Spatial modelling of malaria prevalence associated with geographical factors in Houet province of Burkina Faso, West Africa

International audienceMalaria is a permanent threat to health in western Burkina Faso. Research has shown that geographical variables contribute to the spatial distribution in its transmission. The objective of this study is to assess the relationship between malaria prevalence and potential explanatory geographical variables in the Houet province in Burkina Faso. Statistics on malaria prevalence registered by health centres in the Houet province in 2017 and potential geographical variables identified through a literature review were collected. An Ordinary Least Squares (OLS) regression was used to identify key geographical variables and to measure their association with malaria while the Getis Ord Gi* index was used to locate malaria hotspots. The results showed that average annual temperature, vegetation density, percentage of clay in the soil, total annual rainfall and distance to the nearest waterbody are the main variables associated with malaria prevalence. These variables account for two-thirds of the spatial variability of malaria prevalence observed in Houet province. The intensity and direction of the relationship between malaria prevalence and geographical factors vary according to the variable. Hence, only vegetation density is positively correlated with malaria prevalence. Average temperature, for soil clay content, annual rainfall and for distance to the nearest water body are negatively correlated with the disease prevalence. These results show that even in an endemic area, malaria prevalence has significant spatial variation. The results could contribute to the choice of intervention sites, as this choice is crucial for reducing the malaria burden

Les parasitoses qui minent les nouveaux pôles de développement au Burkina Faso : cas des schistosomoses et des géohelminthes dans le complexe hydroagricole du Sourou

L’image qui prévaut en Afrique sahélo-soudanienne, est souvent celle d’une précarité accélérée des conditions de productions végétales et animales. Les populations, devant l’hostilité grandissante de la nature, ont longtemps choisi des stratégies traditionnelles de conservation des eaux et des sols ou la migration. Ainsi, l’aménagement hydraulique en particulier les barrages, en tant qu’action anthropique sur les milieux naturels, notion souvent liée à celle du risque environnemental et sanitaire, apparaît comme une alternative négociable, une réponse aux incertitudes climatiques et à la pression démographique. Au Burkina Faso, la construction des barrages est souhaitée par les populations. Et cela, d’abord parce qu’il en résulte une disponibilité en eau pour l’alimentation des hommes et des animaux. Ensuite la présence d’eau permet les cultures de décrue, l’irrigation, la pêche, le pâturage. La satisfaction que représente la proximité d’un plan d’eau est suffisamment ressentie par les populations dans toutes les régions et aujourd’hui les petits barrages et les aménagements hydro-agricoles qui sont souvent associés, font de plus en plus partie des paysages Burkinabè.Dans ces conditions, les barrages et les aménagements hydro-agricoles constituent les nouveaux pôles de développement afin de faire face à la diminution de la disponibilité alimentaire par habitant, elle-même consécutive à l’accroissement démographique. Toutefois, ces choix ne doivent pas masquer les nombreux risques sanitaires susceptibles d’être associés aux hydro-aménagements. Parmi les parasitoses eau-dépendante, les  bilharzioses et les géohelminthes apparaissent comme des affections particulièrement sensibles aux modifications des relations entre la communauté humaine et leur environnement aquatique car l’un de leurs traits caractéristiques est leur capacité à s’adapter et à bénéficier des transformations du milieu induites par les aménagements hydro-agricoles. Plusieurs facteurs sont souvent indexés à leur survenue, à leur expansion et aux difficultés de contrôle entre autres : la typologie des biotopes aquatiques, leur juxtaposition dans l’espace, la distribution et la dynamique des populations de parasites, de vecteurs et d’hôtes intermédiaires, les mouvements des populations humaines avec différentes souches de parasites et leur  état immunitaire,  les comportements de l’homme (contact homme-eau - parasite) et l’hygiène du milieu, la perception des maladies par les populations humaines, les chemins thérapeutiques et par conséquent la pertinence de l’IEC, le statut de la femme et de l’enfant dans les schémas de transmission parasitaire et de recours aux soins. Il ressort que les aménagements hydrauliques constituent des facteurs amplificateurs de la prolifération des vecteurs de transmission et des flux parasitaires hôte-parasite. Tous les acteurs (aménageurs, populations et scientifiques) sont interpellés pour atténuer voir réduire le développement des maladies qui amoindrissent le bénéfice attendu des aménagements hydro-agricoles.The existing image in the Sahel Sudan Africa is often that of accelerated insecurity of plant and animal production conditions. Face with the growing hostility of nature, the people have for a long time adopted water and soil conservation strategies or migration. Thus, water development, especially the dam as an anthropic activity on the natural landscape, a notion linked to that of environmental and health risk seems to be a negotiable alternative, an answer to climatic vagaries. In Burkina Faso, the people want the construction of dams because, firstly, they provide water for man and animals, secondly, water provides food for man and animals. It is also used for dry season farming, irrigation, fishing and grazing. The satisfaction that the proximity of a dam gives is sufficiently felt by the people in all the regions, and today, small dams and hydro-agricultural developments which are often interrelated are more and more becoming part and parcel of the Burkinabe countryside. Under these conditions, the dams and farms are the new development poles aimed at solving the decreasing problem of food production per head which is the result of increasing population. However, these choices must not overshadow the numerous health risks associated with irrigation farming. Among the water-borne diseases; schistosomiasis and geohelminthis seem to be the most sensitive disease to changes in the relations between the human community and their aquatic environment, because one of their characteristic traits is their ability to adapt and benefit from the newly-created environment that resulted from the hydroagricultural development. There are several factors leading to their outbreak, their spread and the difficulty in controlling them among others: the framework of aquatic biotope, their juxtaposition in space, distribution and the development process of the number of the parasites, vectors and the intermediary hosts, movement of the human population with different lines of parasites and their state of immunity, the behaviour of man-man-water-parasite relations and the hygiene of the environment, the perception of the people about the disease, the therapeutic means, and consequently the pertinence of the IEC, the statue of women and children in the parasite transmission and treatment programme. It has been realised that hydro arming is one of the factors that enhance the proliferation of vectors of transmission and flux of parasite hosts. All the players, (land developers, the population and scientists) have been urged to use all the means at their disposal to alleviate or even stop the spread of the disease which is decreasing the expected agricultural returns

