Dengue is an emerging infectious disease of global significance. Although this virus has been reported for a long time, its significance within the burden of diseases in West Africa is not obvious, especially in Burkina Faso. Our objective was to evaluate flavivirus presence in Ouagadougou (Burkina Faso) and the link between anti-flavivirus antibody seroprevalence and urbanization modes. A population-based cross-sectional survey was conducted and 3015 children were enrolled from Ouagadougou districts with different types and degrees of urbanization (with/without equipment and high/low building density). Flavivirus (FLAV) IgM MAC-ELISA and FLAV indirect IgG ELISA were performed. Associations between FLAV IgG presence (sign of past infection) and various independent variables were assessed using the chi-square test and a multivariate logistic regression analysis. The apparent prevalence of past flavivirus infections among the enrolled children was 22.7% (95% CI: 22.4–26.7) (n = 685). Eleven children (0.4%; 95% CI: 0.61–2.14) were positive for FLAV IgM, indicating active transmission. Factors associated with flavivirus infection were identified among the enrolled children (age, sex), householders (educational level, asset index) and in the environment (building density, water access, waste management and house appearance); however, they showed great variability according to the city districts. The water access modality did not significantly influence FLAV IgG positivity. Conversely, apparently good practices of waste management had unexpected consequences (increased risk related to municipal dumpsters). Given the scale of ongoing urbanization and the spread of arboviral diseases, close collaboration between health and city stakeholders is needed.

BackgroundMany cities in developing countries experience an unplanned and rapid growth. Several studies have shown that the irregular urbanization and equipment of cities produce different health risks and uneven exposure to specific diseases. Consequently, health surveys within cities should be carried out at the micro-local scale and sampling methods should try to capture this urban diversity.MethodsThis article describes the methodology used to develop a multi-stage sampling protocol to select a population for a demographic survey that investigates health disparities in the medium-sized city of Bobo-Dioulasso, Burkina Faso. It is based on the characterization of Bobo-Dioulasso city typology by taking into account the city heterogeneity, as determined by analysis of the built environment and of the distribution of urban infrastructures, such as healthcare structures or even water fountains, by photo-interpretation of aerial photographs and satellite images. Principal component analysis and hierarchical ascendant classification were then used to generate the city typology.ResultsFive groups of spaces with specific profiles were identified according to a set of variables which could be considered as proxy indicators of health status. Within these five groups, four sub-spaces were randomly selected for the study. We were then able to survey 1045 households in all the selected sub-spaces. The pertinence of this approach is discussed regarding to classical sampling as random walk method for example.ConclusionThis urban space typology allowed to select a population living in areas representative of the uneven urbanization process, and to characterize its health status in regards to several indicators (nutritional status, communicable and non-communicable diseases, and anaemia). Although this method should be validated and compared with more established methods, it appears as an alternative in developing countries where geographic and population data are scarce.

Mayotte, territoire français de l’archipel des Comores, est devenue le 101 e département français en 2011. Le processus de départementalisation initié dans les années 1990 s’est traduit par d’importants efforts en termes d’infrastructures, de santé ou d’enseignement, puis par l’alignement institutionnel de l’île sur la métropole, et la transformation des piliers économiques, sociaux, politiques et culturels du territoire mahorais. La rapidité et la brutalité des transformations de la société mahoraise et des conditions de vie des populations placent la santé au cœur des conflits qui sous-tendent l’ouverture du territoire à son nouveau statut. Les résultats d’une étude en géographie sociale réalisée à Mayotte en 2010 permettent de comprendre les principales modalités de l’intégration territoriale de Mayotte à la France, et d’analyser les liens entre les évolutions du statut politique de Mayotte et la mise en place de l’organisation actuelle du système de santé dans l’île. Il s’agit également d’appréhender les répercussions du processus de départementalisation sur l’accès et l’accessibilité des populations au système sanitaire. Ces résultats illustrent enfin les corollaires sanitaires des dynamiques de restructurations territoriales passées et présentes à Mayotte à travers son profil épidémiologique.