The seasonality of cholera in sub-Saharan Africa

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.

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The seasonality of cholera in sub-Saharan Africa

10.1101/2021.11.23.21265642 ◽

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.

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An Overview of Cholera Epidemiology: A Focus on Africa; with a Keen Interest on Nigeria

International Journal of TROPICAL DISEASE & Health ◽

10.9734/ijtdh/2019/v40i330229 ◽

2020 ◽

pp. 1-17

Author(s):

Tarh, Jacqueline Ebob

Keyword(s):

Local Government ◽

Task Force ◽

Case Fatality ◽

Sub Saharan Africa ◽

Polluted Water ◽

The People ◽

Sanitation And Hygiene ◽

The World ◽

Sub Saharan ◽

Sanitary Conditions

Cholera is still a problem in the world today. A huge population of deaths due to cholera disease still occur in Sub-Saharan Africa (Nigeria most especially), Asia, the Americas and other developing countries, where approximately 1.7 billion inhabitants are still served by faecally polluted water sources. Approximately, 2.4 billion inhabitants of these areas of the world lack the majorly required sanitary conditions of living. Legros, asserts that, as of 2019, about forty-seven countries of the globe, are still affected by cholera. Raw or undercooked, contaminated seafood, serves as a vehicle for the transmission (especially to non-endemic areas). A Case Fatality Rate of 4.87% was recorded from 34 Local Government Areas of Bauchi, Borno, Kaduna, Kano and Zamfara state in Nigeria by the 34th week, in 2018, while 298 confirmed cases and 38 deaths (CFR 1.5%) were recorded from three Local Government Areas in two States (Adamawa & Borno) by Epidemiological week 41 in 2019. Cholera in some cases is regarded as a “disease of the poor” because the populations most affected are those that cannot afford to provide the basic health facilities for themselves. For example, waste management systems, and good accommodation with toilet facilities (the living and health conditions of the people) are wanting. In 2017, A Global Roadmap to 2030 was launched by the Global Task Force on Cholera Control (GTFCC Ending Cholera) to decrease the death rate due to cholera by 90%. By so doing, the disease can be eradicated from at least half of the 47 cholera-affected countries. The objectives of this roadmap are: to fortify health systems, water, sanitation and hygiene (WASH), and to coordinate different ways by which cholera can be controlled in these countries by 2030 (ensuring early detection and prompt response to contain outbreaks). This review aimed to understand the epidemiology of cholera in Nigeria, Africa and the world at large, to access the level of spread, management and preventive measures so far implemented in the endemic regions.

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The effect of recombination on the evolution of a population of Neisseria meningitidis

10.1101/2020.04.08.031906 ◽

2020 ◽

Author(s):

Neil MacAlasdair ◽

Maiju Pesonen ◽

Ola Brynildsrud ◽

Vegard Eldholm ◽

Paul A. Kristiansen ◽

...

Keyword(s):

Population Structure ◽

Burkina Faso ◽

Neisseria Meningitidis ◽

Large Scale ◽

Invasive Disease ◽

Pathogen Transmission ◽

Sub Saharan Africa ◽

Health Concern ◽

Recombination Hotspots ◽

Sub Saharan

Neisseria meningitidis (the meningococcus) is a major human pathogen with a history of high invasive disease burden, particularly in sub-Saharan Africa. Our current understanding of the evolution of meningococcal genomes is limited by the rarity of large-scale genomic population studies and lack of in-depth investigation of the genomic events associated with routine pathogen transmission. Here we fill this knowledge gap by a detailed analysis of 2,839 meningococcal genomes obtained through a carriage study of over 50,000 samples collected systematically in Burkina Faso, West Africa, before, during, and after the serogroup A vaccine rollout, 2009-2012. Our findings indicate that the meningococcal genome is highly dynamic, with recombination hotspots and frequent gene sharing across deeply separated lineages in a structured population. Furthermore, our findings illustrate the profound effect of population structure on genome flexibility, with some lineages in Burkina Faso being orders of magnitude more recombinant than others. We also examine the effect of selection on the population, in particular how it is correlated with recombination. We find that recombination principally acts to prevent the accumulation of deleterious mutations, although we do also find an example of recombination acting to speed the adaptation of a gene. In general, we show the importance of recombination in the evolution of a geographically expansive population with deep population structure in a short timescale. This has important consequences for our ability to both foresee the outcomes of vaccination programmes and, using surveillance data, predict when lineages of the meningococcus are likely to become a public health concern.

