Evaluation in vitro de la sensibilité de Pythium aphanidermatum aux fongicides utilisés dans les plantations de papayers en Côte d’Ivoire

La pourriture des racines et du collet du papayer en Côte d’Ivoire sévit dans les plantations, causant des pertes énormes. Cependant, malgré les traitements fongiques, la maladie persiste. L’objectif de cette étudeest de tester in vitro la sensibilité de Pythium aphanidermatum, responsable de la maladie, aux fongicides utilisés dans les plantations de papaye. Ainsi, l’efficacité des fongicides Callomil, Aliette, Volley, Opal et Callicuivre a été testé in vitro sur P. aphanidermatum. Ces pesticides ont été incorporés dans le milieu synthétique PDA, avec le milieu témoin constitué de PDA sans fongicide. Le diamètre moyen du mycélium du champignon a été mesuré. Puis, l’inhibition de la croissance du champignon a été déterminée en fonction du fongicide utilisé. Pythium aphanidermatum s’est montré hautement sensible à Callomil, sensible à Aliette, résistant à Volley et hautement résistant à Opal et Callicuivre. La sensibilité du pathogène vis-à-vis des fongicides varie également en fonction de la quantité de matière active (μg/ml) apportée en boîte de Pétri à l’exception de Callicuivre pour lequel le champignon s’est révélé hautement résistant à toutes les doses utilisées. Les résultats confirment l’inefficacité de l’oxychlorure de cuivre observée en plantation. Des tests in vivo permettront de confirmer les résultats.© 2009 International Formulae Group. All rights reservedMots clés : Champignon; pesticides ; milieu synthétique ; résistant

Les Altérations Hydrothermales Associées À La Minéralisation Aurifère Du Gisement De Dougbafla (District d’Oumé-Hiré, Centre-Ouest De La Côte d’Ivoire)

The Dougbafla gold deposit is located in the West-Central part of Côte d’Ivoire at about 240 km from Abidjan, on the Birimian greenstone belt of Fettèkro (West African craton). The lithologies of this deposit can be divided into three lithotectonic units which correspond to volcanic, sedimentary, and plutonic assemblages metamorphosed in the shale facies. Hydrothermalism, on the one hand, caused a pervasive alteration of the primary paragenesis marked by sericitic, silica, and carbonate alteration. On the other hand, it causes a vein alteration materialized by quartz veins. These hydrothermal alterations induced two types of gold mineralization in the Dougbafla deposit. These are: (i) disseminated gold and sulphide mineralization in the granophyre associated with sericite, silica and dolomite alteration in which no quartz vein has been reported; this type however is controlled by the intrusion of granophyre and (ii) a quartz vein mineralization controlled by deformation

Dynamique du peuplement des Oiseaux d’une riziculture et ses environs dans la zone humide d’importance internationale de Grand-Bassam

Objectifs : cette étude vise à actualiser les connaissances sur l’avifaune de la zone humide de Grand- Bassam et à déterminer les variations annuelles du peuplement d’Oiseaux. Méthodologie et résultats : l’avifaune a été inventoriée de janvier 2011 à février 2013 par la méthode des transects itinérants avec des points d’arrêt de 15 minutes aux endroits appropriés. Au total, 218 espèces appartenant à 51 familles et 17 ordres ont été identifiées. La présente étude révèle 49 espèces nouvellement observées dans la zone humide de Grand-Bassam. Le peuplement d’Oiseaux rencontré renferme un grand nombre d’individus dont le pic annuel est atteint en juillet. Ce peuplement est dominé par les populations de tisserin gendarme (Ploceus cucullatus), de travailleur à tête rouge (Quelea erythrops) et de capucin nonnette (Spermestes cucullata). Conclusion et application : cette étude contribue à une meilleure connaissance de l’avifaune de la zone humide de Grand-Bassam et fournit des données préliminaires sur l’importance numérique des différentes espèces inventoriées. Face à une anthropisation de plus en plus prononcée de la zone humide, liée au développement de la ville et aux activités agricoles, ces résultats serviront de base scientifique à l’établissement d’un système de gestion durable de l’avifaune dans les rizicultures.Mots clés : Oiseaux, Biodiversité, Dynamique du peuplement, Zone humide Riziculture, Grand- Bassam.Dynamics of birds’ community, of international importance in the rice fields and surrounding areas in the Grand-Bassam wetland.  Objectives: This study aims to update the knowledge on birds’ community of the Grand-Bassam wetland and it annual variation. Methodology and Results: Birds were surveyed from January 2011 to February 2013 by the method of line transects with a 15 minutes points count in the appropriated places. A total 218 species belonging to 51 families of 17 orders were identified. The study found 49 newly observed species in the Grand- Bassam Ramsar site. The birds’ community is rich of an important number of individuals which maximum is in July. This bird’s community is dominated by populations of Village Weaver( Ploceus cucullatus),, Red-headed Quelea (Quelea erythrops) and Bronze Mannikin (Spermestes cucullata).. Conclusion and application: This study has contributed to a better knowledge of the avifauna of Grand- Bassam Ramsar site and provides preliminary data on the size of the different species. Facing a more pronounced anthropisation due to the development of the city and farming, these results can served as a first scientific basis for the establishment of a sustainable management of the avifauna in ricefields.Keywords: Birds, Biodiversity, Community Dynamics, Wetlands, Ricefield, Grand-Bassa

