The article presents the results of a spatio-temporal analysis of the changes of the favorability of climatic conditions for the transmission of vivax malaria in the Moscow megacity and its surroundings during the period from 1977 to 2016. Using the historical temperature records at urban and rural weather stations, we calculated the key indicators of climate favorability for malaria transmission, viz. the sum of effective temperatures, the duration of the season of effective infectiveness, and a new integral index of climate favorability. We demonstrated a dramatic increase of all three indicators, which accelerated after 1984, and a high spatial heterogeneity among them. Due to the urban heat island effect, the degree of climatic favorability is especially high in the densely urbanized areas of Moscow megacity compared with the suburban and rural areas. Climatic conditions for vivax malaria in Moscow are better now than before. The season of effective infectiveness continues in the central part of the city for 25 days longer, and the integral index of climate favorability is 85% higher in comparison to mean values over the rural surroundings. The study contains an alert regarding the risk of malaria resurgence in the Moscow region in the case of the sufficient importation of cases from abroad.
Background: Between 1999 and 2008 Russia experienced a flare-up of transmission of vivax malaria following its massive importation with more than 500 autochthonous cases in European Russia, the Moscow region being the most affected. The outbreak waned soon after a decrease in importation in mid-2000s and strengthening the control measures. Compared with other post-eradication epidemics in Europe this one was unprecedented by its extension and duration. Methods: The aim of this study is to identify geographical determinants of transmission. The degree of favourability of climate for vivax malaria was assessed by measuring the sum of effective temperatures and duration of season of effective infectivity using data from 22 weather stations. For geospatial analysis, the locations of each of 405 autochthonous cases detected in Moscow region have been ascertained. A MaxEnt method was used for modelling the territorial differentiation of Moscow region according to the suitability of infection re-emergence based on the statistically valid relationships between the distribution of autochthonous cases and environmental and climatic factors. Results: In 1999-2004, in the beginning of the outbreak, meteorological conditions were extremely favourable for malaria in 1999, 2001 and 2002, especially within the borders of the city of Moscow and its immediate surroundings. The greatest number of cases occurred at the northwestern periphery of the city and in the adjoining rural areas. A significant role was played by rural construction activities attracting migrant labour, vegetation density and landscape division. A cutoff altitude of 200 m was observed, though the factor of altitude did not play a significant role at lower altitudes. Most likely, the urban heat island additionally amplified malaria re-introduction. Conclusion: The malariogenic potential in relation to vivax malaria was high in Moscow region, albeit heterogeneous. It is in Moscow that the most favourable conditions exist for vivax malaria re-introduction in the case of a renewed importation. This recent event of large-scale re-introduction of vivax malaria in a temperate area can serve as a case study for further research.
BackgroundNatural-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”.MethodsThe 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.).ResultsA 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.ConclusionsThis 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.
No abstract
The spread of almost all diseases caused by living pathogens is determined primarily by environmental conditions. These pathogens like any other biological objects are the components of the certain natural ecosystems. An essential part of any medicogeographical assessment is the search for links between the spread of diseases and factors of the geographical environment. The role of factors that affect the spread of the natural diseases is unequal. The climatic factor is deemed one of the main determinants for the spread of naturally-determined diseases. This factor manifests itself at all levels of territorial differentiation. The goal of these studies was to identify the natural and climatic suitability of the certain territory for spread of diseases in order to assess the possible influence of the climatic factor on the medico-geographical situation in the context of the regional environment. The objectives are to estimate the role of climatic and weather parameters in the functioning of natural foci in Russia; to assess the natural and climatic suitability of the territory for spread of diseases; and to identify the climatic preconditions of spread of particular climate-dependent infections. In this study, on the example of several climatedepended diseases different approaches to medico-geographical assessment have been implemented and number of new methodological solutions have been proposed.
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