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Find video protocols related to scientific articles indexed in Pubmed.
In vivo selection of Plasmodium falciparum Pfcrt and Pfmdr1 variants by Artemether-Lumefantrine and Dihydroartemisinin Piperaquine in Burkina Faso.
Antimicrob. Agents Chemother.
PUBLISHED: 11-19-2014
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Plasmodium falciparum Pfcrt-76 and Pfmdr1-86 gene polymorphisms were determined during a clinical trial in Burkina Faso comparing the efficacy of dihydroartemisinin-piperaquine (DHA-PPQ) and artemether-lumefantrine (AL). A significant selection of Pfcrt-K76 was observed after exposure to AL and DHA-PPQ, as well as of Pfmdr1-N86 after AL but not after DHA-PPQ treatment, suggesting a reverse selection on the Pfcrt gene by PPQ. These results support the rational use of DHA-PPQ in settings where CQ resistance is high.
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Participation in medical research as a resource-seeking strategy in socio-economically vulnerable communities: call for research and action.
Trop. Med. Int. Health
PUBLISHED: 10-11-2014
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The freedom to consent to participate in medical research is a complex subject, particularly in socio-economically vulnerable communities, where numerous factors may limit the efficacy of the informed consent process. Informal consultation among members of the Switching the Poles Clinical Research Network coming from various sub-Saharan African countries, that is Burkina Faso, The Gambia, Rwanda, Ethiopia, the Democratic Republic of Congo (DRC) and Benin, seems to support the hypothesis that in socio-economical vulnerable communities with inadequate access to health care, the decision to participate in research is often taken irrespectively of the contents of the informed consent interview, and it is largely driven by the opportunity to access free or better quality care and other indirect benefits. Populations' vulnerability due to poverty and/or social exclusion should obviously not lead to exclusion from medical research, which is most often crucially needed to address their health problems. Nonetheless, to reduce the possibility of exploitation, there is the need to further investigate the complex links between socio-economical vulnerability, access to health care and individual freedom to decide on participation in medical research. This needs bringing together clinical researchers, social scientists and bioethicists in transdisciplinary collaborative research efforts that require the collective input from researchers, research sponsors and funders.
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Molecular-based isothermal tests for field diagnosis of malaria and their potential contribution to malaria elimination.
J. Antimicrob. Chemother.
PUBLISHED: 09-17-2014
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In countries where malaria transmission has decreased substantially, thanks to the scale-up of control interventions, malaria elimination may be feasible. Nevertheless, this goal requires new strategies such as the active detection and treatment of infected individuals. As the detection threshold for the currently used diagnostic methods is 100 parasites/?L, most low-density, asymptomatic infections able to maintain transmission cannot be detected. Identifying them by molecular methods such as PCR is a possible option but the field deployment of these tests is problematic. Isothermal amplification of nucleic acids (at a constant temperature) offers the opportunity of addressing some of the challenges related to the field deployment of molecular diagnostic methods. One of the novel isothermal amplification methods for which a substantial amount of work has been done is the loop-mediated isothermal amplification (LAMP) assay. The present review describes LAMP and several other isothermal nucleic acid amplification methods, such as thermophilic helicase-dependent amplification, strand displacement amplification, recombinase polymerase amplification and nucleic acid sequence-based amplification, and explores their potential use as high-throughput, field-based molecular tests for malaria diagnosis.
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Delayed Parasite Clearance after Treatment with Dihydroartemisinin-Piperaquine in Plasmodium falciparum Malaria Patients in Central Vietnam.
Antimicrob. Agents Chemother.
PUBLISHED: 09-15-2014
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Reduced susceptibility of Plasmodium falciparum toward artemisinin derivatives has been reported from the Thai-Cambodian and Thai-Myanmar borders. Following increasing reports from central Vietnam of delayed parasite clearance after treatment with dihydroartemisinin-piperaquine (DHA-PPQ), the current first-line treatment, we carried out a study on the efficacy of this treatment. Between September 2012 and February 2013, we conducted a 42-day in vivo and in vitro efficacy study in Quang Nam Province. Treatment was directly observed, and blood samples were collected twice daily until parasite clearance. In addition, genotyping, quantitative PCR (qPCR), and in vitro sensitivity testing of isolates was performed. The primary endpoints were parasite clearance rate and time. The secondary endpoints included PCR-corrected and uncorrected cure rates, qPCR clearance profiles, in vitro sensitivity results (for chloroquine, dihydroartemisinin, and piperaquine), and genotyping for mutations in the Kelch 13 propeller domain. Out of 672 screened patients, 95 were recruited and 89 available for primary endpoint analyses. The median parasite clearance time (PCT) was 61.7 h (interquartile range [IQR], 47.6 to 83.2 h), and the median parasite clearance rate had a slope half-life of 6.2 h (IQR, 4.4 to 7.5 h). The PCR-corrected efficacy rates were estimated at 100% at day 28 and 97.7% (95% confidence interval, 91.2% to 99.4%) at day 42. At day 3, the P. falciparum prevalence by qPCR was 2.5 times higher than that by microscopy. The 50% inhibitory concentrations (IC50s) of isolates with delayed clearance times (?72 h) were significantly higher than those with normal clearance times for all three drugs. Delayed parasite clearance (PCT, ?72 h) was significantly higher among day 0 samples carrying the 543 mutant allele (47.8%) than those carrying the wild-type allele (1.8%; P = 0.048). In central Vietnam, the efficacy of DHA-PPQ is still satisfactory, but the parasite clearance time and rate are indicative of emerging artemisinin resistance. (This study has been registered at ClinicalTrials.gov under registration no. NCT01775592.).
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Community-based scheduled screening and treatment of malaria in pregnancy for improved maternal and infant health in The Gambia, Burkina Faso and Benin: study protocol for a randomized controlled trial.
Trials
PUBLISHED: 08-28-2014
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In sub-Saharan Africa, malaria continues to cause over 10,000 maternal deaths and 75,000 to 200,000 infant deaths. Successful control of malaria in pregnancy could save lives of mothers and babies and is an essential part of antenatal care in endemic areas. The primary objective is to determine the protective efficacy of community-scheduled screening and treatment (CSST) using community health workers (CHW) against the primary outcome of prevalence of placental malaria. The secondary objectives are to determine the protective efficacy of CSST on maternal anaemia, maternal peripheral infection, low birth weight, selection of sulfadoxine-pyrimethamine (SP) resistance markers, and on antenatal clinic (ANC) attendance and coverage of intermittent preventive treatment during pregnancy (IPTp-SP).
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Multimedia Informed Consent Tool for a Low Literacy African Research Population: Development and Pilot-Testing.
