Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 18 de 18
Filtrar
1.
J Travel Med ; 2024 Mar 18.
Artigo em Inglês | MEDLINE | ID: mdl-38498330

RESUMO

BACKGROUND: The effect of clothing colour on the biting rates of different vector mosquito species is not well understood. Studies under tropical field conditions are lacking. This study aimed to determine the influence of clothing colours on mosquito biting rates in rural and suburban settings in West Africa. METHODS: We performed a simulated field study in a suburban and a rural site in Mali using Mosquito-Magnet traps utilizing CO2 and other attractants, which were covered with black, white, and black/white striped textile sheets covers. These targets operated continuously for 10 consecutive days with bright nights (around full moon) and 10 consecutive days with dark nights (around new moon). Trapped mosquitoes were collected and catch rates counted hourly. Mosquitoes were morphologically identified to the species complex level (Anopheles gambiae s.l. and Culex pipiens s.l.) or species level (Aedes aegypti). A subset of Anopheles specimens were further identified by molecular methods. RESULTS: Under bright-night conditions, An. gambiae s.l. was significantly more attracted to black targets than to white and striped targets; during dark nights, no target preference was noted. During bright nights, Cx. pipiens s.l. was significantly more attracted to black and striped targets than to white targets; a similar trend was noted during dark nights (not significant). For day-active Ae. aegypti, striped targets were more attractive than the other targets and black were more attractive than white targets. CONCLUSIONS: The study firstly demonstrated that under field conditions in Mali, West Africa, mosquito catch rates were influenced by different clothing colours, depending on mosquito species and light conditions. Overall, light colours were least attractive to host-seeking mosquitoes. Using white or other light-coloured clothing can potentially reduce bite exposure and risk of disease transmission in endemic tropical regions.

2.
Sensors (Basel) ; 23(15)2023 Jul 28.
Artigo em Inglês | MEDLINE | ID: mdl-37571534

RESUMO

With the ever-growing reliance on IoT-enabled sensors to age in place, a need arises to protect them from malicious actors and detect malfunctions. In an IoT smart home, it is reasonable to hypothesize that sensors near one another can exhibit linear or nonlinear correlations. If substantiated, this property can be beneficial for constructing relationship trends between the sensors and, consequently, detecting attacks or other anomalies by measuring the deviation of their readings against these trends. In this work, we confirm the presence of correlations between co-located sensors by statistically analyzing two public smart-home datasets and a dataset we collected from our experimental setup. Additionally, we leverage the sliding window approach and supervised machine learning to develop a contextual-anomaly-detection model. This model reaches a true positive rate of 89.47% and a false positive rate of 0%. Our work not only substantiates the correlations but also introduces a novel anomaly-detection technique to enhance security in IoT smart homes.

3.
Clin Infect Dis ; 77(4): 606-614, 2023 08 22.
Artigo em Inglês | MEDLINE | ID: mdl-37052469

RESUMO

BACKGROUND: Data on human immunodeficiency virus (HIV) seroconversion among men who have sex with men (MSM) using pre-exposure prophylaxis (PrEP) in West Africa are needed. This study aimed to document HIV seroconversion and associated determinants, PrEP adherence, plasma drug concentrations, and HIV drug resistance in MSM using event-driven or daily PrEP in Burkina Faso, Côte d'Ivoire, Mali, and Togo. METHODS: A prospective cohort study was conducted in 2017-2021 among HIV-seronegative MSM aged 18 or over who were at high risk of HIV infection. Participants could choose between event-driven and daily PrEP, switch regimens, and discontinue or restart PrEP. The determinants of HIV incidence were investigated using a multivariate mixed-effects Poisson regression analysis. RESULTS: A total of 647 participants were followed for a total time of 1229.3 person-years. Of 5371 visits, event-driven PrEP was chosen in 3873 (72.1%), and daily PrEP in 1400 (26.1%). HIV incidence was 2.4 per 100 person-years (95% confidence interval [CI] 1.5-3.6) for event-driven PrEP, and 0.6 per 100 person-years (95% CI .1-2.3) for daily PrEP (adjusted incidence rate ratio 4.40, 95% CI 1.00-19.36, P = .050). Adequate adherence was lower with event-driven than daily PrEP (44.3% vs 74.9%, P < .001). Plasma drug concentrations were undetectable in 92 (97.9%) of the 94 measures taken for 23 participants who seroconverted. Only 1 participant had resistance to PrEP drugs. CONCLUSIONS: HIV seroconversions mainly occurred in participants who chose event-driven PrEP. The study's data highlighted major difficulties with adherence to this regimen. Improving adherence to event-driven PrEP constitutes a major research and public health priority in this context.


