Caractérisation Hydrogéochimique des Aquifères du Bassin de Timia (Massif de l’Aïr, Nord du Niger)

Le bassin de Timia est situé dans le massif de l’Aïr (Nord du Niger). Dans cette zone, les ressources en eaux sont représentées par les aquifères altérés et fissurés du socle et ceux des alluvions. Ces aquifères, sont sollicités pour l’alimentation des populations, et pour l’irrigation. Ces activités, ont eu comme conséquence la dégradation de la qualité de ces eaux. L’objectif de la présente étude est de déterminer les caractéristiques physico-chimiques et les mécanismes d’acquisition de la minéralisation des eaux souterraines de la zone de Timia. La méthodologie basée sur les approches hydrochimiques et l’analyse en composante principale montre que les facies chimiques des eaux souterraines sont dominés par les facies de type bicarbonatés calciques et magnésiens (52%). Les facies bicarbonatés sodiques et potassiques sont aussi important (29%) tandis que les eaux hyper-bicarbonatées sodiques (13%) sont faiblement représentées. Les sources de la minéralisation des eaux sont principalement de trois types : les apports superficiels (pollution), l’hydrolyse des minéraux silicatés et les activités volcaniques. The Timia Basin is located in the Aïr Massif (Northern Niger). In this area, water resources are represented by altered and fissured basement and alluvial aquifers. These aquifers, are solicited for the water supply, and irrigation. These activities have for consequences the degradation of the quality of these waters. The objective of this study is to determine the physicochemical characteristics and the mechanisms house control the mineralization of groundwater in Timia area. The methodology based on hydrochemical approaches and principal component analysis shows that groundwater chemistry are dominated by calcium-magnesium bicarbonate facies (52%). Sodium-potassium bicarbonate facies are also important (29%) while, sodium hyper-bicarbonate waters (13%) are poorly represented. The sources who controlled the water mineralization are mainly of three types: superficial supply (pollution), hydrolysis of silicate minerals and volcanic activities

The evolving SARS-CoV-2 epidemic in Africa: Insights from rapidly expanding genomic surveillance

INTRODUCTION Investment in Africa over the past year with regard to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sequencing has led to a massive increase in the number of sequences, which, to date, exceeds 100,000 sequences generated to track the pandemic on the continent. These sequences have profoundly affected how public health officials in Africa have navigated the COVID-19 pandemic. RATIONALE We demonstrate how the first 100,000 SARS-CoV-2 sequences from Africa have helped monitor the epidemic on the continent, how genomic surveillance expanded over the course of the pandemic, and how we adapted our sequencing methods to deal with an evolving virus. Finally, we also examine how viral lineages have spread across the continent in a phylogeographic framework to gain insights into the underlying temporal and spatial transmission dynamics for several variants of concern (VOCs). RESULTS Our results indicate that the number of countries in Africa that can sequence the virus within their own borders is growing and that this is coupled with a shorter turnaround time from the time of sampling to sequence submission. Ongoing evolution necessitated the continual updating of primer sets, and, as a result, eight primer sets were designed in tandem with viral evolution and used to ensure effective sequencing of the virus. The pandemic unfolded through multiple waves of infection that were each driven by distinct genetic lineages, with B.1-like ancestral strains associated with the first pandemic wave of infections in 2020. Successive waves on the continent were fueled by different VOCs, with Alpha and Beta cocirculating in distinct spatial patterns during the second wave and Delta and Omicron affecting the whole continent during the third and fourth waves, respectively. Phylogeographic reconstruction points toward distinct differences in viral importation and exportation patterns associated with the Alpha, Beta, Delta, and Omicron variants and subvariants, when considering both Africa versus the rest of the world and viral dissemination within the continent. Our epidemiological and phylogenetic inferences therefore underscore the heterogeneous nature of the pandemic on the continent and highlight key insights and challenges, for instance, recognizing the limitations of low testing proportions. We also highlight the early warning capacity that genomic surveillance in Africa has had for the rest of the world with the detection of new lineages and variants, the most recent being the characterization of various Omicron subvariants. CONCLUSION Sustained investment for diagnostics and genomic surveillance in Africa is needed as the virus continues to evolve. This is important not only to help combat SARS-CoV-2 on the continent but also because it can be used as a platform to help address the many emerging and reemerging infectious disease threats in Africa. In particular, capacity building for local sequencing within countries or within the continent should be prioritized because this is generally associated with shorter turnaround times, providing the most benefit to local public health authorities tasked with pandemic response and mitigation and allowing for the fastest reaction to localized outbreaks. These investments are crucial for pandemic preparedness and response and will serve the health of the continent well into the 21st century

Evolution of Pumping and Piezometry of the Carboniferous Aquifers, Western Border of Aïr Massif: Case of the Tarat Aquifer in the Arlit Sector

The Tarat aquifer provides drinking water for the population of the city of Arlit and also provides water to industries. The exploitation of this aquifer has considerably increased in recent years. The main objective of this study is to contribute to a better understanding of the functioning of the Tarat aquifer. Thus, a methodological approach focusing mainly on the piezometric study and the analysis of evolution and estimation of the volumes of water pumped, since its development from 1969 to 2012, which has resulted in highlighting not only a general decline in the level of the Tarat aquifer, but also the piezometer level (Arli_182), reacts strongly to the solicitations of the aquifer. On this same piezometer, the water table was lowered by 30 m from 1980 to 2006 (26 years), so a drawdown of 0.86 /year

Land, Climate, Energy, Agriculture and Development in the Sahel: Synthesis paper of case studies under the Sudano-Sahelian Initiative for Regional Development, Jobs, and Food Security

