Evaluation des propriétés hydrauliques des aquifères fracturés des formations cristalline et métamorphique dans la région des Lacs (centre de la Côte d’Ivoire)

Groundwater is the main source of water supply for rural populations in the Region des Lacs area in central Côte d’Ivoire (West Africa). The area is underlain by the metamorphic and crystalline fractured hard rock aquifers. This paper focuses on the assessment of their hydraulic properties. To this end, a data base comprising pumping tests data and the technical reports were gathered. 105 values of transmissivity (T ) and specific capacity (Q/s) have been deduced after pumping tests interpretation by the Jacob recovery method. Statistical analyses of all these data have been done. Depth of wells range from 49.50 to 99 m with an average of 69 m. The thickness of the weathered zone has averaged 16.52 m and lies between 1.90 and 63.10 m. Wells average rate is 2.32 m3/s. The depths of open fractures are significantly in the first 60 meters of hard rock drilling and averaged 42.94 m. The transmissivity and specific capacity of each aquifer span over several orders of magnitude revealing the strong heterogeneity of the aquifer. Both variables are lognormal variables A significant empirical relationship between T and Q/s was found T = 0,937(Q/s)^1.118 with a coefficient of determination (R^2 = 0.82). This relationship enabled the transmissivity data to be supplemented with the 95% prediction interval in order to assess the uncertainty associated with the estimates of transmissivity in the area of the study. These results are significant and can be used as an input in forthcoming modeling these aquifers and facilitate groundwater management policy.[fr] Dans la région des Lacs, centre de la Côte d’Ivoire (Afrique de l’Ouest), l’alimentation en eau potable des populations rurales est assurée en majorité par les eaux souterraines contenues dans les aquifères discontinus cristallin et cristallophyllien. L’objet de cet article est d’évaluer les propriétés hydrauliques de ces aquifères afin d’entreprendre des études pour la gestion optimale de cette ressource. Pour ce faire, une compilation de données regroupant les fiches techniques de forage de même que les essais de pompage disponibles dans la région a été faite. L’interprétation des essais de pompage par la méthode de remontée de Jacob a permis de déterminer 105 valeurs de transmissivité (T ) et de débit spécifique (Q/s). Une analyse statistique des paramètres de forages et des paramètres hydrauliques déterminés a été réalisée. Les forages ont une profondeur totale qui varie de 49,50 à 99 m avec une moyenne de 69 m. L’épaisseur des altérites est comprise entre 1,90 et 63,10 m pour une moyenne de 16,52 m. Les forages ont un débit moyen de 2,32 m3/s. Les profondeurs de venues d’eau sont en moyenne de 42,94 m dans la roche non altérée. Les transmissivités et les débits spécifiques s’échelonnent sur trois ordres de grandeur avec des coefficients de variation supérieurs à 100% traduisant ainsi l’hétérogénéité structurale du milieu aquifère. Ces deux paramètres sont également distribués selon la loi log-normale au seuil de 10%. Une relation empirique significative entre la transmissivité et le débit spécifique a été établie. Elle permet d’estimer la transmissivité par l’expressionT = 0,937(Q/s)^1,118 avec R^2 = 0,82 dans un intervalle de confiance de 95% pour les aquifères de la zone d’étude. Ces résultats sont importants car, ils seront utiles dans les études de modélisation de ces aquifères et faciliteront la politique de gestion des eaux souterraines