Assuntos
Fármacos Anti-HIV , Infecções por HIV , Soropositividade para HIV , Profilaxia Pré-Exposição , Minorias Sexuais e de Gênero , Masculino , Humanos , Infecções por HIV/epidemiologia , Infecções por HIV/prevenção & controle , Infecções por HIV/tratamento farmacológico , Homossexualidade Masculina , Soropositividade para HIV/epidemiologia , Soropositividade para HIV/tratamento farmacológico , Estudos Prospectivos , Fármacos Anti-HIV/uso terapêutico , Soroconversão , Burkina Faso , HIV
4.
Sex Transm Infect ; 98(2): 85-94, 2022 03.
Artigo em Inglês | MEDLINE | ID: mdl-33753460

RESUMO

OBJECTIVE: Although men who have sex with men (MSM) are at high risk of STI, their access to tailored healthcare services remains limited in West Africa. We assessed the change in STI symptoms incidence over time among MSM enrolled in a quarterly HIV prevention and care programme in four cities in Burkina Faso, Côte d'Ivoire, Mali and Togo. METHODS: We performed a prospective cohort study in MSM followed up between 2015 and 2019. Men aged over 18 who reported anal sex with another man within the previous 3 months were offered quarterly syndromic diagnosis and treatment for STI, as well as HIV testing, peer-led counselling and support. Condoms and lubricants were also provided. The change in STI symptoms incidence during follow-up was investigated using a non-parametric trend test and mixed-effect Poisson regression models. RESULTS: 816 participants were followed for a total duration of 1479 person-years. 198 participants (24.3%) had at least one STI symptom during follow-up. Overall, STI symptoms incidence was 20.4 per 100 person-years (95% CI 18.4 to 22.6), ranging from 15.3 in Abidjan to 33.1 in Ouagadougou (adjusted incidence rate ratio (aIRR) 2.39, 95% CI 1.55 to 3.69, p<0.001). STI symptoms incidence was 16.8 and 23.0 per 100 person-years in HIV-positive and HIV-negative participants, respectively (aIRR 0.77, 95% CI 0.57 to 1.04, p=0.087). STI symptoms incidence decreased significantly from 29.9 per 100 person-years in the first 6 months to 8.6 at 30-35 months of follow-up (aIRR per 6-month increase 0.84, 95% CI 0.77 to 0.92, p<0.001). CONCLUSION: STI symptoms incidence decreased over time but the overall burden of STI appeared to be very high in MSM followed up in West Africa. STI services including counselling, diagnosis and treatment should be reinforced. Laboratory tests that allow accurate diagnosis of STI are required. Strengthening STI services will be critical for controlling the HIV and STI epidemics in this vulnerable population and in the general population. TRIAL REGISTRATION NUMBER: NCT02626286.


Assuntos
Infecções por HIV/epidemiologia , Infecções por HIV/prevenção & controle , Homossexualidade Masculina/estatística & dados numéricos , Serviços Preventivos de Saúde/estatística & dados numéricos , Infecções Sexualmente Transmissíveis/epidemiologia , Adulto , Burkina Faso/epidemiologia , Côte d'Ivoire/epidemiologia , Humanos , Incidência , Masculino , Mali/epidemiologia , Profilaxia Pré-Exposição , Estudos Prospectivos , Infecções Sexualmente Transmissíveis/tratamento farmacológico , Togo/epidemiologia
5.
AIDS ; 35(13): 2201-2210, 2021 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-34352834