J Clin Res Bioeth
PUBLISHED: 08-19-2014
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International guidelines recommend the use of appropriate informed consent procedures in low literacy research settings because written information is not known to guarantee comprehension of study information.
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Severe malaria not responsive to artemisinin derivatives in man returning from Angola to Vietnam.
Emerging Infect. Dis.
PUBLISHED: 06-26-2014
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Resistance to artemisinin derivatives, the most potent antimalarial drugs currently used, has emerged in Southeast Asia and threatens to spread to Africa. We report a case of malaria in a man who returned to Vietnam after 3 years in Angola that did not respond to intravenous artesunate and clindamycin or an oral artemisinin-based combination.
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Digitised audio questionnaire for assessment of informed consent comprehension in a low-literacy African research population: development and psychometric evaluation.
BMJ Open
PUBLISHED: 06-26-2014
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To develop and psychometrically evaluate an audio digitised tool for assessment of comprehension of informed consent among low-literacy Gambian research participants.
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Pharmacokinetics of co-formulated mefloquine and artesunate in pregnant and non-pregnant women with uncomplicated Plasmodium falciparum infection in Burkina Faso.
J. Antimicrob. Chemother.
PUBLISHED: 06-02-2014
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Mefloquine/artesunate has recently been developed as a fixed-dose combination, providing a promising rescue/alternative treatment for malaria during pregnancy. However, limited data are available on the effect of pregnancy on its pharmacokinetic properties. This study was conducted to assess the pharmacokinetic properties of mefloquine/carboxymefloquine and artesunate/dihydroartemisinin in pregnant and non-pregnant women with uncomplicated malaria.
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A modified surgical technique for root coverage with an allograft: a 12-month randomized clinical trial.
J. Periodontol.
PUBLISHED: 05-30-2014
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The aim of this randomized controlled clinical study is to investigate whether a modified surgical technique could provide better results for root coverage and greater amounts of keratinized tissue (KT) with the acellular dermal matrix graft (ADMG).
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Patterns of selection on Plasmodium falciparum erythrocyte-binding antigens after the colonization of the New World.
Mol. Ecol.
PUBLISHED: 05-17-2014
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Pathogens, which have recently colonized a new host species or new populations of the same host, are interesting models for understanding how populations may evolve in response to novel environments. During its colonization of South America from Africa, Plasmodium falciparum, the main agent of malaria, has been exposed to new conditions in distinctive new human populations (Amerindian and populations of mixed origins) that likely exerted new selective pressures on the parasite's genome. Among the genes that might have experienced strong selective pressures in response to these environmental changes, the eba genes (erythrocyte-binding antigens genes), which are involved in the invasion of the human red blood cells, constitute good candidates. In this study, we analysed, in South America, the polymorphism of three eba genes (eba-140, eba-175, eba-181) and compared it to the polymorphism observed in African populations. The aim was to determine whether these genes faced selective pressures in South America distinct from what they experienced in Africa. Patterns of genetic variability of these genes were compared to the patterns observed at two housekeeping genes (adsl and serca) and 272 SNPs to separate adaptive effects from demographic effects. We show that, conversely to Africa, eba-140 seemed to be under stronger diversifying selection in South America than eba-175. In contrast, eba-181 did not show any sign of departure from neutrality. These changes in the patterns of selection on the eba genes could be the consequence of changes in the host immune response, the host receptor polymorphisms and/or the ability of the parasite to silence or express differentially its invasion proteins.
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Doctors and vampires in sub-Saharan Africa: ethical challenges in clinical trial research.
Am. J. Trop. Med. Hyg.
PUBLISHED: 05-12-2014
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Collecting blood samples from individuals recruited into clinical research projects in sub-Saharan Africa can be challenging. Strikingly, one of the reasons for participant reticence is the occurrence of local rumors surrounding "blood stealing" or "blood selling." Such fears can potentially have dire effects on the success of research projects--for example, high dropout rates that would invalidate the trial's results--and have ethical implications related to cultural sensitivity and informed consent. Though commonly considered as a manifestation of the local population's ignorance, these rumors represent a social diagnosis and a logical attempt to make sense of sickness and health. Born from historical antecedents, they reflect implicit contemporary structural inequalities and the social distance between communities and public health institutions. We aim at illustrating the underlying logic governing patients' fear and argue that the management of these beliefs should become an intrinsic component of clinical research.
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The prevalence of glucose-6-phosphate dehydrogenase deficiency in Gambian school children.
Malar. J.
PUBLISHED: 04-13-2014
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Primaquine, the only available drug effective against Plasmodium falciparum sexual stages, induces also a dose-dependent haemolysis, especially in glucose-6-phosphate dehydrogenase deficient (G6PDd) individuals. Therefore, it is important to determine the prevalence of this deficiency in areas that would potentially benefit from its use. The prevalence of G6PD deficiency by genotype and enzyme activity was determined in healthy school children in The Gambia.
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Ex vivo anti-malarial drugs sensitivity profile of Plasmodium falciparum field isolates from Burkina Faso five years after the national policy change.
Malar. J.
PUBLISHED: 04-02-2014
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The recent reports on the decreasing susceptibility of Plasmodium falciparum to artemisinin derivatives along the Thailand and Myanmar border are worrying. Indeed it may spread to India and then Africa, repeating the same pattern observed for chloroquine resistance. Therefore, it is essential to start monitoring P. falciparum sensitivity to artemisinin derivatives and its partner drugs in Africa. Efficacy of AL and ASAQ were tested by carrying out an in vivo drug efficacy test, with an ex vivo study against six anti-malarial drugs nested into it. Results of the latter are reported here.
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Defining the malaria burden in Nchelenge District, northern Zambia using the World Health Organization malaria indicators survey.
Malar. J.
PUBLISHED: 02-17-2014
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Malaria is considered as one of the major public health problems and among the diseases of poverty. In areas of stable and relatively high transmission, pregnant women and their newborn babies are among the higher risk groups. A multicentre trial on the safety and efficacy of several formulations of artemisinin-based combination therapy (ACT) during pregnancy is currently on-going in four African countries, including Zambia, whose study site is in Nchelenge district. As the study outcomes may be influenced by the local malaria endemicity, this needs to be characterized. A cross-sectional survey to determine the prevalence and intensity of infection among <10 years old was carried out in March-April 2012 in Nchelenge district.
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Effectiveness of artesunate-amodiaquine vs. artemether-lumefantrine for the treatment of uncomplicated falciparum malaria in Nanoro, Burkina Faso: a non-inferiority randomised trial.
