Introduction: A steady increase in the incidence of malignant neoplasms was registered in the Primorsky Region in 2009–2019 with the rate rising by 26.1 %. The statistical analysis of the relationship between quality of life indicators and disease contributes to identifying significant risk factors, the consideration of which will improve the set of measures aimed at promoting a healthy lifestyle and encouraging regular medical checkups in order to reduce cancer incidence and mortality rates.
Objective: To establish external carcinogenic risk factors in the Primorsky Region.
Materials and methods: The study was conducted based on statistical data from the local offices of the Federal Service for State Statistics and the Federal Service for Surveillance on Consumer Rights Protection and Human Wellbeing for 2007–2019. We did correlation and regression analyses of the collected information and applied the principal component analysis to reduce dimensionality of the data.
Results: The statistical data analysis revealed the principal components and their association with the incidence of malignant neoplasms of five sites in the Primorsky Region.
Conclusion: In addition to genetic predispositions, the lifestyle strongly contributes to the development of cancer, which must be taken into account when elaborating appropriate preventive measures at the regional level.

Background: Characteristics of silicon and its compounds found in water bodies and recently updated standards for their content in drinking water regulated by Russian Sanitary Rules and Norms SanPiN 2.1.4.3685–21, Hygienic standards and requirements for ensuring safety and/or harmlessness of environmental factors for humans, necessitate optimal and affordable methods of determination of silicon for drinking water quality control purposes.
Objective: To summarize published data on the forms of silicon and methods of their quantitative determination in source and drinking water.
Materials and methods: Information and analytical methods based on summarization and analysis of data of scientific papers published in 1923–2020 and cited by Scopus and RSCI international scientometric databases were applied. The search terms included silicon, drinking water, silicon compounds, and methods of quantitative determination. The initial sample consisted of 57 articles, of which 14 were excluded after primary screening and 43 publications compliant with selection criteria were reviewed.
Results: Published data summarization has demonstrated the prevalence monomeric and dimeric species of silicic acid and soluble silicate ions in most water bodies.
Conclusion: The silicomolybdic acid spectrophotometry is the method of choice for determination of silicon concentrations in source water.

Introduction: Many urban residents use water from alternative sources, such as springs, which are natural discharge points of subterranean water at the surface of the groundwater, for drinking and cooking. Their quality is largely determined by local environmental conditions, soil barrier functions and underlying rocks.
Objective: To assess spring water quality in the city of Vladimir in terms of safety and integral toxicity.
Materials and methods: We took water samples from six springs located in different districts of the regional center and popular with its citizens. The samples were tested according to standard potentiometric, conductometric, and titrimetric methods. Integral toxicity of spring water samples was determined using a Biotox-10M luminometer. We then analyzed data on 31 biochemical and microbiological parameters and integral toxicity of spring water in the city for 2017–2022.
Results: We established that spring water in Vladimir does not quite comply with the standards established by Russian Sanitary Rules and Norms SanPiN 1.2.3685-21, Hygienic standards and requirements for ensuring safety and/or harmlessness of environmental factors for humans. We identified priority pollutants of spring water causing deterioration of its quality for the years 2017–2021. We also noted low levels of magnesium and fluorine ions in spring water, which means that its regular intake may lead to deficiency of these essential elements in the local population. A recent increase in bacterial contamination of spring water was primarily attributed to human economic activities.
Conclusion: Judging by its trace levels of pollutants posing no health risks, spring water in Vladimir is not toxic. We still recommend permanent cleaning of spring areas, improvement of groundwater collection facilities, and boiling of spring water before use.

Introduction: Current school teaching methods including distance learning may have adverse health effects in children.
Objective: To assess health effects of online education in students of comprehensive secondary schools and gymnasiums.
Materials and methods: We developed a questionnaire to establish the impact of distance learning on the functional state and health of students comprising three sections: educational activities, daily routine and self-rated health. In May 2020, 3,026 fifth to ninth-year students from eight comprehensive schools and five gymnasiums of the city of Nizhny Novgorod, including 1,430 boys and 1,596 girls, filled out the questionnaire and their answers were then analyzed using IBM SPSS Statistics software, version 5.1.
Results: Distance learning included online and offline classes (70.7 % in total) and self-study assignments, the latter being more common in the comprehensive schools than in the gymnasiums. The majority of the respondents from the schools (73.4 %) and gymnasiums (67.0 %) noted a greater amount of homework during e-learning compared to offline education. They also reported less time spent outdoors and much more passive leisure. Complaints of increased back and wrist pain and headaches were more frequent in the students of comprehensive secondary schools.
Conclusions: Our findings show that distance learning changed the way of life of all the children surveyed. We observed an increased screen time, the prevalence of static activities, and the development of musculoskeletal and eye disorders. The comprehensive school students noted more negative consequences of online learning compared to their peers studying in the gymnasiums.

