Identification Et Cartographie Des Zones Potentielles De Recharge Des Eaux Dans La Région De Dosso (Sud-Ouest, Niger) Par Analyse Multicritère

Les eaux souterraines constituent la principale sourced’approvisionnement en eau des populations de la région de Dosso, située dansle Sud-Ouest du bassin des Iullemmeden. En dépit du climat aride à semi-aridequi caractérise cette région, le renouvellement des eaux des nappessouterraines s’effectue à travers les pluies. Cette recharge des eaux, quiconstitue un élément essentiel dans le cycle hydrologique, se faitpréférentiellement selon des zones qui peuvent aussi être des zonesvulnérables à la pollution des nappes. L’objectif principal de cette étudeconsiste à identifier puis à cartographier les zones potentielles de recharge deseaux. La démarche méthodologique utilisée dans le cadre de ce travail anécessité l’utilisation de l’analyse multicritère combinant le Systèmed’Information Géographique (SIG) et la télédétection. Après le traitement desimages Landsat de Dosso, tous les paramètres influençant les processus derecharge des eaux ont été intégrés au SIG. Il s’agit : des types de sol, del’occupation du sol, des densités des fractures et du drainage, de la lithologiede la zone non saturée et de la pente du terrain. La carte des zones potentiellesde recharge des eaux montre que la majorité de la zone étudiée présente unpotentiel réel d’infiltration des eaux lié à : la nature sableuse des sols, laprésence des zones de cultures pluviales, la présence de fractures et la densitédu réseau hydrographique. Cette carte a aussi permis de confirmer que leszones à potentiel élevé de recharge se situent dans les lits des mares et des"dallols" (larges vallées sèches), qui deviennent ainsi des zones plusvulnérables. Ce support cartographique constitue de ce fait un outil d’aide à ladécision. Groundwater is the main source of water supply in the Dosso regionwhich is located in the southwestern part of the Iullemmeden Basin. Despitethe arid to semi-arid climate that characterizes this region, groundwaterrecharge is occuring mainly through rainfall. This recharge of water which isan essential element in the hydrological cycle is prefentially done accordingto zones which can also be vulnerable to groundwater pollution. The mainobjective of this study is to identify and mapped the potential recharge areas.A methodology based on a multicriteria analysis integrating GIS and remotesensing was used to map the potential recharge areas. After processing theLandsat satellite images of Dosso region, all the parameters influencing thehydrological recharge processes were obtained and integrated into GIS. Theseparameters are: soil types, land cover, fracture density, drainage density,lithology and slope. The map of potential recharge areas obtained shows thatthe majority of the study areas has great recharge potential. According to thisstudy, this great potentiality could be linked to: the sandy nature of the soil,the cultivable areas, the presence of fractures and density of hydrographicnetwork. This map also confirmed that areas with high recharge potential arelocated in the beds of ponds and "dallols" (wide dry valleys), which thusbecome more vulnerable areas. This map of potential recharge areasconstitutes therefore a tool for decision makers

Caractérisation de la déformation des dépôts oligocènes du Continental terminal 3 (Ct3) dans la région de Niamey (Bordure Orientale du Craton Ouest Africain, Bassin des Iullemmeden)

