138 research outputs found
HIV prevention and care services for female sex workers : efficacy of a community-based intervention package among young female sex workers in Ouagadougou (Burkina Faso)
No full textContexte: Les travailleuses du sexe (TS) sont un groupe à risque de l’infection à VIH, jouant un rôle majeur dans la dynamique de l’épidémie en Afrique de l’Ouest. Les interventions de prévention et de prise en charge du VIH ciblant ces femmes sont donc indispensables, mais leur contenu reste à définir. Nous avons conçu un paquet d’intervention qui combinait la prévention et les soins, et estimé son impact sur l’incidence du VIH. Méthodes: Entre septembre 2009 et septembre 2010, nous avons réalisé une étude transversale à Ouagadougou (Burkina Faso) suivie d’une étude de cohorte interventionnelle chez des jeunes TS âgées de 18 à 25 ans, avec un suivi trimestriel pendant 21 mois maximum. Le paquet d’intervention de la cohorte combinait des activités de prévention effectuées par des pairs (sessions de communication pour un changement de comportement) et de soins (IST, VIH, soins généraux, santé sexuelle et reproductive, soutien psychologique).A chaque visite, les comportements sexuels étaient collectés par un questionnaire ; des tests VIH, HSV-2 et de grossesses étaient réalisés. L’incidence de l’infection à VIH observée dans la cohorte a été comparée à l’incidence attendue en absence d’intervention. Cette dernière a été estimée grâce à un modèle mathématique de Bernouilli utilisant les données collectées chez les clients des TS, et des estimations de paramètres clés issus de la littérature.Durant le suivi, nous avons défini un comportement à risque comme le premier épisode d’un évènement biologique résultant d’un rapport sexuel non-protégé : grossesse non-désirée, primo-infection HSV-2 ou à T. vaginalis. Nous avons utilisé un modèle logistique à effet aléatoire pour identifier les déterminants de ces comportements à risque durant le suivi.Résultats: Parmi les 609 travailleuses du sexe pré-sélectionnées dont 188 (30,9%) professionnelles, la prévalence du VIH était de 10,3% chez les professionnelles et 6,5% chez les non-professionnelles l’âge médian était de 21 ans. Au total, 41,2% des professionnelles et 47,5% des non-professionnelles rapportaient une utilisation non systématique du préservatif, principalement avec leurs partenaires réguliers.Dans cette étude transversale, l’infection à VIH était associée à l’âge (aOR=1,44; IC95%: 1,22-1,71), la vie en couple (AOR=2,70; IC95%: 1,21-6,04), et l’infection à T. vaginalis (aOR=9,63; IC95%: 2,93-31,59), tandis que la réalisation antérieure d’un test VIH réduisait nettement ce risque (AOR=0,18; IC95%: 0,08-0,40). Les 321 TS non-infectées par le VIH incluses dans la cohorte ont effectué un suivi total de 409 personne-années (p-a). Aucune participante n’a fait une séroconversion au VIH durant le suivi (0/409 p-a) alors que l’incidence attendue modélisée était de 5,05/409 p-a (IC95%, 5,01-5,08) soit 1,23 infection/100 p-a (p=0,005). Cette incidence nulle était associée à une réduction du nombre de partenaires réguliers et de clients réguliers ainsi qu’à une augmentation du taux d’utilisation constante du préservatif avec les nouveaux clients (aOR =2,19; IC95%, 1,16-4,14) et avec les clients réguliers (aOR=2,18; IC95%, 1,26-3,76). Cependant, les comportements à risque restaient élevés durant l’intervention : 26,7/100 p-a (IC95%, 24,1-33,7). Ce risque résiduel était plus élevé chez les TS vivant en couple (aOR =7,47, IC95%, 1,70-30,80) et chez les non-professionnelles (AOR =5,53, IC95%, 1,75-16,84). Ces dernières avaient le plus tendance à ne pas déclarer les comportements à risque lors des interviews. Conclusions: Notre étude a démontré la nécessité de cibler les jeunes TS par des interventions adaptées.Notre paquet d’intervention combinant la prévention du VIH et les soins a permis de réduire l’incidence du VIH chez les jeunes travailleuses du sexe au Burkina Faso. Les interventions devront se focaliser sur le dépistage du VIH, les TS non-professionnelles et les partenaires réguliers.Background: In West Africa, interventions targeting female sex workers (FSW) are crucial to impact on the HIV dynamics. However, the contents and efficacy of these interventions are unclear, and identifying the most at risk FSW in order to adapt these interventions remain challenging, partly because of the limitations of self-reported sexual behaviours. We therefore designed a comprehensive dedicated intervention targeting young female sex workers, and assessed its impact on HIV incidence in Burkina Faso and the reliability of interview data. Methods: From September 2009 to September 2010 we conducted a cross sectional study in Ouagadougou, Burkina Faso. Then HIV-uninfected FSW aged 18-25 years were enrolled in a prospective interventional cohort. The participants were followed quarterly for a maximum of 21 months. The