Introduction: Nowadays, many hygienic factors determine health and development of children and adolescents. The learning process takes place in educational organizations of various types, which primarily affect the lifestyle and characteristics of student’s daily routine. Cadet corps occupy a special place in the structure of schools affecting children’s health. Round-the-clock stay on their territory accounts for the fact that school environment determines the development and wellbeing of the boys.
Objective: Hygienic assessment of the daily routine of cadets of the Cossack Corps in the Astrakhan Region.
Materials and methods: We analyzed the daily routine of cadets in grades 5–11 (aged 11–17) based on the approved schedule of the Cossack Corps of the Astrakhan Region for the 2020–2021 school year. We analyzed the academic load including the duration of lessons and breaks, physical activities, eating schedule and meal duration, overnight sleep duration, and the time spent on extracurricular activities and leisure.
Results: The daily routine of the cadets was characterized by optimal alternation of all components. We established that the intensity of the academic load was noncompliant with the age of the cadets; besides, the time spent outdoors and night sleep duration were insufficient. Positive findings included intense physical activities exceeding those of other secondary school students and a limited gadget use.
Conclusion: Further studies of the educational process of cadet corps will help eliminate the identified shortcomings in the cadet education system and create conditions for health promotion in children and adolescents.

Background: Diseases induced by such physical factors as noise and vibration rank high in the structure of occupational disorders; their proportion increased from 36.6 % in 2004 to 51.15 % in the year 2019.
Objective: To assess risks of hearing loss among the seafaring personnel of Novoship PJSC exposed to occupational noise.
Materials and methods: The observation group included men with 10, 20 and 30 years of work experience. In accordance with generally accepted methods, an a priori occupational risk was determined for workers exposed to noise at workplaces in the years 2014–2016.
Results: We established that the limit of the equivalent sound level of 80 dBA was exceeded by 13–16 dBA at the workplaces of mechanics, electricians, and motor mechanics of the shipping company. In accordance with R 2.2.1766–03, Guidelines on occupational risk assessment for workers’ health: Organizational and methodological aspects, principles and criteria, the health risk posed by noise exposure was moderate (significant), category 2, for mechanics and senior stokers (turners) and high (intolerable), category 2, for first-class stokers. In accordance with the Russian National Standard GOST R ISO 1999-2017, Acoustics. Estimation of noise-induced hearing loss, methodology, the probability of mild hearing loss by 26 dB (first degree of sensorineural hearing loss) in seafarers of the studied occupations at the age of 40, 50 and 60 years with a 10-year work experience years was 13.1 %, 29.7 %, and 50.4 %, respectively; the probability of moderate hearing loss by 41 dB (second degree of sensorineural hearing loss) was 0 % for the age of 40 and 50 years and 17.0 % for the age of 60 years; the probability of mild hearing loss by 26 dB at the age of 50 with a work experience of 20 and 30 years was 36.7 % and 52.2 %, at the age of 60 – 58.2 % and 72.2 %; the probability of moderate hearing loss by 41 dB for these age groups was 0 % and 23.2 % for the seafarers with 20 years of experience, 27.4 % and 44.7 % for the seafarers with 30 years of experience, respectively.
Conclusion: Effective planning of measures for noise-induced occupational disease prevention requires a legislative decision on compulsory assessment of occupational risks of noise-induced hearing loss based on the results of audiometry of workers exposed to sound levels above 80 dBA within annual health checkups.

