Biometric Relationships and Evaluation of the Density of Tagelus angulatus Gray, 1847 (Mollusca, Solecurtidae) on the West African Coasts in Three Villages of the Community Protected Area of Urok, Guinea-Bissau

Aims: This study aimed to examin the biometric relationships, size frequencies and density of Tagelus angulatus in the Community Marine Protected Area of the Bijagós Islands of Guinea Bissau. Methodology: Sampling was carried out in three villages (Formosa, Nago and TChediã) of the Community Marine Protected Area. A total of 1596 individuals were collected. On each mudflat, four random transects 30 m apart and oriented from the shore to the sea were established. On each transect, individuals of Tagelus angulatus were collected on 6 plots of 1m² that were separated by 10 m. Results: The length of the individuals sampled ranged from 12 mm to 69 mm in all three of the villages studied with an average length of 48.65 ± 9.53 mm and a main mode equal to 53 mm. The results showed a positive allometry. The length and width of the species are also strongly correlated. The mean density for all three villages was 16.63 individuals. Conclusion: Management of the shellfish industry generally requires the knowledge and use of biometric relationships to translate data collected in the field into indicators that can be used for the development of management plans. This study provided knowledges on biometric relationships and density of Tagelus angulatus

Use of HRP-2-based rapid diagnostic test for Plasmodium falciparum malaria: assessing accuracy and cost-effectiveness in the villages of Dielmo and Ndiop, Senegal

Background: In 2006, the Senegalese National Malaria Control Programme (NMCP) has recommended artemisinin-based combination therapy (ACT) as the first-line treatment for uncomplicated malaria and, in 2007, mandated testing for all suspected cases of malaria with a Plasmodium falciparum HRP-2-based rapid diagnostic test for malaria (RDT(Paracheck (R)). Given the higher cost of ACT compared to earlier anti-malarials, the objectives of the present study were i) to study the accuracy of Paracheck (R) compared to the thick blood smear (TBS) in two areas with different levels of malaria endemicity and ii) analyse the cost-effectiveness of the strategy of the parasitological confirmation of clinically suspected malaria cases management recommended by the NMCP. Methods: A cross-sectional study was undertaken in the villages of Dielmo and Ndiop (Senegal) nested in a cohort study of about 800 inhabitants. For all the individuals consulting between October 2008 and January 2009 with a clinical diagnosis of malaria, a questionnaire was filled and finger-prick blood samples were taken both for microscopic examination and RDT. The estimated costs and cost-effectiveness analysis were made considering five scenarios, the recommendations of the NMCP being the reference scenario. In addition, a sensitivity analysis was performed assuming that all the RDT-positive patients and 50% of RDT-negative patients were treated with ACT. Results: A total of 189 consultations for clinically suspected malaria occurred during the study period. The sensitivity, specificity, positive and negative predictive values were respectively 100%, 98.3%, 80.0% and 100%. The estimated cost of the reference scenario was close to 700(sic) per 1000 episodes of illness, approximately twice as expensive as most of the other scenarios. Nevertheless, it appeared to us cost-effective while ensuring the diagnosis and the treatment of 100% of malaria attacks and an adequate management of 98.4% of episodes of illness. The present study also demonstrated that full compliance of health care providers with RDT results was required in order to avoid severe incremental costs. Conclusions: A rational use of ACT requires laboratory testing of all patients presenting with presumed malaria. Use of RDTs inevitably has incremental costs, but the strategy associating RDT use for all clinically suspected malaria and prescribing ACT only to patients tested positive is cost-effective in areas where microscopy is unavailable

Contribution to the Study of the Size Structure, the Length-Weight Relationship, the Condition Factor and the Sex-ration of Shrimp Farfantepenaeus notialis (Pérez Farfante, 1967) in the Estuary of Sine-Saloum (Senegal)

This study was carried out within the context of USAID/COMFISH project for establihing a biological data base for some fish species including shrimp Farfantepenaeus notialis to support management plans for these species. This study on Farfantepenaeus notialis in the Sine-Saloum estuary revealed that the sampled individuals are relatively small sizes.The average cephalothoracic sizes are less than 20 mm at Bettenty (male = 18.0 ± 2.9; female=18.5 ± 3.9) and at Foundiougne (male = 17.6 ± 2.9; female = 18.5 ± 3.8). The allometric rate «b» is more important at Bettenty (b = 2.94) than at Foundiougne (b = 2.75) and condition factor K is higher during the hot season in both locations (Bettenty: K = 0.80 in hot season; K = 0.78 in cold season; Foundiougne: K = 0.82 in hot season, K = 0.75 in cold season). The sex ratio of Farfantepenaeus notialis is in favor of females at Bettenty (54.6%) and at Foundiougne (51.2%). The size classes show that below 15 mm and beyond 20 mm, the number of female is higher than that of male. Beween 15 to 20 mm, male are higher.