Cette étude porte sur la détermination des phases de déformations affectant les dépôts oligocènes du Ct3, correspondant aux derniers dépôts de comblement du bassin des Iullemmeden dans la région de Niamey (Ouest, Niger). La méthodologie mise en œuvre est basée sur l’analyse microtectonique de terrain soutenue par des données cartographiques et de l’imagerie satellitaire. Les résultats de cette étude montrent que les dépôts oligocènes du Ct3 ont enregistré deux évènements majeurs de l’histoire tectonique de l’Afrique de l’Ouest au Cénozoïque : la distension oligocène et la phase compressive post-oligocène, d’âge présumée miocène. La phase distensive oligocène orientée ~N50° à ~N80° serait étroitement contrôlée par la dynamique mantellique prévalant à cette époque, qui confère une structuration en dômes et bassins à l’Afrique de l’Ouest. Ces mouvements mantelliques descendants, concomitant au dernier épisode de comblement du bassin des Iullemmeden, favoriseraient le rejeu en normal de la plupart des failles d’orientation NW-SE. La phase compressive ~N140°, présumée d’âge miocène, se serait produite dans un contexte régional marqué par la poursuitende la convergence Afrique-Europe. Au cours de cette phase compressive, les failles héritées ont été réactivées en décrochements soit senestres soit dextres en fonction de leur orientation par rapport à la direction de raccourcissement. The aim of this study is about the determination deformations phases that affect the Ct3 Oligocene deposits in the Niamey area (West, Niger), which correspond to the last deposits of the Iullemmeden basin. The methodology implemented is based on the microtectonic field investigation supported by cartographic data and satellite imagery analysis. The results of this study show that the Oligocene deposits of Ct3 recorded two major events of the West Africa tectonic history during Cenozoic period: the first one was Oligocene distension and the second was a post-Oligocene compressive phase, presumed to be Miocene in age. The Oligocene distensive phase oriented ~N50° to ~N80° would be closely controlled by the mantle dynamics prevailing at that time, which gave domes and basins structuring in West Africa. These downward mantle movements, concomitantly with the last episode of the Iullemmeden basin infilling, would favor the normal reactivation of the most NW-SE trending faults. The ~N140° compressive phase, presumed to be Miocene in age, would have occurred in a regional shortening context, which was marked by the continuation of the Africa-Europe convergence. During this compressive phase, the inherited structures such as faults were reactivated in either senestral or dextral strike-slip faults according to their orientation with the shortening direction

Impacts of Deep Water Structuring on Seabed Pollution Levels: Evidence from Radiogenic Isotopes (Pb-Sr-Nd) in Surface Sediments Along the Reykjanes Ridge (Southern Iceland)

Significant proportions of debris containing pollutants are present in remote and unknown areas of the deep seabed. Although identified amongst the top threats to marine ecosystem and human health, the mechanisms that particulate materials entered rapidly these deep ocean systems are still matter of debate. This study use depicting radiogenic isotopes (Sr, Nd, Pb) to question the relationship between the seabed sediment contamination levels and ambient stratification in the North Atlantic Ocean. On this basis, we studied sedimentary inputs and related mechanisms from more recent sequences collected at three locations representing different deep-sea hydrodynamics along the Reykjanes Ridge. Sm-Nd concentrations, as well as Sm-Nd-Sr-Pb isotopic compositions, were determined in digested and purified fraction of the sediment cores by Thermal Ionization Mass Spectrometry (TIMS). The Sm-Nd-Sr-Pb data simply reflect the scale of the perturbation of upper part (0-15 cm) of the sequences, which is much more pronounced in east flank than crossing and west bordering ridge areas. The Pb-Pb systematics show that the intensity of water mass mixing modulates degree of contamination and induced the modal transport of detrital components. As consequence of ambient stratification in this region, two major transport processes of pollutant downwards to the sediments are proposed: (i) sediments entrainment in the eastern flank and over ridge axis primarily dominated by vertical flux of particulates controlled by repackage and dislocation by strong mechanical mixing; and (ii) in the west flank, advection of abyssal waters, due to well-stratified mixing layer, provides particulates from the NEADW1 and DSOW

Feasibility and acceptability of ACT for the community case management of malaria in urban settings in five African sites

