Characterization and evaluation of accessions of Bambara groundnut (Vigna subterranea (L.) Verdcourt) from Burkina Faso

Three hundred and ten (310) Bambara groundnut accessions mainly from the Northern semi arid zone of Burkina Faso were assessed for phenotypic variability of agronomic and morphological traits. Mixture of seed types in a given accession is common in Northern area of Burkina Faso. Two to twelve types of seeds compose the majority of accessions collected (82%) and only 18% of accessions are homogeneous. Characters like canopy spread, number of pods per plant, number of seeds per pod, seed length, seed width and weight of 100 seeds are positively correlated to yield per plant. A negative correlation was revealed between days to 50% flowering and yield per plant indicating that plants which take more time on vegetative stage have less yield in semi-arid conditions of production. Accessions from Burkina assessed for agronomic and morphological characteristics in this study are less variable than 1384 accessions assessed by IITA in 1985 and 1986. This result can be explained by the restricted origin of accessions from Burkina Faso.La variabilité phénotypique des traits agronomiques et morphologiques de 310 accessions de pois Bambara collectées principalement dans la zone semi aride nord du Burkina Faso a été évaluée. Le mélange de différents types de semences dans les accessions est une pratique répandue dans le Nord du Burkina Faso. Deux à douze types de semence composent la majorité des accessions (82%) et seulement 18% des accessions sont homogènes. Les caractères tels que la largeur du feuillage, le nombre de gousses par plante, le nombre de graines par gousse, la longueur et largeur des graines et le poids de 100 graines ont une corrélation positive avec le rendement en graine par plante. Une corrélation négative a été mise en évidence entre la date de 50% floraison et le rendement par plante montrant que les plantes qui prennent plus de temps pour leur phase végétative produisent moins dans les conditions de production semi arides. Les accessions du Burkina évaluées pour leurs caractéristiques agronomiques et morphologiques sont moins variables que les 1384 accessions évaluées par l\'IITA en 1985 et 1986. Ce résultat peut s\'expliquer l\'origine restreinte des accessions originaires du Burkina. Keywords: Agronomic evaluation, Bambara groundnut, Mixture of seeds, Phenotypic variability, Vigna subterranea.Sciences & Nature Vol. 5 (2) 2008: pp. 191-19

Evaluation de l’efficacité d’un bio-fongicide à base de Lecanicillium lecanii (Zimmerm) sur les cercosporioses de l’arachide (Arachis hypogaea L.) en milieu réel

La lutte biologique est une méthode alternative à la lutte chimique ayant des effets néfastes sur la santé des producteurs, des consommateurs et de l’environnement. Les maladies foliaires, en l’occurrence les cercosporioses causées par Cercospora arachidicola et Phaeoisariopsis personata handicapent la production arachidière dans le monde en général, et particulièrement au Burkina Faso. Cette étude a consisté à utiliser une souche A de Lecanicillium lecanii, à des traitements différents contre le développement des cercosporioses. Pour ce faire, quatre traitements, T1, T2, T3 et T4, ont été appliqués sur deux variétés, la TS32-1 et la PC79-79 respectivement chaque deux jour, chaque semaine, chaque dix jour et chaque deux semaine. Le dispositif expérimental est un bloc de Fisher complètement randomisé à trois répétitions, constituée chacune de 5 blocs dont 4 blocs correspondant chacun à un traitement et un bloc constituant le témoin. L’étude, conduite à Gampèla, au Burkina Faso a permis de mesurer les paramètres tels que la levée au 21ème JAS, la densité de peuplement au 32ème JAS, l’incidence des cercosporioses et l’envahissement foliaire, le taux de survie, le pourcentage de défoliation et les composantes de rendement. L’étude a permis de montrer que les traitements ont eu un effet réductif sur le développement des cercosporioses au niveau des deux variétés, surtout sur la variété sensible TS32-1. Le traitement effectué chaque deux jour a donné le meilleur contrôle des cercosporioses avec une note moyenne de 3,5 sur TS32- 1 et de 2,75 sur PC79-79. Sur les composantes du rendement, les traitements ont également permis d’obtenir de bons résultats comparés aux résultats du témoin pour les deux variétés. En effet, le témoin a enregistré de 318,7 et 402,3 kg/ha respectivement pour les variétés TS32-1 et PC79-79 et les autres traitements ont obtenu des rendements compris entre 507,7 et 1656,7 kg/ha. Biological control is an alternative method to chemical control, which has adverse effects on the health of producers, consumers and the environment. Foliar diseases, in this case cercosporioses caused by Cercospora arachidicola and Phaeoisariopsis personata, handicap peanut production in the world in general, and particularly in Burkina Faso. This study consisted in using a Lecanicillium lecanii strain A, with different treatments against the development of cercosporioses. To do this, four treatments, T1, T2, T3 and T4, were applied to two varieties, TS32-1 and PC79-79 respectively every two days, every week, every ten days and every two weeks. The experimental set-up was a completely randomised Fisher block with three replicates, each consisting of five blocks, four of which corresponded to a treatment and one to a control. The study, conducted in Gampèla, Burkina Faso, measured parameters such as emergence at 21 days after planting, stand density at 32 days after planting, incidence of cercosporiosis and leaf invasion, survival rate, defoliation percentage and yield components. The study showed that the treatments had a reducing effect on cercosporium development in both varieties, especially in the susceptible variety TS32-1. The treatment applied every second day gave the best cercospora control with an average score of 3.5 on TS32-1 and 2.75 on PC79- 79. On the output components, the treatments also performed well compared to the control for both varieties. Indeed, the control recorded 318.7 and 402.3 kg/ha for TS32-1 and PC79-79 respectively and the other treatments obtained yields between 507.7 and 1656.7 kg/ha

