Efficacy of Olyset Duo, a bednet containing pyriproxyfen and permethrin, versus a permethrin-only net against clinical malaria in an area with highly pyrethroid-resistant vectors in rural Burkina Faso: a cluster-randomised controlled trial

Background Substantial reductions in malaria incidence in sub-Saharan Africa have been achieved with massive deployment of long-lasting insecticidal nets (LLINs), but pyrethroid resistance threatens control. Burkina Faso is an area with intense malaria transmission and highly pyrethroid-resistant vectors. We assessed the effectiveness of bednets containing permethrin, a pyrethroid, and pyriproxyfen, an insect growth regulator, versus permethrin-only (standard) LLINs against clinical malaria in children younger than 5 years in Banfora, Burkina Faso. Methods In this two-group, step-wedge, cluster-randomised, controlled, superiority trial, standard LLINs were incrementally replaced with LLINs treated with permethrin plus pyriproxyfen (PPF) in 40 rural clusters in Burkina Faso. In each cluster, 50 children (aged 6 months to 5 years) were followed up by passive case detection for clinical malaria. Cross-sectional surveys were done at the start and the end of the transmission seasons in 2014 and 2015. We did monthly collections from indoor light traps to estimate vector densities. Primary endpoints were the incidence of clinical malaria, measured by passive case detection, and the entomological inoculation rate. Analyses were adjusted for clustering and for month and health centre. This trial is registered as ISRCTN21853394. Findings 1980 children were enrolled in the cohort in 2014 and 2157 in 2015. At the end of the study, more than 99% of children slept under a bednet. The incidence of clinical malaria was 2·0 episodes per child-year in the standard LLIN group and 1·5 episodes per child-year in the PPF-treated LLIN group (incidence rate ratio 0·88 [95% CI 0·77–0·99; p=0·04]). The entomological inoculation rate was 85 (95% CI 63–108) infective bites per transmission season in the standard LLIN group versus 42 (32–52) infective bites per transmission season in the PPF-treated LLIN group (rate ratio 0·49, 95% CI 0·32–0·66; p<0·0001). Interpretation PPF-treated LLINs provide greater protection against clinical malaria than do standard LLINs and could be used as an alternative to standard LLINs in areas with intense transmission of Plasmodium falciparum malaria and highly pyrethroid-resistant vectors. Funding EU Seventh Framework Programme

Introduction

Face à une augmentation insuffisante de la production agricole en Afrique de l’Ouest, et pour satisfaire la demande alimentaire croissante de la population dans un contexte de variabilité spatio-temporelle de la pluviométrie et de changement climatique, l’intensification écologique des agrosystèmes par le biais de la combinaison judicieuse de systèmes de cultures et d’itinéraires techniques est une option pertinente. En effet, elle pourrait permettre de valoriser les processus biologiques, d’..

A crop model and fuzzy rule based approach for optimizing maize planting dates in Burkina Faso, West Africa

AbstractIn sub-Saharan Africa, with its high rainfall variability and limited irrigation options, the crop planting date is a crucial tactical decision for farmers and therefore a major concern in agricultural decision making. To support decision making in rainfed agriculture, a new approach has been developed to optimize crop planting date. The General Large-Area Model for Annual Crops (GLAM) has been used for the first time to simulate maize yields in West Africa. It is used in combination with fuzzy logic rules to give more flexibility in crop planting date computation when compared with binary logic methods. A genetic algorithm is applied to calibrate the crop model and to optimize the planting dates at the end. The process for optimizing planting dates results in an ensemble of optimized planting rules. This principle of ensemble members leads to a time window of optimized planting dates for a single year and thereby potentially increases the willingness of farmers to adopt this approach. The optimized planting date (OPD) approach is compared with two well-established methods in sub-Saharan Africa. The results suggest earlier planting dates across Burkina Faso, ranging from 10 to 20 days for the northern and central part and less than 10 days for the southern part. With respect to the potential yields, the OPD approach indicates that an average increase in maize potential yield of around 20% could be obtained in water-limited regions in Burkina Faso. The implementation of the presented approach in agricultural decision support is expected to have the potential to improve agricultural risk management in these regions dominated by rainfed agriculture and characterized by high rainfall variability.</jats:p

Grounding the nexus: Examining the integration of small-scale irrigators into a national food security programme in Burkina Faso

The water-food nexus literature examines the synergies and trade-offs of resource use but is dominated by large-scale analyses that do not sufficiently engage the local dimensions of resource management. The research presented here addresses this gap with a local-scale analysis of integrated water and food management in Burkina Faso. Specifically, we analyse the implementation of a national food security campaign (Opération Bondofa) to boost maize production in a subbasin that exhibits two important trends in Africa: a large increase in small-scale irrigators and the decentralisation of water management. As surface water levels dropped in the region, entities at different scales asserted increased control over water allocation, exposing the contested nature of new decentralised institutions, and powerful actors’ preference for local control. These scalar power struggles intersected with a lack of knowledge of small-scale irrigators’ cultural practices to produce an implementation and water allocation schedule that did match small-scale irrigator needs, resulting in low initial enthusiasm for the project. Increased attention from national governments to strengthen decentralised water management committees and spur greater knowledge of, and engagement with, small-scale irrigators can result in improved programme design to better incorporate small-scale irrigators into national food security campaigns

Introduction générale

Le futur de l’Afrique de l’Ouest, son équilibre économique, politique et social dépendent de la capacité du secteur de l’agriculture à s’adapter pour garantir la sécurité alimentaire dans un contexte de pressions multiples comme celles engendrées par le changement climatique et la croissance démographique. Pour faciliter cette adaptation, la recherche a déployé d’importants efforts ces dernières années en améliorant la connaissance sur la compréhension des changements climatiques en Afrique d..