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Control of schistosomiasis in sub-Saharan Africa: progress made, new opportunities and remaining challenges

Parasitology ◽

10.1017/s0031182009991272 ◽

2009 ◽

Vol 136 (13) ◽

pp. 1665-1675 ◽

Cited By ~ 59

Author(s):

J. R. STOTHARD ◽

L. CHITSULO ◽

T. K. KRISTENSEN ◽

J. UTZINGER

Keyword(s):

Large Scale ◽

Neglected Tropical Diseases ◽

Monitoring And Evaluation ◽

Sub Saharan Africa ◽

World Health ◽

African Countries ◽

Schistosomiasis Control ◽

Sub Saharan ◽

Gates Foundation ◽

Made In

SUMMARYSeveral other journal supplements have documented progress made in the control of schistosomiasis in Egypt, China and Brazil, however, with more than 97% of the schistosome infections now estimated to occur in Africa, the relevance of this special issue in Parasitology cannot be overemphasized. In total, 18 articles are presented, inclusive of a lead-editorial from the WHO highlighting a seminal resolution at the 54th World Health Assembly in 2001 that advocated de-worming. Facilitated by a US$ 30 million grant from the Bill and Melinda Gates Foundation in 2002, the Schistosomiasis Control Initiative subsequently fostered implementation of large-scale schistosomiasis (and soil-transmitted helminthiasis) control programmes in six selected African countries. From 2005, CONTRAST, a European union-funded consortium, was formed to conduct multi-disciplinary research pertaining to optimisation of schistosomiasis control. Progress made in schistosomiasis control across sub-Saharan Africa since the turn of the new millennium is reviewed, shedding light on the latest findings stemming from clinical, epidemiological, molecular and social sciences research, inclusive of public health interventions with monitoring and evaluation activities. New opportunities for integrating the control of schistosomiasis and other so-called neglected tropical diseases are highlighted, but more importantly, several opportune questions that arise from it frame the remaining challenges ahead for an enduring solution.

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Geographical distribution of risk factors for invasive non-typhoidal Salmonella at the subnational boundary level in sub-Saharan Africa

BMC Infectious Diseases ◽

10.1186/s12879-021-06198-1 ◽

2021 ◽

Vol 21 (1) ◽

Author(s):

Jung-Seok Lee ◽

Vittal Mogasale ◽

Florian Marks ◽

Jerome Kim

Keyword(s):

Risk Factors ◽

High Risk ◽

Case Fatality ◽

Population Based ◽

Sub Saharan Africa ◽

Health Concern ◽

Risk Level ◽

Accurate Estimation ◽

Risk Areas ◽

Sub Saharan

Abstract Background Invasive non-typhoidal Salmonella (iNTS) is a growing health-concern in many parts of sub-Saharan Africa. iNTS is associated with fatal diseases such as HIV and malaria. Despite high case fatality rates, the disease has not been given much attention. The limited number of population-based surveillance studies hampers accurate estimation of global disease burden. Given the lack of available evidence on the disease, it is critical to identify high risk areas for future surveillance and to improve our understanding of iNTS endemicity. Methods Considering that population-based surveillance data were sparse, a composite index called the iNTS risk factor (iNRF) index was constructed based on risk factors that commonly exist across countries. Four risk factors associated with the prevalence of iNTS were considered: malaria, HIV, malnutrition, and safe water. The iNRF index was first generated based on the four risk factors which were collected within a 50 km radius of existing surveillance sites. Pearson product-moment correlation was used to test statistical associations between the iNRF index and the prevalence of iNTS observed in the surveillance sites. The index was then further estimated at the subnational boundary level across selected countries and used to identify high risk areas for iNTS. Results While the iNRF index in some countries was generally low (i.e. Rwanda) or high (i.e. Cote d’Ivoire), the risk-level of iNTS was variable not only by country but also within a country. At the provincial-level, the highest risk area was identified in Maniema, the Democratic Republic of Congo, whereas Dakar in Senegal was at the lowest risk. Conclusions The iNRF index can be a useful tool to understand the geographically varying risk-level of iNTS. Given that conducting a population-based surveillance study requires extensive human and financial resources, identifying high risk areas for iNTS prior to a study implementation can facilitate an appropriate site-selection process in the future.