This paper synthesizes a set of national case studies conducted in the Sahelian countries during 2019-2020 as a collaboration between national universities and research institutes, and the Center for Development Research (ZEF), University of Bonn, with contributions from the Agrhymet Regional Centre, Permanent Interstate Committee for Drought Control in the Sahel (CILSS). These case studies provide up-to-date knowledge and critical insights on the nexus of land degradation, climate change and energy in the Sahel. The current synthesis paper highlights their major findings and provides crosscutting and cross-regional analytical conclusions. First, the synthesis paper explores current trends in the Sahel region on land use and land degradation, energy use and supply, climate change projections and impacts, as well as their interactions and links to agricultural growth, food security, poverty reduction, and peace in the region. Second, technological, socio-economic and policy solutions at the nexus of land, water, energy and climate challenges that enable environmentally sustainable and socially inclusive rural development in the Sahel are discussed, including their interactions and implications for peace and stability in the region. The findings show that such socio-economic solutions as improving access to markets, strengthening social safety nets, increasing investments to transport and energy infrastructures, promoting land tenure security, expanding off-farm employment opportunities can greatly contribute to rural development in the Sahel, particularly by aiding climate change resilience and sustainable land management. Key technological innovations highlighted across the case studies include expanding irrigation and adopting water use efficient irrigation techniques, crop diversification, expanding agricultural mechanization, investing into restoring and rehabilitating degraded lands through reforestation, afforestation and agroforestry practices. The key lessons learnt from ongoing national policy initiatives for sustainable development highlight the importance of active stakeholder consultation and participation in policy formulation, institution of effective policy monitoring and assessment mechanisms, and avoiding of excessive reliance on external sources of funding for the successful implementation of sustainable development policies and programs. Based on these findings, the synthesis paper proposes an agenda for applied research to provide guidance to and accompany promising development strategies in and for the region

Plasmodium falciparum K13 mutations in Africa and Asia impact artemisinin resistance and parasite fitness

The emergence of mutant K13-mediated artemisinin (ART) resistance in Plasmodium falciparum malaria parasites has led to widespread treatment failures across Southeast Asia. In Africa, K13-propeller genotyping confirms the emergence of the R561H mutation in Rwanda and highlights the continuing dominance of wild-type K13 elsewhere. Using gene editing, we show that R561H, along with C580Y and M579I, confer elevated in vitro ART resistance in some African strains, contrasting with minimal changes in ART susceptibility in others. C580Y and M579I cause substantial fitness costs, which may slow their dissemination in high-transmission settings, in contrast with R561H that in African 3D7 parasites is fitness neutral. In Cambodia, K13 genotyping highlights the increasing spatio-temporal dominance of C580Y. Editing multiple K13 mutations into a panel of Southeast Asian strains reveals that only the R561H variant yields ART resistance comparable to C580Y. In Asian Dd2 parasites C580Y shows no fitness cost, in contrast with most other K13 mutations tested, including R561H. Editing of point mutations in ferredoxin or mdr2, earlier associated with resistance, has no impact on ART susceptibility or parasite fitness. These data underline the complex interplay between K13 mutations, parasite survival, growth and genetic background in contributing to the spread of ART resistance

Global variation in postoperative mortality and complications after cancer surgery: a multicentre, prospective cohort study in 82 countries

© 2021 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY-NC-ND 4.0 licenseBackground: 80% of individuals with cancer will require a surgical procedure, yet little comparative data exist on early outcomes in low-income and middle-income countries (LMICs). We compared postoperative outcomes in breast, colorectal, and gastric cancer surgery in hospitals worldwide, focusing on the effect of disease stage and complications on postoperative mortality. Methods: This was a multicentre, international prospective cohort study of consecutive adult patients undergoing surgery for primary breast, colorectal, or gastric cancer requiring a skin incision done under general or neuraxial anaesthesia. The primary outcome was death or major complication within 30 days of surgery. Multilevel logistic regression determined relationships within three-level nested models of patients within hospitals and countries. Hospital-level infrastructure effects were explored with three-way mediation analyses. This study was registered with ClinicalTrials.gov, NCT03471494. Findings: Between April 1, 2018, and Jan 31, 2019, we enrolled 15 958 patients from 428 hospitals in 82 countries (high income 9106 patients, 31 countries; upper-middle income 2721 patients, 23 countries; or lower-middle income 4131 patients, 28 countries). Patients in LMICs presented with more advanced disease compared with patients in high-income countries. 30-day mortality was higher for gastric cancer in low-income or lower-middle-income countries (adjusted odds ratio 3·72, 95% CI 1·70–8·16) and for colorectal cancer in low-income or lower-middle-income countries (4·59, 2·39–8·80) and upper-middle-income countries (2·06, 1·11–3·83). No difference in 30-day mortality was seen in breast cancer. The proportion of patients who died after a major complication was greatest in low-income or lower-middle-income countries (6·15, 3·26–11·59) and upper-middle-income countries (3·89, 2·08–7·29). Postoperative death after complications was partly explained by patient factors (60%) and partly by hospital or country (40%). The absence of consistently available postoperative care facilities was associated with seven to 10 more deaths per 100 major complications in LMICs. Cancer stage alone explained little of the early variation in mortality or postoperative complications. Interpretation: Higher levels of mortality after cancer surgery in LMICs was not fully explained by later presentation of disease. The capacity to rescue patients from surgical complications is a tangible opportunity for meaningful intervention. Early death after cancer surgery might be reduced by policies focusing on strengthening perioperative care systems to detect and intervene in common complications. Funding: National Institute for Health Research Global Health Research Unit