RESUMO

OBJECTIVE: To assess the time from HIV diagnosis to ART initiation and the effect of rapid ART initiation (i.e. within 7 days of HIV diagnosis) on attrition and virologic and immunologic responses among MSM in Burkina Faso, Côte d'Ivoire, Mali, and Togo. DESIGN: Prospective cohort study between 2015 and 2019. METHODS: MSM aged 18 years or older newly diagnosed with HIV infection were eligible to participate. ART was proposed to participants upon HIV diagnosis, irrespective of clinical stage and CD4+ cell count, and was initiated as soon as possible, with no specific time frame. Determinants of rapid ART initiation and its effect on treatment outcomes were assessed using multivariate analyses. RESULTS: Of 350 MSM, 335 (95.7%) initiated ART after a median time of 5 days. Of the latter, 216 (64.5%) had rapid ART initiation. The 335 participants were followed up for a median time of 24.1 months. One hundred and eleven (33.1%) were not retained in care. Rapid ART initiation was less likely in participants with a CD4+ cell count at least 200 cells/µl [adjusted odds ratio (aOR) 0.37, 95% confidence interval (CI) 0.15-0.88]. It improved viral load suppression (aOR 6.96, 95% CI 1.98-24.46) but had no effect on attrition (aOR 0.87, 95% CI 0.57-1.33) or CD4+ cell count increase (adjusted coefficient 28.23, 95% CI -17.00 to 73.45). CONCLUSION: These results in MSM in West Africa support the WHO recommendation for rapid ART initiation. Clinics need to develop context-specific strategies for rapid ART initiation and for retaining MSM in HIV care.ClinicalTrials.gov, number NCT02626286.


Assuntos
Infecções por HIV , Minorias Sexuais e de Gênero , Burkina Faso/epidemiologia , Infecções por HIV/tratamento farmacológico , Homossexualidade Masculina , Humanos , Masculino , Estudos Prospectivos
6.
Lancet HIV ; 8(7): e420-e428, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-34048794

RESUMO

BACKGROUND: HIV pre-exposure prophylaxis (PrEP) data in men who have sex with men (MSM) in west Africa are essential to guide its large-scale implementation. We assessed the uptake of event-driven and daily PrEP, HIV incidence, and changes over time in sexual behaviours and prevalence of bacterial sexually transmitted infections (STIs) in MSM in Burkina Faso, Côte d'Ivoire, Mali, and Togo. METHODS: We did a prospective cohort study from Nov 20, 2017, to April 14, 2020, in four community-based clinics in Abidjan (Côte d'Ivoire), Bamako (Mali), Lomé (Togo), and Ouagadougou (Burkina Faso). Participants were MSM aged 18 years or older at substantial risk of HIV infection. Participants could choose between event-driven (2+1+1 dosing) and daily oral PrEP (tenofovir disoproxil fumarate 300 mg plus emtricitabine 200 mg), switch regimen, and discontinue or restart PrEP. We compared HIV incidence in this study with that of the same cohort before the availability of PrEP (CohMSM). Statistical analysis included the Kaplan-Meier method and mixed-effects regression models. This study is registered with ClinicalTrials.gov, NCT03459157. FINDINGS: We followed up 598 participants for a total of 743·6 person-years. At enrolment, 445 (74%) of 598 participants chose event-driven PrEP and 153 (26%) of 598 chose daily PrEP. 60 (13%) of 445 and 65 (42%) of 153 participants switched PrEP regimen at least once (p<0·0001). 159 participants (27%) were lost to follow-up. Overall HIV incidence was 2·3 per 100 person-years (95% CI 1·3-3·7; adjusted incidence rate ratio 0·21, 95% CI 0·12-0·36 compared with CohMSM). Adherence was optimal in 802 (41%) of 1946 measures with event-driven PrEP and in 394 (71%) of 554 measures with daily PrEP (p<0·0001). Coverage of sex acts with PrEP only and PrEP and condom decreased during follow-up (p=0·039 if PrEP only; p=0·0025 if PrEP and condom). The frequency of condomless anal sex remained stable (p=0·96). The number of male sexual partners (p<0·0001) and number of sex acts with casual male partners (p=0·0014 for 1-4 sex acts in previous 4 weeks; p=0·030 for ≥5 sex acts) decreased. The prevalence of gonorrhoea, chlamydia, and syphilis remained stable. INTERPRETATION: PrEP availability helped prevent HIV infection and did not lead to an increase in risky sexual behaviours or other STIs. PrEP should be urgently implemented in west Africa. Retention in care and PrEP adherence require special attention to ensure PrEP reaches its full prevention potential. FUNDING: ANRS and Expertise France. TRANSLATION: For the French translation of the abstract see Supplementary Materials section.