Trop. Med. Int. Health
PUBLISHED: 02-05-2014
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Artemisinin-based combination therapies (ACTs) are essential for the effective control of falciparum malaria in endemic countries. However, in most countries, such choice has been carried out without knowing their effectiveness when deployed in real-life conditions, that is, when treatment is not directly observed. We report here the results of a study assessing the effectiveness of the two ACTs currently recommended in Burkina Faso for the treatment of uncomplicated malaria, that is, artemether-lumefantrine (AL) and artesunate-amodiaquine (ASAQ).
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A qualitative study to assess community barriers to malaria mass drug administration trials in The Gambia.
Malar. J.
PUBLISHED: 02-02-2014
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Mass drug administration (MDA) is a strategy widely used in the control of human parasitic diseases but has been rarely attempted with malaria, the most common and dangerous parasitic disease in humans. MDA is an intervention strategy that involves simultaneously dispensing treatment to an entire population in a given geographic area. With some areas in sub-Saharan Africa documenting a decline in malaria transmission, the feasibility of MDA to further reduce malaria transmission is being considered. Understanding community perceptions of such an activity is vitally important for the design of the study and gaining the support of participants in order to maximize compliance and adherence.
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Plasmodium falciparum clearance in clinical studies of artesunate-amodiaquine and comparator treatments in sub-Saharan Africa, 1999-2009.
Malar. J.
PUBLISHED: 01-17-2014
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Artemisinin-based combination therapy (ACT) is the recommended first-line therapy for uncomplicated Plasmodium falciparum malaria worldwide but decreased artemisinin susceptibility, phenotypically characterized as slow parasite clearance time (PCT), has now been reported in Southeast Asia. This makes it all too important to measure the dynamics of parasite clearance in African patients treated with ACT over time, to understand trends and detect changes early enough to intervene
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Population structure and spatio-temporal transmission dynamics of Plasmodium vivax after radical cure treatment in a rural village of the Peruvian Amazon.
Malar. J.
PUBLISHED: 01-06-2014
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Despite the large burden of Plasmodium vivax, little is known about its transmission dynamics. This study explored the population structure and spatio-temporal dynamics of P. vivax recurrent infections after radical cure in a two-year cohort study carried out in a rural community of the Peruvian Amazon.
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Hematopoietic Stem/Progenitor Cell Sources to Generate Reticulocytes for Plasmodium vivax Culture.
PLoS ONE
PUBLISHED: 01-01-2014
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The predilection of Plasmodium vivax (P. vivax) for reticulocytes is a major obstacle for its establishment in a long-term culture system, as this requires a continuous supply of large quantities of reticulocytes, representing only 1-2% of circulating red blood cells. We here compared the production of reticulocytes using an established in vitro culture system from three different sources of hematopoietic stem/progenitor cells (HSPC), i.e. umbilical cord blood (UCB), bone marrow (BM) and adult peripheral blood (PB). Compared to CD34+-enriched populations of PB and BM, CD34+-enriched populations of UCB produced the highest amount of reticulocytes that could be invaded by P. vivax. In addition, when CD34+-enriched cells were first expanded, a further extensive increase in reticulocytes was seen for UCB, to a lesser degree BM but not PB. As invasion by P. vivax was significantly better in reticulocytes generated in vitro, we also suggest that P. vivax may have a preference for invading immature reticulocytes, which should be confirmed in future studies.
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Disease-specific mortality burdens in a rural Gambian population using verbal autopsy, 1998-2007.
Glob Health Action
PUBLISHED: 01-01-2014
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To estimate and evaluate the cause-of-death structure and disease-specific mortality rates in a rural area of The Gambia as determined using the InterVA-4 model.
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School-based countrywide seroprevalence survey reveals spatial heterogeneity in malaria transmission in the gambia.
PLoS ONE
PUBLISHED: 01-01-2014
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As the geographical distribution of malaria transmission becomes progressively clustered, identifying residual pockets of transmission is important for research and for targeting interventions. Malarial antibody-based surveillance is increasingly recognised as a valuable complement to classic methods for the detection of infection foci especially at low transmission levels. The study presents serological evidence for transmission heterogeneity among school children in The Gambia measured during the dry, non-transmission season.
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Safety of daily co-trimoxazole in pregnancy in an area of changing malaria epidemiology: a phase 3b randomized controlled clinical trial.
PLoS ONE
PUBLISHED: 01-01-2014
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Antibiotic therapy during pregnancy may be beneficial and impacts positively on the reduction of adverse pregnancy outcomes. No studies have been done so far on the effects of daily Co-trimoxazole (CTX) prophylaxis on birth outcomes. A phase 3b randomized trial was conducted to establish that daily CTX in pregnancy is not inferior to SP intermittent preventive treatment (IPT) in reducing placental malaria; preventing peripheral parasitaemia; preventing perinatal mortality and also improving birth weight. To establish its safety on the offspring by measuring the gestational age and birth weight at delivery, and compare the safety and efficacy profile of CTX to that of SP.
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Paediatric pharmacovigilance: use of pharmacovigilance data mining algorithms for signal detection in a safety dataset of a paediatric clinical study conducted in seven African countries.
PLoS ONE
PUBLISHED: 01-01-2014
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Pharmacovigilance programmes monitor and help ensuring the safe use of medicines which is critical to the success of public health programmes. The commonest method used for discovering previously unknown safety risks is spontaneous notifications. In this study we examine the use of data mining algorithms to identify signals from adverse events reported in a phase IIIb/IV clinical trial evaluating the efficacy and safety of several Artemisinin-based combination therapies (ACTs) for treatment of uncomplicated malaria in African children.
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A modified semi-nested multiplex malaria PCR (SnM-PCR) for the identification of the five human Plasmodium species occurring in Southeast Asia.
Am. J. Trop. Med. Hyg.
PUBLISHED: 08-26-2013
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We have modified an existing semi-nested multiplex polymerase chain reaction (PCR) by adding one Plasmodium knowlesi-specific nested PCR, and validated the latter against laboratory and clinical samples. This new method has the advantage of being relatively affordable in low resource settings while identifying the five human Plasmodium species with a three-step PCR.
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Serogroup W135 meningococcal disease, The Gambia, 2012.
Emerging Infect. Dis.
PUBLISHED: 08-23-2013
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In 2012, an outbreak of Neisseria meningitidis serogroup W135 occurred in The Gambia. The attack rate was highest among young children. The associated risk factors were male sex, contact with meningitis patients, and difficult breathing. Enhanced surveillance facilitates early epidemic detection, and multiserogroup conjugate vaccine could reduce meningococcal epidemics in The Gambia.
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Clinical signs and symptoms cannot reliably predict Plasmodium falciparum malaria infection in pregnant women living in an area of high seasonal transmission.
Malar. J.
