Neisseria Meningitis

2021 ◽  
Author(s):  
Stephen Clark ◽  
Jay Lucidarme ◽  
Ray Borrow
Keyword(s):  
Meningococcal Disease ◽  
Large Scale ◽  
Case Fatality ◽  
Sub Saharan Africa ◽  
Immune Memory ◽  
Public Health Issue ◽  
Epidemic Disease ◽  
Conjugate Vaccines ◽  
Catch Up ◽  
Sub Saharan

Meningococcal disease is caused by the Gram-negative bacterium Neisseria meningitidis (the meningococcus). It remains a significant public health issue globally causing both endemic and epidemic disease in developed and developing countries. Approximately 10% of humans harmlessly carry N. meningitidis in the oronasopharynx. On very rare occasions the bacteria may cross the epithelium and enter the blood stream causing sudden onset of sepsis and or meningitis with high complication and case fatality rates, even with appropriate antibiotic treatment. A limited number of strains cause the majority of invasive disease and, in normally healthy individuals, these practically always express a protective polysaccharide capsule on their cell surface. There are 12 capsular serogroups, of which A, B, C, W, X and Y cause the vast majority of invasive meningococcal disease worldwide. Polysaccharide-based vaccines target the capsule and so are serogroup-specific. Plain (unconjugated) polysaccharide vaccines were developed first and have been used in control of serogroup A epidemics in sub-Saharan Africa and for controlling serogroup C disease in the military and college students. Associated limitations include poor immunogenicity in young children, hyporesponsiveness with repeat doses, inability to induce immune memory and lack of an effect on carriage. Conjugated polysaccharide vaccines have none of these limitations and, most importantly, significantly reduce carriage. Therefore, large scale vaccination of cohorts with high carriage (catch-up campaigns) are highly effective in inducing herd protection. Serogroup C conjugate vaccines have been hugely successful in dramatically reducing disease in the countries that have instigated immunization programs together with appropriate catch-up campaigns. Meningococcal quadrivalent conjugate vaccines are now being implemented into schedules. With the development and introduction of a meningococcal serogroup A conjugate vaccine, serogroup A disease has disappeared from those sub-Saharan countries who have implemented campaigns. The serogroup B polysaccharide is poorly immunogenic and so broad coverage protein-based serogroup B vaccines have been developed.

Neisseria-meningitidis-diseases

2021 ◽  
Author(s):  
Stephen Clark ◽  
Jay Lucidarme ◽  
Ray Borrow
Keyword(s):  
Neisseria Meningitidis ◽  
Meningococcal Disease ◽  
Case Fatality ◽  
Sub Saharan Africa ◽  
Immune Memory ◽  
Public Health Issue ◽  
Epidemic Disease ◽  
Conjugate Vaccines ◽  
Catch Up ◽  
Sub Saharan

Meningococcal disease is caused by the Gram-negative bacterium Neisseria meningitidis (the meningococcus). It remains a significant public health issue globally causing both endemic and epidemic disease in developed and developing countries. Approximately 10% of humans harmlessly carry N. meningitidis in the oronasopharynx. On very rare occasions the bacteria may cross the epithelium and enter the blood stream causing sudden onset of sepsis and or meningitis with high complication and case fatality rates, even with appropriate antibiotic treatment. A limited number of strains cause the majority of invasive disease and, in normally healthy individuals, these practically always express a protective polysaccharide capsule on their cell surface. There are 12 capsular serogroups, of which A, B, C, W, X and Y cause the vast majority of invasive meningococcal disease worldwide. Polysaccharide-based vaccines target the capsule and so are serogroup-specific. Plain (unconjugated) polysaccharide vaccines were developed first and have been used in control of serogroup A epidemics in sub-Saharan Africa and for controlling serogroup C disease in the military and college students. Associated limitations include poor immunogenicity in young children, hyporesponsiveness with repeat doses, inability to induce immune memory and lack of an effect on carriage. Conjugated polysaccharide vaccines have none of these limitations and, most importantly, significantly reduce carriage. Therefore, large scale vaccination of cohorts with high carriage (catch-up campaigns) are highly effective in inducing herd protection. Serogroup C conjugate vaccines have been hugely successful in dramatically reducing disease in the countries that have instigated immunization programs together with appropriate catch-up campaigns. Meningococcal quadrivalent conjugate vaccines are now being implemented into schedules. With the development and introduction of a meningococcal serogroup A conjugate vaccine, serogroup A disease has disappeared from those sub-Saharan countries who have implemented campaigns. The serogroup B polysaccharide is poorly immunogenic and so broad coverage protein-based serogroup B vaccines have been developed.

scholarly journals The seasonality of cholera in sub-Saharan Africa

2021 ◽  
Author(s):  
Javier Perez-Saez ◽  
Justin Lessler ◽  
Elizabeth C. Lee ◽  
Francisco J. Luquero ◽  
Espoir B. Malembaka ◽  
...  
Keyword(s):  
Large Scale ◽  
Task Force ◽  
Case Fatality ◽  
Sub Saharan Africa ◽  
Health Concern ◽  
National Differences ◽  
Sub Saharan ◽  
Eastern And Southern Africa ◽  
Positive Correlations ◽  
Gates Foundation