Assuntos
Fármacos Anti-HIV/uso terapêutico , Infecções por HIV/prevenção & controle , Homossexualidade Masculina/estatística & dados numéricos , Adulto , África Ocidental , Emtricitabina/uso terapêutico , Infecções por HIV/psicologia , Homossexualidade Masculina/psicologia , Humanos , Masculino , Projetos Piloto , Profilaxia Pré-Exposição , Estudos Prospectivos , Comportamento Sexual , Tenofovir/uso terapêutico , Adulto Jovem
7.
BMC Public Health ; 21(1): 972, 2021 05 22.
Artigo em Inglês | MEDLINE | ID: mdl-34022820

RESUMO

BACKGROUND: Access to tailored HIV prevention services remains limited for West African MSM. We assessed adherence to quarterly HIV prevention services and its impact on HIV incidence in MSM followed up in four cities in Burkina Faso, Côte d'Ivoire, Mali, and Togo. METHODS: We performed a prospective cohort study between 2015 and 2018. HIV-negative MSM aged over 18 benefited from quarterly medical visits which included a clinical examination, HIV testing, screening and treatment for other sexually transmitted infections, peer-led counselling and support, and the provision of condoms and lubricants. Determinants of adherence to quarterly follow-up visits and incident HIV infections were identified using generalized estimating equation models and Cox proportional hazard models, respectively. RESULTS: 618 MSM were followed up for a median time of 20.0 months (interquartile range 15.2-26.3). Overall adherence to quarterly follow-up visits was 76.5% (95% confidence interval [CI] 75.1-77.8), ranging from 66.8% in Abidjan to 87.3% in Lomé (p < 0.001). 78 incident HIV infections occurred during a total follow-up time of 780.8 person-years, giving an overall incidence of 10.0 per 100 person-years (95% CI 8.0-12.5). Adherence to quarterly follow-up visits was not associated with the risk of incident HIV infection (adjusted hazard ratio 0.80, 95% CI 0.44-1.44, p = 0.545). CONCLUSIONS: Strengthening HIV prevention services among MSM in West Africa, including the use of PrEP, will be critical for controlling the epidemic, not only in this key population but also in the general population. Quarterly follow-up of MSM, which is essential for PrEP delivery, appears feasible. TRIAL REGISTRATION: ClinicalTrials.gov, number NCT02626286 (December 10, 2015).


Assuntos
Infecções por HIV , Minorias Sexuais e de Gênero , Idoso , Burkina Faso/epidemiologia , Côte d'Ivoire , França , Infecções por HIV/epidemiologia , Infecções por HIV/prevenção & controle , Homossexualidade Masculina , Humanos , Incidência , Masculino , Mali , Estudos Prospectivos , Togo
8.
Clin Infect Dis ; 73(12): 2184-2192, 2021 12 16.
Artigo em Inglês | MEDLINE | ID: mdl-33606001

RESUMO

BACKGROUND: Men who have sex with men (MSM) are at high risk of human papillomavirus (HPV) infection. We assessed (i) the prevalence of high-risk HPV (HR-HPV) infection and associated factors, and (ii) the prevalence of vaccine-preventable HPV infections in MSM in Burkina Faso, Côte d'Ivoire, Mali, and Togo. METHODS: A cross-sectional study was conducted in 2017-2018 among MSM ≥18 years old followed in community-based clinics. HPV infection was investigated in oral and anal samples using the e-BRID system. Factors associated with HR-HPV infection were identified using multivariate logistic regressions. RESULTS: Among 631 participants, 425 were HIV-negative and 206 HIV-positive. HR-HPV prevalence ranged from 9.2% to 34.8% in the former, and 33.3% to 71.0% in the latter, according to the study country. In multivariate analysis, HIV infection (adjusted odds ratio (aOR) 3.61, 95% confidence interval (CI) 2.48-5.27) and study country (4.73, 2.66-8.43 for Mali; 3.12, 1.68-5.80 for Burkina Faso; 3.51, 1.92-6.42 for Togo) were associated with HR-HPV infection. Other associated factors were low educational level, self-defined homosexual identity, and condomless anal sex. The prevalence of infections which can be prevented with bivalent, quadrivalent, and nonavalent vaccines was 5.9, 27.1, and 34.6% in HIV-negative participants, and 18.9, 43.7, and 54.9% in HIV-positive participants, respectively. CONCLUSIONS: HR-HPV prevalence was very heterogeneous between the study countries in both HIV-negative and HIV-positive MSM. Vaccine-preventable HPV infections predominated. Vaccination should be proposed to young MSM to reduce the burden of HPV infection in this vulnerable population and their female partners in West Africa.