Feeding behaviour of potential vectors of West Nile virus in Senegal

Background: West Nile virus (WNV) is a widespread pathogen maintained in an enzootic cycle between mosquitoes and birds with occasional spill-over into dead-end hosts such as horses and humans. Migratory birds are believed to play an important role in its dissemination from and to the Palaearctic area, as well as its local dispersion between wintering sites. The Djoudj Park, located in Senegal, is a major wintering site for birds migrating from Europe during the study period (Sept. 2008-Jan. 2009). In this work, we studied the seasonal feeding behaviour dynamics of the potential WNV mosquito vectors at the border of the Djoudj Park, using a reference trapping method (CDC light CO(2)-baited traps) and two host-specific methods (horse- and pigeon-baited traps). Blood meals of engorged females were analysed to determine their origin. Results: Results indicated that Culex tritaeniorhynchus and Cx. neavei may play a key role in the WNV transmission dynamics, the latter being the best candidate bridging-vector species between mammals and birds. Moreover, the attractiveness of pigeon-and horse-baited traps for Cx. neavei and Cx. tritaeniorhynchus varied with time. Finally, Cx. tritaeniorhynchus was only active when the night temperature was above 20 degrees C, whereas Cx. neavei was active throughout the observation period. Conclusions: Cx. neavei and Cx. tritaeniorhynchus are the main candidate vectors for the transmission of WNV in the area. The changes in host attractiveness might be related to variable densities of the migratory birds during the trapping period. We discuss the importance of these results on the risk of WNV transmission in horses and humans

Epidemiology of Subpatent Plasmodium Falciparum Infection: Implications for Detection of Hotspots with Imperfect Diagnostics.

