scholarly journals A high throughput multi-locus insecticide resistance marker panel for tracking resistance emergence and spread inAnopheles gambiae

2019 ◽  
Author(s):  
Eric R. Lucas ◽  
Kirk A. Rockett ◽  
Amy Lynd ◽  
John Essandoh ◽  
Nelson Grisales ◽  
...  
Keyword(s):  
Insecticide Resistance ◽  
High Throughput ◽  
Democratic Republic Of Congo ◽  
Novel Mutation ◽  
Sub Saharan Africa ◽  
Mutant Form ◽  
Evolutionary Origins ◽  
Wild Type Counterpart ◽  
Control Programmes ◽  
Sub Saharan

AbstractThe spread of resistance to insecticides in the mosquito vectors of diseases such as malaria and dengue poses a threat to the effectiveness of control programmes, which rely largely on insecticide-based interventions. Monitoring the resistance status of mosquito populations is therefore essential, but obtaining direct phenotypic measurements of resistance is laborious and error-prone. In contrast, high-throughput genotyping offers the prospect of quick and repeatable estimates of resistance, while also allowing the genotypic markers of resistance to be tracked and studied. We developed a panel of 28 known or putative markers of resistance in the major malaria vectorAnopheles gambiae, which we use to test the association of these markers with resistance and to study their geographic distribution. We screened resistance-phenotypedAn.gambiaefrom populations from a wide swathe of Sub-Saharan Africa (Burkina Faso, Ghana, Democratic Republic of Congo (DRC) and Kenya), and found evidence of resistance association for four mutations, including a novel mutation in the detoxification geneGste2(Gste2-119V). We also identified a gene duplication inGste2which combines a resistance-associated mutant form of the gene with its wild-type counterpart, potentially alleviating the costs of resistance. Finally, we describe the distribution of the multiple evolutionary origins ofkdrresistance, finding unprecedented levels of diversity in the DRC. This panel represents the first step towards developing a quantitative predictive genotypic model of insecticide resistance that can be used to screenAn.gambiaepopulations and predict resistance status.

scholarly journals A high throughput multi-locus insecticide resistance marker panel for tracking resistance emergence and spread in Anopheles gambiae

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Eric R. Lucas ◽  
Kirk A. Rockett ◽  
Amy Lynd ◽  
John Essandoh ◽  
Nelson Grisales ◽  
...  
Keyword(s):  
Insecticide Resistance ◽  
Anopheles Gambiae ◽  
High Throughput ◽  
Democratic Republic Of Congo ◽  
Novel Mutation ◽  
Sub Saharan Africa ◽  
Wild Type Counterpart ◽  
Control Programmes ◽  
Resistance Markers ◽  
Sub Saharan

Abstract The spread of resistance to insecticides in disease-carrying mosquitoes poses a threat to the effectiveness of control programmes, which rely largely on insecticide-based interventions. Monitoring mosquito populations is essential, but obtaining phenotypic measurements of resistance is laborious and error-prone. High-throughput genotyping offers the prospect of quick and repeatable estimates of resistance, while also allowing resistance markers to be tracked and studied. To demonstrate the potential of highly-mulitplexed genotypic screening for measuring resistance-association of mutations and tracking their spread, we developed a panel of 28 known or putative resistance markers in the major malaria vector Anopheles gambiae, which we used to screen mosquitoes from a wide swathe of Sub-Saharan Africa (Burkina Faso, Ghana, Democratic Republic of Congo (DRC) and Kenya). We found resistance association in four markers, including a novel mutation in the detoxification gene Gste2 (Gste2-119V). We also identified a duplication in Gste2 combining a resistance-associated mutation with its wild-type counterpart, potentially alleviating the costs of resistance. Finally, we describe the distribution of the multiple origins of kdr resistance, finding unprecedented diversity in the DRC. This panel represents the first step towards a quantitative genotypic model of insecticide resistance that can be used to predict resistance status in An. gambiae.

scholarly journals Fanconi Bickel syndrome: clinical phenotypes and genetics in a cohort of Sudanese children

2020 ◽  
Vol 2020 (1) ◽  
Author(s):  
Salwa A. Musa ◽  
Areej A. Ibrahim ◽  
Samar S. Hassan ◽  
Matthew B Johnson ◽  
Asmahan T. Basheer ◽  
...  
Keyword(s):  
Glucose Transporter ◽  
Novel Mutation ◽  
Wide Spectrum ◽  
Rare Condition ◽  
Neonatal Diabetes ◽  
Abdominal Ultrasound ◽  
Sub Saharan Africa ◽  
High Rate ◽  
Genetic Characteristics ◽  
Sub Saharan