PUBLISHED: 08-20-2013
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Malaria in pregnancy is a major public health problem in endemic countries. Though the signs and symptoms of malaria among pregnant women have been already described, clinical presentation may vary according to intensity of transmission and local perceptions. Therefore, determining common signs and symptoms among pregnant women with a malaria infection may be extremely useful to identify those in need of further investigation by rapid diagnostic test or microscopy.
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Assessing malaria transmission in a low endemicity area of north-western Peru.
Malar. J.
PUBLISHED: 05-10-2013
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Where malaria endemicity is low, control programmes need increasingly sensitive tools for monitoring malaria transmission intensity (MTI) and to better define health priorities. A cross-sectional survey was conducted in a low endemicity area of the Peruvian north-western coast to assess the MTI using both molecular and serological tools.
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Slow axial drift in three-dimensional granular tumbler flow.
Phys Rev E Stat Nonlin Soft Matter Phys
PUBLISHED: 05-07-2013
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Models of monodisperse particle flow in partially filled three-dimensional tumblers often assume that flow along the axis of rotation is negligible. We test this assumption, for spherical and double cone tumblers, using experiments and discrete element method simulations. Cross sections through the particle bed of a spherical tumbler show that, after a few rotations, a colored band of particles initially perpendicular to the axis of rotation deforms: particles near the surface drift toward the pole, while particles deeper in the flowing layer drift toward the equator. Tracking of mm-sized surface particles in tumblers with diameters of 8-14 cm shows particle axial displacements of one to two particle diameters, corresponding to axial drift that is 1-3% of the tumbler diameter, per pass through the flowing layer. The surface axial drift in both double cone and spherical tumblers is zero at the equator, increases moving away from the equator, and then decreases near the poles. Comparing results for the two tumbler geometries shows that wall slope causes axial drift, while drift speed increases with equatorial diameter. The dependence of axial drift on axial position for each tumbler geometry is similar when both are normalized by their respective maximum values.
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Impact of retreatment with an artemisinin-based combination on malaria incidence and its potential selection of resistant strains: study protocol for a randomized controlled clinical trial.
Trials
PUBLISHED: 04-20-2013
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Artemisinin-based combination therapy is currently recommended by the World Health Organization as first-line treatment of uncomplicated malaria. Recommendations were adapted in 2010 regarding rescue treatment in case of treatment failure. Instead of quinine monotherapy, it should be combined with an antibiotic with antimalarial properties; alternatively, another artemisinin-based combination therapy may be used. However, for informing these policy changes, no clear evidence is yet available. The need to provide the policy makers with hard data on the appropriate rescue therapy is obvious. We hypothesize that the efficacy of the same artemisinin-based combination therapy used as rescue treatment is as efficacious as quinine + clindamycin or an alternative artemisinin-based combination therapy, without the risk of selecting drug resistant strains.
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Good clinical practice in resource-limited settings: translating theory into practice.
Am. J. Trop. Med. Hyg.
PUBLISHED: 04-05-2013
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A Good Clinical Practices (GCPs) course, based on the combination of theoretical modules with a practical training in real-life conditions, was held in 2010 in Burkina Faso. It was attended by 15 trainees from nine African, Asian, and Latin American countries. There were some discrepancies between the average good results at the end of the theoretical phase and the GCP application during the first days of the practical phase, underlying the difficulties of translating theoretical knowledge into good practices. Most of the findings were not unexpected and reflected the challenges commonly faced by clinical investigators in resource-poor contexts (i.e., the high workload at peripheral health facilities, the need to conciliate routine clinical activities with clinical research, and the risk of creating a double standard among patients attending the same health facility [free care for recruited patients versus user fees for non-recruited patients with the same medical condition]). Even if limited in number and time, these observations suggest that a theoretical training alone may not be sufficient to prepare trainees for the challenges of medical research in real-life settings. Conversely, when a practical phase immediately follows a theoretical one, trainees can immediately experience what the research methodology implicates in terms of work organization and relationship with recruited and non-recruited patients. This initial experience shows the complexity of translating GCP into practice and suggests the need to rethink the current conception of GCP training.
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Prenatal lipid-based nutrient supplements increase cord leptin concentration in pregnant women from rural Burkina Faso.
J. Nutr.
PUBLISHED: 03-27-2013
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In developing countries, prenatal lipid-based nutrient supplements (LNSs) were shown to increase birth size; however, the mechanism of this effect remains unknown. Cord blood hormone concentrations are strongly associated with birth size. Therefore, we hypothesize that LNSs increase birth size through a change in the endocrine regulation of fetal development. We compared the effect of daily prenatal LNSs with multiple micronutrient tablets on cord blood hormone concentrations using a randomized, controlled design including 197 pregnant women from rural Burkina Faso. Insulin-like growth factors (IGF) I and II, their binding proteins IGFBP-1 and IGFBP-3, leptin, cortisol, and insulin were quantified in cord sera using immunoassays. LNS was associated with higher cord blood leptin mainly in primigravidae (+57%; P = 0.02) and women from the highest tertile of BMI at study inclusion (+41%; P = 0.02). We did not find any significant LNS effects on other measured cord hormones. The observed increase in cord leptin was associated with a significantly higher birth weight. Cord sera from small-for-gestational age newborns had lower median IGF-I (-9 ?g/L; P = 0.003), IGF-II (-79 ?g/L; P = 0.003), IGFBP-3 (-0.7 ?g/L; P = 0.007), and leptin (-1.0 ?g/L; P = 0.016) concentrations but higher median cortisol (+18 ?g/L; P = 0.037) concentrations compared with normally grown newborns. Prenatal LNS resulted in increased cord leptin concentrations in primigravidae and mothers with higher BMI at study inclusion. The elevated leptin concentrations could point toward a higher neonatal fat mass.
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1912-2012: a century of research on Plasmodium vivax in vitro culture.
Trends Parasitol.
PUBLISHED: 03-22-2013
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The development of a continuous Plasmodium vivax blood cycle in vitro was first attempted 100 years ago. Since then, and despite the use of different methods, only short-term cultures have been achieved so far. The available literature has been reviewed in order to provide a critical overview of the currently available knowledge on P. vivax blood cycle culture systems and identify some unexplored ways forward. Results show that data accumulated over the past century remain fragmented and often contradictory, making it difficult to draw conclusions. There is the need for an international consortium on P. vivax culture able to collect, update, and share new evidence, including negative results, and thus better coordinate current efforts towards the establishment of a continuous P. vivax culture.
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Artemisinin resistance in rodent malaria--mutation in the AP2 adaptor ?-chain suggests involvement of endocytosis and membrane protein trafficking.
Malar. J.
