Spatial and temporal patterns of haemorrhagic fever with renal syndrome (HFRS) and the impact of environmental drivers in a border area of the Russian Far East.

AIMS: Haemorrhagic fever with renal syndrome (HFRS) is a significant zoonotic disease transmitted by rodents. The distribution of HFRS in the European part of Russia has been studied quite well; however, much less is known about the endemic area in the Russian Far East. The mutual influence of the epidemic situation in the border regions and the possibility of cross-border transmission of infection remain poorly understood. This study aims to identify the spatiotemporal hot spots of the incidence and the impact of environmental drivers on the HFRS distribution in the Russian Far East. METHODS AND RESULTS: A two-scale study design was performed. Kulldorf's spatial scan statistic was used to conduct spatiotemporal analysis at a regional scale from 2000 to 2020. In addition, an ecological niche model based on maximum entropy was applied to analyse the contribution of various factors and identify spatial favourability at the local scale. One spatiotemporal cluster that existed from 2002 to 2011 and located in the border area and one pure temporal cluster from 2004 to 2007 were revealed. The best suitability for orthohantavirus persistence was found along rivers, including those at the Chinese-Russian border, and was mainly explained by land cover, NDVI (as an indicator of vegetation density and greenness) and elevation. CONCLUSIONS: Despite the stable incidence in recent years in, targeted prevention strategies are still needed due to the high potential for HRFS distribution in the southeast of the Russian Far East.

The impact of climatic factors on tick-related hospital visits and borreliosis incidence rates in European Russia.

Tick-borne diseases are among the challenges associated with warming climate. Many studies predict, and already note, expansion of ticks' habitats to the north, bringing previously non-endemic diseases, such as borreliosis and encephalitis, to the new areas. In addition, higher temperatures accelerate phases of ticks' development in areas where ticks have established populations. Earlier works have shown that meteorological parameters, such as temperature and humidity influence ticks' survival and define their areas of habitat. Here, we study the link between climatic parameters and tick-related hospital visits as well as borreliosis incidence rates focusing on European Russia. We have used yearly incidence rates of borreliosis spanning a period of 20 years (1997-2016) and weekly tick-related hospital visits spanning two years (2018-2019). We identify regions in Russia characterized by similar dynamics of incidence rates and dominating tick species. For each cluster, we find a set of climatic parameters that are significantly correlated with the incidence rates, though a linear regression approach using exclusively climatic parameters to incidence prediction was less than 50% effective. On a weekly timescale, we find correlations of different climatic parameters with hospital visits. Finally, we trained two long short-term memory neural network models to project the tick-related hospital visits until the end of the century, under the RCP8.5 climate scenario, and present our findings in the evolution of the tick season length for different regions in Russia. Our results show that the regions with an expected increase in both tick season length and borreliosis incidence rates are located in the southern forested areas of European Russia. Oppositely, our projections suggest no prolongation of the tick season length in the northern areas with already established tick population.

Climatic Factors Influencing the Anthrax Outbreak of 2016 in Siberia, Russia.

In 2016, an outbreak of anthrax killing thousands of reindeer and affecting dozens of humans occurred on the Yamal peninsula, Northwest Siberia, after 70 years of epidemiological situation without outbreaks. The trigger of the outbreak has been ascribed to the activation of spores due to permafrost thaw that was accelerated during the summer heat wave. The focus of our study is on the dynamics of local environmental factors in connection with the observed anthrax revival. We show that permafrost was thawing rapidly for already 6 years before the outbreak. During 2011-2016, relatively warm years were followed by cold years with a thick snow cover, preventing freezing of the soil. Furthermore, the spread of anthrax was likely intensified by an extremely dry summer of 2016. Concurrent with the long-term decreasing trend in the regional annual precipitation, the rainfall in July 2016 was less than 10% of its 30-year mean value. We conclude that epidemiological situation of anthrax in the previously contaminated Arctic regions requires monitoring of climatic factors such as warming and precipitation extremes.

Reindeer Anthrax in the Russian Arctic, 2016: Climatic Determinants of the Outbreak and Vaccination Effectiveness.

