Le paludisme urbain à Brazzaville : hétérogénéité locale, enjeu global: De la géographie du risque aux stratégies de lutte antipaludique

National audienceMalaria is still a sanitary curse in many sub‐Saharan countries. In central Africa, this disease is the first cause of mortality and one of the first causes of children'mortality. In Brazzaville, this sanitary issue is not solved at all. In Brazzaville, the capital of Congo, the malaria transmission is high and permanent all over the year. The aim of this study is to analyze the geographical impact of the control measures of malaria risk. This analysis enables to mix world and local observation scales in order to establish whether the nature of those control measures is complementary. Another sensitive question which has to be studied in order to consider all the factors responsible for the disease persistence, is: the correlation between disease and the social and political context. Twelve years of war, a delay in development and above all a health sector with a lack of medical staff, in addition to poor infrastructures and limited investments, are among the major causes of the malaria burden in Central Africa. The sanitary strategies must be regarded as primordial in the struggle against disease.Le paludisme reste encore une urgence sanitaire dans beaucoup de pays du monde, particulièrement en Afrique Centrale où cette maladie est la première cause de morbidité et une des premières causes de mortalité infantile. À Brazzaville, capitale du Congo, ce problème de santé est loin d'être résolu et la transmission reste permanente tout au long de l'année. L'enjeu de cette étude est d'analyser l'impact géographique des mesures de contrôle du risque paludique. Une analyse transversale basée sur un jeu d'échelles du global au local permettrait de constater la nature complémentaire ou non des politiques sanitaires mises en place. Enfin, pour explorer la globalité des facteurs responsables de la persistance de la pathologie, un dernier point mérite d'être étudié : la relation entre la maladie et son contexte social et politique. Douze ans de guerre, un retard de développement et un secteur de la santé souffrant de manque de personnels, d'infrastructures défectueuses et de peu d'investissements sont autant d'éléments responsables du fardeau socio‐économique que représente le paludisme en Afrique Centrale. Les stratégies de santé doivent donc être considérées comme primordiales dans la lutte contre cette pathologie

Entre distance géographique et distance sociale : le risque de paludisme-infection en milieu urbain africain: L'exemple de l'agglomération de Dakar, Sénégal

This thesis applies an Exploratory Spatial Data Analysis (ESDA) approach to study a complex phenomenon in a data scarce environment: malaria infection in Dakar. Each component of the malaria pathogenic system is necessary but not sufficient to result in an infection when acting in isolation. For malaria infection to occur, three components need to interact: the parasite, the vector, and the human host. The identification of areas where these three components can easily interact is therefore essential in the fight against malaria and the improvement of programs for the prevention and control or elimination of the disease. ESDA, still rarely applied in developing countries, is thus defined as a research approach but also as a way to provide answers to global health challenges. It leads to observation, from different angles, on the social and spatial determinants of malaria infection, as well as the examination of existing interactions between its three components.Several streams of quantitative information were collected, both directly and indirectly related to the study of malaria. More specifically, multi-temporal satellite imagery, census data, and results from social and health surveys have been integrated into a Geographic Information System (GIS) to describe the city and its inhabitants. Combining these datasets has enabled to study the spatial variability of the risk of malaria infection. The use of statistical and geostatistical analysis, including both bi- and multivariate statistics, has revealed that the risk of infection in Dakar is highly dependent on the so-called ’social distance’. It describes the physical or economic ability of residents to move away from potential areas at risk, by avoiding the pathogenic areas, i.e., places where potentially infected vectors proliferate. Thus, a strong link between exposure (which results in a bigger parasite reservoir in marginalized areas) and social vulnerability of individuals (which increases substantially the risk of malaria infection) has been outlined.Cette thèse défend l’intérêt d’appliquer une démarche d’analyse exploratoire de données spatiales pour examiner un phénomène complexe irréductible, dans un contexte limité en données : le paludisme-infection à Dakar. Chaque partie du système pathogène du paludisme est nécessaire mais non suffisante au fonctionnement du système. Il n’y a paludisme-infection que lorsque les trois composantes sont en contact : le parasite, le vecteur et l’hôte humain. La recherche des lieux où ces contacts peuvent s’opérer facilement est donc primordiale dans la lutte contre le paludisme et l’amélioration des programmes visant à la diminution voire l’élimination de la maladie. L’analyse exploratoire, encore très peu appliquée dans les pays dits du Sud, se définit ainsi comme une démarche de recherche mais aussi comme un moyen d’apporter des réponses aux besoins sanitaires. Elle pousse à l’observation, sous différents angles, des déterminants sociaux et spatiaux qui sont impliqués dans la réalisation du phénomène, tout comme à l’examen des interactions existantes entre eux.Nous avons récolté des informations quantitatives variées, en lien direct et indirect avec l’étude du paludisme. Interprétation d’images satellites, données censitaires, résultats d’enquêtes sociales et sanitaires ont été intégrées dans un système d’information géographique pour décrire la ville et ses habitants. Le croisement de ces sources a permis d’étudier les faces spatiales du risque épidémique palustre. Le recours à des analyses statistiques et géostatistiques, bivariées et multivariées, a permis de souligner que le risque d’infection des populations dépendait fortement d’une distance, que l’on a qualifié de sociale. Celle-ci décrit la faculté des habitants à s'extraire du risque d'infection en s'éloignant, physiquement ou matériellement, des espaces pathogènes, lieux de prolifération de vecteurs potentiellement infectés. On a pu ainsi montrer le lien fort existant entre l'exposition (qui favorise un réservoir parasitaire plus important dans les quartiers défavorisés), et la vulnérabilité sociale des individus (qui augmente considérablement le risque d’infection au paludisme)