At the local level, malaria transmission clusters in hotspots, which may be a group of households that experience higher than average exposure to infectious mosquitoes. Active case detection often relying on rapid diagnostic tests for mass screen and treat campaigns has been proposed as a method to detect and treat individuals in hotspots. Data from a cross-sectional survey conducted in north-western Tanzania were used to examine the spatial distribution of Plasmodium falciparum and the relationship between household exposure and parasite density. Dried blood spots were collected from consenting individuals from four villages during a survey conducted in 2010. These were analysed by PCR for the presence of P. falciparum, with the parasite density of positive samples being estimated by quantitative PCR. Household exposure was estimated using the distance-weighted PCR prevalence of infection. Parasite density simulations were used to estimate the proportion of infections that would be treated using a screen and treat approach with rapid diagnostic tests (RDT) compared to targeted mass drug administration (tMDA) and Mass Drug Administration (MDA). Polymerase chain reaction PCR analysis revealed that of the 3,057 blood samples analysed, 1,078 were positive. Mean distance-weighted PCR prevalence per household was 34.5%. Parasite density was negatively associated with transmission intensity with the odds of an infection being subpatent increasing with household exposure (OR 1.09 per 1% increase in exposure). Parasite density was also related to age, being highest in children five to ten years old and lowest in those > 40 years. Simulations of different tMDA strategies showed that treating all individuals in households where RDT prevalence was above 20% increased the number of infections that would have been treated from 43 to 55%. However, even with this strategy, 45% of infections remained untreated. The negative relationship between household exposure and parasite density suggests that DNA-based detection of parasites is needed to provide adequate sensitivity in hotspots. Targeting MDA only to households with RDT-positive individuals may allow a larger fraction of infections to be treated. These results suggest that community-wide MDA, instead of screen and treat strategies, may be needed to successfully treat the asymptomatic, subpatent parasite reservoir and reduce transmission in similar settings

Reproducibility of Liver Stiffness Measurement by Ultrasonographic Elastometry

Background & AimsFibroscan is a noninvasive device that assesses liver fibrosis by liver stiffness evaluation (LSE) with ultrasonographic elastometry. We evaluated LSE reproducibility and its influencing factors. Methods LSE was performed by 4 experienced physicians (>100 LSEs) in 46 patients with chronic liver disease at 4 different anatomic sites. Additional LSEs were performed for ancillary aims, so that 534 LSEs were available. Results Overall interobserver agreement for LSE results was considered as excellent, with intraclass coefficient correlation (Ric) of 0.93. Low LSE level, nonrecommended sites, LSE interquartile range > 25%, and body mass index ≥25 independently decreased agreement. Thus, agreement was fair (Ric = 0.53) for LSE < 9 kilopascals and excellent (Ric = 0.90) beyond. The best measurement site for LSE reproducibility was the median axillary line on the first intercostal space under the liver dullness upper limit, with the patient lying in dorsal decubitus. When LSE results were categorized into fibrosis Metavir stages, interobserver discordance was noticed in about 25% of the cases and was the highest for F2 and F3 stages and the lowest for F4. Intraobserver (Ric = 0.94), intersite (Ric = 0.92–0.98), and interequipment (Ric = 0.92) agreements for LSE results were excellent. Preliminary standard ultrasonography or probe pressure changes did not improve interobserver agreement. Conclusions The best measurement site for LSE is the one generally used for liver biopsy. Reproducibility of LSE is globally excellent but is fair in patient with low liver stiffness. The fibrosis diagnosis by ultrasonographic elastometry in low stages or categorized into fibrosis Metavir stages must be interpreted with caution

Epidémiologie des cancers digestifs en milieu hospitalier à Bamako

Les cancers digestifs sont de plus en plus constatés dans nos régions, probablement du fait de la disponibilité plus importante des moyens diagnostiques. Le but principal de notre travail était d’étudier l’épidémiologie de ces affections dans les services d’hépato-gastro-entérologie et de chirurgie générale du CHU Gabriel Touré. Il s’agissait d’une étude transversale portant sur les patients hospitalisés de février à juin 2007 puis de février à juin 2008. Nous avons retrouvé 115 cancers digestifs sur 1 547 patients hospitalisés, soit une fréquence de 7,4 %. Le sex ratio était de 1,5 en faveur des hommes et l’âge moyen des patients était de 56,6 ± 2,4 ans. Les cancers de l’estomac et le CHC étaient plus fréquents avec respectivement : 59,1 % et 19,1 % des cas. Les femmes au foyer et les cultivateurs (couches socio-économiques défavorisées) étaient plus fréquemment atteints, avec respectivement 34,8 % et 33 % des cas. La salaison, la fumaison, la consommation de tabac, de tô (pâte cuite de céréale) avec potasse ont été les facteurs de risque les plus retrouvés dans respectivement 74,8 %, 80,9 %, 33,9 % et 99,1 % des cas. Les cancers digestifs constituent un véritable problème de santé publique.Digestive cancers are increasingly found in our regions, probably due to the greater availability of diagnosis facilities. The main goal of our work was to study the epidemiological aspects of these diseases in the hepatology and gastro intestinal tract unit and in the general surgery unit in the University hospital Gabriel Touré. It was a cross-sectional study about in-patient from February to June 2007 and from February to June 2008. We found 115 gastro-intestinal tract cancers among 1 547 in-patients (7.4%). The sex-ratio was 1.5 for men and the patient’s mean age was 56.6 ± 2.4 years. Gastric cancers and hepatocellular carcinoma were more frequent with 59.1% and 19.1% of the cases. Housewives and farmers (low incomes group) were more frequently affected with respectively 34.8% and 33% of the cases. Salt intake, smoking, chewing tobacco, tô (cereal dough with potash) consumption were the strongest risk factor found respectively in 74.8%, 80.9%, and 99.1% of the cases. Digestive cancer is thus a major public health concern

