Search

The expansion of people speaking Bantu languages is the most dramatic demographic event in Late Holocene Africa and fundamentally reshaped the linguistic, cultural and biological landscape of the continent 1-7 . With a comprehensive genomic dataset, including newly generated data of modern-day and ancient DNA from previously unsampled regions in Africa, we contribute insights into this expansion that started 6,000-4,000 years ago in western Africa. We genotyped 1,763 participants, including 1,526 Bantu speakers from 147 populations across 14 African countries, and generated whole-genome sequences from 12 Late Iron Age individuals 8 . We show that genetic diversity amongst Bantu-speaking populations declines with distance from western Africa, with current-day Zambia and the Democratic Republic of Congo as possible crossroads of interaction. Using spatially explicit methods 9 and correlating genetic, linguistic and geographical data, we provide cross-disciplinary support for a serial-founder migration model. We further show that Bantu speakers received significant gene flow from local groups in regions they expanded into. Our genetic dataset provides an exhaustive modern-day African comparative dataset for ancient DNA studies 10 and will be important to a wide range of disciplines from science and humanities, as well as to the medical sector studying human genetic variation and health in African and African-descendant populations., (© 2023. The Author(s).)

Pottery traditions reflect the socioeconomic framework of past cultures, while the spatial distribution of pottery indicates exchange patterns and interaction processes. Material and earth sciences are employed here to determine raw material sourcing, selection and processing. The Kongo kingdom, internationally renowned since the late fifteenth century, is one of the most famous precolonial states in Central Africa. Despite the large number of historical studies relying on African and European oral and written chronicles, there are still considerable gaps in our current understanding of this political unit. Here, we provide new insights into pottery production and circulation within the Kongo kingdom. Implementing a multi-analytical approach, namely XRD, TGA, petrographic analysis, XRF, VP-SEM-EDS and ICP-MS, on selected samples, we determined their petrographic, mineralogical and geochemical signatures. Our results allowed us to correlate the archaeological objects to naturally occurring materials and to establish ceramic traditions. We identified production templates, exchange patterns, distribution of high-quality goods and interaction processes through technological knowledge transmission. Our results demonstrate that political centralisation in the Lower Congo region of Central Africa had a direct impact on pottery production and circulation. We expect our study to provide a sound basis for further comparative research to contextualise the region., (© 2022. The Author(s).)

South Eastern Bantu-speaking (SEB) groups constitute more than 80% of the population in South Africa. Despite clear linguistic and geographic diversity, the genetic differences between these groups have not been systematically investigated. Based on genome-wide data of over 5000 individuals, representing eight major SEB groups, we provide strong evidence for fine-scale population structure that broadly aligns with geographic distribution and is also congruent with linguistic phylogeny (separation of Nguni, Sotho-Tswana and Tsonga speakers). Although differential Khoe-San admixture plays a key role, the structure persists after Khoe-San ancestry-masking. The timing of admixture, levels of sex-biased gene flow and population size dynamics also highlight differences in the demographic histories of individual groups. The comparisons with five Iron Age farmer genomes further support genetic continuity over ~400 years in certain regions of the country. Simulated trait genome-wide association studies further show that the observed population structure could have major implications for biomedical genomics research in South Africa.

The present-day distribution of Bantu languages is commonly thought to reflect the early stages of the Bantu Expansion, the greatest migration event in African prehistory. Using 1149 radiocarbon dates linked to 115 pottery styles recovered from 726 sites throughout the Congo rainforest and adjacent areas, we show that this is not the case. Two periods of more intense human activity, each consisting of an expansion phase with widespread pottery styles and a regionalization phase with many more local pottery styles, are separated by a widespread population collapse between 400 and 600 CE followed by major resettlement centuries later. Coinciding with wetter climatic conditions, the collapse was possibly promoted by a prolonged epidemic. Comparison of our data with genetic and linguistic evidence further supports a spread-over-spread model for the dispersal of Bantu speakers and their languages., (Copyright © 2021 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works. Distributed under a Creative Commons Attribution NonCommercial License 4.0 (CC BY-NC).)

