Les aspects parasitologiques de l'épidémiologie du paludisme dans le Sahara malien

Dans le cadre de l'évaluation épidémiologique de la Transsaharienne, une enquête transversale paludométrique a été réalisée d'Août 1988 à Septembre 1988 le long du tronçon malien. Neuf localités ont été visitées : Douentza, Gossi, Bourem, Almoustarat, Anefis, Aguel-Hoc, Tarlit, Tessalit, Kidal, Bouressa. 2185 unités ont été prélevées pour les études cliniques, parasitologiques et immunologiques. L'indice plasmodique global est de 5,3 % avec une grande variation du Sud (44,6 %) au Nord (0 %). L'indice gamétocytique et l'indice splénique sont très faibles. #P. falciparum est l'espèce dominante. #P. malariae a été décrit une fois en association avec #P. falciparum. #P. ovale n'a jamais été observé. Par contre un cas de #P. vivax a été décrit chez une jeune fille leucoderme de 8 ans à Kidal. #A. gambiae s.s. (forme Mopti) et #A. arabiensis sont les principaux vecteurs au Nord du Mali. Une hypothèse de circulation de #P. vivax dans le Sahara malien est émise. (Résumé d'auteur

Development and Utilisation of Improved WhiteSeeded, Tan-Plant Grain Sorghum Cultivars in Mali

The pedigree breeding method was successfully adopted to develop high yielding, white-seeded, grain sorghum cultivars with other attributes including “tan” plants, sensitivity to photoperiod and excellent adaptation to the Sudanian and Sahelian agro-ecological conditions in Mali. The new cultivars possess an excellent grain quality which added value for processing. The breeding process included crossing of local guinea race cultivars and improved or introduced Caudatum race varieties, selected from F2, F3, F4, F5 and F6 generations, conducting yield and grain quality trials of advanced lines on station and on-farm with farmer participatory selection. Processing quality of the grain was evaluated through measuring the decortication yield of each cultivar using the TADD (Tangential Abrasive Dehuller Device); measuring shelf life of processed flour in bags made of polyethylene for 3 months; manufacturing of new products by partially substituting wheat flour with flour of new sorghum varieties in pastry and biscuits. The study revealed a series of improved lines with "tan" plants, white grain, Guinea race type characterised by a loose panicle, long glumes and a hard grain. The best example of new cultivars N’Tenimissa, was described as the first white, “tan” plant, straw-coloured glume, photoperiod sensitive and high yielding sorghum cultivar with a white endosperm, and a thin pericarp developed in Mali. The cultivar has almost the same decortication yield with already adopted varieties by farmers. Its flour yield is similar to that of local guinea cultivars, and its flour is nearly as white as wheat flour. The analysis of various organoleptic parameters indicated that partially substituting wheat with 20% sorghum flour made the preferred biscuit by consumers prompting the commercial manufacturing of a biscuit called Deliken by the General Alimentation du Mali (GAM). A commercial sorghum supply chain was initiated by linking smallholders producing the new cultivar to a grain trader for selling the grain to the industry. This shows a path for the future in the diversification of uses of a local staple crop, sorghum. It is based on a strong Public-Private Partnership to link smallholders to the commercial supply chain, providing an incentive for farmers to grow new and highly productive cultivars for the development of value-added products

Differential infectivity of gametocytes after artemisinin-based combination therapy of uncomplicated falciparum malaria

Background: Most malaria-endemic countries use artemisinin-based combination therapy (ACT) as their first-line treatment. ACTs are known to be highly effective on asexual stages of the malaria parasite. Malaria transmission and the spread of resistant parasites depend on the infectivity of gametocytes. The effect of the current ACT regimens on gametocyte infectivity is unclear. Objectives: This study aimed to determine the infectivity of gametocytes to Anopheles gambiae following ACT treatment in the field. Methods: During a randomised controlled trial in Bougoula-Hameau, Mali, conducted from July 2005 to July 2007, volunteers with uncomplicated malaria were randomised to receive artemether-lumefantrine, artesunate-amodiaquine, or artesunate-sulfadoxine/pyrimethamine. Volunteers were followed for 28 days, and gametocyte carriage was assessed. Direct skin feeding assays were performed on gametocyte carriers before and after ACT administration. Results: Following artemether-lumefantrine treatment, gametocyte carriage decreased steadily from Day 0 to Day 21 post-treatment initiation. In contrast, for the artesunate-amodiaquine and artesunate-sulfadoxine/pyrimethamine arms, gametocyte carriage increased on Day 3 and remained constant until Day 7 before decreasing afterward. Mosquito feeding assays showed that artemether-lumefantrine and artesunate-amodiaquine significantly increased gametocyte infectivity to Anopheles gambiae sensu lato (s.l.) (p < 10−4), whereas artesunate-sulfadoxine/pyrimethamine decreased gametocyte infectivity in this setting (p = 0.03). Conclusion: Different ACT regimens could lead to gametocyte populations with different capacity to infect the Anopheles vector. Frequent assessment of the effect of antimalarials on gametocytogenesis and gametocyte infectivity may be required for the full assessment of treatment efficacy, the potential for spread of drug resistance and malaria transmission in the field

Rice yields enhanced through integrated management of cover crops and phosphate rock in phosphorus-deficient ultisols in West Africa