Assuntos
Infecções por HIV , Infecções por Papillomavirus , Minorias Sexuais e de Gênero , Adolescente , Canal Anal , Burkina Faso/epidemiologia , Estudos Transversais , Feminino , HIV , Infecções por HIV/complicações , Infecções por HIV/epidemiologia , Homossexualidade Masculina , Humanos , Masculino , Papillomaviridae/genética , Infecções por Papillomavirus/complicações , Infecções por Papillomavirus/epidemiologia , Infecções por Papillomavirus/prevenção & controle , Prevalência , Fatores de Risco
9.
Sante Publique ; Vol. 31(3): 451-458, 2019.
Artigo em Francês | MEDLINE | ID: mdl-31640333

RESUMO

INTRODUCTION: The study had for object to identify factors associated to the cessation of the exclusive breast-feeding at the mothers of children from 0 to 6 months in the urban and rural circles in Mali. METHOD: The study was longitudinal forward-looking, realized in Bamako (urban area) and in Dialakoroba (rural area) from April till November, 2016. in total, 218 mothers were enlisted (114 by area) in a voluntary way in health centers. A monthly follow-up of six months was realized in the place of residence. The SPSS 20 software was used for the seizure and the data analysis. The expected event was to give to the child another food than maternal milk. Test statistics such as Chi2 of Log Rank and Hazard Ratio (HR) were used with threshold of meaning p ≤ 0,05. RESULTS: In urban zones and rural respectively 68,5 % and 71,5% of the mothers had stopped the Exclusive Breast-feeding (EBF) before six months. Factors associated to this cessation of the EBF were: the use of the feeding-bottle (HR=2,61; IC 95%: [1,46-4,48]), the care of the child during less than three months as main occupation (HR=3,18; IC 95%: [1,95-5,20]), the support for the mother during less than three months (HR=3,79; IC 95%: [2,31-6,22]), the advice(council) on the EBF (HR=0,64; IC 95%: [0,46-0,98]) and the experience (experiment) of breastfeeding (HR=0,34; IC 95%: [0,15-0,84]). CONCLUSION: The consideration of the identified factors(mailmen) will allow to improve the practice of the EBF in six months in the sites of the study.


Assuntos
Aleitamento Materno/estatística & dados numéricos , Mães/psicologia , População Rural/estatística & dados numéricos , População Urbana/estatística & dados numéricos , Feminino , Seguimentos , Humanos , Lactente , Recém-Nascido , Mali , Mães/estatística & dados numéricos
10.
Open Forum Infect Dis ; 6(7): ofz249, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31281855

RESUMO

BACKGROUND: Although men who have sex with men (MSM) are at high risk of hepatitis B virus (HBV) infection, they do not have access to vaccination in West Africa, which is a highly endemic region. We investigated HBV prevalence and associated factors, as well as acceptability and difficulties of vaccination in MSM enrolled in an operational research program in Burkina Faso, Côte d'Ivoire, Mali, and Togo. METHODS: We followed up 779 MSM in 2015-2018. Participants who were negative for both hepatitis B surface antigen (HBsAg) and antibodies (anti-HBs) at enrollment were offered HBV vaccination. Factors associated with HBV infection were identified using logistic regression models. RESULTS: Overall, HBV prevalence was 11.2% (95% confidence interval [CI], 9.0%-13.6%). It was lower in Togo than in Côte d'Ivoire (2.7% vs 17.3%; adjusted odds ratio [aOR], 0.12; 95% CI, 0.02-0.28) and higher in participants with 6+ recent male sexual partners (21.0% vs 9.3%; aOR, 1.48; 95% CI, 1.12-1.97). Of 528 participants eligible for vaccination, 484 (91.7%) were willing to be vaccinated and received at least 1 dose (ranging from 68.2% in Abidjan to 96.4% in Bamako; P < .001). Of the latter, 390 (80.6%) received 3 or 4 doses. The proportion of participants for whom the minimum required time between each dose was respected ranged from 10.9% in Bamako to 88.6% in Lomé (P < .001). CONCLUSIONS: MSM in West Africa should be targeted more for HBV screening and vaccination. Although vaccination is well accepted by MSM, greater training of health care workers and education of MSM are required.