Africa hosts the greatest human genetic diversity globally, but legacies of ancient population interactions and dispersals across the continent remain understudied. Here, we report genome-wide data from 20 ancient sub-Saharan African individuals, including the first reported ancient DNA from the DRC, Uganda, and Botswana. These data demonstrate the contraction of diverse, once contiguous hunter-gatherer populations, and suggest the resistance to interaction with incoming pastoralists of delayed-return foragers in aquatic environments. We refine models for the spread of food producers into eastern and southern Africa, demonstrating more complex trajectories of admixture than previously suggested. In Botswana, we show that Bantu ancestry post-dates admixture between pastoralists and foragers, suggesting an earlier spread of pastoralism than farming to southern Africa. Our findings demonstrate how processes of migration and admixture have markedly reshaped the genetic map of sub-Saharan Africa in the past few millennia and highlight the utility of combined archaeological and archaeogenetic approaches., (Copyright © 2020 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works. Distributed under a Creative Commons Attribution License 4.0 (CC BY).)

Objectives: To assess access to adequate water, sanitation and hygiene (WASH) among people with disabilities at the household and individual level., Design: Cross-sectional surveys., Setting: Data were included from five district-level or regional-level surveys: two in Bangladesh (Bangladesh-1, Bangladesh-2), and one each in Cameroon, Malawi and India., Participants: 99 252 participants were sampled across the datasets (range: 3567-75 767), including 2494 with disabilities (93-1374)., Outcome: Prevalence of access to WASH at household and individual level., Data Analysis: Age/sex disaggregated disability prevalence estimates were calculated accounting for survey design. The Unicef/WHO Joint Monitoring Programme definitions were used to classify facilities as improved/unimproved. Multivariable logistic regression was undertaken to compare between households with/without a person with a disability, and to identify predictors of access among people with disabilities., Results: There were no differences in access to improved sanitation or water sources between households with/without members with disabilities across the datasets. In Bangladesh-2, households including a person with a disability were more likely to share facilities with other households (OR 1.3, 95% CI 1.1 to 1.5). Households with people with disabilities were more likely to spend >30 min (round-trip) collecting drinking water than households without in both Cameroon (OR 1.8, 95% CI 1.0 to 3.4) and India (OR 2.3, 95% CI 1.2 to 4.7). Within households, people with disabilities reported difficulties collecting water themselves (23%-80% unable to) and accessing the same sanitation facilities as other household members, particularly without coming into contact with faeces (up to 47% in Bangladesh-2). These difficulties were most marked for people with more severe impairments., Conclusions: People with disabilities may not have poorer access to WASH at the household level, but may have poorer quality of access within their households. Further programmatic work is needed to ensure WASH facilities are inclusive of people with disabilities., Competing Interests: Competing interests: None declared., (© Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.)

Raman spectroscopy and X-ray fluorescence (XRF) analysis are commonly applied to archaeological objects as a fast and nondestructive way to characterize the materials. Here, micro-Raman spectroscopy and chemometrics on handheld XRF results were used to completely characterize beads found during archaeological excavations in the Congo. Metallic objects, organogenic materials, and glass beads were studied. Special attention was paid to the glassy materials, as they seem to be of European production. The matrix family and crystalline phases assemblage, as well as the results from principal components analysis on the elemental data, were used to define groups of beads of similar composition, and therefore probably of similar origin. This research project establishes the feasibility of this approach to archaeological glasses, and can be used to confirm and support the bead typologies used by archaeologists., (© The Author(s) 2015.)

Unlike most other biological species, humans can use cultural innovations to occupy a range of environments, raising the intriguing question of whether human migrations move relatively independently of habitat or show preferences for familiar ones. The Bantu expansion that swept out of West Central Africa beginning ∼5,000 y ago is one of the most influential cultural events of its kind, eventually spreading over a vast geographical area a new way of life in which farming played an increasingly important role. We use a new dated phylogeny of ∼400 Bantu languages to show that migrating Bantu-speaking populations did not expand from their ancestral homeland in a "random walk" but, rather, followed emerging savannah corridors, with rainforest habitats repeatedly imposing temporal barriers to movement. When populations did move from savannah into rainforest, rates of migration were slowed, delaying the occupation of the rainforest by on average 300 y, compared with similar migratory movements exclusively within savannah or within rainforest by established rainforest populations. Despite unmatched abilities to produce innovations culturally, unfamiliar habitats significantly alter the route and pace of human dispersals.