Background Cholera remains a major threat in Sub-Saharan Africa (SSA) where some of the highest case fatality risks are reported. Knowing in what months and where cholera tends to occur across the continent can aid in improving efforts to eliminate cholera as a public health concern; though largely due to lack of unified large-scale datasets, no continent-wide estimates exist. In this study we aim to estimate cholera seasonality across SSA. Methods We leverage the Global Task Force on Cholera Control (GTFCC) global cholera database with statistical models to synthesize data across spatial and temporal scale in order to infer the seasonality of excess suspected cholera occurrence in SSA. We developed a Bayesian statistical model to infer the monthly risk of excess cholera at the first and/or second administrative levels. Seasonality patterns were then grouped into spatial clusters. Finally, we studied the association between seasonality estimates and hydro-climatic variables. Findings The majority of studied countries (24/34) have seasonal patterns in excess cholera, corresponding to approximately 85% of the SSA population. Most countries (19/24) also had sub-national differences in seasonality patterns, with strong differences in seasonality strength between regions. Seasonality patterns clustered into two macro-regions (West Africa and the Sahel vs. Eastern and Southern Africa), which were composed of sub-regional clusters with varying degrees of seasonality. Exploratory association analysis found most consistent and positive correlations between cholera seasonality and precipitation, and to a lesser extent with temperature and flooding. Interpretation Widespread cholera seasonality in SSA offers opportunities for intervention planning. Further studies are needed to study the association between cholera and climate. Funding The NASA Applied Sciences Program and the Bill and Melinda Gates Foundation.

scholarly journals The seasonality of cholera in sub-Saharan Africa

2021 ◽  
Author(s):  
Francisco Javier Perez-Saez ◽  
Justin Lessler ◽  
Elizabeth C. Lee ◽  
Francisco J. Luquero ◽  
Espoir B. Malembaka ◽  
...  
Keyword(s):  
Large Scale ◽  
Task Force ◽  
Case Fatality ◽  
Sub Saharan Africa ◽  
Health Concern ◽  
National Differences ◽  
Administrative Unit ◽  
Sub Saharan ◽  
Eastern And Southern Africa ◽  
Gates Foundation

BackgroundCholera remains a major threat in Sub-Saharan Africa (SSA) where some of the highest case fatality risks are reported. Knowing in what months and where cholera tends to occur across the continent can aid in improving efforts to eliminate cholera as a public health concern; though largely due to lack of unified large-scale datasets, no continent-wide estimates exist. In this study we aim to estimate cholera seasonality across SSA. MethodsWe leverage the Global Task Force on Cholera Control (GTFCC) global cholera database with statistical models to synthesize data across spatial and temporal scale in order to infer the seasonality of excess suspected cholera occurrence in SSA. Cholera excess occurrence was defined based on exceeding previously published estimates of mean monthly cholera incidence estimates in a given administrative unit. We developed a Bayesian statistical model to infer the monthly risk of excess cholera at the first and/or second administrative levels. Seasonality patterns were then grouped into spatial clusters. Finally, we studied the association between seasonality estimates and hydro-climatic variables.FindingsWe find that the majority of studied countries (26/38) have seasonal excess cholera patterns, corresponding to ~85% of the SSA population. Most countries (20/38) also had sub-national differences in seasonality patterns, with strong differences in seasonality strength between regions. Seasonality patterns clustered into two macro-regions (West Africa and the Sahel vs. Eastern and Southern Africa), which were composed of sub-regional clusters with varying degrees of seasonality. Exploratory association analysis found most consistent and positive correlations between cholera seasonality and precipitation, and to a lesser extent with temperature and flooding.InterpretationWidespread cholera seasonality in SSA offers opportunities for intervention planning. Further studies are needed to study the association between cholera and climate. FundingThe NASA Applied Sciences Program and the Bill and Melinda Gates Foundation.

scholarly journals Precision Agriculture for Resource Use Efficiency in Smallholder Farming Systems in Sub-Saharan Africa: A Systematic Review

2021 ◽  
Vol 13 (3) ◽  
pp. 1158
Author(s):  
Cecilia M. Onyango ◽  
Justine M. Nyaga ◽  
Johanna Wetterlind ◽  
Mats Söderström ◽  
Kristin Piikki
Keyword(s):  
Resource Use ◽  
Precision Agriculture ◽  
Large Scale ◽  
English Language ◽  
Management Practices ◽  
Smallholder Farmers ◽  
Management Strategies ◽  
Sub Saharan Africa ◽  
Smallholder Farming ◽  
Sub Saharan

Opportunities exist for adoption of precision agriculture technologies in all parts of the world. The form of precision agriculture may vary from region to region depending on technologies available, knowledge levels and mindsets. The current review examined research articles in the English language on precision agriculture practices for increased productivity among smallholder farmers in Sub-Saharan Africa. A total of 7715 articles were retrieved and after screening 128 were reviewed. The results indicate that a number of precision agriculture technologies have been tested under SSA conditions and show promising results. The most promising precision agriculture technologies identified were the use of soil and plant sensors for nutrient and water management, as well as use of satellite imagery, GIS and crop-soil simulation models for site-specific management. These technologies have been shown to be crucial in attainment of appropriate management strategies in terms of efficiency and effectiveness of resource use in SSA. These technologies are important in supporting sustainable agricultural development. Most of these technologies are, however, at the experimental stage, with only South Africa having applied them mainly in large-scale commercial farms. It is concluded that increased precision in input and management practices among SSA smallholder farmers can significantly improve productivity even without extra use of inputs.

