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Tiono A.B.,Center National Of Recherche Et Of Formation Sur Le Paludisme Cnrfp | Pinder M.,Durham University | Pinder M.,Medical Research Council Unit The Gambia | N'Fale S.,Center National Of Recherche Et Of Formation Sur Le Paludisme Cnrfp | And 3 more authors.
Trials | Year: 2015

Background: Recent reductions in malaria in sub-Saharan Africa have been associated with increased coverage with long-lasting insecticidal nets (LLINs). Pyrethroids are currently the only insecticide class used for treating nets, and the rapid increase in resistance to pyrethroids in vector mosquitoes may jeopardise future vector control. Nets containing a novel combination of permethrin, a pyrethroid, and pyriproxyfen, an insect juvenile hormone mimic, (PPF-LLIN) may enhance malaria control, as well as reducing the spread of pyrethroid-resistant mosquitoes. This trial will determine whether PPF-LLINs provide incremental protection against malaria over current best practice of LLINs and prompt treatment in an area with pyrethroid-resistant vectors. Methods: A 2 armed cluster-randomised controlled trial will be conducted in Burkina Faso to assess whether PPF-LLIN (containing 2% permethrin and 1% pyriproxyfen w/w) provide better protection against clinical malaria in children than 2% permethrin-treated LLINs. Study subjects will be recruited and provided with LLINs at the start of the study. The LLINs will be exchanged for PPF-LLIN by cluster in a step-wedge fashion so 3 months before the end of the 2 year trial all participants will have a PPF-LLIN. The primary endpoint will be clinical malaria incidence measured by passive case detection in a cohort of children, aged 6 months to 5 years. Anaemia and parasite prevalence will also be measured in children during cross-sectional surveys. Exposure to malaria parasites will be assessed using light traps followed by identification of common vector species and their sporozoite infection rates. Safety evaluation will include recording of adverse events and pregnancy outcomes. The main endpoint analysis will include adjusting for distance between village clusters with different types of nets, as the impact of PPF-LLIN is likely to increase as larger areas are dominated by PPF-LLIN, reducing the spill over of mosquitoes from villages with LLINs. Discussion: The step-wedge design is to measure the impact of an incrementally delivered environmental intervention where we expect the degree of control to be improved as more people use PPF-LLIN over a larger area. Trial findings will help inform policy makers on the effectiveness of PPF-LLIN nets for malaria control in areas of pyrethroid resistance. © 2015 Tiono et al.

Dia I.,Institute Pasteur Of Dakar | Sagnon N.,Center National Of Recherche Et Of Formation Sur Le Paludisme Cnrfp | Guelbeogo M.W.,Center National Of Recherche Et Of Formation Sur Le Paludisme Cnrfp | Diallo M.,Institute Pasteur Of Dakar
Journal of Vector Ecology | Year: 2011

Anopheles funestus is one of the major vectors of malaria in Africa. Cytogenetic studies conducted on populations from West Africa have shown variable degrees of polymorphism with a genetic structure leading to the description of two chromosomal forms called "Folonzo" and "Kiribina" that exhibit limited gene flow. Because studies on allopatric populations showed bionomical heterogeneities, the present study was undertaken during three consecutive years (2006, 2007, and 2008) in an area of sympatry in Senegal, in order to assess their bionomical characteristics and compare their epidemiologic role in malaria transmission. Overall, the two forms coexisted in the study area; the Kiribina form being more abundant and exhibiting higher biting rates. Based on an enzyme-linked immunosorbent assay, the anthropophilic rates were statistically comparable and were, respectively, 30.7% and 28.6% for Kiribina and Folonzo. Plasmodium falciparum circumsporozoite rates were also comparable and were 2.7% for Kiribina and 3.1% for Folonzo. Both forms were involved in malaria transmission; Kiribina being responsible for 68% of transmission. Thus, due to the limited gene flow between the two forms, the introduction of transgene for Plasmodium resistance in one of the two forms could be a disadvantage for the implementation of control strategies based on the use of Plasmodium-refractory genetically modified individuals. Nevertheless, it could represent an advantage limiting the insurgence of insecticide resistance gene spread between forms and should be taken into account for the implementation of control strategies. © 2011 The Society for Vector Ecology.

