Publications by authors named "Mamadou O Ndiath"

Background: Arthropod vectors feeding on the blood of individuals treated with ivermectin have substantially increased mortality. Whether this effect will translate into a useful tool for reducing malaria burden at scale is not clear. Our trial aimed to assess whether using ivermectin as an adjunct to mass drug administration (MDA) with dihydroartemisinin-piperaquine would further reduce malaria prevalence.

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Article Synopsis
  • Anopheles melas, a lesser-known malaria-carrying mosquito, was studied for its population genetics in the Bijagós Archipelago, with the first whole-genome sequencing of this species in the area.
  • A total of 30 individual mosquitoes were sequenced, revealing no insecticide resistance mutations commonly found in other malaria mosquitoes, but some structural variations in relevant genes.
  • The findings also indicated two distinct genetic groups among the An. melas populations based on mitochondrial DNA, highlighting the need for further research to clarify their role in malaria transmission.
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Background: In 2022 the WHO recommended the discretionary expansion of the eligible age range for seasonal malaria chemoprevention (SMC) to children older than 4 years. Older children are at lower risk of clinical disease and severe malaria so there has been uncertainty about the cost-benefit for national control programmes. However, emerging evidence from laboratory studies suggests protecting school-age children reduces the infectious reservoir for malaria and may significantly impact on transmission.

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Article Synopsis
  • Insecticide resistance is diminishing the effectiveness of malaria control measures in the Bijagós Archipelago, prompting a need to understand the molecular markers associated with this resistance.
  • A study analyzed 214 Anopheles mosquitoes from 13 islands using advanced sequencing techniques to identify 17 molecular markers related to insecticide resistance, finding four significant mutations.
  • This research is the first to document specific genetic markers, such as vgsc L995F, in malaria vectors on the Bijagós, highlighting higher prevalence in the more populated Bubaque Island, indicating potential links between population density and resistance.
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Background: As the control of malaria remains heavily dependent on vector management interventions, it is important to understand the impact of these on mosquito populations. Age-grading is a valuable tool for this; however, logistical challenges in remote, resource-poor areas make current methodologies difficult to incorporate into clinical trials and routine surveillance. Our aim was to validate a methodology that could be easily implemented in such settings.

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Introduction: As malaria declines, innovative tools are required to further reduce transmission and achieve elimination. Mass drug administration (MDA) of artemisinin-based combination therapy (ACT) is capable of reducing malaria transmission where coverage of control interventions is already high, though the impact is short-lived. Combining ACT with ivermectin, an oral endectocide shown to reduce vector survival, may increase its impact, while also treating ivermectin-sensitive co-endemic diseases and minimising the potential impact of ACT resistance in this context.

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Background: Thioester-containing protein 1 (TEP1) is a highly polymorphic gene playing an important role in mosquito immunity to parasite development and associated with Anopheles gambiae vectorial competence. Allelic variations in TEP1 could render mosquito either susceptible or resistant to parasite infection. Despite reports of TEP1 genetic variations in An.

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The geographic and evolutionary origins of the SARS-CoV-2 Omicron variant (BA.1), which was first detected mid-November 2021 in Southern Africa, remain unknown. We tested 13,097 COVID-19 patients sampled between mid-2021 to early 2022 from 22 African countries for BA.

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Background: Vector control interventions in sub-Saharan Africa rely on insecticide-treated nets and indoor residual spraying. Insecticide resistance, poor coverage of interventions, poor quality nets and changes in vector behavior threaten the effectiveness of these interventions and, consequently, alternative tools are needed. Mosquitoes die after feeding on humans or animals treated with ivermectin (IVM).

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Background: The outbreak of COVID-19 disease and rapid spread of the virus outside China led to its declaration as a Public Health Emergency of International Concern (PHEIC) in January 2020. Key elements of the early intervention strategy focused on laboratory diagnosis and screening at points of entry and imposition of restrictions in crossborder activities.

Objective: We report the role the Medical Research Council Unit, The Gambia (MRCG) played in the early implementation of molecular testing for COVID-19 in The Gambia as part of the national outbreak response.