Abstract Background Fanconi-Bickel syndrome (FBS) is a rare condition of carbohydrate metabolism, caused by a recessive defect in the facilitative glucose transporter GLUT2 encoded by the SLC2A2 gene and characterized by a wide spectrum of phenotypical features. There is a paucity of reported data on FBS from Sub-Saharan Africa. Here, we describe the clinical, biochemical and genetic characteristics of our patients with FBS from Sudan, a country with a high consanguinity rate. Patients & methods Eleven patients from ten unrelated Sudanese families were included. Clinical & biochemical data were documented and imaging studies done including bone survey and abdominal ultrasound. Liver biopsy was done to confirm the pathological diagnosis in 45% of cases and molecular genetics was performed through contribution with the Exeter genomics laboratory for ten patients. Results Reported consanguinity was 70% among our patients. Growth was significantly impaired at presentation with mean weights of (-5.3 ± 1.8) SD and heights (-5.4 ± 2.5) SD. Severe chest deformity was present in (27%) and all patients showed features of rickets at presentation. Three patients had neonatal diabetes requiring insulin therapy of which one has been reported before. Six families lost undiagnosed siblings with similar clinical presentations. We identified a total of four homozygous pathogenic SLC2A2 variants in our patients, one of whom had a novel mutation. Conclusions FBS is not uncommon in Sudan where there is a high rate of consanguinity. Many cases are likely missed because of variable presentation and lack of public and professionals’ awareness. This is the first series to describe this condition from Sub-Saharan Africa.

scholarly journals Competing interests, clashing ideas and institutionalizing influence: insights into the political economy of malaria control from seven African countries

2020 ◽  
Author(s):  
Justin Parkhurst ◽  
Ludovica Ghilardi ◽  
Jayne Webster ◽  
Robert W Snow ◽  
Caroline A Lynch
Keyword(s):  
Decision Making ◽  
Malaria Control ◽  
Qualitative Interviews ◽  
Sub Saharan Africa ◽  
African Countries ◽  
Health Community ◽  
Control Programmes ◽  
Control Decision ◽  
Sub Saharan ◽  
Economic Considerations

Abstract This article explores how malaria control in sub-Saharan Africa is shaped in important ways by political and economic considerations within the contexts of aid-recipient nations and the global health community. Malaria control is often assumed to be a technically driven exercise: the remit of public health experts and epidemiologists who utilize available data to select the most effective package of activities given available resources. Yet research conducted with national and international stakeholders shows how the realities of malaria control decision-making are often more nuanced. Hegemonic ideas and interests of global actors, as well as the national and global institutional arrangements through which malaria control is funded and implemented, can all influence how national actors respond to malaria. Results from qualitative interviews in seven malaria-endemic countries indicate that malaria decision-making is constrained or directed by multiple competing objectives, including a need to balance overarching global goals with local realities, as well as a need for National Malaria Control Programmes to manage and coordinate a range of non-state stakeholders who may divide up regions and tasks within countries. Finally, beyond the influence that political and economic concerns have over programmatic decisions and action, our analysis further finds that malaria control efforts have institutionalized systems, structures and processes that may have implications for local capacity development.

scholarly journals Evaluating survey designs for targeting preventive chemotherapy against Schistosoma haematobium and Schistosoma mansoni across Sub-Saharan Africa: a geostatistical analysis and modelling study

2020 ◽  
Author(s):  
Kimberly Fornace ◽  
Claudio Fronterrè ◽  
Fiona M Fleming ◽  
Hope Simpson ◽  
Honorat Zoure ◽  
...  
Keyword(s):  
Cost Effectiveness ◽  
Schistosoma Haematobium ◽  
Sampling Strategy ◽  
Sub Saharan Africa ◽  
Spatial Distributions ◽  
Preventive Chemotherapy ◽  
School Based ◽  
Control Programmes ◽  
Sub Saharan ◽  
Survey Designs

Abstract Background: Schistosomiasis control programmes primarily use school-based surveys to identify areas for mass drug administration of preventive chemotherapy. However, as the spatial distribution of schistosomiasis can be highly focal, transmission may not be detected by surveys implemented at districts or larger spatial units. Improved mapping strategies are required to accurately and cost-effectively target preventive chemotherapy to remaining foci across all possible spatial distributions of schistosomiasis. Methods: Here, we use geostatistical models to quantify the spatial heterogeneity of Schistosoma haematobium and S. mansoni across sub-Saharan Africa using the most comprehensive dataset available on school-based surveys. Applying this information to parameterise simulations, we assess the accuracy and cost of targeting alternative implementation unit sizes across the range of plausible schistosomiasis distributions. We evaluate the consequences of decisions based on survey designs implemented at district and subdistrict levels sampling different numbers of schools. Cost data were obtained from field surveys conducted across multiple countries and years, with cost effectiveness evaluated as the cost per correctly identified school. Results: Models identified marked differences in prevalence and spatial distributions between countries and species; however, results suggest implementing surveys at subdistrict level increase the accuracy of treatment classifications across most scenarios. While sampling intensively at the subdistrict level resulted in the highest classification accuracy, this sampling strategy resulted in the highest costs. Alternatively, sampling the same numbers of schools currently recommended at the district level but stratifying by subdistrict increased cost effectiveness.Conclusions: This study provides a new tool to evaluate schistosomiasis survey designs across a range of transmission settings. Results highlight the importance of considering spatial structure when designing sampling strategies, illustrating that a substantial proportion of children may be undertreated even when an implementation unit is correctly classified. Control programmes need to weigh the increased accuracy of more detailed mapping strategies against the survey costs and treatment priorities.