PubMed | Medical Research Council Unit The Gambia, Komfo Anoyke Teaching Hospital, University of Melbourne, University of Buea and 17 more.
Type: | Journal: eLife | Year: 2017

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is believed to confer protection against

Samadoulougou S.,Catholic University of Louvain | Kirakoya-Samadoulougou F.,Catholic University of Louvain | Sarrassat S.,London School of Hygiene and Tropical Medicine | Tinto H.,Institute Of Recherche En Science Of La Sante Irss | And 3 more authors.
Malaria Journal | Year: 2014

Background: Over the past ten years, Rapid Diagnostic Tests (RDT) played a major role in improving the use of biological malaria diagnosis, in particular in poor-resources settings. In Burkina Faso, a recent Demography and Health Survey (DHS) gave the opportunity to assess the performance of the Paracheck® test in under five children nationwide at community level. Methods. A national representative sample of 14,947 households was selected using a stratified two-stage cluster sampling. In one out of two households, all under five children were eligible to be tested for malaria using both RDT and microscopy diagnosis. Paracheck® performance was assessed using miscroscopy as the gold standard. Sensitivity and specificity were calculated as well as the diagnosis accuracy (DA) and the Youden index. Results: The malaria infection prevalence was estimated at 66% (95% CI: 64.8-67.2) according to microscopy and at 76.2% (95% CI: 75.1-77.3) according to Paracheck®. The sensitivity and specificity were estimated at 89.9% (95% CI: 89.0-90.8) and 50.4% (95% CI: 48.3-52.6) respectively with a Diagnosis Accuracy of 77% and a Youden index of 40%. The positive predictive value for malaria infection was 77.9% (95% CI: 76.7-79.1) and the negative predictive value was 72.1% (95% CI: 69.7-74.3). Variations were found by age group, period of the year and urban and rural areas, as well as across the 13 regions of the country. Conclusion: While the sensitivity of the Paracheck® test was high, its specificity was poor in the general under five population of Burkina Faso. These results suggest that Paracheck® is not suitable to assess malaria infection prevalence at community level in areas with high malaria transmission. In such settings, malaria prevalence in the general population could be estimated using microscopy. © 2014 Samadoulougou et al.; licensee BioMed Central Ltd.

Bendel D.,Xidea Solutions Ltd | Rulisa S.,University of Kigali | Ansah P.,Navrongo Health Research Center | Sirima S.,Center National Of Recherche Et Of Formation Sur Le Paludisme Cnrfp
Antimicrobial Agents and Chemotherapy | Year: 2015

The efficacy of sublingual artemether (ArTiMist) was investigated in two studies. In study 1,31 children were randomized to sublingual artemether (n = 16) or intravenous (i.v.) quinine (n = 15). In study 2,151 children were randomized to sublingual artemether (n = 77) or i.v. quinine (n = 74). For both studies, patients weighed between 5 and 15 kg and had either severe or complicated malaria based on WHO criteria, or they had uncomplicated malaria but were unable to tolerate oral medication as a result of nausea, vomiting, or diarrhea. Patients received either 3 mg/kg of body weight of sublingual artemether or a loading dose of 20 mg/kg of i.v. quinine followed by 10 mg/kg every 8 h i.v. thereafter. The primary endpoint was parasitological success, defined as a reduction in parasite count of ≥90% ofthat at baseline at 24 h after the first dose. Other endpoints based on parasite clearance and clinical response were evaluated. In study 1, there were parasitological success rates of 93.3% (14/15) and 66.7% (10/15) for the sublingual artemether and quinine treatments, respectively. In study 2,94.3% (66/70) of the ArTiMist-treated patients and 39.4% (28/71) of the quinine-treated patients had parasitological success (P < 0.0001). Indicators of parasite clearance (parasite clearance time [PCT], time for parasite count to fall by 50% [PCT50], time for parasite count to fall by 90% [PCT90], and percent reduction in parasitemia from baseline at 24 h [PRR24]) were significantly superior for children treated with sublingual artemether compared to those treated with i.v. quinine. There were no differences between treatments for the clinical endpoints, such as fever clearance time. The local tolerability of sublingual artemether was good. Sublingual artemether leads to rapid parasite clearance and clinical recovery. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Tiono A.B.,Center National Of Recherche Et Of Formation Sur Le Paludisme Cnrfp | Ouedraogo A.,Center National Of Recherche Et Of Formation Sur Le Paludisme Cnrfp | Diarra A.,Center National Of Recherche Et Of Formation Sur Le Paludisme Cnrfp | Coulibaly S.,Center National Of Recherche Et Of Formation Sur Le Paludisme Cnrfp | And 6 more authors.
Malaria Journal | Year: 2014