Bantu speech communities expanded over large parts of sub-Saharan Africa within the last 4000-5000 years, reaching different parts of southern Africa 1200-2000 years ago. The Bantu languages subdivide in several major branches, with languages belonging to the Eastern and Western Bantu branches spreading over large parts of Central, Eastern, and Southern Africa. There is still debate whether this linguistic divide is correlated with a genetic distinction between Eastern and Western Bantu speakers. During their expansion, Bantu speakers would have come into contact with diverse local populations, such as the Khoisan hunter-gatherers and pastoralists of southern Africa, with whom they may have intermarried. In this study, we analyze complete mtDNA genome sequences from over 900 Bantu-speaking individuals from Angola, Zambia, Namibia, and Botswana to investigate the demographic processes at play during the last stages of the Bantu expansion. Our results show that most of these Bantu-speaking populations are genetically very homogenous, with no genetic division between speakers of Eastern and Western Bantu languages. Most of the mtDNA diversity in our dataset is due to different degrees of admixture with autochthonous populations. Only the pastoralist Himba and Herero stand out due to high frequencies of particular L3f and L3d lineages; the latter are also found in the neighboring Damara, who speak a Khoisan language and were foragers and small-stock herders. In contrast, the close cultural and linguistic relatives of the Herero and Himba, the Kuvale, are genetically similar to other Bantu-speakers. Nevertheless, as demonstrated by resampling tests, the genetic divergence of Herero, Himba, and Kuvale is compatible with a common shared ancestry with high levels of drift, while the similarity of the Herero, Himba, and Damara probably reflects admixture, as also suggested by linguistic analyses.

Some Bantu languages spoken in southwestern Zambia and neighboring regions of Botswana, Namibia, and Angola are characterized by the presence of click consonants, whereas their closest linguistic relatives lack such clicks. As clicks are a typical feature not of the Bantu language family, but of Khoisan languages, it is highly probable that the Bantu languages in question borrowed the clicks from Khoisan languages. In this paper, we combine complete mitochondrial genome sequences from a representative sample of populations from the Western Province of Zambia speaking Bantu languages with and without clicks, with fine-scaled analyses of Y-chromosomal single nucleotide polymorphisms and short tandem repeats to investigate the prehistoric contact that led to this borrowing of click consonants. Our results reveal complex population-specific histories, with female-biased admixture from Khoisan-speaking groups associated with the incorporation of click sounds in one Bantu-speaking population, while concomitant levels of potential Khoisan admixture did not result in sound change in another. Furthermore, the lack of sequence sharing between the Bantu-speaking groups from southwestern Zambia investigated here and extant Khoisan populations provides an indication that there must have been genetic substructure in the Khoisan-speaking indigenous groups of southern Africa that did not survive until the present or has been substantially reduced.

In this article, the oldest Bantu dictionary hitherto known is explored, that is the Vocabularium Latinum, Hispanicum, e Congense , handed down to us through a manuscript from 1652 by the Flemish Capuchin Joris van Gheel, missionary in the Kongo (present-day north-western Angola and the southern part of the Lower Congo Province of the DRC). The manuscript was heavily reworked by the Belgian Jesuits Joseph van Wing and Constant Penders, and published in 1928. Both works are currently being digitized, linked and added to an interlingual and multimedia database that revolves around Kikongo and the early history of the Kongo kingdom. In Sections 1 and 2 the origins of Bantu lexicography in general and of Kikongo metalexicography in particular are revisited. Sections 3 and 4 are devoted to a study of Van Gheel's manuscript and an analysis of Van Wing and Penders' rework. In Sections 5 and 6 translation equivalence and lexicographical structure in both dictionaries are scrutinized and compared. In Section 7, finally, all the material is brought together.