intervention group received a package which combined prevention and care within the same setting, and consisting of peer-led education sessions, psychological support, sexually transmitted infections and HIV care, general routine health care, and reproductive health services. At each visit, behavioural characteristics were collected and HIV, HSV-2 and pregnancy were tested. High-risk behaviour was defined as the first occurrence of any biological event resulting from unsafe sex, including unexpected pregnancy or HSV-2 or T. vaginalis infection. We used random logistic models to assess the relationship between socio-demographic characteristics and the residual high risk behaviours during the intervention.We compared the cohort HIV incidence with a Bernoulli modelled expected incidence in the absence of intervention, using data collected at the same time from FSW clients and key parameters from the litterature. Results: We screened 609 FSW including 188 (30.9%) professionals. Their median age was 21 years [IQR, 19-23], and the prevalence of HIV was 10.3% among professionals and 6.5% among non-professionals. Overall, 277 (45.6%) women reported high-risk behaviours (41.2% among professionals and 47.5% among non-professionals), which were driven mainly by non-consistent condom use with regular partners. In multivariable analysis, before the intervention, HIV infection was associated with older age (AOR=1.44; 95%CI: 1.22-1.71), with being married/cohabiting (AOR=2.70; 95%CI: 1.21-6.04), and with T. vaginalis infection (AOR=9.63; 95%CI: 2.93-31.59), while previous HIV testing was associated with a decreased risk (AOR=0.18; 95%CI: 0.08-0.40).The 321 HIV-uninfected FSW enrolled in the cohort completed 409 person-years of follow-up. No participant seroconverted for HIV during the study while the expected modelled number of HIV infections were 5.05 (95%CI, 5.01-5.08) during the same follow-up (409 person-years) or 1.23 infection per 100 person-years (p=0.005). This null incidence was related to a reduction in the number of regular partners and regular clients, and to an increase in consistent condom use with casual clients (AOR =2.19; 95%CI, 1.16-4.14, p=0.01) and with regular clients (AOR=2.18; 95%CI, 1.26-3.76, p=0.005). However, the incidence of residual risk was high, at 26.7/100 person-years (95% CI, 24.1-33.7). The residual risk was higher among FSW living in couple (adjusted odd ratio [AOR] =7.47, 95% CI, 1.70-30.80) and among those for whom sex work was not the main source of income (AOR =5.53, 95% CI, 1.75-16.84). The latter also tended not to report high-risk behaviours during face –to–face interview. Conclusions: This study highlights the need for targeted interventions among young FSW focusing particularly on non-professionals, sexual behaviours with regular partners and regular HIV testing. The ANRS 1222 study intervention package which combined peer-based prevention and care within the same setting markedly reduced HIV incidence among young female sex workers in Burkina Faso, through reduced risky behaviours
Contribution de la formation en épidémiologie de terrain (FETP) au renforcement des systèmes de surveillance et des ripostes contre les épidémies et autres évènements de santé publique: Contribution of training in field epidemiology (FETP) to strengthening surveillance systems and responses to epidemics and other public health events
No full textIntroduction: De janvier 2008 à juin 2016, le Mali n'a notifié aucun cas de coqueluche. En juillet 2016, Bafoulabé a signalé 38 cas suspects de coqueluche dans le village de Djombomadji à Dialakon. L’objectif était de décrire cette épidémie en temps, lieu et personne. Méthodes: Nous avons mené une étude transversale descriptive à Dialakon de mars à août 2016. Un cas suspect de coqueluche était toute personne présentant une toux paroxystique avec ou sans vomissements, fièvre, dyspnée ou éternuement. Nous avons effectué une recherche active de cas. Les données ont été collectées à l’aide d’un questionnaire et analysées en temps, lieu et personne. Résultats: Au total, 112 cas suspects de coqueluche enregistrés sur 7238 habitants (taux d'attaque : 16/1000) avec zéro décès. L'âge médian était de 4 ans, étendu de 3 mois-13 ans, 52% étaient de sexe féminin. Parmi les cas, 4% étaient complètement vaccinés contre la coqueluche. Tous les cas provenaient du village de Djombomadji. L'épidémie avait commencé le 10 mars, avec 2 pics le 16 mai et le 16 juin 2016 qui avaient respectivement 20 et 16 cas. Le nombre de cas a ensuite progressivement diminué jusqu'au 26 juillet 2016 quand les 2 derniers cas ont été enregistrés. Conclusion: L'épidémie a duré 5 mois, la majorité des cas ont eu lieu le 16 mai 2016, étaient du sexe féminin, n'étaient pas vaccinés et provenaient du village de Djombomadji. Tous les cas ont été traités, les enfants non malades ont été vaccinés et la population a été sensibilisée.