A Trial of Early Antiretrovirals and Isoniazid Preventive Therapy in Africa

BACKGROUND: In sub-Saharan Africa, the burden of human immunodeficiency virus (HIV)-associated tuberculosis is high. We conducted a trial with a 2-by-2 factorial design to assess the benefits of early antiretroviral therapy (ART), 6-month isoniazid preventive therapy (IPT), or both among HIV-infected adults with high CD4+ cell counts in Ivory Coast. METHODS: We included participants who had HIV type 1 infection and a CD4+ count of less than 800 cells per cubic millimeter and who met no criteria for starting ART according to World Health Organization (WHO) guidelines. Participants were randomly assigned to one of four treatment groups: deferred ART (ART initiation according to WHO criteria), deferred ART plus IPT, early ART (immediate ART initiation), or early ART plus IPT. The primary end point was a composite of diseases included in the case definition of the acquired immunodeficiency syndrome (AIDS), non-AIDS-defining cancer, non-AIDS-defining invasive bacterial disease, or death from any cause at 30 months. We used Cox proportional models to compare outcomes between the deferred-ART and early-ART strategies and between the IPT and no-IPT strategies. RESULTS: A total of 2056 patients (41% with a baseline CD4+ count of ≥500 cells per cubic millimeter) were followed for 4757 patient-years. A total of 204 primary end-point events were observed (3.8 events per 100 person-years; 95% confidence interval [CI], 3.3 to 4.4), including 68 in patients with a baseline CD4+ count of at least 500 cells per cubic millimeter (3.2 events per 100 person-years; 95% CI, 2.4 to 4.0). Tuberculosis and invasive bacterial diseases accounted for 42% and 27% of primary end-point events, respectively. The risk of death or severe HIV-related illness was lower with early ART than with deferred ART (adjusted hazard ratio, 0.56; 95% CI, 0.41 to 0.76; adjusted hazard ratio among patients with a baseline CD4+ count of ≥500 cells per cubic millimeter, 0.56; 95% CI, 0.33 to 0.94) and lower with IPT than with no IPT (adjusted hazard ratio, 0.65; 95% CI, 0.48 to 0.88; adjusted hazard ratio among patients with a baseline CD4+ count of ≥500 cells per cubic millimeter, 0.61; 95% CI, 0.36 to 1.01). The 30-month probability of grade 3 or 4 adverse events did not differ significantly among the strategies. CONCLUSIONS: In this African country, immediate ART and 6 months of IPT independently led to lower rates of severe illness than did deferred ART and no IPT, both overall and among patients with CD4+ counts of at least 500 cells per cubic millimeter. (Funded by the French National Agency for Research on AIDS and Viral Hepatitis; TEMPRANO ANRS 12136 ClinicalTrials.gov number, NCT00495651.)

Effect of isoniazid preventive therapy on risk of death in west African, HIV-infected adults with high CD4 cell counts: long-term follow-up of the Temprano ANRS 12136 trial.

BACKGROUND: Temprano ANRS 12136 was a factorial 2 × 2 trial that assessed the benefits of early antiretroviral therapy (ART; ie, in patients who had not reached the CD4 cell count threshold used to recommend starting ART, as per the WHO guidelines that were the standard during the study period) and 6-month isoniazid preventive therapy (IPT) in HIV-infected adults in Côte d'Ivoire. Early ART and IPT were shown to independently reduce the risk of severe morbidity at 30 months. Here, we present the efficacy of IPT in reducing mortality from the long-term follow-up of Temprano. METHODS: For Temprano, participants were randomly assigned to four groups (deferred ART, deferred ART plus IPT, early ART, or early ART plus IPT). Participants who completed the trial follow-up were invited to participate in a post-trial phase. The primary post-trial phase endpoint was death, as analysed by the intention-to-treat principle. We used Cox proportional models to compare all-cause mortality between the IPT and no IPT strategies from inclusion in Temprano to the end of the follow-up period. FINDINGS: Between March 18, 2008, and Jan 5, 2015, 2056 patients (mean baseline CD4 count 477 cells per μL) were followed up for 9404 patient-years (Temprano 4757; post-trial phase 4647). The median follow-up time was 4·9 years (IQR 3·3-5·8). 86 deaths were recorded (Temprano 47 deaths; post-trial phase 39 deaths), of which 34 were in patients randomly assigned IPT (6-year probability 4·1%, 95% CI 2·9-5·7) and 52 were in those randomly assigned no IPT (6·9%, 5·1-9·2). The hazard ratio of death in patients who had IPT compared with those who did not have IPT was 0·63 (95% CI, 0·41 to 0·97) after adjusting for the ART strategy (early vs deferred), and 0·61 (0·39-0·94) after adjustment for the ART strategy, baseline CD4 cell count, and other key characteristics. There was no evidence for statistical interaction between IPT and ART (pinteraction=0·77) or between IPT and time (pinteraction=0·94) on mortality. INTERPRETATION: In Côte d'Ivoire, where the incidence of tuberculosis was last reported as 159 per 100 000 people, 6 months of IPT has a durable protective effect in reducing mortality in HIV-infected people, even in people with high CD4 cell counts and who have started ART. FUNDING: National Research Agency on AIDS and Viral Hepatitis (ANRS)

