L’urbanisation non maîtrisée des villes africaines en déficit de services de gestion des déchets urbains génère des paysages qui deviennent des lieux d’interactions multiples et variées entre santé et environnement. Soumise à une forte croissance urbaine dans un contexte de sous-équipement en services d’assainissement, la ville de Nouakchott n’échappe pas à cette situation qui se traduit par la propagation de nombreuses pathologies posant ainsi de multiples problèmes de santé publique. Afin d’étudier les risques sanitaires auxquels s’exposent les populations, une enquête transversale a été menée en août 2004 auprès de 836 ménages dans trois quartiers de la ville. Les résultats de l’étude montrent les principaux problèmes de santé (syndrome du paludisme, syndrome de l’appareil respiratoire, syndrome l’appareil digestif) ressentis par les populations tout en mettant en évidence la prévalence des maladies les plus récurrentes dont les infections respiratoires aiguës (28,0 %) et les diarrhées (17,2 %) ainsi que les facteurs environnementaux d’exposition aux risques sanitaires. Ainsi, l’importance des maladies hygiéniques dans la morbidité globale montre que la ville présente des conditions écologiques favorables au développement de la pathologie urbaine. Le poids déterminant des conditions environnementales dans l’occurrence de ces pathologies permet de conforter les conceptions sur les liens entre santé et environnement. Par ailleurs, ces interactions traduisent l’incidence de la pauvreté urbaine très marquée dans les quartiers étudiés. Ces résultats appellent à une approche intégrée des questions de santé, d’environnement et de pauvreté dans les politiques de développement des villes.

BackgroundThe epidemiology of malaria in the Senegal River Gorgol valley, southern Mauritania, requires particular attention in the face of ongoing and predicted environmental and climate changes. While “malaria cases” are reported in health facilities throughout the year, past and current climatic and ecological conditions do not favour transmission in the dry season (lack of rainfall and very high temperatures). Moreover, entomological investigations in neighbouring regions point to an absence of malaria transmission in mosquito vectors in the dry season. Because the clinical signs of malaria are non-specific and overlap with those of other diseases (e.g. acute respiratory infections and diarrhoea), new research is needed to better understand malaria transmission patterns in this region to improve adaptive, preventive and curative measures.MethodsWe conducted a multipurpose cross-sectional survey in the city of Kaédi in April 2011 (dry season), assessing three major disease patterns, including malaria. Plasmodium spp. parasite rates were tested among children aged 6–59 months who were recruited from a random selection of households using a rapid diagnostic test and microscopic examination of Giemsa-stained thick and thin blood films. Acute respiratory infection and diarrhoea were the two other diseases investigated, administering a parental questionnaire to determine the reported prevalence among participating children.FindingsNo Plasmodium infection was found in any of the 371 surveyed preschool-aged children using two different diagnostic methods. Acute respiratory infections and diarrhoea were reported in 43.4% and 35.0% of the participants, respectively. About two thirds of the children with acute respiratory infections and diarrhoea required medical follow-up by a health worker.ConclusionsMalaria was absent in the present dry season survey in the capital of the Gorgol valley of Mauritania, while acute respiratory infections and diarrhea were highly prevalent. Surveys should be repeated towards the end of rainy season, which will enhance our understanding of the potential changes in malaria transmission in a region known as ‘hot spot’ of predicted climate change.

Therefore, exposure to diarrheal diseases through the prism of water and sanitation is a real public health problem that requires a systemic and integrated approach to improving environmental health.

In Kaédi, a secondary city of Mauritania with approximately 71,000 inhabitants, the analyses of historical climate time series data (1919-2010) and some projections showed a likely occurrence of more frequent heavy rains and higher risks of flooding events in the future. Vulnerability assessments, facilitated through transversal household surveys toward the end of the rainy season that covered the entire city and followed a stratified sampling approach, showed that the community's water supply comprises more than 100 wells, 33% of households report using water from wells for drinking purposes, 12% of households have their own wells in the yard, and 69% of households have latrines in the yard. The analysis also revealed considerable spatial heterogeneity of vulnerability. Considering the risks of cross-contamination of wells water by onsite sanitation facilities during flood events, communities and local governance actors should find appropriate adaptation to climate change strategies for water and health sectors starting with thematic vulnerability maps.

Abstract. Access to sufficient quantities of safe drinking water is a human right. Moreover, access to clean water is of public health relevance, particularly in semi-arid and Sahelian cities due to the risks of water contamination and transmission of water-borne diseases. We conducted a study in Nouakchott, the capital of Mauritania, to deepen the understanding of diarrhoeal incidence in space and time. We used an integrated geographical approach, combining socio-environmental, microbiological and epidemiological data from various sources, including spatially explicit surveys, laboratory analysis of water samples and reported diarrhoeal episodes. A geospatial technique was applied to determine the environmental and microbiological risk factors that govern diarrhoeal transmission. Statistical and cartographic analyses revealed concentration of unimproved sources of drinking water in the most densely populated areas of the city, coupled with a daily water allocation below the recommended standard of 20 l per person. Bacteriological analysis indicated that 93% of the non-piped water sources supplied at water points were contaminated with 10-80 coliform bacteria per 100 ml. Diarrhoea was the second most important disease reported at health centres, accounting for 12.8% of health care service consultations on average. Diarrhoeal episodes were concentrated in municipalities with the largest number of contaminated water sources. Environmental factors (e.g. lack of improved water sources) and bacteriological aspects (e.g. water contamination with coliform bacteria) are the main drivers explaining the spatio-temporal distribution of diarrhoea. We conclude that integrating environmental, microbiological and epidemiological variables with statistical regression models facilitates risk profiling of diarrhoeal diseases. Modes of water supply and water contamination were the main drivers of diarrhoea in this semi-arid urban context of Nouakchott, and hence require a strategy to improve water quality at the various levels of the supply chain.