Abstract. Background: Rapid diagnostic tests (RDTs) are immune chromatographic tests targeting antigens of one or more Plasmodium species and offer the potential to extend accurate malaria diagnosis in endemic areas. In this study, the performance of Plasmodium falciparum-specific histidine-rich protein-2 (PfHRP-2) RDT in the detection of asymptomatic carriers from a hyperendemic region of Burkina Faso was compared with microscopy to gain further insight on its relevance in community-based interventions. Methods. The performance of HRP-2 test was evaluated in terms of sensitivity, specificity, positive and negative predictive values, discordant values, likelihood ratios, accuracy, and precision using microscopy as the 'gold standard'. This analysis was carried out in a controlled, parallel, cluster-randomized (18 clusters; 1:1) study in children and adults. The effect of systematic treatment of P. falciparum asymptomatic carriers during three consecutive monthly community screening campaigns on the incidence of symptomatic malaria episodes over a 12-month period was compared with no treatment of asymptomatic carriers. Results: Sensitivity of HRP-2 test in asymptomatic carriers was higher in campaign 1 (92.4%) when compared to campaign 2 (84.0%) and campaign 3 (77.8%). The sensitivity of HRP-2 test increased as parasite density increased across all the age groups. Highest sensitivity (≥97.0%) was recorded at parasite densities of 1,000-4,999/μl, except for children aged 10 to 14 years. The specificity of HRP-2 test was comparable across age groups and highest in campaign 3 (95.9%). The negative predictive values were high across the three campaigns (≥92.7%) while the positive predictive values ranged from 23.2 to 73.8%. False-positive and false-negative rates were high in campaign 1 and campaign 3, respectively. Conclusion: The performance of HRP-2 test in detecting asymptomatic carriers of P. falciparum varied by age and parasite density. Although the use of HRP-2 test is beneficial for the diagnosis of acute malaria, its low sensitivity in screening asymptomatic carriers may limit its utility in pre-elimination interventional settings. The use of a practical and more sensitive test such as loop-mediated isothermal amplification in combination with a cost effective HRP-2 test may be worth exploring in such settings. © 2014 Tiono et al.; licensee BioMed Central Ltd.

Tiono A.B.,Center National Of Recherche Et Of Formation Sur Le Paludisme Cnrfp | Guelbeogo M.W.,Center National Of Recherche Et Of Formation Sur Le Paludisme Cnrfp | Sagnon N.F.,Center National Of Recherche Et Of Formation Sur Le Paludisme Cnrfp | Nebie I.,Center National Of Recherche Et Of Formation Sur Le Paludisme Cnrfp | And 3 more authors.
BMC Infectious Diseases | Year: 2013

Background: In malaria-endemic countries, large proportions of individuals infected with Plasmodium falciparum are asymptomatic and constitute a reservoir of parasites for infection of newly hatched mosquitoes.Methods: Two studies were run in parallel in Burkina Faso to evaluate the impact of systematic identification and treatment of asymptomatic carriers of P. falciparum, detected by rapid diagnostic test, on disease transmission and susceptibility to clinical malaria episodes. A clinical study assessed the incidence of symptomatic malaria episodes with a parasite density >5,000/μL after three screening and treatment campaigns ~1 month apart before the rainy season; and an entomological study determined the effect of these campaigns on malaria transmission as measured by entomological inoculation rate.Results: The intervention arm had lower prevalence of asymptomatic carriers of asexual parasites and lower prevalence of gametocyte carriers during campaigns 2 and 3 as compared to the control arm. During the entire follow-up period, out of 13,767 at-risk subjects, 2,516 subjects (intervention arm 1,332; control arm 1,184) had symptomatic malaria. Kaplan-Meier analysis of the incidence of first symptomatic malaria episode with a parasite density >5,000/μL showed that, in the total population, the two treatment arms were similar until Week 11-12 after campaign 3, corresponding with the beginning of the malaria transmission season, after which the probability of being free of symptomatic malaria was lower in the intervention arm (logrank p < 0.0001). Similar trends were observed in infants and children <5 years and in individuals ≥5 years of age. In infants and children <5 years old who experienced symptomatic malaria episodes, the geometric mean P. falciparum density was lower in the intervention arm than the control arm. This trend was not seen in those individuals aged ≥5 years. Over the year, monthly variation in mosquito density and entomological inoculation rate was comparable in both arms, with September peaks in both indices.Conclusion: Community screening and targeted treatment of asymptomatic carriers of P. falciparum had no effect on the dynamics of malaria transmission, but seemed to be associated with an increase in the treated community's susceptibility to symptomatic malaria episodes after the screening campaigns had finished. These results highlight the importance of further exploratory studies to better understand the dynamics of disease transmission in the context of malaria elimination. © 2013 Tiono et al.; licensee BioMed Central Ltd.