11.
Artigo em Francês | AIM (África) | ID: biblio-1271848

RESUMO

Les accidents du travail (AT) sont fréquents et s'accompagnent souvent de lourdes conséquences pour l'individu, la communauté et l'employeur, occasionnant dans certains cas des séquelles dont il faut déterminer le taux d'incapacité permanente partielle (IPP). L'étude était transversale et analytique. Elle s'est déroulée sur une période de cinq années allant de 2012 à 2016, et a concerné tous les dossiers complets d'accidents du travail avec Incapacité Permanente Partielle AT/IPP enregistrés à la Direction régionale de Ouagadougou de la Caisse Nationale de Sécurité Sociale. Les résultats descriptifs ont été présentés sous forme univariée et bivariée. L'échantillon était constitué de 221 cas d'AT/IPP extraits parmi les dossiers d'AT déclarés à Ouagadougou, soit un taux de 4,49 % (221/4922). L'échantillon était constitué de 54 femmes (24,4 3%) et 167 hommes (75,57 %). L'âge moyen était de 40,09 ± 8,8 ans (16 - 62 ans), avec une sinistralité plus fréquente dans le secteur des « services fournis à la collectivité, services sociaux et services personnels » (38,46 %). Plus de 2/3 des cas étaient des « employés » (67,42 %). Les accidents de trajet constituaient la majorité des sinistres (62 %). Ils survenaient en matinée entre 6 heures et 8 heures (45,25 %) et le véhicule de transport était le principal élément agent matériel causal (64,71 %). Les AT/IPP ont causé des fractures des membres (48,88 %) et entrainé 110 cas d'impotence fonctionnelle (49 %) et en moyenne 103 journées de travail perdues (3 - 848 jours). La prévention des AT/IPP devra intégrer des modules sur la sécurité routière


Assuntos
Acidentes de Trabalho/prevenção & controle , Acidentes de Trabalho/estatística & dados numéricos , Acidentes de Trânsito , Burkina Faso , Fratura-Luxação , Inabilitação Profissional , Previdência Social
12.
Artigo em Francês | AIM (África) | ID: biblio-1271849

RESUMO

Dans le monde du travail, l'alcoolisation de certains travailleurs est une préoccupation aussi bien de l'employeur que des autres salariés. En effet, l'alcool est un facteur démultiplicateur du risque professionnel. Cependant très peu de données sont disponibles dans les pays de la sous-région. L'objectif était d'étudier l'ampleur de la consommation d'alcool chez les travailleurs à Ouagadougou. Nous avons procédé à un échantillonnage stratifié simple. Le questionnaire AUDIT a été administré aux travailleurs ayant donné leur consentement. Les résultats ont été présentés sous formes univariées. L'échantillon était constitué de 350 travailleurs avec un taux de participation de 100 %. La prévalence de la consommation d'alcool était de 65,14 % avec une fréquence de consommation inférieure ou égale à 4 fois par mois chez 50 % des travailleurs. La quantité d'alcool consommée un jour typique de consommation était inférieure ou égale à 4 verres chez 57,02 %. Les travailleurs qui avaient une consommation à faible risque étaient les plus représentés avec 39,43 %. Le sexe masculin, la confession religieuse non musulmane et le niveau d'instruction supérieur étaient les facteurs associés à la consommation d'alcool chez les travailleurs. La consommation d'alcool chez les travailleurs dans la ville de Ouagadougou est importante. Cela interpelle les acteurs de la prévention quant à la nécessité d'en tenir compte dans la politique santé et sécurité au travail en entreprise