The Yamal Peninsula in the Russian Federation experienced a massive outbreak of anthrax in reindeer (Rangifer tarandus) in July-August 2016, with 2,650 (6.46% of the total susceptible population) animals infected, of which 2,350 died (case fatality rate of 88.67%). In our study, we analyzed climatic and epidemiological factors that could have triggered the outbreak. The cancelation of reindeer vaccination against anthrax in 2007 resulted in an increase in population susceptibility. In response to the outbreak, total vaccination of all susceptible animals was resumed. To assess the vaccination effectiveness, we tested 913 samples of blood serum taken from vaccinated reindeer using an antigenic erythrocyte diagnostic kit to detect specific anti-anthrax antibodies via an indirect hemagglutination assay (IHA) 9 months after vaccination. We found that 814 samples had sufficiently high levels of anti-anthrax antibodies to indicate a protection level of 89% (95% confidence interval: 87-91%) of the whole reindeer population. Abnormally high ambient temperature in the summer of 2016 contributed to the thawing of permafrost and viable Bacillus anthracis spores could have become exposed to the surface; the monthly average air temperatures in June, July, and August 2016 were 20-100% higher than those of the previous 30-year period, while the maximum air temperatures were 16-75% higher. Using the projected climate data for 2081-2100 according to the "worst case" RCP8.5 scenario, we demonstrated that the yearly air temperature may average above 0°C across the entire Yamal Peninsula, while the yearly number of days with a mean temperature above 0°C may rise by 49 ± 6 days, which would provide conditions for reactivation of soil anthrax reservoirs. Our results showed that the outbreak of anthrax occurred under conditions of a significant increase in air temperature in the study area, underlined the importance of vaccination for controlling the epidemic process, and demonstrated the effectiveness of monitoring studies using the IHA diagnostic kit for detecting erythrocyte anthrax antigens.

Ecological and Socio-Economic Determinants of Livestock Animal Leptospirosis in the Russian Arctic.

Leptospirosis is a re-emerging zoonotic infectious disease caused by pathogenic bacteria of the genus Leptospira. Regional differences in the disease manifestation and the role of ecological factors, specifically in regions with a subarctic and arctic climate, remain poorly understood. We here explored environmental and socio-economic features associated with leptospirosis cases in livestock animals in the Russian Arctic during 2000-2019. Spatial analysis suggested that the locations of the majority of 808 cases were in "boreal" or "polar" climate regions, with "cropland," "forest," "shrubland," or "settlements" land-cover type, with a predominance of "Polar Moist Cropland on Plain" ecosystem. The cases demonstrated seasonality, with peaks in March, June, and August, corresponding to the livestock pasturing practices. We applied the Forest-based Classification and Regression algorithm to explore the relationships between the cumulative leptospirosis incidence per unit area by municipal districts (G-rate) and a number of socio-economic, landscape, and climatic factors. The model demonstrated satisfactory performance in explaining the observed disease distribution (R 2 = 0.82, p < 0.01), with human population density, livestock units density, the proportion of crop area, and budgetary investments into agriculture per unit area being the most influential socio-economic variables. Climatic factors demonstrated a significantly weaker influence, with nearly similar contributions of mean yearly precipitation and air temperature and number of days with above-zero temperatures. Using a projected climate by 2100 according to the RCP8.5 scenario, we predict a climate-related rise of expected disease incidence across most of the study area, with an up to 4.4-fold increase in the G-rate. These results demonstrated the predominant influence of the population and agricultural production factors on the observed increase in leptospirosis cases in livestock animals in the Russian Arctic. These findings may contribute to improvement in the regional system of anti-leptospirosis measures and may be used for further studies of livestock leptospirosis epidemiology at a finer scale.

Abortion and infant mortality change driven by socioeconomic conditions in Russia.

Increasing fertility and decreasing mortality are major response strategies in Russian demographic reform, which has led to significant decreases in both abortion rate (AR) and infant mortality. This study explores mechanisms influencing the socioeconomic conditions leading to abortion and infant mortality. Spatial panel economic analysis using data from the 83 regions of the country covering four time periods was applied. Every 1000 USD increase in per capita gross regional product (GRP) can lead to a decrease of the AR by 0.075, while one year life expectancy increase would lower it by 0.441. For infant mortality rate (IMR), GRP also shows a positive impact, particularly in recent years, while the population size of the region has a negative impact. Every 1000 USD increase in per capita GRP would result in a rate decrease of 0.064 in IMR, and every increase of 1000 added population would lead to an increased IMR by 2.05. The harvest effect between AR and infant mortality that was evident earlier, but not in the recent years, implies that the health care system in Russia is effective. A comprehensive improvement in wellbeing, income, etc. can contribute to mitigation of abortion and infant mortality. Theoretically, this study extends current research by comprehensively displaying the spatio-temporal patterns of abortion and infant mortality in Russia and qualifies the impact of regional socioeconomic disparities with regard to these two issues.

Emerging Natural Focal Infectious Diseases in Russia: A Medical-Geographical Study.