Non-invasive genomics of respiratory pathogens infecting wild great apes using hybridisation capture

Human respiratory pathogens have repeatedly caused lethal outbreaks in wild great apes across Africa, leading to population declines. Nonetheless, our knowledge of potential genomic changes associated with pathogen introduction and spread at the human-great ape interface remains sparse. Here, we made use of target enrichment coupled with next generation sequencing to non-invasively investigate five outbreaks of human-introduced respiratory disease in wild chimpanzees living in Taï National Park, Ivory Coast. By retrieving 34 complete viral genomes and three distinct constellations of pneumococcal virulence factors, we provide genomic insights into these spillover events and describe a framework for non-invasive genomic surveillance in wildlife.Peer Reviewe

Detection and identification of pathogenic trypanosome species in tsetse flies along the Comoe River in Cote d'Ivoire

In order to identify pathogenic trypanosomes responsible for African trypanosomiasis, and to better understand tsetse-trypanosome relationships, surveys were undertaken in three sites located in different eco-climatic areas in Cote d'Ivoire during the dry and rainy seasons. Tsetse flies were caught during five consecutive days using biconical traps, dissected and microscopically examined looking for trypanosome infection. Samples from infected flies were tested by PCR using specific primers for Trypanosoma brucei s.l., T. congolense savannah type, T. congolense forest type and T. vivax. Of 1941 tsetse flies caught including four species, i.e. Glossina palpalis palpalis, G. p. gambiensis, G. tachinoides and G. medicorum, 513 (26%) were dissected and 60 (12%) were found positive by microscopy. Up to 41% of the infections were due to T. congolense savannah type, 30% to T. vivax, 20% to T. congolense forest type and 9% due to T. brucei s.l. All four trypanosome species and subgroups were identified from G. tachinoides and G. p. palpalis, while only two were isolated from G. p. gambiensis (T. brucei s.l., T. congolense savannah type) and G. medicorum (T. congolense forest, savannah types). Mixed infections were found in 25% of cases and all involved T. congolense savannah type with another trypanosome species. The simultaneous occurrence of T. brucei s.l., and tsetse from the palpalis group may suggest that human trypanosomiasis can still be a constraint in these localities, while high rates of T. congolense and T. vivax in the area suggest a potential risk of animal trypanosomiasis in livestock along the Comoe River

Outcrop Groundwater Prospecting, Drilling, and Well Construction in Hard Rocks in Semi-arid Regions

This chapter presents some recommendations for prospecting, drilling and well construction in hard rocks in semi-arid regions. Considering that these conditions are present in many countries where technology is not always available, the chapter concentrates on the most basic and simple methods to plan where best to drill and maximize success through the direct observation of rock types, weathering and fracturing. The advantage for the geologist and hydrogeologist in an arid or semi-arid environment is that vegetation is normally scarce and the weathering layer thin, allowing a direct view of the rock in circumstances impossible in other climate regions of the world. The close observation of the weathering material, and especially of the fracture network, mainly the fracture density, dip, extension and interconnection, can provide important information for a field hydrogeologist who can then plan the best place for drilling. The most appropriate drilling technique, if available in the area, is rotary percussion, also designated as down-the-hole drilling, with drilling rates that can achieve 100 m per day in normal circumstances. This allows a well to be constructed in about two days, essential in the case of disaster relief. Finally, some information is given about well construction, careful planning of the work, protection to preserve the water quality, avoiding problems of partial or total collapse of the hole during construction or of the well and after completion, and how to avoid direct contact between the surface or sub-surface waters with the aquifer along the walls of the well to protect the well and the aquifer against contamination

Application De L’ultrason A L’étude De L’homogénéité Des Briques Réfractaires

The quality of refractory bricks such as their ability to resist to thermal shocks essentially depends on the homogeneity of their structure. The imperfections observed in the structure of some refractory bricks arise from the mode of their preparation. Thus, the homogeneity of bricks manually elaborated with refractory clays and sintered at 1280°C was studied. The speed of ultrasounds in different areas of the bricks was measured with an ultrasound auscultation device. The results point out the speeds of ultrasounds may vary from one zone to another revealing heterogeneities into some bricks. This technique allows showing the distribution of possible heterogeneities in these materials