The expansion of Bantu languages represents one of the most momentous events in the history of Africa. While it is well accepted that Bantu languages spread from their homeland (Cameroon/Nigeria) approximately 5000 years ago (ya), there is no consensus about the timing and geographical routes underlying this expansion. Two main models of Bantu expansion have been suggested: The 'early-split' model claims that the most recent ancestor of Eastern languages expanded north of the rainforest towards the Great Lakes region approximately 4000 ya, while the 'late-split' model proposes that Eastern languages diversified from Western languages south of the rainforest approximately 2000 ya. Furthermore, it is unclear whether the language dispersal was coupled with the movement of people, raising the question of language shift versus demic diffusion. We use a novel approach taking into account both the spatial and temporal predictions of the two models and formally test these predictions with linguistic and genetic data. Our results show evidence for a demic diffusion in the genetic data, which is confirmed by the correlations between genetic and linguistic distances. While there is little support for the early-split model, the late-split model shows a relatively good fit to the data. Our analyses demonstrate that subsequent contact among languages/populations strongly affected the signal of the initial migration via isolation by distance.

Technological and cultural innovations as well as climate changes are thought to have influenced the diffusion of major language phyla in sub-Saharan Africa. The most widespread and the richest in diversity is the Niger-Congo phylum, thought to have originated in West Africa ∼ 10,000 years ago (ya). The expansion of Bantu languages (a family within the Niger-Congo phylum) ∼ 5,000 ya represents a major event in the past demography of the continent. Many previous studies on Y chromosomal variation in Africa associated the Bantu expansion with haplogroup E1b1a (and sometimes its sublineage E1b1a7). However, the distribution of these two lineages extends far beyond the area occupied nowadays by Bantu-speaking people, raising questions on the actual genetic structure behind this expansion. To address these issues, we directly genotyped 31 biallelic markers and 12 microsatellites on the Y chromosome in 1,195 individuals of African ancestry focusing on areas that were previously poorly characterized (Botswana, Burkina Faso, Democratic Republic of Congo, and Zambia). With the inclusion of published data, we analyzed 2,736 individuals from 26 groups representing all linguistic phyla and covering a large portion of sub-Saharan Africa. Within the Niger-Congo phylum, we ascertain for the first time differences in haplogroup composition between Bantu and non-Bantu groups via two markers (U174 and U175) on the background of haplogroup E1b1a (and E1b1a7), which were directly genotyped in our samples and for which genotypes were inferred from published data using linear discriminant analysis on short tandem repeat (STR) haplotypes. No reduction in STR diversity levels was found across the Bantu groups, suggesting the absence of serial founder effects. In addition, the homogeneity of haplogroup composition and pattern of haplotype sharing between Western and Eastern Bantu groups suggests that their expansion throughout sub-Saharan Africa reflects a rapid spread followed by backward and forward migrations. Overall, we found that linguistic affiliations played a notable role in shaping sub-Saharan African Y chromosomal diversity, although the impact of geography is clearly discernible.

Background: Diarrhoeal diseases are a leading cause of mortality and morbidity, especially among young children in low-income countries, and are associated with exposure to human excreta., Objectives: To assess the effectiveness of interventions to improve the disposal of human excreta for preventing diarrhoeal diseases., Search Strategy: We searched the Cochrane Infectious Disease Group Specialized Register; the Cochrane Central Register of Controlled Trials (CENTRAL), published in The Cochrane Library; MEDLINE; EMBASE; LILACS; the metaRegister of Controlled Trials (mRCT); and Chinese-language databases available under the Wan Fang portal, and the China National Knowledge Infrastructure (CNKI-CAJ). We also handsearched relevant conference proceedings, and contacted researchers and organizations working in the field, as well as checking references from identified studies., Selection Criteria: Randomized, quasi-randomized, and non-randomized controlled trials (RCTs) were selected, comparing interventions aimed at improving the disposal of human excreta to reduce direct or indirect human contact with no such intervention. Cluster (eg at the level of household or community) controlled trials were included., Data Collection and Analysis: We determined study eligibility, extracted data, and assessed methodological quality in accordance with the methods prescribed by the protocol. We described the results and summarized the information in tables. Due to substantial heterogeneity among the studies in terms of study design and type of intervention, no pooled effects were calculated., Main Results: Thirteen studies from six countries covering over 33,400 children and adults in rural, urban, and school settings met the review's inclusion criteria. In all studies the intervention was allocated at the community level. While the studies reported a wide range of effects, 11 of the 13 studies found the intervention was protective against diarrhoea. Differences in study populations and settings, in baseline sanitation levels, water, and hygiene practices, in types of interventions, study methodologies, compliance and coverage levels, and in case definitions and outcome surveillance limit the comparability of results of the studies included in this review. The validity of most individual study results are further compromised by the non-random allocation of the intervention among study clusters, an insufficient number of clusters, the lack of adjustment for clustering, unclear loss to follow-up, potential for reporting bias and other methodological shortcomings., Authors' Conclusions: This review provides some evidence that interventions to improve excreta disposal are effective in preventing diarrhoeal disease. However, this conclusion is based primarily on the consistency of the evidence of beneficial effects. The quality of the evidence is generally poor and does not allow for quantification of any such effect. The wide range of estimates of the effects of the intervention may be due to clinical and methodological heterogeneity among the studies, as well as to other important differences, including exposure levels, types of interventions, and different degrees of observer and respondent bias. Rigorous studies in multiple settings are needed to clarify the potential effectiveness of excreta disposal on diarrhoea.