<p>Abstract</p> <p>Background</p> <p>The community case management of malaria (CCMm) is now an established route for distribution of artemisinin-based combination therapy (ACT) in rural areas, but the feasibility and acceptability of the approach through community medicine distributors (CMD) in urban areas has not been explored. It is estimated that in 15 years time 50% of the African population will live in urban areas and transmission of the malaria parasite occurs in these densely populated areas.</p> <p>Methods</p> <p>Pre- and post-implementation studies were conducted in five African cities: Ghana, Burkina Faso, Ethiopia and Malawi. CMDs were trained to educate caregivers, diagnose and treat malaria cases in < 5-year olds with ACT. Household surveys, focus group discussions and in-depth interviews were used to evaluate impact.</p> <p>Results</p> <p>Qualitative findings: In all sites, interviews revealed that caregivers' knowledge of malaria signs and symptoms improved after the intervention. Preference for CMDs as preferred providers for malaria increased in all sites.</p> <p>Quantitative findings: 9001 children with an episode of fever were treated by 199 CMDs in the five study sites. Results from the CHWs registers show that of these, 6974 were treated with an ACT and 6933 (99%) were prescribed the correct dose for their age. Fifty-four percent of the 3,025 children for which information about the promptness of treatment was available were treated within 24 hours from the onset of symptoms.</p> <p>From the household survey 3700 children were identified who had an episode of fever during the preceding two weeks. 1480 (40%) of them sought treatment from a CMD and 1213 of them (82%) had received an ACT. Of these, 1123 (92.6%) were administered the ACT for the correct number of doses and days; 773 of the 1118 (69.1%) children for which information about the promptness of treatment was available were treated within 24 hours from onset of symptoms, and 768 (68.7%) were treated promptly and correctly.</p> <p>Conclusions</p> <p>The concept of CCMm in an urban environment was positive, and caregivers were generally satisfied with the services. Quality of services delivered by CMDs and adherence by caregivers are similar to those seen in rural CCMm settings. The proportion of cases seen by CMDs, however, tended to be lower than was generally seen in rural CCMm. Urban CCMm is feasible, but it struggles against other sources of established healthcare providers. Innovation is required by everyone to make it viable.</p

Beta-Lactamase-Producing Genes and Integrons in <em>Escherichia coli</em> from Diarrheal Children in Ouagadougou, Burkina Faso

This study aimed to determine the resistance of diarrheagenic Escherichia coli (DEC) strains to β-lactams antibiotics and to perform the molecular characterization of extended-spectrum β-lactamases (ESBLs) and integrons genes. It was carried out from August 2013 to October 2015 and involved 31 DEC strains isolated from diarrheal stools samples collected from children less than 5 years. The identification and characterization of DEC strains were done through the standard biochemical tests that were confirmed using API 20E and polymerase chain reaction (PCR). The antibiogram was realized by the disk diffusion method, then an amplification of the β-lactamase resistance genes and integrons by PCR was done. Out of the 419 E. coli, 31 isolates (7.4%) harbored the DEC virulence genes. From these DEC, 21 (67.7%) were ESBL-producing E. coli. Susceptibility to ESBL-producing E. coli showed that the majority of isolates were highly resistant to amoxicillin (77.4%), amoxicillin-clavulanic acid (77.4%), and piperacillin (64.5%). The following antibiotic resistance genes and integron were identified: blaTEM (6.5%), blaSHV (19.4%), blaOXA (38.7%), blaCTX-M (9.7%), Int1 (58.1%), and Int3 (19.4%). No class 2 integron (Int2) was characterized. Because of the high prevalence of multidrug-resistant ESBL organisms found, there is a need of stringent pediatric infection control measures

An open dataset of Plasmodium falciparum genome variation in 7,000 worldwide samples.

MalariaGEN is a data-sharing network that enables groups around the world to work together on the genomic epidemiology of malaria. Here we describe a new release of curated genome variation data on 7,000 Plasmodium falciparum samples from MalariaGEN partner studies in 28 malaria-endemic countries. High-quality genotype calls on 3 million single nucleotide polymorphisms (SNPs) and short indels were produced using a standardised analysis pipeline. Copy number variants associated with drug resistance and structural variants that cause failure of rapid diagnostic tests were also analysed.  Almost all samples showed genetic evidence of resistance to at least one antimalarial drug, and some samples from Southeast Asia carried markers of resistance to six commonly-used drugs. Genes expressed during the mosquito stage of the parasite life-cycle are prominent among loci that show strong geographic differentiation. By continuing to enlarge this open data resource we aim to facilitate research into the evolutionary processes affecting malaria control and to accelerate development of the surveillance toolkit required for malaria elimination