Les parasitoses qui minent les nouveaux pôles de développement au Burkina Faso : cas des schistosomoses et des géohelminthes dans le complexe hydroagricole du Sourou

The existing image in the Sahel Sudan Africa is often that of accelerated insecurity of plant and animal production conditions. Face with the growing hostility of nature, the people have for a long time adopted water and soil conservation strategies or migration. Thus, water development, especially the dam as an anthropic activity on the natural landscape, a notion linked to that of environmental and health risk seems to be a negotiable alternative, an answer to climatic vagaries. In Burkina Faso, the people want the construction of dams because, firstly, they provide water for man and animals, secondly, water provides food for man and animals. It is also used for dry season farming, irrigation, fishing and grazing. The satisfaction that the proximity of a dam gives is sufficiently felt by the people in all the regions, and today, small dams and hydro-agricultural developments which are often interrelated are more and more becoming part and parcel of the Burkinabe countryside.Under these conditions, the dams and farms are the new development poles aimed at solving the decreasing problem of food production per head which is the result of increasing population. However, these choices must not overshadow the numerous health risks associated with irrigation farming.Among the water-borne diseases; schistosomiasis and geohelminthis seem to be the most sensitive disease to changes in the relations between the human community and their aquatic environment, because one of their characteristic traits is their ability to adapt and benefit from the newly-created environment that resulted from the hydroagricultural development. There are several factors leading to their outbreak, their spread and the difficulty in controlling them among others: the framework of aquatic biotope, their juxtaposition in space, distribution and the development process of the number of the parasites, vectors and the intermediary hosts, movement of the human population with different lines of parasites and their state of immunity, the behaviour of man-man-water-parasite relations and the hygiene of the environment, the perception of the people about the disease, the therapeutic means, and consequently the pertinence of the IEC, the statue of women and children in the parasite transmission and treatment programme. It has been realised that hydro arming is one of the factors that enhance the proliferation of vectors of transmission and flux of parasite hosts. All the players, (land developers, the population and scientists) have been urged to use all the means at their disposal to alleviate or even stop the spread of the disease which is decreasing the expected agricultural returns