Ogutu B.,Kenya Medical Research Institute | Tiono A.B.,Center National Of Recherche Et Of Formation Sur Le Paludisme Cnrfp | Makanga M.,European and Developing Countries Clinical Trials | Premji Z.,University of Dar es Salaam | And 4 more authors.
Malaria Journal | Year: 2010

Background: Increased investment and commitment to malaria prevention and treatment strategies across Africa has produced impressive reductions in the incidence of this disease. Nevertheless, it is clear that further interventions will be necessary to meet the international target of a reversal in the incidence of malaria by 2015. This article discusses the prospective role of an innovative malaria control strategy - the community-based treatment of asymptomatic carriers of Plasmodium falciparum, with artemisinin-based combination therapy (ACT). The potential of this intervention was considered by key scientists in the field at an Advisory Board meeting held in Basel, in April 2009. This article summarizes the discussions that took place among the participants. Presentation of the hypothesis. Asymptomatic carriers do not seek treatment for their infection and, therefore, constitute a reservoir of parasites and thus a real public-health risk. The systematic identification and treatment of individuals with asymptomatic P. falciparum as part of a surveillance intervention strategy should reduce the parasite reservoir, and if this pool is greatly reduced, it will impact disease transmission. Testing the hypothesis. This article considers the populations that could benefit from such a strategy and examines the ethical issues associated with the treatment of apparently healthy individuals, who represent a neglected public health risk. The potential for the treatment of asymptomatic carriers to impair the development of protective immunity, resulting in a 'rebound' and age escalation of malaria incidence, is also discussed. For policymakers to consider the treatment of asymptomatic carriers with ACT as a new tool in their malaria control programmes, it will be important to demonstrate that such a strategy can produce significant benefits, without having a negative impact on the efficacy of ACT and the health of the target population. Implications of the hypothesis. The treatment of asymptomatic carriers with ACT is an innovative and essential tool for breaking the cycle of infection in some transmission settings. Safe and effective medicines can save the lives of children, but the reprieve is only temporary so long as the mosquitoes can become re-infected from the asymptomatic carriers. With improvements in rapid diagnostic tests that allow easier identification of asymptomatic carriers, the elimination of the pool of parasites is within reach. © 2010 Ogutu et al; licensee BioMed Central Ltd.

Soulama I.,Center National Of Recherche Et Of Formation Sur Le Paludisme Cnrfp | Bougouma E.C.,Center National Of Recherche Et Of Formation Sur Le Paludisme Cnrfp | Diarra A.,Center National Of Recherche Et Of Formation Sur Le Paludisme Cnrfp | Nebie I.,Center National Of Recherche Et Of Formation Sur Le Paludisme Cnrfp | Sirima S.B.,Center National Of Recherche Et Of Formation Sur Le Paludisme Cnrfp
Tropical Medicine and International Health | Year: 2010

Objective To assess the impact of seasonal variation on the distribution of the eba-175 allelic forms in the area where malaria transmission is markedly seasonal. Methods Blood samples were collected from 291 and 239 children under 5 years of age during the low and the high malaria transmission season, respectively, in four villages named Dawelgué, Kounda, Tanghin and Watenga of Saponé Health District, then screened for eba 175 F- and C- alleles by nested PCR analysis. Results F- alleles were more prevalent than C-alleles in the low [0.66 vs. 0.34 (P < 0.0001)] and high transmission season [0.67 vs. 0.33 (P < 0.0001)]. No significant seasonal variation was observed in the distribution of the two alleles. However, according to Sewall Wright rules, the population pairwise FST values, between Dawelgué and Tanghin during the low transmission season (FST- value = 0.10415, P-value = 0.0090 and during the high season (F ST-value = 0.08244, P-value < 0.00001), between Tanghin and Watenga during the low season (FST value = 0.07414, P-value = 0.009) indicated a moderate but statistically significant genetic differentiation. Conclusion Although there was a moderate but significant genetic differentiation between some study villages at different times of the year, this study result in the seasonal stability of eba-175 allele's distribution in the study area. © 2009 Blackwell Publishing Ltd.

Siribie M.,Groupe de Recherche Action en Sante GRAS | Diarra A.,Center National Of Recherche Et Of Formation Sur Le Paludisme Cnrfp | Tiono A.B.,Groupe de Recherche Action en Sante GRAS | Soulama I.,Center National Of Recherche Et Of Formation Sur Le Paludisme Cnrfp | Sirima S.B.,Groupe de Recherche Action en Sante GRAS
Bulletin de la Societe de Pathologie Exotique | Year: 2012

In order to implement community case management of malaria strategy in a rural area of intense transmission, of children using artemether-lumefantrine combination, we assessed the therapeutic efficacy of the medicine. We conducted an open label and uncontrolled clinical trial in an unique centre from September 2009 to December 2009 in children 6-59 months old who consulted at health facilities for uncomplicated malaria. The primary endpoint was clinical and parasitological cure rate at day 28 corrected by PCR. In total 106 children were enrolled. Parasite clearance at day 2 was 99.04% and the adequate clinical and parasitological response corrected by PCR at day 28 was 90.5%. Our results confirm that artemether-lumefantrine combination is still effective. © 2012 Société de pathologie exotique et Springer-Verlag France.

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