scholarly journals Seroprevalence of Bovine Brucellosis in Selected Districts of Zambia

2020 ◽  
Author(s):  
Ruth Lindizyani Mfune ◽  
Melai Mubanga ◽  
Isaac Silwamba ◽  
Frederick Sagamiko ◽  
Jacques Godfroid ◽  
...  
Keyword(s):  
Cross Sectional Study ◽  
Sub Saharan Africa ◽  
Brucella Species ◽  
Sectional Study ◽  
Bovine Brucellosis ◽  
Cross Sectional ◽  
Serial Testing ◽  
Control Programmes ◽  
Sub Saharan ◽  
Cattle Herds

Brucellosis is an infectious zoonosis that has huge economic and public health implications globally. The disease is prevalent in humans, livestock and wildlife in Sub Saharan Africa. A cross-sectional study was conducted between 6th May 2017 and 31st July 2020 during which 1712 sera from 177 cattle herds in Southern, Western and Eastern provinces of Zambia was collected and screened against brucellosis. Rose Bengal Test and c-ELISA were used in serial testing for detection of antibodies against Brucella species. Results: A total of 127 animals and 37 herds tested positive, giving an overall individual and herd seroprevalence of 7.42% (CI: 0.61-0.86) and 20.9% respectively. Namwala district recorded the highest seroprevalence (12.2%) while Lundazi had the lowest (0%). A higher seropositivity was observed among female animals (8.5%), those aged between 11 and 17 years (14.1%) and pregnant cows (13.8%). Conclusions: Brucella seroprevalence among traditional cattle in Zambia remains high. It is vital that control programmes against bovine brucellosis are introduced in order to reduce its zoonotic impact on human health and increase animal production.

scholarly journals Perceptions du climat d'apprentissage universitaire : une approche emipirique à la qualitè de l'enseignement en République Démocratique du Congo/Goma

2021 ◽  
Author(s):  
Semerita Kavira Kamundu
Keyword(s):  
Social Relations ◽  
Democratic Republic Of Congo ◽  
Sub Saharan Africa ◽  
Learning Climate ◽  
Structured Interviews ◽  
République Démocratique Du Congo ◽  
Theoretical Sampling ◽  
Sub Saharan ◽  
Further Development

This study focuses on learning climate in universities in the Democratic Republic of Congo. Learning climate constitutes one of the most important criteria for educational quality as it influences the learning outcome. The study is conducted in the DRC, one of the developing countries of Sub-Saharan Africa, where the quality of education is very important to remedy the traditional educational system applied in several schools and universities. Using a qualitative approach with semi-structured interviews (n = 32) based on a theoretical sampling, following grounded theory, four types of climate were revealed in the data analysis: The climate based on learning where the learner feels better considered, the climate based on social relations where the interactions between the teacher and the learner are positive, the climate based on the teacher where the learner is passive, and the climate based on the use of authority where the learner only submits to the decisions of the authority. These four types are discussed in relation to their functionality to learning and recommendations for the further development of universities are given.

scholarly journals Modelling the drivers of the spread of Plasmodium falciparum hrp2 gene deletions in sub-Saharan Africa

eLife ◽  
2017 ◽  
Vol 6 ◽  
Author(s):  
Oliver J Watson ◽  
Hannah C Slater ◽  
Robert Verity ◽  
Jonathan B Parr ◽  
Melchior K Mwandagalirwa ◽  
...  
Keyword(s):  
Democratic Republic Of Congo ◽  
False Negative ◽  
Malaria Diagnosis ◽  
Parasite Prevalence ◽  
Malaria Prevalence ◽  
Sub Saharan Africa ◽  
Gene Deletions ◽  
High Frequencies ◽  
Sub Saharan ◽  
Selection Of

Rapid diagnostic tests (RDTs) have transformed malaria diagnosis. The most prevalent P. falciparum RDTs detect histidine-rich protein 2 (PfHRP2). However, pfhrp2 gene deletions yielding false-negative RDTs, first reported in South America in 2010, have been confirmed in Africa and Asia. We developed a mathematical model to explore the potential for RDT-led diagnosis to drive selection of pfhrp2-deleted parasites. Low malaria prevalence and high frequencies of people seeking treatment resulted in the greatest selection pressure. Calibrating our model against confirmed pfhrp2-deletions in the Democratic Republic of Congo, we estimate a starting frequency of 6% pfhrp2-deletion prior to RDT introduction. Furthermore, the patterns observed necessitate a degree of selection driven by the introduction of PfHRP2-based RDT-guided treatment. Combining this with parasite prevalence and treatment coverage estimates, we map the model-predicted spread of pfhrp2-deletion, and identify the geographic regions in which surveillance for pfhrp2-deletion should be prioritised.

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