of the disease. To eliminate the effect of confounders on research results, we applied the author’s method of estimating the conditional incidence as the difference between the theoretical and observed rates.

The article presents the results of analyzing the correlation between relative humidity and COVID-19 incidence rates in 19 regions of the Russian Federation. Without exception, all the equations contained two or three extrema of the incidence in time, at which air humidity had the greatest impact on its rates. We associate these extrema with the time of getting infected and the disease onset and they enable us to quantitatively predict the latent period of this infectious disease in different atmospheric conditions.

Conclusion: The observed correlations demonstrate relative humidity levels posing higher and lower risks of getting infected with COVID-19 in various regions of the Russian Federation. By means of mathematical methods, we confirmed the hypothesis about the persistence of SARS-CoV-2 in the environment for more than two weeks.

Introduction: Today, the novel coronavirus disease (hereinafter referred to as COVID-19) is spreading very quickly, and the healthcare workers exposed to COVID-19 patients represent the most vulnerable occupational cohort at risk of this contagious disease. Issues of immunological protection and health monitoring in medical personnel are of special interest and importance during the pandemic.

The objective of our study was to assess humoral immunity in healthcare professionals by the presence of class G (IgG) antibodies to the nucleocapsid protein of SARS-CoV-2.

Methods: We selected 345 healthcare workers of different specialties who might have been exposed to COVID-19 patients in hospitals and 72 ageand sex-matched controls (engineers, IT-personnel, and accountants) working elsewhere. Blood immunoglobulins G to the nucleocapsid protein of SARS-CoV-2 were tested by enzyme immunoassay using the commercial test kit produced by the Scientific Center for Applied Microbiology and Biotechnology, Obolensk, Russian Federation. The presence of IgG antibodies was established by the SARS-CoV-2 IgG antibody response index (index of positivity) calculated as the ratio of the optical density of the sample to the cut-off level of the assay.

Results: The average IgG antibody response index value was significantly higher in the healthcare workers compared to the controls (p < 0.05). IgG antibodies to SARS-CoV-2 were more prevalent in nurses than in physicians (42.2 ± 3.6 % vs 31.0 ± 3.7 %, p < 0.05) and controls (42.2 ± 3.6 % vs 27.8 ± 5.3 %, p < 0.05) and their index values were higher than in the comparison group (p < 0.05).

Conclusion: Our findings demonstrate a high prevalence of diagnostically important SARS-CoV-2 IgG antibody response and higher index values in nurses possibly related to prolonged contacts with COVID-19 patients. IgG antibodies found in 37.1 ± 2.6 % of the healthcare workers may be a consequence of both symptomatic and asymptomatic diseases and requires further study. According to the generally accepted opinion about the mechanisms of immune response to viral infections, we could assume the presence of protective immunity against COVID-19, but this issue requires further investigation. In the current epidemic situation, however, detection of IgG antibodies to SARS-CoV-2 can be used for implementation of preventive strategies among healthcare workers.

Introduction: When ensuring preparedness of constituent entities of the Russian Federation to take anti-epidemic measures in order to respond to imported infections, including the novel coronavirus disease, appropriate training of healthcare workers, specialists of bodies and institutions of the Federal Service for Surveillance on Consumer Rights Protection and Human Wellbeing (Rospotrebnadzor) and non-medical specialists was important.

The objective of our work was to improve methodological support of inter-agency collaboration in implementing activities on sanitary protection of the territories at border patrol checkpoints.

Materials and methods: We analyzed reports on interdepartmental drills at Russian border patrol highway checkpoints, including those conducted within the preparation for 2018 FIFA World Cup, and regulations on the aspects of interdepartmental drills at international border crossing points.

Results: We assessed completeness of implementation, organizational structure, content, and methodological aspects of interdepartmental cooperation in the course of drills at highway checkpoints and proposed a unified approach to conducting training with account for realities of checkpoint functioning and requirements for ensuring biological safety. The article provides recommendations for conducting drills on anti-epidemic measures to be taken when identifying a suspected case of a highly hazardous communicable disease at border patrol checkpoints.

Introduction: The main task of conducting a biomedical research is to obtain statistically significant experimental results. The studies with laboratory animals used as test systems are conducted in research organizations. Owing to the introduction of good laboratory practice (GLP) principles into the world practice, stricter requirements have been imposed on the quality of test systems.

The purpose of our study was to analyze the regulatory, methodological, and legislative framework governing laboratory research using biomodels in order to update a number of regulatory documents that are mandatory for implementation.

 Methods: We searched electronic databases of references and abstracts (Web of Science, PubMed, eLibrary) for appropriate keywords and, having reviewed search results, selected 22 literary sources on the topic.

Results: We established that, based on existing regulations, specialized institutions develop internal instructions to fulfil their goals and objectives. The presence of a program of standard operating procedures allows experiments to be performed with appropriate quality. The quality of laboratory animals can be affected by unfavorable conditions of keeping, lack of balanced feeding, and violation of sanitary and hygienic standards of care. For different categories of laboratory animals, different requirements are imposed on their housing in accordance with the microbiological status. Institutions are implementing a specially developed program for health monitoring in laboratory animals. Healthy-looking animals are carriers of a number of infectious agents that can distort results of an experiment. Veterinarians specializing in laboratory animals should have knowledge of biomodeling and effects of drugs on physiological and pathological processes in animals and should perform adequate anesthesia during painful manipulations. Only employees with high qualifications and skills in working with animals are authorized to handle biomodels.

Conclusions: Our findings demonstrate that the use of high-quality laboratory animals and standardization of all stages of an experiment ensures a quality research compliant with international standards.