Intraclass Correlation Coefficients for Designing Cluster-Randomized Trials in Sub-Saharan Africa Education

2016 ◽  
Vol 40 (6) ◽  
pp. 500-525 ◽  
Author(s):  
Ben Kelcey ◽  
Zuchao Shen ◽  
Jessaca Spybrook
Keyword(s):  
Large Scale ◽  
Randomized Trials ◽  
Intraclass Correlation ◽  
Educational Interventions ◽  
Sub Saharan Africa ◽  
Design Stage ◽  
Education Outcomes ◽  
Randomized Studies ◽  
Sub Saharan ◽  
Variance Explained

Objective: Over the past two decades, the lack of reliable empirical evidence concerning the effectiveness of educational interventions has motivated a new wave of research in education in sub-Saharan Africa (and across most of the world) that focuses on impact evaluation through rigorous research designs such as experiments. Often these experiments draw on the random assignment of entire clusters, such as schools, to accommodate the multilevel structure of schooling and the theory of action underlying many school-based interventions. Planning effective and efficient school randomized studies, however, requires plausible values of the intraclass correlation coefficient (ICC) and the variance explained by covariates during the design stage. The purpose of this study was to improve the planning of two-level school-randomized studies in sub-Saharan Africa by providing empirical estimates of the ICC and the variance explained by covariates for education outcomes in 15 countries. Method: Our investigation drew on large-scale representative samples of sixth-grade students in 15 countries in sub-Saharan Africa and includes over 60,000 students across 2,500 schools. We examined two core education outcomes: standardized achievement in reading and mathematics. We estimated a series of two-level hierarchical linear models with students nested within schools to inform the design of two-level school-randomized trials. Results: The analyses suggested that outcomes were substantially clustered within schools but that the magnitude of the clustering varied considerably across countries. Similarly, the results indicated that covariance adjustment generally reduced clustering but that the prognostic value of such adjustment varied across countries.

Land conflicts and social differentiation in eastern Uganda

2017 ◽  
Vol 55 (3) ◽  
pp. 395-422 ◽  
Author(s):  
Matt Kandel
Keyword(s):  
Large Scale ◽  
Local Level ◽  
Sub Saharan Africa ◽  
Social Differentiation ◽  
Land Conflicts ◽  
Current Period ◽  
Post Conflict ◽  
Sub Saharan ◽  
Historical Developments ◽  
Eastern Uganda

ABSTRACTRising competition and conflict over land in rural sub-Saharan Africa continues to attract the attention of researchers. Recent work has especially focused on land governance, post-conflict restructuring of tenure relations, and large-scale land acquisitions. A less researched topic as of late, though one deserving of greater consideration, pertains to how social differentiation on the local-level shapes relations to land, and how these processes are rooted in specific historical developments. Drawing on fieldwork conducted in Teso sub-region of eastern Uganda, this paper analyses three specific land conflicts and situates them within a broad historical trajectory. I show how each dispute illuminates changes in class relations in Teso since the early 1990s. I argue that this current period of socioeconomic transformation, which includes the formation of a more clearly defined sub-regional middle class and elite, constitutes the most prominent period of social differentiation in Teso since the early 20th century.

scholarly journals Resource frontiers and agglomeration economies: The varied logics of transnational land-based investing in Southern and Eastern Africa

AMBIO ◽  
2022 ◽  
Author(s):  
Dilini Abeygunawardane ◽  
Angela Kronenburg García ◽  
Zhanli Sun ◽  
Daniel Müller ◽  
Almeida Sitoe ◽  
...  
Keyword(s):  
Spatial Data ◽  
Large Scale ◽  
Agglomeration Economies ◽  
Sub Saharan Africa ◽  
Eastern Africa ◽  
Track Record ◽  
Level Data ◽  
Forestry Investments ◽  
Sub Saharan ◽  
Investment Location

AbstractActor-level data on large-scale commercial agriculture in Sub-Saharan Africa are scarce. The peculiar choice of transnational investing in African land has, therefore, been subject to conjecture. Addressing this gap, we reconstructed the underlying logics of investment location choices in a Bayesian network, using firm- and actor-level interview and spatial data from 37 transnational agriculture and forestry investments across 121 sites in Mozambique, Zambia, Tanzania, and Ethiopia. We distinguish four investment locations across gradients of resource frontiers and agglomeration economies to derive the preferred locations of different investors with varied skillsets and market reach (i.e., track record). In contrast to newcomers, investors with extensive track records are more likely to expand the land use frontier, but they are also likely to survive the high transaction costs of the pre-commercial frontier. We highlight key comparative advantages of Southern and Eastern African frontiers and map the most probable categories of investment locations.

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