PUBLISHED: 02-26-2013
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The control of malaria, caused by Plasmodium falciparum, is hampered by the relentless evolution of drug resistance. Because artemisinin derivatives are now used in the most effective anti-malarial therapy, resistance to artemisinin would be catastrophic. Indeed, studies suggest that artemisinin resistance has already appeared in natural infections. Understanding the mechanisms of resistance would help to prolong the effective lifetime of these drugs. Genetic markers of resistance are therefore required urgently. Previously, a mutation in a de-ubiquitinating enzyme was shown to confer artemisinin resistance in the rodent malaria parasite Plasmodium chabaudi.
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Cost-effectiveness of long-lasting insecticide-treated hammocks in preventing malaria in South-central Vietnam.
PLoS ONE
PUBLISHED: 01-31-2013
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Despite much success in reducing the burden of malaria in Vietnam, pockets of malaria persist and eliminating them remains an important development goal. In central Vietnam, insecticide-treated hammocks have recently been introduced to help counter the disease in the highly forested, mountainous areas, where other measures have so far been unsuccessful. This study assesses the cost-effectiveness of using long-lasting insecticide-treated hammocks in this area.
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Efficacy of quinine, artemether-lumefantrine and dihydroartemisinin-piperaquine as rescue treatment for uncomplicated malaria in Ugandan children.
PLoS ONE
PUBLISHED: 01-22-2013
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The treatment of falciparum malaria poses unique challenges in settings where malaria transmission intensity is high because recurrent infections are common. These could be new infections, recrudescences, or a combination of the two. Though several African countries continue to use quinine as the second line treatment for patients with recurrent infections, there is little information on its efficacy when used for rescue therapy. Moreover, such practice goes against the World Health Organisation (WHO) recommendation to use combination therapy for uncomplicated malaria.
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Safety and efficacy of co-trimoxazole for treatment and prevention of Plasmodium falciparum malaria: a systematic review.
PLoS ONE
PUBLISHED: 01-15-2013
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Cotrimoxazole (CTX) has been used for half a century. It is inexpensive hence the reason for its almost universal availability and wide clinical spectrum of use. In the last decade, CTX was used for prophylaxis of opportunistic infections in HIV infected people. It also had an impact on the malaria risk in this specific group.
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Malaria in pregnancy.
Mediterr J Hematol Infect Dis
PUBLISHED: 01-02-2013
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Pregnant women have a higher risk of malaria compared to non-pregnant women. This review provides an update on knowledge acquired since 2000 on P. falciparum and P.vivax infections in pregnancy. Maternal risk factors for malaria in pregnancy (MiP) include low maternal age, low parity, and low gestational age. The main effects of MIP include maternal anaemia, low birth weight (LBW), preterm delivery and increased infant and maternal mortality.P. falciparum infected erythrocytes sequester in the placenta by expressing surface antigens, mainly variant surface antigen (VAR2CSA), that bind to specific receptors, mainly chondroitin sulphate A. In stable transmission settings, the higher malaria risk in primigravidae can be explained by the non-recognition of these surface antigens by the immune system. Recently, placental sequestration has been described also for P.vivax infections. The mechanism of preterm delivery and intrauterine growth retardation is not completely understood, but fever (preterm delivery), anaemia, and high cytokines levels have been implicated.Clinical suspicion of MiP should be confirmed by parasitological diagnosis. The sensitivity of microscopy, with placenta histology as the gold standard, is 60% and 45% for peripheral and placental falciparum infections in African women, respectively. Compared to microscopy, RDTs have a lower sensitivity though when the quality of microscopy is low RDTs may be more reliable. Insecticide treated nets (ITN) and intermittent preventive treatment in pregnancy (IPTp) are recommended for the prevention of MiP in stable transmission settings. ITNs have been shown to reduce malaria infection and adverse pregnancy outcomes by 28-47%. Although resistance is a concern, SP has been shown to be equivalent to MQ and AQ for IPTp. For the treatment of uncomplicated malaria during the first trimester, quinine plus clindamycin for 7 days is the first line treatment and artesunate plus clindamycin for 7 days is indicated if this treatment fails; in the 2(nd) and 3(rd) trimester first line treatment is an artemisinin-based combination therapy (ACT) known to be effective in the region or artesunate and clindamycin for 7 days or quinine and clindamycin. For severe malaria, in the second and third trimester parenteral artesunate is preferred over quinine. In the first trimester, both artesunate and quinine (parenteral) may be considered as options. Nevertheless, treatment should not be delayed and should be started immediately with the most readily available drug.
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Traditional nets interfere with the uptake of long-lasting insecticidal nets in the Peruvian Amazon: the relevance of net preference for achieving high coverage and use.
PLoS ONE
PUBLISHED: 01-02-2013
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While coverage of long-lasting insecticide-treated nets (LLIN) has steadily increased, a growing number of studies report gaps between net ownership and use. We conducted a mixed-methods social science study assessing the importance of net preference and use after Olyset® LLINs were distributed through a mass campaign in rural communities surrounding Iquitos, the capital city of the Amazonian region of Peru.
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Could the decision of trial participation precede the informed consent process? Evidence from burkina faso.
PLoS ONE
PUBLISHED: 01-01-2013
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Over the last years, the number of clinical trials carried out in low-income countries with poor medical infrastructure and limited access to health care has increased. In these settings, the decision of participating in a clinical study may be influenced by factors related to participants vulnerability that limit the efficacy of the informed consent.
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Injections, cocktails and diviners: therapeutic flexibility in the context of malaria elimination and drug resistance in Northeast Cambodia.
PLoS ONE
PUBLISHED: 01-01-2013
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Adherence to effective malaria medication is extremely important in the context of Cambodias elimination targets and drug resistance containment. Although the public sector health facilities are accessible to the local ethnic minorities of Ratanakiri province (Northeast Cambodia), their illness itineraries often lead them to private pharmacies selling "cocktails" and artemether injections, or to local diviners prescribing animal sacrifices to appease the spirits.
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Alternative treatments for indoor residual spraying for malaria control in a village with pyrethroid- and DDT-resistant vectors in the Gambia.
PLoS ONE
PUBLISHED: 01-01-2013
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Malaria vector control is threatened by resistance to pyrethroids, the only class of insecticides used for treating bed nets. The second major vector control method is indoor residual spraying with pyrethroids or the organochloride DDT. However, resistance to pyrethroids frequently confers resistance to DDT. Therefore, alternative insecticides are urgently needed.
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Detecting Foci of Malaria Transmission with School Surveys: A Pilot Study in the Gambia.
PLoS ONE
PUBLISHED: 01-01-2013
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In areas of declining malaria transmission such as in The Gambia, the identification of malaria infected individuals becomes increasingly harder. School surveys may be used to identify foci of malaria transmission in the community.