In Russia, as in other countries, the problem of emerging natural focal infectious diseases (EIDs) became more acute toward the end of the 20th century. However, the situation in Russia is unknown to foreign readers, while the prevention and control of these diseases require international collaboration. The aim of the study is to provide a medical-geographical assessment of the distribution of the main natural focal EIDs in Russia, as well as to present the approaches used in the country to create aggregate maps of risk assessment. To consider its current status, we determined the most important natural focal EIDs for Russia (tick-borne encephalitis, ixodid tick-borne borrelioses, hemorrhagic fever with renal syndrome, Crimean-Congo hemorrhagic fever, West Nile fever, Astrakhan spotted fever, leptospiroses, and tularemia) and analyzed the patterns of their epidemic manifestation. As a result, a working classification of such infections and a series of maps showing the current situation of EID morbidity in Russia were created. To design an aggregated risk map, we developed an original mapping methodology and recalculated the model disease incidence by taking data from administrative units and adjusting them for natural geographical boundaries (biomes) for European Russia, and then evaluated the risk of infection for separate model diseases and for a set of them. The highest risk rates are confined to the northwest regions of European Russia, the Cis-Urals and the Volga region, which are naturally related to forest biomes, as well as to the southern steppe regions of the interfluves between the Volga and the Don, and the foothills of the North Caucasus.

Health risks facing travelers to Russia with special reference to natural-focal diseases.

BACKGROUND: Russia, an enormous country almost completely located within temperate latitudes, has a broad spectrum of natural landscapes which attract increasing numbers of tourists, from arctic deserts in the north to steppes and deserts in the south. Currently, tourism is undergoing active development in Russia: new travel routes, including ones that involve visiting the wilderness, are steadily appearing. Among the multitude of infectious diseases that can endanger travelers, natural-focal diseases, whose agents and/or carriers are integral to natural landscapes, are especially prominent. Some of the results of the study of natural-focal infections and parasitoses, which are necessary to evaluate the recreational and travel potential of the Russian Federation, are presented and discussed in this article. METHOD: A cartographical and statistical analysis of infectious and parasitic natural-focal diseases, spanning more than a decade (1997-2013), is the basis of this article. RESULTS: This analysis, along with that of additional cartographical and textual sources, reveals that natural-focal infections are most diverse between 48° N and 60° N and least diverse in the northern regions of the Far East of Russia. Different regions have different numbers of nosoforms and different morbidity level, which signifies an irregularity in the distribution of parasitic diseases. CONCLUSIONS: This medico-geographical information may be useful both for individual tourists planning trips to Russia and tour agencies organizing tour groups. It also can be used by health advisers when they consult people before a trip, to assess the actual risks, suggest a number of precautions and pick the particular diseases out of those listed that actually constitute a risk in certain regions, and suggest a suitable preventative treatment if needed.

Natural-focal diseases: mapping experience in Russia.

BACKGROUND: Natural-focal diseases constitute a serious hazard for human health. Agents and vectors of such diseases belong to natural landscapes. The aim of this study is to identify the diversity and geography of natural-focal diseases in Russia and to develop cartographic approaches for their mapping, including mathematical-cartographical modeling. Russian medico-geographical mapping of natural-focal diseases is highly developed regionally and locally but extremely limited at the national level. To solve this problem, a scientific team of the Faculty of Geography at Lomonosov Moscow State University has developed and implemented a project of a medico-geographical Atlas of Russia "Natural-Focal Diseases". METHODS: The mapping is based on medical statistics data. The Atlas contains a series of maps on disease incidence, long-term dynamics of disease morbidity, etc. In addition, other materials available to the authors were used: mapping of the natural environment, field data, archival materials, analyzed satellite images, etc. The maps are processed using ArcGIS (ESRI) software application. Different methods of rendering of mapped phenomena are used (geographical ranges, diagrams, choropleth maps etc.). RESULTS: A series of analytical, integrated, and synthetic maps shows disease incidence in the population at both the national and regional levels for the last 15 years. Maps of the mean annual morbidity of certain infections and maps of morbidity dynamics and nosological profiles allow for a detailed analysis of the situation for each of 83 administrative units of the Russian Federation. The degree of epidemic hazard in Russia by natural-focal diseases is reflected in a synthetic medico-geographical map that shows the degree of epidemic risks due to such diseases in Russia and allows one to estimate the risk of disease manifestation in a given region. CONCLUSIONS: This is the first attempt at aggregation and public presentation of diverse and multifaceted information about natural-focal diseases in Russia. Taken in entirety, the maps that have been prepared for the Atlas will enable researchers to evaluate the stability of epidemic manifestation of individual diseases and the susceptibility of a given territory to disease transmission. The results can be used for sanitary monitoring and disease prevention.