Prévalence de l’hépatite B chez les personnes infectées par le VIH à Parakou au Bénin

Introduction: la co-infection avec l'hépatite B est l'un des défis majeurs de la prise en charge du VIH depuis l'amélioration de l'accès aux  antirétroviraux en Afrique. La présente étude visait à estimer la prévalence de l'hépatite B chez les personnes séropositives au VIH à Parakou et décrire les facteurs associés. Méthodes: il s'agit d'une étude transversale menée de Mai 2011 à Juin 2012 dans le service de Médecine du CHU de Parakou. Ont été inclus tous les adultes séropositifs au VIH vus en  consultation ou hospitalisés. Les données ont été collectées par interviews et dépouillement de dossiers médicaux. L'antigène HBs a été recherché par un test rapide et l'ALAT a été dosé. L'analyse des données a été faite avec le logiciel EpiInfo 3.5.1. Les proportions ont été comparées grâce au test de Chi-deux ou au test de Fisher au seuil de significativité de 5%. Un modèle de régression logistique multivariable a permis d'expliquer la prévalence de l'hépatite B.Résultats: sur les 744 sujets inclus on a dénombré 555 femmes. L'âge moyen était de 35,5 + 10,1 ans. La  prévalence de l'hépatite B a été estimée à 16,9% (IC95 : 14,3%-19,9%). Cette prévalence était plus élevée chez les sujets originaires du  Borgou/Alibori et ceux au stade 4 de l'OMS. Conclusion: la prévalence de la co-infection VIH/VHB au CHU Parakou est élevée. Le dispositif national de prise en charge et de prévention de l'hépatite B chez les personnes  séropositives au VIH doit être renforcé

Seasonal performance of a malaria rapid diagnosis test at community health clinics in a malaria-hyperendemic region of Burkina Faso

BACKGOUND: Treatment of confirmed malaria patients with Artemisinin-based Combination Therapy (ACT) at remote areas is the goal of many anti-malaria programs. Introduction of effective and affordable malaria Rapid Diagnosis Test (RDT) in remote areas could be an alternative tool for malaria case management. This study aimed to assess performance of the OptiMAL dipstick for rapid malaria diagnosis in children under five. METHODS: Malaria symptomatic and asymptomatic children were recruited in a passive manner in two community clinics (CCs). Malaria diagnosis by microscopy and RDT were performed. Performance of the tests was determined. RESULTS: RDT showed similar ability (61.2%) to accurately diagnose malaria as microscopy (61.1%). OptiMAL showed a high level of sensitivity and specificity, compared with microscopy, during both transmission seasons (high & low), with a sensitivity of 92.9% vs. 74.9% and a specificity of 77.2% vs. 87.5%. CONCLUSION: By improving the performance of the test through accurate and continuous quality control of the device in the field, OptiMAL could be suitable for use at CCs for the management and control of malaria

Plasmodium falciparum gametocyte density and infectivity in peripheral blood and skin tissue of naturally infected parasite carriers in Burkina Faso

Background: Plasmodium falciparum transmission depends on mature gametocytes that can be ingested by mosquitoes taking a blood meal on human skin. Although gametocyte skin sequestration has long been hypothesized as important contributor to efficient malaria transmission, this has never been formally tested. Methods: In naturally infected gametocyte carriers from Burkina Faso, we assessed infectivity to mosquitoes by direct skin feeding and membrane feeding. We directly quantified male and female gametocytes and asexual parasites in finger-prick and venous blood samples, skin biopsy samples, and in of mosquitoes that fed on venous blood or directly on skin. Gametocytes were visualized in skin tissue with confocal microscopy. Results: Although more mosquitoes became infected when feeding directly on skin then when feeding on venous blood (odds ratio, 2.01; 95% confidence interval, 1.21–3.33; P = .007), concentrations of gametocytes were not higher in the subdermal skin vasculature than in other blood compartments; only sparse gametocytes were observed in skin tissue. Discussion: Our data strongly suggest that there is no significant skin sequestration of P. falciparum gametocytes. Gametocyte densities in peripheral blood are thus informative for predicting onward transmission potential to mosquitoes and can be used to target and monitor malaria elimination initiatives

Plasmodium falciparum Gametocyte Density and Infectivity in Peripheral Blood and Skin Tissue of Naturally Infected Parasite Carriers in Burkina Faso.

