Application of geographically-weighted regression analysis to assess risk factors for malaria hotspots in Keur Soce health and demographic surveillance site.

BACKGROUND: In Senegal, considerable efforts have been made to reduce malaria morbidity and mortality during the last decade. This resulted in a marked decrease of malaria cases. With the decline of malaria cases, transmission has become sparse in most Senegalese health districts. This study investigated malaria hotspots in Keur Soce sites by using geographically-weighted regression. Because of the occurrence of hotspots, spatial modelling of malaria cases could have a considerable effect in disease surveillance. METHODS: This study explored and analysed the spatial relationships between malaria occurrence and socio-economic and environmental factors in small communities in Keur Soce, Senegal, using 6 months passive surveillance. Geographically-weighted regression was used to explore the spatial variability of relationships between malaria incidence or persistence and the selected socio-economic, and human predictors. A model comparison of between ordinary least square and geographically-weighted regression was also explored. Vector dataset (spatial) of the study area by village levels and statistical data (non-spatial) on malaria confirmed cases, socio-economic status (bed net use), population data (size of the household) and environmental factors (temperature, rain fall) were used in this exploratory analysis. ArcMap 10.2 and Stata 11 were used to perform malaria hotspots analysis. RESULTS: From Jun to December, a total of 408 confirmed malaria cases were notified. The explanatory variables-household size, housing materials, sleeping rooms, sheep and distance to breeding site returned significant t values of -0.25, 2.3, 4.39, 1.25 and 2.36, respectively. The OLS global model revealed that it explained about 70 % (adjusted R(2) = 0.70) of the variation in malaria occurrence with AIC = 756.23. The geographically-weighted regression of malaria hotspots resulted in coefficient intercept ranging from 1.89 to 6.22 with a median of 3.5. Large positive values are distributed mainly in the southeast of the district where hotspots are more accurate while low values are mainly found in the centre and in the north. CONCLUSION: Geographically-weighted regression and OLS showed important risks factors of malaria hotspots in Keur Soce. The outputs of such models can be a useful tool to understand occurrence of malaria hotspots in Senegal. An understanding of geographical variation and determination of the core areas of the disease may provide an explanation regarding possible proximal and distal contributors to malaria elimination in Senegal

Vulnérabilité de la commune de Djilor (région de Fatick) aux changements climatiques et stratégies d’adaptation des communautés

La commune de Djilor est marquée par une tendance à la dégradation des ressources. Elles sont soumises aux effets des changements climatiques. Ainsi, l’étude de la vulnérabilité de la commune de Djilor aux changements climatiques et stratégies d’adaptation des communautés fait l’objet de cette contribution. La démarche intègre les outils d’analyse de la vulnérabilité et de la capacité d’adaptation aux changement climatique (AVCA) et d’identification des risques au niveau communautaire - adaptation et moyens d’existence (CRiSTAL). Cela a permis de faire un diagnostic participatif des menaces, contraintes et opportunités liées aux changements climatiques et aux savoirs endogènes en matière de mesure d’adaptation. Les résultats montrent l’existence de 05 catégories de ressources : les ressources naturelles, les ressources physiques, les ressources humaines, les ressources financières et les ressources sociales. L’analyse de la vulnérabilité révèle que des aléas liés directement ou indirectement à ces changements climatiques sont présents et se manifestent plus par la salinisation, la variabilité pluviométrique, la sécheresse et les inondations. Ces aléas influencent négativement ces ressources et entrainent des conséquences sur l’agriculture, l’élevage, la pêche, l’exploitation forestière, le commerce. Face à cette situation, les populations adoptent des stratégies d’adaptation. Néanmoins, la situation persiste et ses effets sont encore remarquables.