Pf7: an open dataset of Plasmodium falciparum genome variation in 20,000 worldwide samples

We describe the MalariaGEN Pf7 data resource, the seventh release of Plasmodium falciparum genome variation data from the MalariaGEN network.  It comprises over 20,000 samples from 82 partner studies in 33 countries, including several malaria endemic regions that were previously underrepresented.  For the first time we include dried blood spot samples that were sequenced after selective whole genome amplification, necessitating new methods to genotype copy number variations.  We identify a large number of newly emerging crt mutations in parts of Southeast Asia, and show examples of heterogeneities in patterns of drug resistance within Africa and within the Indian subcontinent.  We describe the profile of variations in the C-terminal of the csp gene and relate this to the sequence used in the RTS,S and R21 malaria vaccines.  Pf7 provides high-quality data on genotype calls for 6 million SNPs and short indels, analysis of large deletions that cause failure of rapid diagnostic tests, and systematic characterisation of six major drug resistance loci, all of which can be freely downloaded from the MalariaGEN website

Automédication au cours des affections bucco-dentaires à Ouagadougou, Burkina Faso

Introduction : L'automédication est un problème de santé publique majeur au regard des risques engendrés tels les échecs thérapeutiques et l’émergence des bactéries multirésistantes. Elle a déjà été traitée dans sa globalité par plusieurs études. L’objectif de ce travail était d’évaluer l’automédication au cours des affections bucco-dentaires à Ouagadougou. Patients et méthodes : Il s’agit d’une étude prospective conduite au Centre municipal de santé bucco-dentaire sur la période de décembre 2015. Les données ont été recueillies à l’aide de fiches avec le consentement éclairé des patients. Résultats : Des 125 patients interrogés, 38 pratiquaient l’automédication (30,4 %) dont 25 de sexe féminin (65,8 %). Le paracétamol était absorbé seul (21,1 %) ou associé à une autre substance. Les anti-inflammatoires non stéroïdiens étaient utilisés seuls ou associés à du paracétamol ou encore à l’amoxicilline. L’amoxicilline était consommée seule par 15,8 % des patients. Certains (13,1 %) ignoraient la nature des produits utilisés et 10,5 % avaient consulté un tradithérapeute. Trente-et-un avaient acquis leur produit à la pharmacie (81,6 %). Conclusion : Cette étude souligne qu’il est impératif d’accentuer la sensibilisation des populations sur les risques liés à cette pratique afin de réduire l’utilisation des médicaments sans prescription médicale

Détection d’

Introduction : Acinetobacter est une bactérie opportuniste multirésistante. Cette étude visait à détecter Acinetobacter baumanii dans les infections bucco-dentaires au Burkina Faso. Cette bactérie a été retenue compte tenu du caractère émergent de sa résistance aux antibiotiques dans le monde, de sa pathogénicité opportuniste, de son pouvoir de diffusion épidémique et de l’impasse thérapeutique qu’elle engendre. Matériel et méthodes : C’est une étude prospective conduite au Centre municipal de santé bucco-dentaire de Ouagadougou de juin 2014 à octobre 2014. Les données cliniques ont été recueillies à l’aide d’une fiche de collecte. Les bactéries ont été identifiées avec la galerie API 20E. La sensibilité aux antibiotiques et la détection de β-lactamases à spectre étendu (BLSE) ont été réalisées par la méthode de diffusion sur milieu gélosé. Résultats : Une prédominance de la tranche d’âge 19-40 ans (55,2 %) sur les 125 patients reçus a été observée. Trois souches d’Acinetobacter baumannii (2,4 %) ont été isolées des cellulites chroniques et identifiées. Elles étaient totorésistantes aux 21 antibiotiques testés et ne produisaient pas de BLSE. Conclusion : Au regard de la totorésistance d’ Acinetobacter baumannii et de l’impasse thérapeutique qu’elle engendre, sa détection chez un patient doit faire l’objet de déclaration officielle