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The evolution and spread of insecticide resistance mechanisms amongst malaria vectors across the sub-Saharan Africa threaten the effectiveness and sustainability of current insecticide-based vector control interventions. However, a successful insecticide resistance management plan relies strongly on evidence of historical and contemporary mechanisms circulating. This study aims to retrospectively determine the evolution and spread of pyrethroid resistance mechanisms among natural populations in Senegal.

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Background: Although the malaria burden has substantially decreased in sub-Saharan Africa, progress has stalled. We assessed whether mass administration of ivermectin (a mosquitocidal drug) and dihydroartemisinin-piperaquine (an antimalarial treatment) reduces malaria in The Gambia, an area with high coverage of standard control interventions.

Methods: This open-label, cluster-randomised controlled trial was done in the Upper River region of eastern Gambia.

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The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic is evolving differently in Africa than in other regions. Africa has lower SARS-CoV-2 transmission rates and milder clinical manifestations. Detailed SARS-CoV-2 epidemiologic data are needed in Africa.

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Background: The scale-up of indoor residual spraying and long-lasting insecticidal nets, together with other interventions have considerably reduced the malaria burden in The Gambia. This study examined the biting and resting preferences of the local insecticide-resistant vector populations few years following scale-up of anti-vector interventions.

Method: Indoor and outdoor-resting Anopheles gambiae mosquitoes were collected between July and October 2019 from ten villages in five regions in The Gambia using pyrethrum spray collection (indoor) and prokopack aspirator from pit traps (outdoor).

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Background: Pyronaridine-artesunate (PA) is a registered artemisinin-based combination therapy, potentially useful for mass drug administration campaigns. However, further data are needed to evaluate its efficacy, safety and tolerability as full or incomplete treatment in asymptomatic Plasmodium falciparum-infected individuals.

Methods: This phase II, multi-center, open label, randomized clinical trial was conducted in The Gambia and Zambia.

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Background: Malaria is still a heavy public health concern in Madagascar. Few studies combining parasitology and entomology have been conducted despite the need for accurate information to design effective vector control measures. In a Malagasy region of moderate to intense transmission of both Plasmodium falciparum and P.

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Background: Bubaque is the most populous island of the Bijagos archipelago, a group of malaria-endemic islands situated off the coast of Guinea-Bissau, West Africa. Malaria vector control on Bubaque relies almost exclusively on the use of long-lasting insecticidal nets (LLINs). However, there is little information on local vector bionomics and insecticide resistance.

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Vector control has significantly reduced malaria morbidity in many regions of the world where the disease was endemic and is now moving toward malaria elimination. Among the tools available for vector control, the use of long-lasting insecticidal bed nets (LLINs) and indoor residual spraying (IRS) has proved most effective. However, Anopheles mosquitoes are becoming increasingly resistant to insecticides.

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Introduction: In Madagascar, malaria control relies on the countrywide use of long lasting insecticide treated bed nets (LLINs) and on indoor residual spraying (IRS) in the central highland area as well as a small area on the eastern coast. We tested insecticide resistance mechanisms of from Tsararano, a malaria endemic village in the coastal health district of Marovoay.

Methods: Insecticide susceptibility bioassays were done in July 2017 on first-generation (F1) to assess (i) the susceptibility to permethrin (0.

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Background: Knowledge of insecticide resistance status in the main malaria vectors is an essential component of effective malaria vector control. This study presents the first evaluation of the status of insecticide resistance in Anopheles gambiae populations from Bangui, the Central African Republic.

Methods: Anopheles mosquitoes were reared from larvae collected in seven districts of Bangui between September to November 2014.

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Background: In many African countries malaria has declined sharply due to a synergy of actions marked by the introduction of vector control strategies, but the disease remains a leading cause of morbidity and mortality in Central African Republic (CAR). An entomological study was initiated with the aim to characterize the malaria vectors in Bangui, the capital of CAR, and determine their vector competence.

Methods: A cross-sectional entomological study was conducted in 15 sites of the district of Bangui, the capital of CAR, in September-October 2013 and a second collection was done in four of those sites between November and December 2013.

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Background: In the Central African Republic, malaria is a major public health problem and the leading cause of death among children. This disease appears to be hyperendemic but no substantial entomological data, including data on Anopheles spp. susceptibility to insecticides, is available.

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