The bii4africa dataset of faunal and floral population intactness estimates across Africa’s major land uses

Sub-Saharan Africa is under-represented in global biodiversity datasets, particularly regarding the impact of land use on species’ population abundances. Drawing on recent advances in expert elicitation to ensure data consistency, 200 experts were convened using a modified-Delphi process to estimate ‘intactness scores’: the remaining proportion of an ‘intact’ reference population of a species group in a particular land use, on a scale from 0 (no remaining individuals) to 1 (same abundance as the reference) and, in rare cases, to 2 (populations that thrive in human-modified landscapes). The resulting bii4africa dataset contains intactness scores representing terrestrial vertebrates (tetrapods: ±5,400 amphibians, reptiles, birds, mammals) and vascular plants (±45,000 forbs, graminoids, trees, shrubs) in sub-Saharan Africa across the region’s major land uses (urban, cropland, rangeland, plantation, protected, etc.) and intensities (e.g., large-scale vs smallholder cropland). This dataset was co-produced as part of the Biodiversity Intactness Index for Africa Project. Additional uses include assessing ecosystem condition; rectifying geographic/ taxonomic biases in global biodiversity indicators and maps; and informing the Red List of Ecosystems

Socializing One Health: an innovative strategy to investigate social and behavioral risks of emerging viral threats

In an effort to strengthen global capacity to prevent, detect, and control infectious diseases in animals and people, the United States Agency for International Development’s (USAID) Emerging Pandemic Threats (EPT) PREDICT project funded development of regional, national, and local One Health capacities for early disease detection, rapid response, disease control, and risk reduction. From the outset, the EPT approach was inclusive of social science research methods designed to understand the contexts and behaviors of communities living and working at human-animal-environment interfaces considered high-risk for virus emergence. Using qualitative and quantitative approaches, PREDICT behavioral research aimed to identify and assess a range of socio-cultural behaviors that could be influential in zoonotic disease emergence, amplification, and transmission. This broad approach to behavioral risk characterization enabled us to identify and characterize human activities that could be linked to the transmission dynamics of new and emerging viruses. This paper provides a discussion of implementation of a social science approach within a zoonotic surveillance framework. We conducted in-depth ethnographic interviews and focus groups to better understand the individual- and community-level knowledge, attitudes, and practices that potentially put participants at risk for zoonotic disease transmission from the animals they live and work with, across 6 interface domains. When we asked highly-exposed individuals (ie. bushmeat hunters, wildlife or guano farmers) about the risk they perceived in their occupational activities, most did not perceive it to be risky, whether because it was normalized by years (or generations) of doing such an activity, or due to lack of information about potential risks. Integrating the social sciences allows investigations of the specific human activities that are hypothesized to drive disease emergence, amplification, and transmission, in order to better substantiate behavioral disease drivers, along with the social dimensions of infection and transmission dynamics. Understanding these dynamics is critical to achieving health security--the protection from threats to health-- which requires investments in both collective and individual health security. Involving behavioral sciences into zoonotic disease surveillance allowed us to push toward fuller community integration and engagement and toward dialogue and implementation of recommendations for disease prevention and improved health security

Métaux lourds (Cu, Cr, Mn et Zn) dans les sédiments de surface d’une lagune tropicale africaine : cas de la lagune Ebrie (Côte d’Ivoire)