Background: Ever since John Snow's intervention on the Broad St pump, the effect of water quality, hygiene and sanitation in preventing diarrhoea deaths has always been debated. The evidence identified in previous reviews is of variable quality, and mostly relates to morbidity rather than mortality., Methods: We drew on three systematic reviews, two of them for the Cochrane Collaboration, focussed on the effect of handwashing with soap on diarrhoea, of water quality improvement and of excreta disposal, respectively. The estimated effect on diarrhoea mortality was determined by applying the rules adopted for this supplement, where appropriate., Results: The striking effect of handwashing with soap is consistent across various study designs and pathogens, though it depends on access to water. The effect of water treatment appears similarly large, but is not found in few blinded studies, suggesting that it may be partly due to the placebo effect. There is very little rigorous evidence for the health benefit of sanitation; four intervention studies were eventually identified, though they were all quasi-randomized, had morbidity as the outcome, and were in Chinese., Conclusion: We propose diarrhoea risk reductions of 48, 17 and 36%, associated respectively, with handwashing with soap, improved water quality and excreta disposal as the estimates of effect for the LiST model. Most of the evidence is of poor quality. More trials are needed, but the evidence is nonetheless strong enough to support the provision of water supply, sanitation and hygiene for all.

The United Nations has declared 2005-2015 the Fresh Water Decade in which more people than ever before will gain access to water. Despite acknowledging that water quantity is important to health, so far only water quality is used in monitoring the Millennium Development Goals. This study examines the changes in national access figures when both water quality and quantity are taken into account to determine access. Using East Africa as an example shows that the number of people with access to water for the region decreased by 9% (7% urban and 10% rural). The largest difference in access is observed in Eritrea 25% (11% urban and 36% rural). Reduction is higher in rural areas. However, significant reduction in access is also observed in urban Ethiopia (14%). In conclusion, the indicators for access to water would be better articulated by adding water quantity to the indicator which currently only includes water quality, while the Demographic Health Survey and Multiple Indicator Cluster Survey routinely collects information on both aspects.

Population size and density estimates are needed to plan resource requirements and plan health related interventions. Sampling frames are not always available necessitating surveys using non-standard household sampling methods. These surveys are time-consuming, difficult to validate, and their implementation could be optimised. Here, we discuss an example of an optimisation procedure for rapid population estimation using T-Square sampling which has been used recently to estimate population sizes in emergencies. A two-stage process was proposed to optimise the T-Square method wherein the first stage optimises the sample size and the second stage optimises the pathway connecting the sampling points. The proposed procedure yields an optimal solution if the distribution of households is described by a spatially homogeneous Poisson process and can be sub-optimal otherwise. This research provides the first step in exploring how optimisation techniques could be applied to survey designs thereby providing more timely and accurate information for planning interventions.

There are a few sampling methods available to survey households in situations where sample frames are either unavailable or are unreliable. The most popular of these methods is the expanded programme of immunization (EPI) sampling method, which has been used in low-income countries. The purpose of this paper is to explain how mathematical programming can be used to optimize EPI and other household survey sampling methods in these situations.