 
Continuous Authentication using Stylometry
No full textStatic authentication, where user identity is checked once at login time, can be circumvented no matter how strong the authentication mechanism is. Through attacks such as man-in-the-middle and its variants, an authenticated session can be hijacked later after the initial login process has been completed. In the last decade, continuous authentication (CA) using biometrics has emerged as a possible remedy against session hijacking. CA consists of testing the authenticity of the user repeatedly throughout the authenticated session as data becomes available. CA is expected to be carried out unobtrusively, due to its repetitive nature, which means that the authentication information must be collectible without any active involvement of the user and without using any special purpose hardware devices (e.g. biometric readers). Stylometry analysis, which consists of checking whether a target document was written or not by a specific individual, could potentially be used for CA. Although stylometric techniques can achieve high accuracy rates for long documents, it is still challenging to identify an author for short documents, in particular when dealing with large author populations.
In this dissertation, we propose a new framework for continuous authentication using authorship verification based on the writing style. Authorship verification can be checked using stylometric techniques through the analysis of linguistic styles and writing characteristics of the authors. Different from traditional authorship verification that focuses on long texts, we tackle the use of short messages. Shorter authentication delay (i.e. smaller data sample) is essential to reduce the window size of the re-authentication period in CA. We validate our method using different block sizes, including 140, 280, and 500 characters, and investigate shallow and deep learning architectures for machine learning classification. Experimental evaluation of the proposed authorship verification approach based on the Enron emails dataset with 76 authors yields an Equal Error Rate (EER) of 8.21% and Twitter dataset with 100 authors yields an EER of 10.08%. The evaluation of the approach using relatively smaller forgery samples with 10 authors yields an EER of 5.48%.Graduat
Long-term virological, immunological and mortality outcomes in a cohort of HIV-infected female sex workers treated with highly active antiretroviral therapy in Africa.