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Sulfadoxine-pyrimethamine resistance and intermittent preventive treatment during pregnancy: a retrospective analysis of birth weight data in the Democratic Republic of Congo (DRC).
Trop. Med. Int. Health
PUBLISHED: 12-30-2011
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To assess the effect of intermittent preventive treatment with sulfadoxine-pyrimethamine (IPTp-SP) on birth weight in sites with varying degrees of drug resistance.
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Multiple independent introductions of Plasmodium falciparum in South America.
Proc. Natl. Acad. Sci. U.S.A.
PUBLISHED: 12-27-2011
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The origin of Plasmodium falciparum in South America is controversial. Some studies suggest a recent introduction during the European colonizations and the transatlantic slave trade. Other evidence--archeological and genetic--suggests a much older origin. We collected and analyzed P. falciparum isolates from different regions of the world, encompassing the distribution range of the parasite, including populations from sub-Saharan Africa, the Middle East, Southeast Asia, and South America. Analyses of microsatellite and SNP polymorphisms show that the populations of P. falciparum in South America are subdivided in two main genetic clusters (northern and southern). Phylogenetic analyses, as well as Approximate Bayesian Computation methods suggest independent introductions of the two clusters from African sources. Our estimates of divergence time between the South American populations and their likely sources favor a likely introduction from Africa during the transatlantic slave trade.
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First results of phase 3 trial of RTS,S/AS01 malaria vaccine in African children.
Selidji Todagbe Agnandji, Bertrand Lell, Solange Solmeheim Soulanoudjingar, José Francisco Fernandes, Béatrice Peggy Abossolo, Cornelia Conzelmann, Barbara Gaelle Nfono Ondo Methogo, Yannick Doucka, Arnaud Flamen, Benjamin Mordmüller, Saadou Issifou, Peter Gottfried Kremsner, Jahit Sacarlal, Pedro Aide, Miguel Lanaspa, John J Aponte, Arlindo Nhamuave, Diana Quelhas, Quique Bassat, Sofia Mandjate, Eusébio Macete, Pedro Alonso, Salim Abdulla, Nahya Salim, Omar Juma, Mwanajaa Shomari, Kafuruki Shubis, Francisca Machera, Ali Said Hamad, Rose Minja, Ali Mtoro, Alma Sykes, Saumu Ahmed, Alwisa Martin Urassa, Ali Mohammed Ali, Grace Mwangoka, Marcel Tanner, Halidou Tinto, Umberto D'Alessandro, Hermann Sorgho, Innocent Valea, Marc Christian Tahita, William Kaboré, Sayouba Ouédraogo, Yara Sandrine, Robert Tinga Guiguemdé, Jean Bosco Ouédraogo, Mary J Hamel, Simon Kariuki, Chris Odero, Martina Oneko, Kephas Otieno, Norbert Awino, Jackton Omoto, John Williamson, Vincent Muturi-Kioi, Kayla F Laserson, Laurence Slutsker, Walter Otieno, Lucas Otieno, Otsyula Nekoye, Stacey Gondi, Allan Otieno, Bernhards Ogutu, Ruth Wasuna, Victorine Owira, David Jones, Agnes Akoth Onyango, Patricia Njuguna, Roma Chilengi, Pauline Akoo, Christine Kerubo, Jesse Gitaka, Charity Maingi, Trudie Lang, Ally Olotu, Benjamin Tsofa, Philip Bejon, Norbert Peshu, Kevin Marsh, Seth Owusu-Agyei, Kwaku Poku Asante, Kingsley Osei-Kwakye, Owusu Boahen, Samuel Ayamba, Kingsley Kayan, Ruth Owusu-Ofori, David Dosoo, Isaac Asante, George Adjei, Daniel Chandramohan, Brian Greenwood, John Lusingu, Samwel Gesase, Anangisye Malabeja, Omari Abdul, Hassan Kilavo, Coline Mahende, Edwin Liheluka, Martha Lemnge, Thor Theander, Chris Drakeley, Daniel Ansong, Tsiri Agbenyega, Samuel Adjei, Harry Owusu Boateng, Theresa Rettig, John Bawa, Justice Sylverken, David Sambian, Alex Agyekum, Larko Owusu, Francis Martinson, Irving Hoffman, Tisungane Mvalo, Portia Kamthunzi, Ruthendo Nkomo, Albans Msika, Allan Jumbe, Nelecy Chome, Dalitso Nyakuipa, Joseph Chintedza, W Ripley Ballou, Myriam Bruls, Joe Cohen, Yolanda Guerra, Erik Jongert, Didier Lapierre, Amanda Leach, Marc Lievens, Opokua Ofori-Anyinam, Johan Vekemans, Terrell Carter, Didier Leboulleux, Christian Loucq, Afiya Radford, Barbara Savarese, David Schellenberg, Marla Sillman, Preeti Vansadia, .
N. Engl. J. Med.
PUBLISHED: 10-18-2011
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An ongoing phase 3 study of the efficacy, safety, and immunogenicity of candidate malaria vaccine RTS,S/AS01 is being conducted in seven African countries.
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Improving malaria control in West Africa: interruption of transmission as a paradigm shift.
Acta Trop.
PUBLISHED: 08-03-2011
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With the paradigm shift from the reduction of morbidity and mortality to the interruption of transmission, the focus of malaria control broadens from symptomatic infections in children ?5 years of age to include asymptomatic infections in older children and adults. In addition, as control efforts intensify and the number of interventions increases, there will be decreases in prevalence, incidence and transmission with additional decreases in morbidity and mortality. Expected secondary consequences of these changes include upward shifts in the peak ages for infection (parasitemia) and disease, increases in the ages for acquisition of antiparasite humoral and cellular immune responses and increases in false-negative blood smears and rapid diagnostic tests. Strategies to monitor these changes must include: (1) studies of the entire population (that are not restricted to children ?5 or ?10 years of age), (2) study sites in both cities and rural areas (because of increasing urbanization across sub-Saharan Africa) and (3) innovative strategies for surveillance as the prevalence of infection decreases and the frequency of false-negative smears and rapid diagnostic tests increases.
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Cryopreserved Plasmodium vivax and cord blood reticulocytes can be used for invasion and short term culture.
Int. J. Parasitol.
PUBLISHED: 07-26-2011
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The establishment of a Plasmodium vivaxin vitro culture system is critical for the development of new vaccine, drugs and diagnostic tests. Although short-term cultures have been successfully set up, their reproducibility in laboratories without direct access to P. vivax-infected patients has been limited by the need for fresh parasite isolates. We explored the possibility of using parasite isolates and reticulocytes, both cryopreserved, to perform invasion and initiate short-term culture. Invasion results obtained with both cryopreserved isolates and reticulocytes were similar to those obtained with fresh samples. This method should be easily replicated in laboratories outside endemic areas and will substantially contribute to the development of a continuous P. vivax culture. In addition, this model could be used for testing vaccine candidates as well as for studying invasion-specific molecular mechanisms.