Introduction: The progressively growing road traffic intensity leads to a steady increase in the informational, emotional and psychological burden in drivers. Truck drivers are exposed to numerous occupational risk factors, including hard labor, constant psychological stress, vibration, noise, a fixed working position, poor visibility, and excess concentrations of noxious gases, all affecting their psychophysiological status.
Objective: To study the relationship between professional work and characteristics of the psychophysiological status of the male population of the northern region and to establish the presence and strength of correlations between their elemental and psychoemotional status.
Materials and methods: We assessed the psychoemotional status of 182 men aged 32.6 ± 6.2 years, including 94 truck drivers and 88 office workers, living in three northern cities of the Russian Federation. We also established their blood and urinary levels of catecholamines (adrenaline and noradrenaline) using enzyme immunoassay and measured hair magnesium and potassium levels using inductively coupled plasma atomic emission spectroscopy and inductively coupled plasma mass spectrometry.
Results: We observed that the professional drivers of the northern region were more susceptible to psychological stress (p = 0.042…0.001), had higher levels of stress hormones (cortisol and adrenaline) in blood (p = 0.049…0.005) and urine (p = 0.004…0.003), but lower hair levels of magnesium and potassium, the trace elements essential for mental health (p = 0.004…0.003), than male office workers. The correlation analysis of the above parameters proved that psychological stress of the truck drivers was attributed to magnesium and potassium deficiency (r = -0.475…—0.601) and a high level of stress hormones (r = –0.514…–0.828).
Conclusion: In order to stabilize emotional and psychological status and to improve the performance, physical health, and the quality of life of professional drivers, it is important to correct their micronutrient status using multivitamin/multimineral supplements and enriched foods.

Introduction: Vibrio vulnificus is an opportunistic microorganism that is part of the natural flora of the coastal marine environment. Consumption of seafood containing V. vulnificus can result in a severe, lightning-fast systemic infection in humans, which can, in its turn, lead to sepsis and even death in susceptible people. Infections caused by V. vulnificus have been reported in various climate zones around the world. Thus, the understanding of factors contributing to pathogenicity of this bacterium in its natural habitat can help develop new methods of disease prevention, diagnosis and treatment.
Objective: To overview and systematize pathogenicity factors of V. vulnificus described in literary sources.
Materials and methods: We used data analysis techniques to review scientific studies published in Russian and English in such abstract and citation databases as Scopus, PubMed, Russian Science Citation Index, and on information portals in 1976–2020. The main selection criterion was availability of information on the study of pathogenicity factors of V. vulnificus in the papers. Sixty full-text publications meeting the above criteria were chosen.
Results: This review presents the latest achievements in the study of determinants contributing to the pathogenicity of V. vulnificus and examines their roles in pathogenesis. It has been shown that this microorganism, like most pathogens, requires coordinated work of many pathogenicity factors to cause infection. Most of them perform only an auxiliary function in pathogenesis and serve mainly for survival in the environment. However, in the absence of pathogenicity factors such as cytolysins VVH and MARTX, which cause tissue necrosis in the small intestine with subsequent dissemination into the bloodstream and other tissues, V. vulnificus is unable to cause intestinal infection.
Conclusion: The understanding of the determinants contributing the most to the infection is extremely important when analyzing strains circulating in the country and assessing the risks of diseases in humans exposed to this pathogen.

Introduction: Salmonella enteritidis is the most common etiologic agent of salmonellosis in humans in the Stavropol Region, which is in line with the global trend. In this regard, the definition of a serovar provides little information in the course of an epidemiological investigation and necessitates subspecific typing of S. enteritidis isolates.
Objective: MLVA typing of S. enteritidis strains isolated in the Stavropol Region in 2016–2019 and the analysis of the genetic structure of the local Salmonella population.
Materials and methods: We studied 122 strains of S. enteritidis isolated in 2016–2019 from stool samples of patients with acute intestinal infections in the city of Stavropol and the Caucasian Mineral Waters (CMW) of the Stavropol Region. Multi Locus Variable Number Tandem Repeat (MLVA) typing was performed based on five variable loci. The size of amplified loci was determined by capillary electrophoresis.
Results: The studied strains were distinguished by high genetic heterogeneity and belonged to 25 MLVA genotypes. S. enteritidis strains belonging to 24 MLVA types were identified on the territory of Stavropol. The dominant genetic variant in the city was 3-10-5-4-1, which included 40 Salmonella strains (44.4%) isolated in 2016–2019. In some years, the proportion of other genetic variants increased. In the CMW area, strains belonging to seven MLVA genotypes were isolated, most of which belonged to the profile 3-10-5-4-1, while a change in the dominant variant of S. Enteritidis was registered annually. Prevalent regional MLVA types are widespread in the world and have a significant epidemic potential.
Conclusions: We obtained new data on S. enteritidis MLVA genotypes in the Stavropol Region, established dominant genetic variants, and noted differences in the ratio of circulating MLVA genotypes of S. enteritidis in 2016–2019. Our findings necessitate constant molecular genetic monitoring to assess real-time dynamic changes in the genetic structure of the Salmonella population. They can also be used in investigations of possible cases (outbreaks) of salmonellosis to determine their source and routes of transmission.