Research
Social and environmental malaria risk factors in urban areas of Ouagadougou, Burkina Faso
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* Corresponding author: Christophe Rogier christophe.rogier@wanadoo.fr
1 Parasite Biology and Epidemiology Research Dept, UMR 6236 – URMITE, IMTSSA, Parc du Pharo, BP46, 13998 Marseille-Armées, France
2 Environnement urbain et transition sanitaire en Afrique de l'Ouest, IRD, 01 BP 182, Ouagadougou, Burkina Faso
3 Centre Muraz, BP 360 Bobo-Dioulasso, Burkina-Faso
4 Institut Pierre Richet/Institut National de Santé Publique, BP V 47 Abidjan, Côte d'Ivoire
5 Institut de Recherche en Sciences de la Santé (IRSS/CNRST) – 03 BP 7192 Ouagadougou, Burkina Faso
6 Laboratoire Espace, Santé et Territoire, Université Paris X-Nanterre, 200 avenue de la République, 92001 Nanterre Cedex, France
Malaria Journal 2009, 8:13 doi:10.1186/1475-2875-8-13
Published: 13 January 2009Abstract
Background
Despite low endemicity, malaria remains a major health problem in urban areas where a high proportion of fevers are presumptively treated using anti-malarial drugs. Low acquired malaria immunity, behaviour of city-dwellers, access to health care and preventive interventions, and heterogenic suitability of urban ecosystems for malaria transmission contribute to the complexity of the malaria epidemiology in urban areas.
Methods
The study was designed to identify the determinants of malaria transmission estimated by the prevalence of anti-circumsporozoite (CSP) antibodies, the prevalence and density of Plasmodium falciparum infection, and the prevalence of malarial disease in areas of Ouagadougou, Burkina-Faso. Thick blood smears, dried blood spots and clinical status have been collected from 3,354 randomly chosen children aged 6 months to 12 years using two cross-sectional surveys (during the dry and rainy seasons) in eight areas from four ecological strata defined according to building density and land tenure (regular versus irregular). Demographic characteristics, socio-economic information, and sanitary and environmental data concerning the children or their households were simultaneously collected. Dependent variables were analysed using mixed multivariable models with random effects, taking into account the clustering of participants within compounds and areas.
Results
Overall prevalences of CSP-antibodies and P. falciparum infections were 7.7% and 16.6% during the dry season, and 12.4% and 26.1% during the rainy season, respectively, with significant differences according to ecological strata. Malaria risk was significantly higher among children who i) lived in households with lower economic or education levels, iii) near the hydrographic network, iv) in sparsely built-up areas, v) in irregularly built areas, vi) who did not use a bed net, vii) were sampled during the rainy season or ii) had traveled outside of Ouagadougou.
Conclusion
Malaria control should be focused in areas which are irregularly or sparsely built-up or near the hydrographic network. Furthermore, urban children would benefit from preventive interventions (e.g. anti-vectorial devices or chemoprophylaxis) aimed at reducing malaria risk during and after travel in rural areas.