Caractérisation de la variabilité climatique dans la region du centre-nord du burkina faso entre 1961 et 2015

Cette étude a pour but de caractériser la variabilité climatique dans le Centre-Nord du Burkina Faso. L’économie de cette région est particulièrement vulnérable au changement climatique. Les données collectées à cette fin concernent la pluviométrie journalière enregistrée dans onze stations et couvrant la période 1961-2015. L’indice pluviométrique standardisé a été utilisé pour déterminer les périodes sèches et humides. Des tests statistiques ont été appliqués pour analyser la variabilité pluviométrique. Les indices ETCCDMI ont permis de caractériser les extrêmes pluviométriques. Les résultats montrent que la période 1961-2015 est caractérisée par une alternance de phases humides et sèches avec une tendance générale à la baisse des précipitations annuelles. La région a connu une modification de son régime pluviométrique depuis la fin des années 1960. Cette modification s’est traduite par une période de baisse des cumuls pluviométriques et des pluies journalières. Cependant, la pluviométrie régionale a amorcé un retour vers des périodes plus humides depuis la fin des années 1980 et les décennies 1990 et 2000. La reprise est plus prononcée dans la zone sahélienne que dans l’espace soudano-sahélien. Cette étude montre une forte disparité spatiale dans la répartition des jours pluvieux durant ces décennies. En effet, le nombre annuel de jours pluvieux est en hausse dans cinq localités tandis qu’il est en baisse dans les six autres localités. La fréquence des pluies de 50 mm, des pluies intenses et des pluies extrêmes est en hausse depuis la fin des années 1980 et les décennies 1990 et 2000. Le retour des pluies est plutôt lié à une fréquence élevée des évènements de forte intensité pluviométrique qu’à une augmentation des jours pluvieux. Malgré cette évolution, on note une persistance de la sécheresse dans certaines localités du Centre-Nord notamment depuis 2005 à Kongoussi et 2010 à Bouroum

Stochastic linear programming for improved reservoir operations for multiple objectives in Burkina Faso, West Africa

A network of reservoirs and diversion structures in the Comoe River Basin in southwestern Burkina Faso, West Africa, provides municipal water supply and irrigation water for sugarcane agribusiness and a population of farmers. The region is characterized by severe intraseasonal and inter-annual variability with respect to precipitation and reservoir inflows. Reservoir operations are generally conservative, even during wet years. A stochastic linear programming model is introduced which translates seasonal streamflow and precipitation forecasts, in the form of a scenario tree, into optimal release schedules for reservoir operators to implement in real-time as forecasts and system conditions change. Goals include more efficient and equitable releases, and downstream flow maintenance. A VBA-based graphic user interface (GUI) is used to ensure implementation and ease of use by operators. © 2008 ASCE

An atlas to support the progressive control of tsetse-transmitted animal trypanosomosis in Burkina Faso

International audienceBackground African animal trypanosomosis (AAT), transmitted by tsetse flies, is arguably the main disease constraint to integrated crop-livestock agriculture in sub-Saharan Africa, and African heads of state and governments adopted a resolution to rid the continent of this scourge. In order to sustainably reduce or eliminate the burden of AAT, a progressive and evidence-based approach is needed, which must hinge on harmonized, spatially explicit information on the occurrence of AAT and its vectors. Methods A digital repository was assembled, containing tsetse and AAT data collected in Burkina Faso between 1990 and 2019. Data were collected either in the framework of control activities or for research purposes. Data were systematically verified, harmonized, georeferenced and integrated into a database (PostgreSQL). Entomological data on tsetse were mapped at the level of individual monitoring traps. When this was not possible, mapping was done at the level of site or location. Epidemiological data on AAT were mapped at the level of location or village. Results Entomological data showed the presence of four tsetse species in Burkina Faso. Glossina tachinoides , present from the eastern to the western part of the country, was the most widespread and abundant species (56.35% of the catches). Glossina palpalis gambiensis was the second most abundant species (35.56%), and it was mainly found in the west. Glossina morsitans submorsitans was found at lower densities (6.51%), with a patchy distribution in the southern parts of the country. A single cluster of G. medicorum was detected (less than 0.25%), located in the south-west. Unidentified tsetse flies accounted for 1.33%. For the AAT component, data for 54,948 animal blood samples were assembled from 218 geographic locations. The samples were tested with a variety of diagnostic methods. AAT was found in all surveyed departments, including the tsetse-free areas in the north. Trypanosoma vivax and T. congolense infections were the dominant ones, with a prevalence of 5.19 ± 18.97% and 6.11 ± 21.56%, respectively. Trypanosoma brucei infections were detected at a much lower rate (0.00 ± 0.10%). Conclusions The atlas provides a synoptic view of the available information on tsetse and AAT distribution in Burkina Faso. Data are very scanty for most of the tsetse-free areas in the northern part of the country. Despite this limitation, this study generated a robust tool for targeting future surveillance and control activities. The development of the atlas also strengthened the collaboration between the different institutions involved in tsetse and AAT research and control in Burkina Faso, which will be crucial for future updates and the sustainability of the initiative. Graphical Abstrac