L’éléphantiasis vulvo-clitoridien: à propos d’un nouveau cas

L'éléphantiasis vulvo-clitoridien d'origine filarienne est une affection très rare. Nous rapportons un nouveau cas chez une femme de 33 ans suivie dans un service de Maladies Infectieuses pour filariose lymphatique. Elle avait une masse vulvo-clitoridienne qui évoluait depuis plus de 10 ans. Une résection clitoridienne et une plastie vulvaire a été réalisée. Les résultats fonctionnels et esthétiques étaient satisfaisants.Key words: Eléphantiasis, filariose, vulvo-clitoridie

An Exhaustive, Non-Euclidean, Non-Parametric Data Mining Tool for Unraveling the Complexity of Biological Systems – Novel Insights into Malaria

Complex, high-dimensional data sets pose significant analytical challenges in the post-genomic era. Such data sets are not exclusive to genetic analyses and are also pertinent to epidemiology. There has been considerable effort to develop hypothesis-free data mining and machine learning methodologies. However, current methodologies lack exhaustivity and general applicability. Here we use a novel non-parametric, non-euclidean data mining tool, HyperCube®, to explore exhaustively a complex epidemiological malaria data set by searching for over density of events in m-dimensional space. Hotspots of over density correspond to strings of variables, rules, that determine, in this case, the occurrence of Plasmodium falciparum clinical malaria episodes. The data set contained 46,837 outcome events from 1,653 individuals and 34 explanatory variables. The best predictive rule contained 1,689 events from 148 individuals and was defined as: individuals present during 1992–2003, aged 1–5 years old, having hemoglobin AA, and having had previous Plasmodium malariae malaria parasite infection ≤10 times. These individuals had 3.71 times more P. falciparum clinical malaria episodes than the general population. We validated the rule in two different cohorts. We compared and contrasted the HyperCube® rule with the rules using variables identified by both traditional statistical methods and non-parametric regression tree methods. In addition, we tried all possible sub-stratified quantitative variables. No other model with equal or greater representativity gave a higher Relative Risk. Although three of the four variables in the rule were intuitive, the effect of number of P. malariae episodes was not. HyperCube® efficiently sub-stratified quantitative variables to optimize the rule and was able to identify interactions among the variables, tasks not easy to perform using standard data mining methods. Search of local over density in m-dimensional space, explained by easily interpretable rules, is thus seemingly ideal for generating hypotheses for large datasets to unravel the complexity inherent in biological systems

Spatial and temporal dynamics of West Nile virus between Africa and Europe

It is unclear whether West Nile virus (WNV) circulates between Africa and Europe, despite numerous studies supporting an African origin and high transmission in Europe. We integrated genomic data with geographic observations and phylogenetic and phylogeographic inferences to uncover the spatial and temporal viral dynamics of WNV between these two continents. We focused our analysis towards WNV lineages 1 (L1) and 2 (L2), the most spatially widespread and pathogenic WNV lineages. Our study shows a Northern-Western African origin of L1, with back-and-forth exchanges between West Africa and Southern-Western Europe; and a Southern African origin of L2, with one main introduction from South Africa to Europe, and no back introductions observed. We also noticed a potential overlap between L1 and L2 Eastern and Western phylogeography and two Afro-Palearctic bird migratory flyways. Future studies linking avian and mosquito species susceptibility, migratory connectivity patterns, and phylogeographic inference are suggested to elucidate the dynamics of emerging viruse

Wall velocity gradients and vortices in Taylor-Couette flow

Ce travail est une étude expérimentale permettant de mettre en évidence la cartographie générale de l’ensemble des états d’écoulement obtenus entre le régime laminaire de Couette et la turbulence. L’ensemble des expériences a été réalisé dans un dispositif appelé système Taylor-Couette (STC), composé de deux cylindres concentriques avec le cylindre intérieur tournant. Ces différentes instabilités (SPI, TVF, WVF, MWVF, TTVF), qui dépendent principalement du nombre de Taylor (Ta), seront obtenues avec ou sans débit axial dans le STC selon des protocoles d’analyse bien définis et nous notons que le nombre de Reynolds axial (Reax) a un effet de stabilisation de l’écoulement. Les vortex de Taylor toroïdaux, ondulés ou ondulés modulés, ont été caractérisés en termes de gradient pariétal de vitesse, de nombre d’ondes, de longueur d’ondes axiales et azimutales, de la vitesse de déplacement axial, de fréquence et de la vitesse de révolution ; la polarographie sera utilisée comme technique de mesure. La vitesse du cylindre intérieur (Ta) est essentiellement le seul phénomène agissant sur l’évolution de ces paramètres. L’utilisation de la sonde tri-segmentée dans la caractérisation des structures tourbillonnaires a contribué à la compréhension des mécanismes d’interaction vortex-paroi et à la détermination des composantes azimutale et axiale du gradient pariétal de vitesse.This work is an experimental study to highlight general mapping of the set of states obtained from the Couette laminar flow to turbulence. All experiments were performed in a device called Taylor-Couette system (TCS) which consists of two concentric cylinders with the inner cylinder rotating. The flow regimes (SPI, TVF, WVF, MWVF, TTVF), which depend mainly on the Taylor number (Ta), were obtained with or without axial flow in the TCS according to well-defined experimental protocols. We noted that the axial Reynolds number (Reax) has astabilizing effect on the flow. Using electrodiffusion method and analysis of films, the toroidal Taylor vortices, wavy or wavy modulated flow, were characterized in terms of the wall velocity gradients, wave number, axial and azimuthal wavelength, the axial velocity of vortex displacement, and there frequencies. The Taylor number has substantial effect on the evolution of these parameters in the investigated range. The use of three-segment electrodiffusion has contributed to the understanding of the mechanisms of vortex-wall interaction and the determination of the azimuthal and axial components of the wall velocity gradient

Wall velocity gradients in Taylor-Couette-Poiseuille flow

Experiments were carried out in the flow between concentric cylinders with the inner cylinder rotating and outercylinder fixed. The radius and aspect ratios were 0.8 and 44, respectively. The electrodiffusion method with athree-segment and simple micro-electrodes was used for study of the axial and azimuthal components of velocitygradient at the outer cylinder. The axial distributions of the components of wall velocity gradient were obtained bysweeping the vortices along the probes using axial flow. The wavelength and phase celerity of waves, height ofvortices and their drifting velocity were calculated from the measured limiting diffusion currents