Les sédiments de la lagune Ebrié (Côte d’Ivoire) ont été étudiés en vue de déterminer leur degré de pollution par les métaux lourds. L’étude a consisté à déterminer les métaux lourds (Cr, Cu, Mn et Zn) au niveaudes sédiments superficiels par spectrophotomètre d’absorption atomique VARIAN 1275 AA. Les données ont été analysées par les méthodes d’Analyse en Composantes Principales (ACP) et l’Index de géo-accumulation afin de connaître l’origine, les zones sensibles et les variables responsables de cette pollution. Les concentrations en métaux varient en fonction de la granulométrie du sédiment pour le cuivre, le zinc et le chrome à l’exception du manganèse. La zone d’étude est divisée en deux secteurs en fonction des valeurs de l’index de géo-accumulation du cuivre et du zinc qui varie de 0 à 1. Les parties Est et Ouest ont un index nul alors que la partie centrale qui regroupe les baies a un index compris entre 0 et 1. Ces différentes baies (Banco, Biétry, Cocody et Marcory) sont les réceptacles des effluents urbains, industriels et des eaux de ruissellement de la ville d’Abidjan. Les teneurs élevées en Cu, Cr et Zn dans les sédiments de ces baies sont dues à une pollution d’origine anthropique. Mots clés : Pollution, Lagune Ebrié, Métaux lourds, Sédiments, Côte d’Ivoire

Modélisation de la dynamique du paysage forestier dans la région de transition forêt-savane à l’est de la Côte d’Ivoire.

peer reviewe

Effets de l'association du compost et de la fumure minérale sur la productivité d'un système de culture à base de cotonnier et de maïs au Burkina Faso

Effects of the Association of Compost and Mineral Fertilizer on the Productivity of Cotton and Maize Cropping System in Burkina Faso. To improve the productivity of a cotton - maize rotation using organic and mineral fertilization, a study was carried out in experimental station from 2008 to 2010. Five levels of compost (0, 2, 6, 9 and 12 t of dry matter ha­1) combined to four rate of mineral fertilizer were compared in split­plot statistical design. The physical and chemical characteristics of soil, crop yields, as well as the mineral nutrition of maize and cotton plants were evaluated. The results show that the content of assimilable P and available K was significantly improved in amended soils by compost which had no significant effect on the carbon content. In amended soils, compost improved plants nutrition which was correct in nitrogen and potassium for cotton and deficient in nitrogen and phosphorus for maize. Compared to control soil, compost combined to mineral fertilizers increased significantly yields with a better efficacy for the recommended mineral manure. The application of 2 t ha­1 of compost per year was as effective as high doses of compost in the second year, and more effective than the latter in the third year. An economy on the recommended dose of mineral fertilizer could be considered, with an annual input of 2 t ha­1 of compost to the mineral fertilizers necessary to maintain the productivity of the cotton­cereal cropping systems

Comparative efficacy of essential oils of three aromatic plants as alternatives in the control of Phytophthora spp., agent of cocoa tree (Theobroma cacao L.) black pod disease in Côte d'Ivoire

This study aimed at comparing the efficacy of essential oils from three aromatic plants species (Cymbopogon citratus, Eucalyptus citriodora and Ocimum gratissimum) in vitro and in vivo against two Phytophthora strains (Phytophthora palmivora and P. megakarya) in a view to developing new biofongicides for the control of cocoa tree black pod disease. Essential oils were applied at four different concentrations (0.5; 1; 3 and 5 mL/L) in vitro and in vivo on leaf discs of three cocoa clones (NA32, PA150 and SCA6) whichsusceptibility is known. As results, all three essential oils significantly (p˂ 0.05) reduced in vitro mycelial growth of both Phytophthora strains and also reduced the leaf susceptibility to these strains. Inhibition rates in vitro of Phytophthora strains mycelial growth ranged from 83.80 to 100% for the essential oils of Cymbopogon citratus and Ocimum gratissimum species and from 17.7 to 100% for which of Eucalyptus citriodora species. In the biotests, the leaf susceptibility index of clone NA32 (susceptible) was reduced from 3.14 to 0.40. This correspond to reduction rates ranged from 64.87 to 86.70% of leaf susceptibility to both Phytophthora strains. Essential oils (HS and HO) from Cymbopogon citratus and Ocimum gratissimum species were most effective than which from Eucalyptus citriodora species. However, all three essential oils revealed antifungal properties. Therefore, they could be recommended as biofungicides for a sustainable control of cocoa tree black pod disease in Côte d'Ivoire.   &nbsp