Towards the Pharmacological Validation and Phytochemical Profiling of the Decoction and Maceration of Bruguiera gymnorhiza (L.) Lam.-A Traditionally Used Medicinal Halophyte

Decoctions (leaves and roots) of Bruguiera gymnorhiza (L.) Lam. are traditionally used against diabetes in many countries, including Mauritius. This study endeavoured to evaluate the inhibitory potential of leaves, roots, twigs and fruits extracts (decoction and maceration) of B. gymnorhiza against key enzymes relevant to diabetes. Considering complications related to diabetes, other clinical enzymes, namely, acetylcholinesterase (AChE), butyrylcholinesterase (BChE), tyrosinase, elastase and pancreatic lipase, were used. Identification of compounds was carried out using ultra-high-performance liquid chromatography/electrospray ionization tandem mass spectrometry (UHPLC-ESI-MS/MS). Antioxidant capacities were assessed using DPPH, ABTS, FRAP, CUPRAC, phosphomolybdenum, metal chelating. The relationship between mode of extraction, plant parts and biological activities was determined using multivariate analysis. Macerated fruits, rich in phytochemicals (phenolic, flavanol, tannin, and triterpenoid), exhibited substantially high antioxidant capacities related to radical scavenging (DPPH: 547.75 ± 10.99 and ABTS: 439.59 ± 19.13 mg TE/g, respectively) and reducing potential (CUPRAC: 956.04 ± 11.90 and FRAP: 577.26 ± 4.55 mg TE/g, respectively). Additionally, the same extract significantly depressed AChE and BChE (3.75 ± 0.03 and 2.19 ± 0.13 mg GALAE/g, respectively), tyrosinase (147.01 ± 0.78 mg KAE/g), elastase (3.14 ± 0.08 mg OE/g) and amylase (1.22 ± 0.01 mmol ACAE/g) enzymatic activities. Phytochemical results confirmed the presence of 119 compounds in all maceration and 163 compounds in all decoction samples. The screening also revealed important compounds in the extracts, namely, quinic acid, brugierol, bruguierol A, epigallocatechin, chlorogenic acid, to name a few. Multivariate analysis reported that the plant parts of B. gymnorhiza greatly influenced the observed biological activities in contrast to the types of extraction methods employed. Docking calculations have supported the findings of the experimental part through the high binding affinity and strong interactions of some compounds against tyrosinase, AChE, BChE and elastase enzymes. The decocted root and leaf of B. gymnorhiza showed low to moderate antidiabetic activity, thereby partially supporting its traditional uses in the management of diabetes. However, the fruit, the most active organ, can be used as a diet supplement to reduce the risk of diabetes complications after evaluating its cytotoxic effects.Funding: This research was funded by UAEU Program for Advanced Research, grant number 31S398-UPAR to Yusra Al Dhaheri.Scopu

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.)

Multiple DNA viruses identified in multimammate mouse (Mastomys natalensis) populations from across regions of sub-Saharan Africa

Abstract The multimammate mouse (Mastomys natalensis; M. natalensis) serves as the main reservoir for the zoonotic arenavirus Lassa virus (LASV), and this has led to considerable investigation into the distribution of LASV and other related arenaviruses in this host species. In contrast to the situation with arenaviruses, the presence of other viruses in M. natalensis remains largely unexplored. In this study, herpesviruses and polyomaviruses were identified and partially characterized by PCR methods, sequencing, and phylogenetic analysis. In tissues sampled from M. natalensis populations in Côte d'Ivoire and Mali, six new DNA viruses (four betaherpesviruses, one gammaherpesvirus and one polyomavirus) were identified. Phylogenetic analysis based on glycoprotein B amino acid sequences showed that the herpesviruses clustered with cytomegaloviruses and rhadinoviruses of multiple rodent species. The complete circular genome of the newly identified polyomavirus was amplified by PCR. Amino acid sequence analysis of the large T antigen or VP1 showed that this virus clustered with a known polyomavirus from a house mouse (species Mus musculus polyomavirus 1). These two polyomaviruses form a clade with other rodent polyomaviruses, and the newly identified virus represents the third known polyomavirus of M. natalensis. This study represents the first identification of herpesviruses and the discovery of a novel polyomavirus in M. natalensis. In contrast to arenaviruses, we anticipate that these newly identified viruses represent a low zoonotic risk due to the normally highly restricted specificity of members of these two DNA virus families to their individual mammalian host species.</jats:p