Assuntos
Consumo de Bebidas Alcoólicas/epidemiologia , Consumo de Bebidas Alcoólicas/prevenção & controle , Consumo de Bebidas Alcoólicas/tendências , Burkina Faso
13.
IEEE Trans Cybern ; 44(4): 458-72, 2014 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-23757560

RESUMO

Accurate recognition of free text keystroke dynamics is challenging due to the unstructured and sparse nature of the data and its underlying variability. As a result, most of the approaches published in the literature on free text recognition, except for one recent one, have reported extremely high error rates. In this paper, we present a new approach for the free text analysis of keystrokes that combines monograph and digraph analysis, and uses a neural network to predict missing digraphs based on the relation between the monitored keystrokes. Our proposed approach achieves an accuracy level comparable to the best results obtained through related techniques in the literature, while achieving a far lower processing time. Experimental evaluation involving 53 users in a heterogeneous environment yields a false acceptance ratio (FAR) of 0.0152% and a false rejection ratio (FRR) of 4.82%, at an equal error rate (EER) of 2.46%. Our follow-up experiment, in a homogeneous environment with 17 users, yields FAR=0% and FRR=5.01%, at EER=2.13%.

14.
IEEE Trans Syst Man Cybern B Cybern ; 42(5): 1343-56, 2012 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-22514203

RESUMO

Continuous authentication (CA) consists of authenticating the user repetitively throughout a session with the goal of detecting and protecting against session hijacking attacks. While the accuracy of the detector is central to the success of CA, the detection delay or length of an individual authentication period is important as well since it is a measure of the window of vulnerability of the system. However, high accuracy and small detection delay are conflicting requirements that need to be balanced for optimum detection. In this paper, we propose the use of sequential sampling technique to achieve optimum detection by trading off adequately between detection delay and accuracy in the CA process. We illustrate our approach through CA based on user command line sequence and naïve Bayes classification scheme. Experimental evaluation using the Greenberg data set yields encouraging results consisting of a false acceptance rate (FAR) of 11.78% and a false rejection rate (FRR) of 1.33%, with an average command sequence length (i.e., detection delay) of 37 commands. When using the Schonlau (SEA) data set, we obtain FAR = 4.28% and FRR = 12%.


Assuntos
Algoritmos , Inteligência Artificial , Redes de Comunicação de Computadores , Segurança Computacional , Reconhecimento Automatizado de Padrão/métodos , Tamanho da Amostra , Processamento de Sinais Assistido por Computador
15.
Am J Trop Med Hyg ; 86(2): 194-8, 2012 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-22302847

RESUMO

We identified 480 persons with positive thick smears for asexual Plasmodium falciparum parasites, of whom 454 had positive rapid diagnostic tests (RDTs) for the histidine-rich protein 2 (HRP2) product of the hrp2 gene and 26 had negative tests. Polymerase chain reaction (PCR) amplification for the histidine-rich repeat region of that gene was negative in one-half (10/22) of false-negative specimens available, consistent with spontaneous deletion. False-negative RDTs were found only in persons with asymptomatic infections, and multiplicities of infection (MOIs) were lower in persons with false-negative RDTs (both P < 0.001). These results show that parasites that fail to produce HRP2 can cause patent bloodstream infections and false-negative RDT results. The importance of these observations is likely to increase as malaria control improves, because lower MOIs are associated with false-negative RDTs and false-negative RDTs are more frequent in persons with asymptomatic infections. These findings suggest that the use of HRP2-based RDTs should be reconsidered.


Assuntos
Antígenos de Protozoários/genética , Testes Diagnósticos de Rotina/métodos , Deleção de Genes , Malária Falciparum/diagnóstico , Proteínas de Protozoários/genética , Adolescente , África , Antígenos de Protozoários/metabolismo , Criança , Pré-Escolar , Reações Falso-Negativas , Frequência do Gene , Humanos , Lactente , Malária Falciparum/parasitologia , Plasmodium falciparum/genética , Plasmodium falciparum/isolamento & purificação , Proteínas de Protozoários/metabolismo , Sensibilidade e Especificidade , Análise de Sequência de DNA
16.
BMC Int Health Hum Rights ; 9 Suppl 1: S13, 2009 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-19828057