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A reliable ex vivo invasion assay of human reticulocytes by Plasmodium vivax.
Blood
PUBLISHED: 07-18-2011
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Currently, there are no reliable RBC invasion assays to guide the discovery of vaccines against Plasmodium vivax, the most prevalent malaria parasite in Asia and South America. Here we describe a protocol for an ex vivo P vivax invasion assay that can be easily deployed in laboratories located in endemic countries. The assay is based on mixing enriched cord blood reticulocytes with matured, trypsin-treated P vivax schizonts concentrated from clinical isolates. The reliability of this assay was demonstrated using a large panel of P vivax isolates freshly collected from patients in Thailand.
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Safety and efficacy of dihydroartemisinin-piperaquine versus artemether-lumefantrine in the treatment of uncomplicated Plasmodium falciparum malaria in Zambian children.
Malar. J.
PUBLISHED: 02-28-2011
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Malaria in Zambia remains a public health and developmental challenge, affecting mostly children under five and pregnant women. In 2002, the first-line treatment for uncomplicated malaria was changed to artemether-lumefantrine (AL) that has proved to be highly efficacious against multidrug resistant Plasmodium falciparum.
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Reductions in malaria and anaemia case and death burden at hospitals following scale-up of malaria control in Zanzibar, 1999-2008.
Malar. J.
PUBLISHED: 02-18-2011
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In Zanzibar, the Ministry of Health and partners accelerated malaria control from September 2003 onwards. The impact of the scale-up of insecticide-treated nets (ITN), indoor-residual spraying (IRS) and artemisinin-combination therapy (ACT) combined on malaria burden was assessed at six out of seven in-patient health facilities.
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Likely health outcomes for untreated acute febrile illness in the tropics in decision and economic models; a Delphi survey.
PLoS ONE
PUBLISHED: 02-03-2011
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Modelling is widely used to inform decisions about management of malaria and acute febrile illnesses. Most models depend on estimates of the probability that untreated patients with malaria or bacterial illnesses will progress to severe disease or death. However, data on these key parameters are lacking and assumptions are frequently made based on expert opinion. Widely diverse opinions can lead to conflicting outcomes in models they inform.
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Double ethical review of North-South collaborative clinical research: hidden paternalism or real partnership?
Trop. Med. Int. Health
PUBLISHED: 02-01-2011
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Despite their universal character, the ethical principles governing clinical research need to be translated into procedures and practices, which will vary among countries and regions because of differences in local cultural norms and in the available resources. Double ethical review, by which a research protocol is submitted for ethical clearance both in the country or countries where the research takes place and in the country of the sponsor or funding agency, will then help ensure that all relevant perspectives are taken into account. In addition, a geographically and culturally close ethics committee can do a much better informed and comprehensive assessment of the respective skills of the clinical sites and of the sponsor. But the practical implementation of double ethical review can bring significant difficulties and delays, especially in multi-site and multi-country researches. Currently, most ethics committees do not proactively seek communication with others evaluating the same research protocol in different socio-economical and cultural contexts, so in practice there is no mutual learning process. Proactive communication would help to build collaborative partnership among ethical bodies, promoting common practices and resolving conflicting opinions.
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Quinine, an old anti-malarial drug in a modern world: role in the treatment of malaria.
Malar. J.
PUBLISHED: 01-31-2011
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Quinine remains an important anti-malarial drug almost 400 years after its effectiveness was first documented. However, its continued use is challenged by its poor tolerability, poor compliance with complex dosing regimens, and the availability of more efficacious anti-malarial drugs. This article reviews the historical role of quinine, considers its current usage and provides insight into its appropriate future use in the treatment of malaria. In light of recent research findings intravenous artesunate should be the first-line drug for severe malaria, with quinine as an alternative. The role of rectal quinine as pre-referral treatment for severe malaria has not been fully explored, but it remains a promising intervention. In pregnancy, quinine continues to play a critical role in the management of malaria, especially in the first trimester, and it will remain a mainstay of treatment until safer alternatives become available. For uncomplicated malaria, artemisinin-based combination therapy (ACT) offers a better option than quinine though the difficulty of maintaining a steady supply of ACT in resource-limited settings renders the rapid withdrawal of quinine for uncomplicated malaria cases risky. The best approach would be to identify solutions to ACT stock-outs, maintain quinine in case of ACT stock-outs, and evaluate strategies for improving quinine treatment outcomes by combining it with antibiotics. In HIV and TB infected populations, concerns about potential interactions between quinine and antiretroviral and anti-tuberculosis drugs exist, and these will need further research and pharmacovigilance.
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Plasmodium vivax sub-patent infections after radical treatment are common in Peruvian patients: results of a 1-year prospective cohort study.
PLoS ONE
PUBLISHED: 01-28-2011
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There is an increasing body of literature reporting treatment failure of the currently recommended radical treatment of Plasmodium vivax infections. As P. vivax is the main malaria species outside the African continent, emerging tolerance to its radical treatment regime could have major consequences in countries like Peru, where 80% of malaria cases are due to P. vivax. Here we describe the results of a 1-year longitudinal follow up of 51 confirmed P. vivax patients living around Iquitos, Peruvian Amazon, and treated according to the Peruvian national guidelines.
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Case management of severe malaria--a forgotten practice: experiences from health facilities in Uganda.
PLoS ONE
PUBLISHED: 01-18-2011
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Severe malaria is a life-threatening medical emergency and requires prompt and effective treatment to prevent death. There is paucity of published information on current practices of severe malaria case management in sub-Saharan Africa; we evaluated the management practices for severe malaria in Ugandan health facilities
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True versus apparent malaria infection prevalence: the contribution of a Bayesian approach.
PLoS ONE
PUBLISHED: 01-10-2011
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To present a new approach for estimating the "true prevalence" of malaria and apply it to datasets from Peru, Vietnam, and Cambodia.
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Malaria incidence and prevalence among children living in a peri-urban area on the coast of benin, west Africa: a longitudinal study.
Am. J. Trop. Med. Hyg.
PUBLISHED: 09-03-2010
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Clinical malaria incidence was determined over 18 months in a cohort of 553 children living in a peri-urban area near Cotonou. Three cross-sectional surveys were also carried out. Malaria incidence showed a marked seasonal distribution with two peaks: the first corresponding to the long rainy season, and the second corresponding to the overflowing of Lake Nokoue. The overall Plasmodium falciparum incidence rate was estimated at 84/1,000 person-months, and its prevalence was estimated at over 40% in the two first surveys and 68.9% in the third survey. Multivariate analysis showed that girls and people living in closed houses had a lower risk of clinical malaria. Bed net use was associated with a lower risk of malaria infection. Conversely, children of families owing a pirogue were at higher risk of clinical malaria. Considering the high pyrethroids resistance, indoor residual spraying with either a carbamate or an organophospate insecticide may have a major impact on the malaria burden.