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Neisseria Meningitis

10.33442/vt202134 ◽

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.

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Adolescent Suicidality as Seen in Rural Northeastern Uganda

Crisis ◽

10.1027/0227-5910/a000059 ◽

2011 ◽

Vol 32 (1) ◽

pp. 43-51 ◽

Cited By ~ 17

Author(s):

Eugene Kinyanda ◽

Ruth Kizza ◽

Jonathan Levin ◽

Sheila Ndyanabangi ◽

Catherine Abbo

Keyword(s):

Low Socioeconomic Status ◽

Sub Saharan Africa ◽

Psychosocial Risk ◽

Psychiatric Nurses ◽

Health Concern ◽

Cross Sectional ◽

Childhood Experiences ◽

Low Socioeconomic ◽

Dsm Iv ◽

Sub Saharan

Background: Suicidal behavior in adolescence is a public health concern and has serious consequences for adolescents and their families. There is, however, a paucity of data on this subject from sub-Saharan Africa, hence the need for this study. Aims: A cross-sectional multistage survey to investigate adolescent suicidality among other things was undertaken in rural northeastern Uganda. Methods: A structured protocol administered by trained psychiatric nurses collected information on sociodemographics, mental disorders (DSM-IV criteria), and psychological and psychosocial risk factors for children aged 3–19 years (N = 1492). For the purposes of this paper, an analysis of a subsample of adolescents (aged 10–19 years; n = 897) was undertaken. Results: Lifetime suicidality in this study was 6.1% (95% CI, 4.6%–7.9%). Conclusions: Factors significantly associated with suicidality included mental disorder, the ecological factor district of residence, factors suggestive of low socioeconomic status, and disadvantaged childhood experiences.

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

Sustainability ◽

10.3390/su13031158 ◽

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.

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Genetic polymorphism and population structure ofEchinococcus ortleppi

Parasitology ◽

10.1017/s0031182016001840 ◽

2016 ◽

Vol 144 (4) ◽

pp. 450-458 ◽

Cited By ~ 17

Author(s):

F. ADDY ◽

M. WASSERMANN ◽

F. BANDA ◽

H. MBAYA ◽

J. ASCHENBORN ◽

...

Keyword(s):

Genetic Polymorphism ◽

South America ◽

Southern Africa ◽

Dna Sequences ◽

Intraspecific Variability ◽

Sensu Stricto ◽

Sub Saharan Africa ◽

Geographical Regions ◽

Sub Saharan ◽

Eastern And Southern Africa

SUMMARYThe zoonotic cestodeEchinococcus ortleppi(Lopez-Neyra and Soler Planas, 1943) is mainly transmitted between dogs and cattle. It occurs worldwide but is only found sporadically in most regions, with the notable exception of parts of southern Africa and South America. Its epidemiology is little understood and the extent of intraspecific variability is unknown. We have analysed in the present study the genetic diversity among 178E. ortleppiisolates from sub-Saharan Africa, Europe and South America using the complete mitochondrialcox1(1608 bp) andnad1(894 bp) DNA sequences. Genetic polymorphism within the loci revealed 15cox1and sixnad1haplotypes, respectively, and 20 haplotypes of the concatenated genes. Presence of most haplotypes was correlated to geographical regions, and only one haplotype had a wider spread in both eastern and southern Africa. Intraspecific microvariance was low in comparison withEchinococcus granulosussensu stricto, despite the wide geographic range of examined isolates. In addition, the various sub-populations showed only subtle deviation from neutrality and were mostly genetically differentiated. This is the first insight into the population genetics of the enigmatic cattle adaptedEchinococcus ortleppi. It, therefore, provides baseline data for biogeographical comparison amongE. ortleppiendemic regions and for tracing its translocation paths.

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

Evaluation Review ◽

10.1177/0193841x16660246 ◽

2016 ◽

Vol 40 (6) ◽

pp. 500-525 ◽

Cited By ~ 10

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.

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