The relatively low solubility and availability of phosphorus (P) from indigenous phosphate rock could be enhanced by legumes in the acid soils of humid forest agroecosystems. Crotalaria micans L. was grown in a screenhouse without P or with P from triple superphosphate (TSP) and Malian Tilemsi Rock P. The P response of 20 cover crops was field-evaluated using TSP and Rock P. In both experiments, the fertilized cover crops were followed by upland rice without mineral N or P application. Mean rice grain yield and agronomic residual P-use efficiency were similar for both P sources. In the field, 1-year fallow treatment of Canavalia ensiformis (velvet bean) supplied with Mali Rock P gave the highest rice grain yield of 3.1 Mg ha-1, more than 180% that of 2-year continuous unfertilized rice (cv. 'WAB 56-50'). Among continuous rice plots, 'NERICA 2' (interspecific rice) supplied with Rock P produced the highest yield (2.0 Mg ha-1), suggesting that 'NERICA 2' might have greater potential to solubilize rock P. Results indicate that when combined with an appropriate legume, indigenous rock-P can release sufficient P to meet the P requirement of the legume and a following upland rice crop in rotation

Options de Modèles d’Affaires pour Assurer la Durabilité de l’Utilisation des Services d’Information Climatique au Sénégal

USAID/CINSERE (Services d’information climatiques pour améliorer la résilience et la productivité au Sénégal) est un projet de résilience qui vise à renforcer les capacités nationales pour la production, l’accès et la diffusion efficiente d’informations météorologiques et climatiques (IC) et de développer des stratégies pour une mise à l’échelle durable de l’utilisation des services d’information météorologiques et climatiques (SIC) sur toute l’étendue du territoire national. Le projet est financé par l’USAID et mis en oeuvre par le Programme de Recherche du CGIAR sur le Changement Climatique, l’Agriculture et la Sécurité Alimentaire hébergé par ICRISAT (CCAFS/ICRISAT) en collaboration avec l’ANACIM. La zone d’intervention du projet est celle des projets Feed the Future (FtF) au Sénégal, notamment Naatal Mbay (clôturé en 2019), Yaajeende (remplacé par Kawolor en 2018), ERA (remplacé par Youth in Agriculture en 2018) et COMFISH (remplacé par Dekkal Geej en 2019). Démarré en Mai 2016 pour une durée de trois ans (Jusqu’en mai 2019), le projet a bénéficié d’une extension d’un an. Ainsi, cette première phase de l’USAID/CINSERE prend fin en avril 2020. Durant presque quatre années de mise en oeuvre, des résultats assez probants ont été atteints tant dans la production des SIC, la communication et l’utilisation de ces SIC, que dans le renforcement des capacités des bénéficiaires à utiliser de façon efficiente ces SIC. Dans le souci de préserver les acquis du projet et d’assurer une mise à l’échelle soutenue du système de développement et de fourniture des IC en vue d’une utilisation durable des IC au Sénégal, l’USAID a recommandé l’identification, le test, la validation et la mise en oeuvre de modèles économiques viables impliquant des partenaires aussi bien du public que du privé (PPP). Le projet USAID/CINSERE s’est donc inspiré des expériences et leçons apprises au Sénégal, au Ghana, au Mali, en Inde et en Amérique Latine (Colombie) en matière de modèles économiques dans la fourniture des SIC pour bâtir des modèles adaptés au contexte du Sénégal. Ce document présente les modèles identifiés ainsi que les défis et perspectives

Population genetic structure of Schistosoma haematobium and Schistosoma haematobium x Schistosoma bovis hybrids among school-aged children in Côte d'Ivoire

While population genetics of Schistosoma haematobium have been investigated in West Africa, only scant data are available from Cote d'Ivoire. The purpose of this study was to analyze both genetic variability and genetic structure among S. haematobium populations and to quantify the frequency of S. haematobium x S. bovis hybrids in school-aged children in different parts of Cote d'Ivoire. Urine samples were subjected to a filtration method and examined microscopically for Schistosoma eggs in four sites in the western and southern parts of Cote d'Ivoire. A total of 2692 miracidia were collected individually and stored on Whatman((R)) FTA cards. Of these, 2561 miracidia were successfully genotyped for species and hybrid identification using rapid diagnostic multiplex mitochondrial cox1 PCR and PCR Restriction Fragment Length Polymorphism (PCR-RFLP) analysis of the nuclear ITS2 region. From 2164 miracidia, 1966 (90.9%) were successfully genotyped using at least 10 nuclear microsatellite loci to investigate genetic diversity and population structure. Significant differences were found between sites in all genetic diversity indices and genotypic differentiation was observed between the site in the West and the three sites in the East. Analysis at the infrapopulation level revealed clustering of parasite genotypes within individual children, particularly in Duekoue (West) and Sikensi (East). Of the six possible cox1-ITS2 genetic profiles obtained from miracidia, S. bovis cox1 x S. haematobium ITS2 (42.0%) was the most commonly observed in the populations. We identified only 15 miracidia (0.7%) with an S. bovis cox1 x S. bovis ITS2 genotype. Our study provides new insights into the population genetics of S. haematobium and S. haematobium x S. bovis hybrids in humans in Cote d'Ivoire and we advocate for researching hybrid schistosomes in animals such as rodents and cattle in Cote d'Ivoire