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Malaria transmission and vector behaviour in a forested malaria focus in central Vietnam and the implications for vector control.
Malar. J.
PUBLISHED: 07-20-2010
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In Vietnam, malaria is becoming progressively restricted to specific foci where human and vector characteristics alter the known malaria epidemiology, urging for alternative or adapted control strategies. Long-lasting insecticidal hammocks (LLIH) were designed and introduced in Ninh Thuan province, south-central Vietnam, to control malaria in the specific context of forest malaria. An entomological study in this specific forested environment was conducted to assess the behavioural patterns of forest and village vectors and to assess the spatio-temporal risk factors of malaria transmission in the province.
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Trends in pregnancy outcomes in Malawian adolescents receiving antimalarial and hematinic supplements.
Acta Obstet Gynecol Scand
PUBLISHED: 06-10-2010
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To describe pregnancy outcomes of adolescent and adult primigravidae receiving antimalarials and hematinic supplementation and compare findings with a survey in this area a decade earlier.
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Adherence to 7-day primaquine treatment for the radical cure of P. vivax in the Peruvian Amazon.
Am. J. Trop. Med. Hyg.
PUBLISHED: 06-04-2010
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Despite being free of charge, treatment adherence to 7-day primaquine for the radical cure of Plasmodium vivax was estimated at 62.2% among patients along the Iquitos-Nauta road in the Peruvian Amazon. The principal reason for non-adherence was the perceived adverse effects related to local humoral illness conceptions that hold that malaria produces a hot state of body, which is further aggravated by the characteristically hot medical treatment. Notably, patients were willing to adhere to the first 3 days of treatment during which symptoms are most apparent and include the characteristic chills. Nevertheless, as symptoms abate, the perceived aggravating characteristics of the medication outweigh the perceived advantages of treatment adherence. Improving community awareness about the role of primaquine to prevent further malaria transmission and fostering a realistic system of direct observed treatment intake, organized at community level, can be expected to improve adherence to the radical cure of P. vivax in this area.
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Multilocus genotyping reveals high heterogeneity and strong local population structure of the Plasmodium vivax population in the Peruvian Amazon.
Malar. J.
PUBLISHED: 03-12-2010
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Peru is one of the Latin American countries with the highest malaria burden, mainly due to Plasmodium vivax infections. However, little is known about P. vivax transmission dynamics in the Peruvian Amazon, where most malaria cases occur. The genetic diversity and population structure of P. vivax isolates collected in different communities around Iquitos city, the capital of the Peruvian Amazon, was determined.
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Bottlenecks for high coverage of intermittent preventive treatment in pregnancy: the case of adolescent pregnancies in rural Burkina Faso.
PLoS ONE
PUBLISHED: 03-04-2010
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While IPTp-SP is currently being scaled up in sub-Saharan Africa (SSA), the coverage with the required>or=2 doses of SP remains considerably short of the Roll Back Malaria (RBM) goal of 80%, not to mention of the recently advocated universal coverage.
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The effect of food consumption on lumefantrine bioavailability in African children receiving artemether-lumefantrine crushed or dispersible tablets (Coartem) for acute uncomplicated Plasmodium falciparum malaria.
Trop. Med. Int. Health
PUBLISHED: 02-17-2010
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Artemether-lumefantrine (AL) is first-line treatment for uncomplicated malaria in many African countries. Concomitant food consumption may affect absorption of lumefantrine but data in the most important target population, i.e. children, are lacking. Therefore, we evaluated the effect of food intake on oral lumefantrine bioavailability in African children with malaria.
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High complexity of Plasmodium vivax infections in symptomatic patients from a rural community in central Vietnam detected by microsatellite genotyping.
Am. J. Trop. Med. Hyg.
PUBLISHED: 02-06-2010
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Fourteen published and three newly identified polymorphic microsatellites were used to genotype 69 Plasmodium vivax samples obtained from 39 patients detected over a period of two years who lived in a rural community of central Vietnam. All samples were polyclonal with an average expected heterozygosity of 0.86. Among the 39 patients, 16 experienced 1-5 recurrent episodes of P. vivax malaria, most of them (83%) with a different genotype profile compared with previous infections. The minimal set of microsatellites required for differentiating the genotype profiles of the recurrent infections compared with the full set of 17 microsatellites was explored. A combination of five markers was sufficient to identify all recurrent infections with an unrelated or different genotype profile compared with all previous episodes.
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In vivo parasitological measures of artemisinin susceptibility.
J. Infect. Dis.
PUBLISHED: 01-21-2010
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Parasite clearance data from 18,699 patients with falciparum malaria treated with an artemisinin derivative in areas of low (n=14,539), moderate (n=2077), and high (n=2083) levels of malaria transmission across the world were analyzed to determine the factors that affect clearance rates and identify a simple in vivo screening measure for artemisinin resistance. The main factor affecting parasite clearance time was parasite density on admission. Clearance rates were faster in high-transmission settings and with more effective partner drugs in artemisinin-based combination treatments (ACTs). The result of the malaria blood smear on day 3 (72 h) was a good predictor of subsequent treatment failure and provides a simple screening measure for artemisinin resistance. Artemisinin resistance is highly unlikely if the proportion of patients with parasite densities of <100,000 parasites/microL given the currently recommended 3-day ACT who have a positive smear result on day 3 is <3%; that is, for n patients the observed number with a positive smear result on day 3 does not exceed (n + 60)/24.
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Low perception of malaria risk among the Ra-glai ethnic minority in south-central Vietnam: implications for forest malaria control.
Malar. J.
PUBLISHED: 01-20-2010
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Despite Vietnams success in reducing malaria mortality and morbidity over the last decade, malaria persists in the forested and mountainous areas of the central and southern provinces, where more than 50% of the clinical cases and 90% of severe cases and malaria deaths occur.
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JoVE Visualize is a tool created to match the last 5 years of PubMed publications to methods in JoVE's video library.

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In developing our video relationships, we compare around 5 million PubMed articles to our library of over 4,500 methods videos. In some cases the language used in the PubMed abstracts makes matching that content to a JoVE video difficult. In other cases, there happens not to be any content in our video library that is relevant to the topic of a given abstract. In these cases, our algorithms are trying their best to display videos with relevant content, which can sometimes result in matched videos with only a slight relation.