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.)

Learning curve and interobserver reproducibility evaluation of liver stiffness measurement by transient elastography:

Background/Aims: Fibroscan allows liver stiffness examination (LSE) that is well correlated with fibrosis stages. Our main objective was to evaluate LSE learning curve.Methods: LSE results of five novice observers with different medical status were compared with those of five expert observers (physicians with >100 examinations) in 250 patients with chronic liver disease. Each novice–expert pair had to blindly examine 50 consecutive patients divided into five consecutive subgroups of 10 patients. Results: In each observer group, novice–expert agreement [intraclass correlation coefficient (Ric)] for LSE results was excellent from the first to the last subgroup. Novice–expert agreement for LSE results varied with liver stiffness level: <9 kPa: Ric=0.49; ≥9 kPa: Ric=0.87. Relative difference (%) between novice and expert LSE results was independently associated with the number of valid LSE measurements, and stabilizes around 20–30% after the fourth valid measurement. In each observer group, novice–expert agreement (Ric) for LSE success rate progressively increased as a function of time. Conclusion: LSE requires no learning curve: a novice is able to obtain a reliable result after a single training session, whatever the professional status. However, success rate will progressively increase. An LSE with less than four valid measurements should not be considered as reliable

Dynamics of transmission of Plasmodium falciparum by Anopheles arabiensis and the molecular forms M and S of Anopheles gambiae in Dielmo, Senegal

<p>Abstract</p> <p>Background</p> <p>The adaptation of <it>Anopheles gambiae </it>to humans and its environment involves an ongoing speciation process that can be best demonstrated by the existence of various chromosomal forms adapted to different environments and of two molecular forms known as incipient taxonomic units.</p> <p>Methods</p> <p>The aim of this study was to compare the epidemiologic role of <it>Anopheles arabiens </it>is and the molecular forms M and S of <it>Anopheles gambiae </it>in the transmission of Plasmodium in a rural areas of southern Senegal, Dielmo. The sampling of mosquitoes was carried out monthly between July and December 2004, during the rainy season, by human volunteers and pyrethrum spray catches.</p> <p>Results</p> <p><it>Anopheles arabiensis</it>, <it>An. gambiae </it>M and S forms coexisted during the rainy season with a predominance of the M form in September and the peak of density being observed in August for the S form. Similar parity rates were observed in <it>An. arabiensis </it>[70.9%] (n = 86), <it>An</it>. <it>gambiae </it>M form [68.7%] (n = 64) and <it>An</it>. <it>gambiae </it>S form [81.1%] (n = 156). The circumsporozoite protein (CSP) rates were 2.82% (n = 177), 3.17% (n = 315) and 3.45% (n = 405), with the mean anthropophilic rates being 71.4% (n = 14), 86.3% (n = 22) and 91.6% (n = 24) respectively for <it>An</it>. <it>arabiensis </it>and <it>An</it>. <it>gambiae </it>M and S forms. No significant difference was observed either in host preference or in <it>Plasmodium falciparum </it>infection rates between sympatric M and S populations.</p> <p>Conclusion</p> <p>No difference was observed either in host preference or in <it>Plasmodium falciparum </it>infection rates between sympatric M and S populations, but they present different dynamics of population. These variations are probably attributable to different breeding conditions.</p