No full textBACKGROUND: Concerns have been raised that marginalised populations may not achieve adequate compliance to antiretroviral therapy. Our objective was to describe the long-term virological, immunological and mortality outcomes of providing highly active antiretroviral therapy (HAART) with strong adherence support to HIV-infected female sex workers (FSWs) in Burkina Faso and contrast outcomes with those obtained in a cohort of regular HIV-infected women. METHODS: Prospective study of FSWs and non-FSWs initiated on HAART between August 2004 and October 2007. Patients were followed monthly for drug adherence (interview and pill count), and at 6-monthly intervals for monitoring CD4 counts and HIV-1 plasma viral loads (PVLs) and clinical events. RESULTS: 95 women, including 47 FSWs, were followed for a median of 32 months (interquartile range [IQR], 20-41). At HAART initiation, the median CD4 count was 147 cells/μl (IQR, 79-183) and 144 cells/μl (100-197), and the mean PVLs were 4.94 log10 copies/ml (95% confidence interval [CI], 4.70-5.18) and 5.15 log10 copies/ml (4.97-5.33), in FSWs and non-FSWs, respectively. Four FSWs died during follow-up (mortality rate: 1.7 per 100 person-years) and none among other women. At 36 months, the median CD4 count increase was 230 cells/μl (IQR, 90-400) in FSWs vs. 284 cells/μl (193-420) in non-FSWs; PVL was undetectable in 81.8% (95% CI, 59.7-94.8) of FSWs vs. 100% (83.9-100) of non-FSWs; and high adherence to HAART (> 95% pills taken) was reported by 83.3% (95% CI, 67.2-93.6), 92.1% (95% CI, 78.6-98.3), and 100% (95% CI, 54.1-100) of FSWs at 6, 12, and 36 months after HAART initiation, respectively, with no statistical difference compared to the pattern observed among non-FSWs. CONCLUSIONS: Clinical and biological benefits of HAART can be maintained over the long-term among FSWs in Africa and could also lead to important public health benefits
CONFLITS AGROPASTORAUX EN COTE D’IVOIRE (CAS DE BOUNA)
No full textSitué dans le nord-est de la Côte d’Ivoire, le département de Bouna connait une perturbation dans la quiétude de son climat social du fait des affrontements récurrents entre agriculteurs et éleveurs. Alors, à l’aide d’une enquête qualitative et quantitative auprès des populations de la zone dont, 157 personnes forment l’échantillon. Ce travail a eu pour objet de s’interroger sur les facteurs explicatifs de la persistance de ces conflits. En hypothèse nous soutenons que la persistance des conflits provient de l’irrespect des règles édictées pour une meilleure cohabitation des activités agricoles et pastorales dans le département de Bouna. Les résultats de terrain montrent que l’opposition entre lobis et Koulangos revêt un caractère de lutte pour l’affranchissement des lobis, les affrontements entre lobis et peulhs sont dus à une difficulté d’accès aux ressources naturelles. En effet, les changements climatiques conjugués à la croissance démographique ont entraîné une pénurie des terres cultivables. Par manque d’espaces cultivables, les paysans lobis exploitent les pistes de transhumance destinées aux éleveurs et leur bétail, malgré l’existence d’accord administratif et politique dans ce sens
The role of Plasmodium falciparum var genes in malaria in pregnancy
No full textSequestration of Plasmodium falciparum-infected erythrocytes in the placenta is responsible for many of the harmful effects of malaria during pregnancy. Sequestration occurs as a result of parasite adhesion molecules expressed on the surface of infected erythrocytes binding to host receptors in the placenta such as chondroitin sulphate A (CSA). Identification of the parasite ligand(s) responsible for placental adhesion could lead to the development of a vaccine to induce antibodies to prevent placental sequestration. Such a vaccine would reduce the maternal anaemia and infant deaths that are associated with malaria in pregnancy. Current research indicates that the parasite ligands mediating placental adhesion may be members of the P. falciparum variant surface antigen family PfEMP1, encoded by var genes. Two relatively well-conserved subfamilies of var genes have been implicated in placental adhesion, however, their role remains controversial. This review examines the evidence for and against the involvement of var genes in placental adhesion, and considers whether the most appropriate vaccine candidates have yet been identified
From the Theory of the African Origin of Humankind to Modern Social, Legal and Technological Innovations: a Brief Analytical Excursion into Anthroposociogenesis
No full textObjective: to trace the evolution of humanity and to identify the role of various social institutions in order to understand the existential role of laws aimed at ensuring the coexistence of society in the context of technological innovations.Methods: the author used general scientific and special methods of cognition, which allowed tracing the dialectical development of humanity, social transformations and technological innovations.Results: looking back at the history of humanity, which originated on the African continent (the theory of African descent), the author notes the most important changes in the human way of life and environment, which led to the need to build organized societies and regulate social behavior with the help of legislative norms. Law is seen as part of the evolutionary process that was to emerge in the course of human evolution. The critical importance of law in overcoming the global challenges and existential questions of humanity’s continued coexistence arising in the course of evolution is