BACKGROUND: Plasmodium falciparum transmission depends on mature gametocytes that can be ingested by mosquitoes taking a blood meal on human skin. Although gametocyte skin sequestration has long been hypothesized as important contributor to efficient malaria transmission, this has never been formally tested. METHODS: In naturally infected gametocyte carriers from Burkina Faso, we assessed infectivity to mosquitoes by direct skin feeding and membrane feeding. We directly quantified male and female gametocytes and asexual parasites in finger-prick and venous blood samples, skin biopsy samples, and in of mosquitoes that fed on venous blood or directly on skin. Gametocytes were visualized in skin tissue with confocal microscopy. RESULTS: Although more mosquitoes became infected when feeding directly on skin then when feeding on venous blood (odds ratio, 2.01; 95% confidence interval, 1.21-3.33; P = .007), concentrations of gametocytes were not higher in the subdermal skin vasculature than in other blood compartments; only sparse gametocytes were observed in skin tissue. DISCUSSION: Our data strongly suggest that there is no significant skin sequestration of P. falciparum gametocytes. Gametocyte densities in peripheral blood are thus informative for predicting onward transmission potential to mosquitoes and can be used to target and monitor malaria elimination initiatives

Null Controllability of a Four Stage and Age-Structured Population Dynamics Model

This paper is devoted to study the null controllability properties of a population dynamics model with age structuring and nonlocal boundary conditions. More precisely, we consider a four-stage model with a second derivative with respect to the age variable. The null controllability is related to the extinction of eggs, larvae, and female population. Thus, we estimate a time T to bring eggs, larvae, and female subpopulation density to zero. Our method combines fixed point theorem and Carleman estimate. We end this work with numerical illustrations

Null Controllability of a Nonlinear Age Structured Model for a Two-Sex Population

This paper is devoted to study the null controllability properties of a nonlinear age and two-sex population dynamics structured model without spatial structure. Here, the nonlinearity and the couplage are at the birth level. In this work, we consider two cases of null controllability problem. The first problem is related to the extinction of male and female subpopulation density. The second case concerns the null controllability of male or female subpopulation individuals. In both cases, if A is the maximal age, a time interval of duration A after the extinction of males or females, one must get the total extinction of the population. Our method uses first an observability inequality related to the adjoint of an auxiliary system, a null controllability of the linear auxiliary system, and after Kakutani’s fixed-point theorem

Mapping of the brain hemodynamic responses to sensorimotor stimulation in a rodent model: A BOLD fMRI study.

Blood Oxygenation Level Dependent functional MRI (BOLD fMRI) during electrical paw stimulation has been widely used in studies aimed at the understanding of the somatosensory network in rats. However, despite the well-established anatomical connections between cortical and subcortical structures of the sensorimotor system, most of these functional studies have been concentrated on the cortical effects of sensory electrical stimulation. BOLD fMRI study of the integration of a sensorimotor input across the sensorimotor network requires an appropriate methodology to elicit functional activation in cortical and subcortical areas owing to the regional differences in both neuronal and vascular architectures between these brain regions. Here, using a combination of low level anesthesia, long pulse duration of the electrical stimulation along with improved spatial and temporal signal to noise ratios, we provide a functional description of the main cortical and subcortical structures of the sensorimotor rat brain. With this calibrated fMRI protocol, unilateral non-noxious sensorimotor electrical hindpaw stimulation resulted in robust positive activations in the contralateral sensorimotor cortex and bilaterally in the sensorimotor thalamus nuclei, whereas negative activations were observed bilaterally in the dorsolateral caudate-putamen. These results demonstrate that, once the experimental setup allowing necessary spatial and temporal signal to noise ratios is reached, hemodynamic changes related to neuronal activity, as preserved by the combination of a soft anesthesia with a soft muscle relaxation, can be measured within the sensorimotor network. Moreover, the observed responses suggest that increasing pulse duration of the electrical stimulus adds a proprioceptive component to the sensory input that activates sensorimotor network in the brain, and that these activation patterns are similar to those induced by digits paw's movements. These findings may find application in fMRI studies of sensorimotor disorders within cortico-basal network in rodents

Quality Comparison of Fraudulent and Registered Pesticides in Mali

Key Findings -Pesticide markets have grown rapidly in West Africa over the past decade and a half, far faster than regulatory monitoring capacity. -As a result, fraudulent pesticides (unregistered and counterfeit) are widely sold throughout Mali. -Purchase of 100 glyphosate samples from 50 different retailers across Mali indicate that that 45% were fraudulent products. -Laboratory testing indicates that fraudulent glyphosate products contain 8-10% less active ingredient than registered products. -Farmers can protect themselves by purchasing only pesticides duly registered by the Comité Sahélien des Pesticides (CSP)

Number of activated voxels as a function of the echo time (TE).

<p>Number of activated voxels as a function of the echo time (TE).</p