RESUMO

BACKGROUND: In 1986, the Government of Mali launched its Expanded Program on Immunization (EPI) with the goal of vaccinating, within five years, 80% of all children under the age of five against six target diseases: diphtheria, tetanus, pertussis, poliomyelitis, tuberculosis, and measles. The Demographic and Health Survey carried out in 2001 revealed that, in Kita Circle, in the Kayes region, only 13% of children aged 12 to 23 months had received all the EPI vaccinations. A priority program was implemented in 2003 by the Regional Health Department in Kayes to improve EPI immunization coverage in this area. METHODS: A cross-sectional survey using Henderson's method (following the method used by the Demographic and Health Surveys) was carried out in July 2006 to determine the level of vaccination coverage among children aged 12 to 23 months in Kita Circle, after implementation of the priority program. Both vaccination cards and mothers' declarations (in cases where the mother cannot make the declaration, it is made by the person responsible for the child) were used to determine coverage. RESULTS: According to the vaccination cards, 59.9% [CI 95% (54.7-64.8)] of the children were fully vaccinated, while according to the mothers' declarations the rate was 74.1% [CI 95% (69.3-78.4)]. The drop-out rate between DTCP1 and DTCP3 was 5.5%, according to the vaccination cards. The rate of immunization coverage was higher among children whose mothers had received the anti-tetanus vaccine [OR = 2.1, CI 95% (1.44-3.28)]. However, our study found no difference associated with parents' knowledge about EPI diseases, distance from the health centre, or socio-economic status. Lack of information was one reason given for children not being vaccinated against the six EPI diseases. CONCLUSION: Three years after the implementation of the priority program (which included decentralization, the active search for missing children, and deployment of health personnel, material and financial resources), our evaluation of the vaccination coverage rates shows that there is improvement in the EPI immunization coverage rate in Kita Circle. The design of our study did not, however, enable us to determine the extent to which different aspects of the program contributed to this increase in coverage. Efforts should nevertheless be continued, in order to reach the goal of 80% immunization coverage. ABSTRACT IN FRENCH: See the full article online for a translation of this abstract in French.

17.
Gastroenterol Clin Biol ; 29(6-7): 652-5, 2005.
Artigo em Inglês | MEDLINE | ID: mdl-16141997

RESUMO

AIM: To study schistomasiasis infection in school children in Molodo, an irrigated rice growing region of Mali, by determining the prevalence of schistomasiasis and lesions identified by ultrasonography among children living in this region. METHODS: This cross sectional study included 346 children aged 7 to 14 years selected at random from five schools in Molodo. We tested for hematuria using urine dipsticks and searched for Schistosoma haematobium eggs in urine and S. mansoni eggs in stools. Ultrasonography of the liver, spleen and urinary tract was performed. RESULTS: The prevalences of Schistosoma haematobium and S. mansoni infection were 72% (range: 66.9-76.6%) and 68.2% (range: 60.9-71.2%) respectively; 55.1% of the children had co-infection. Ultrasonography of the urinary tract revealed an irregular bladder wall as the most frequent abnormality (3.4% of children). Abdominal ultrasonography demonstrated type B hepatic fibrosis in four children (1.1%), type C in one (0.3%) and type D in one (0.3%). CONCLUSION: Few schistosomiasis lesions were detected by ultrasonography compared with the prevalence of S. haematobium and S. mansoni infections. This observation is probably related to mass treatment programs conducted during a national anti-schistosomiasis program.


Assuntos
Schistosoma haematobium/patogenicidade , Schistosoma mansoni/patogenicidade , Esquistossomose Urinária/diagnóstico por imagem , Esquistossomose Urinária/epidemiologia , Esquistossomose Japônica/diagnóstico por imagem , Esquistossomose Japônica/epidemiologia , Sistema Urinário/diagnóstico por imagem , Adolescente , Animais , Criança , Estudos Transversais , Fezes/parasitologia , Feminino , Hematúria/etiologia , Humanos , Masculino , Prevalência , Schistosoma haematobium/isolamento & purificação , Schistosoma mansoni/isolamento & purificação , Ultrassonografia , Sistema Urinário/parasitologia
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...