emphasized. In this regard, the historical significance of the Kurukan Fuga Charter of the Malian Empire is emphasized as one of the oldest constitutions in the world, recognized internationally as an important source of legal and political norms for modern societies, regulating the structure of state power and social behaviour, although preserved largely in oral form. It is argued that social and technological change often served as the impetus for the development of new laws. Humanity has many times intervened in its own biological evolution with the help of technology; now it is an important moment from the viewpoint of law and ethics when technology may interfere in further human evolution. The greatest concern in this regard is the era of rapid development of artificial intelligence, which makes new demands on a human being.Scientific novelty: the article shows the role of the African continent in the origin and development of humanity and socio-legal institutions in the light of modern transformations and the construction of a new social reality.Practical significance: the conducted research creates prerequisites for further development of the theory of anthroposociogenesis and in-depth conceptual historical and legal study of the role of the African continent in the development of humanity and its social institutions
A well-conserved Plasmodium falciparum var gene shows an unusual stage-specific transcript pattern
No full textThe var multicopy gene family encodes Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) variant antigens, which, through their ability to adhere to a variety of host receptors, are thought to be important virulence factors. The predominant expression of a single cytoadherent PfEMP1 type on an infected red blood cell, and the switching between different PfEMP1 types to evade host protective antibody responses, are processes thought to be controlled at the transcriptional level. Contradictory data have been published on the timing of var gene transcription. Reverse transcription-polymerase chain reaction (RT-PCR) data suggested that transcription of the predominant var gene occurs in the later (pigmented trophozoite) stages, whereas Northern blot data indicated such transcripts only in early (ring) stages. We investigated this discrepancy by Northern blot, with probes covering a diverse var gene repertoire. We confirm that almost all var transcript types were detected only in ring stages. However, one type, the well-conserved varCSA transcript, was present constitutively in different laboratory parasites and does not appear to undergo antigenic variation. Although varCSA has been shown to encode a chondroitin sulphate A (CSA)-binding PfEMP1, we find that the presence of full-length varCSA transcripts does not correlate with the CSA-binding phenotype
Heme Adventures: Roles In Catalysis and Structural Insights
No full textThe full text of this item is not available at this time because the author has placed this item under an embargo until May 15, 2030.Heme enzymes represent a vast class of biological catalysts that enable diverse oxidative transformations essential to life. This dissertation explores the roles of heme in catalysis through detailed biochemical, structural, and mechanistic studies of four distinct enzymes. Beginning with a comprehensive analysis of charge maintenance in non-heme iron oxygenases, the work highlights how ligand scaffolds and substrate interactions govern reaction outcomes. This is followed by subsequent investigations into tyrosine hydroxylase which reveal a novel free radical pathway, providing new insight into substrate oxidation. Structural and functional characterization of Mycobacterium tuberculosis catalase-peroxidase (KatG) identifies a unique indole-N-linked hydroperoxyl adduct that modulates enzymatic activity. The study of RufO, a heme enzyme implicated in rufomycin biosynthesis, suggests that tyrosine is not the native substrate, supported by spectroscopic, crystallographic, docking analyses. Finally, structural and spectroscopic studies of the streptococcal heme-binding protein HupZ demonstrate an unusual mode of heme coordination influenced by C-terminal tagging. Together, these studies underscore the diverse catalytic strategies enabled by heme and iron cofactors and offer broader implications for the design of biomimetic catalysts and therapeutic targets.Chemistr
Toponymie et histoire dans l’Ouest du Burkina Faso
No full textDans l’Ouest du Burkina Faso, au moins une vingtaine d’ethnies s’interpénètrent à tel point que certaines localités présentent deux ou trois groupes de populations appartenant à des ethnies différentes. Aujourd’hui, avec l’arrivée de nouveaux immigrants, attirés par la culture du coton et un climat moins rude que chez eux, ce chevauchement atteint jusqu’à dix ethnies différentes dans les gros villages des zones cotonnières. Pourtant, cet arc-en-ciel ethnique contraste avec une certaine homogénéité « julaïsante » de la toponymie. L'auteur tente d'expliquer cette toponymie à la lumière de l’histoire et de montrer les enjeux qu’elle présente aujourd’hui..In Western Burkina-Faso, some twenty ethnic groups intertwine in such a way that in some villages two or three ethnic groups can be found together. Nowadays, with the arrival of new migrants in cotton growing areas, more than ten different ethnic groups can be found in big villages. However, in spite of this ethnic rainbow, toponomy demonstrates a strong jula influence. The author tries to explain this toponymy through historical factors
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