Climate Change Vulnerability Assessment in Mauritania: Reflections on Data Quality, Spatial Scales, Aggregation and Visualizations

International audienceMauritania is vulnerable to climate change due to its location along the Sahel, the desert climate of the Sahara, and its socioeconomic characteristics. To support the identification of climate change adaptation measures in Brakna and Assaba in Mauritania, a spatial assessment of vulnerability to climate change targeting the livelihood sectors of agriculture and pastoralism was carried out. Based on the identification of relevant drivers of climate change vulnerability in a broad consultation process among national and local stakeholders, a variety of geospatial indicators were identified and integrated in the assessments based on a standardized vulnerability assessment approach. In this paper, we provide a reflection on the methodology applied and identify lessons to be learnt on data quality, spatial scales, aggregation and visualizations. The primary conclusion is that users of the assessment results and stakeholders need to be engaged in the entire assessment process in order to reflect local characteristics more fully, and to ensure that the results are reflected in informed decision-making

Impeded Migration as Adaptation: COVID-19 and Its Implications for Translocal Strategies of Environmental Risk Management

In the debates over environmental impacts on migration, migration as adaptation has been acknowledged as a potential risk management strategy based on risk spreading and mutual insurance of people living spatially apart: migrants and family members that are left behind stay connected through a combination of financial and social remittances, joint decision-making and mutual commitment. Conceptualizing migration as adaptation through the lens of translocal livelihood systems enables us to identify the differentiated vulnerabilities of households and communities. COVID-19 and the restrictions on public life and mobility imposed by governments worldwide constituted a complex set of challenges for translocal systems and strategies, especially in the Global South. Focusing on examples, we highlight two points: first, the COVID-19 crisis shows the limits of migration and translocal livelihoods for coping with, and adapting to, climate and environmental risks. Second, as these restrictions hit on a systemic level and affect places of destination as well as origin, the crisis reveals specific vulnerabilities of the translocal livelihood systems themselves. Based on the translocal livelihoods approach, we formulate insights and recommendations for policies that move beyond the narrow, short-term focus on the support of migrant populations alone and address the longer-term root causes of the vulnerabilities in translocal livelihoods systems

Migration influenced by environmental change in Africa:A systematic review of empirical evidence

BACKGROUND Despite an increase in scholarly and policy interest regarding the impacts of environmental change on migration, empirical knowledge in the field remains varied, patchy, and limited. Generalised discourse on environmental migration frequently oversimplifies the complex channels through which environmental change influences the migration process. OBJECTIVE This paper aims to systematise the existing empirical evidence on migration influenced by environmental change with a focus on Africa, the continent most vulnerable to climate change. METHODS We select 53 qualitative and quantitative studies on the influence of environmental change on migration from the comprehensive Climig database and systematically analyse the literature considering the multidimensional drivers of migration. RESULTS Environmental change influences migration in Africa in an indirect way by affecting other drivers of migration, including sociodemographic, economic, and political factors. How and in what direction environmental change influences migration depends on socioeconomic and geographical contexts, demographic characteristics, and the type and duration of migration. CONCLUSIONS The contextually contingent nature of migration-environment relationships prevents us from drawing a universal conclusion, whether environmental change will increase or suppress migration in Africa. However, this study unravels the complex interactions between the nature and duration of the environmental pressure, the livelihood of the populations, the role of kinship ties and the role of demographic differentials on migration response. CONTRIBUTION The review provides an initial systematic and comprehensive summary of empirical evidence on the environmental drivers of migration in Africa. It also discusses the implications of the scale, materials, and methods used in the 53 studies

Asymptomatic Carriage of Plasmodium in Urban Dakar: The Risk of Malaria Should Not Be Underestimated

Introduction: The objective of this study was to measure the rate of asymptomatic carriage of plasmodium in the Dakar region two years after the implementation of new strategies in clinical malaria management. Methodology: Between October and December 2008, 2952 households selected in 50 sites of Dakar area, were visited for interviews and blood sampling. Giemsa-stained thick blood smears (TBS) were performed for microscopy in asymptomatic adult women and children aged 2 to 10 years. To ensure the quality of the microscopy, we performed a polymerase chai

Out of sight, out of mind. How research can help make vulnerable population visibleThe case study of displaced population to Ganges River bank erosion in Malda, district of West Bengal, India

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Integrating EO-based data into vulnerability assessment: Case study and reflection on urban health research

International audienc