Climate change and health in the Sahel: a systematic review.

The Sahel region is projected to be highly impacted by the more frequent hazards associated with climate change, including increased temperature, drought and flooding. This systematic review examined the evidence for climate change-related health consequences in the Sahel. The databases used were Medline (PubMed), Embase (Ovid), Web of Science (Clarivate) and CABI Global Health. Hand searches were also conducted, which included directly engaging Sahelian researchers and hand-searching in the African Journals Online database. Of the 4153 studies found, 893 were identified as duplicates and the remaining 3260 studies were screened (title and abstract only) and then assessed for eligibility. A total of 81 studies were included in the systematic review. Most studies focused on vector-borne diseases, food security, nutrition and heat-related stress. Findings suggest that mosquito distribution will shift under different climate scenarios, but this relationship will not be linear with temperature, as there are other variables to consider. Food insecurity, stunting (chronic malnutrition) and heat-related mortality are likely to increase if no action is taken owing to the projected impact of climate change on environmental factors and agriculture. Seventy-one per cent of manuscripts (n = 58) had first authors from institutions in North America or Europe, of which 39.7% (n = 23) included co-authors from African institutions.

Awareness and use of improved livestock feed technologies among agro-pastoral households in the West African Sahel.

Seasonal scarcity of quality feed continues to be a bottleneck for agro-pastoralists and is the most important limitation to livestock production in agro-pastoral systems in the West African Sahel. In this regard, diverse promising technologies to increase the production and availability of quality feed have been introduced. Despite the introduction of various feed technologies in the region, the adoption rate by smallholder farmers is very low. The objective of this study was to identify factors affecting the likelihood of using improved livestock feed technologies among agro-pastoral households in two regions of Niger. A logit model was employed using data collected from randomly selected 218 agro-pastoral households between February and April 2023. The study revealed low awareness and use of improved livestock feed technologies among agro-pastoral households. The findings suggested the positive impact of education level, membership of farmer groups and ownership of small ruminant on enhancing the probability of using improved livestock feed technologies. Households' geographical area was one of the determinant factors in using improved livestock feed technologies. The use of improved livestock feed technologies was also influenced by family size. The study provides guidance to inform strategies by the decision-makers to enhance the utilization of improved livestock feed technologies among agro-pastoral households in the West African Sahel. Suggested strategies may in turn alleviate the current problem of low productivity of livestock, contribute to improving household food security and nutrition among agro-pastoral communities.

Supplementing zebu cattle with crop co-products helps to reduce enteric emissions in West Africa.

In Africa, a wide variety of diets (forage + crop co-products or other agricultural by-products) is being used by livestock farmers in different production systems to adapt to climate change. This study aimed to assess the performance of various local feeding strategies on Sudanese Fulani zebu cattle. Two experiments were carried out on 10 steers aged initially 33 months (142 kg body weight - BW). The animals were fed eight different diets at an intake level of 3.2% LW in dry matter (DM), including two control diets of 100% rangeland forage (100% RF) and six experimental diets made up of forage and crop co-products (75:25 DM ratio). In the first experiment, the control diet was made up of rangeland forage (RF) and supplements consisted of four cereal co-products (CC), i.e. maize, sorghum, millet, and rice straws. In the second experiment, the control diet consisted of Panicum maximum (Pmax) hay, and the supplements tested were two legume co-products (LC), i.e. cowpea and peanut haulms. Each experiment lasted 3 weeks, including 2 weeks of adaptation to the diet and 1 week of data collection on individual animals (intake, apparent digestibility, and enteric methane). The NDF content of the diets was different within each experiment (p < 0.05). Among diets containing CC, DM intake [g/kg BW] was significantly higher (+31%; p = 0.025) for the diet containing rice straw than for the other diets, which showed similar levels to the RF diet. Among diets containing LC, intake was significantly higher (p = 0.004) than for the Pmax diet. Intake was higher for the peanut haulm diet than for the cowpea haulm diet. The DM digestibility was similar between the different diets in each experiment. Enteric methane (eCH4) yield [g/kg DMI] from the CC and LC-containing diets were reduced by an average of 23% and 20% compared to the RF and Pmax control diets respectively. Raising awareness among agro-pastoralists about the use of crop co-products offers real prospects for eCH4 emissions mitigation in the Sahel region.

Forensic DNA database and criminal investigation in the Sahel region: a need to update the national security policy?

Ongoing terrorist attacks in the Sahel region call for strengthening the security system by using human DNA identification technology. In this context, public opinion must be considered when establishing solid standards and universal safeguards for one of the most invasive forms of surveillance and profiling. For this purpose, we gathered internet users' opinions in Burkina Faso (a country located in the Sahel region) on the use of DNA technology to support criminal investigations. The results revealed that 91.7% (431) of the 470 participants believed that this technology is currently necessary for the Burkina Faso's criminal justice system. However, the respondents expressed concerns about the custody and management of a national forensic DNA database. In this particular security setting, the public opinion of this study may provide leaders and political policymakers with clues for considering genetic fingerprints and implementing an national forensic DNA database to support criminal investigations in Burkina Faso whilst also considering the ethical implications.

Implementation of lockdown, quarantine, and isolation measures in the context of COVID-19 among internally displaced persons in Burkina Faso: a qualitative study.

BACKGROUND: The triple political, security, and health crisis in Burkina Faso has impacted the lives of Burkinabè people, resulting in massive internal displacement. These internally displaced persons (IDPs) are very vulnerable to epidemic diseases, which was exacerbated by the recent COVID-19 pandemic., The implementation of public health measures to curb the spread of COVID-19 represented a major concern among IDPs. The objective of this study was to document knowledge, difficulties, adjustments, and challenges faced by IDPs and humanitarian authorities/actors during implementation of lockdown, quarantine, and isolation measures in response to COVID-19. METHODS: The study was conducted in Burkina Faso, in the north-central region Kaya, a commune which hosts the largest number of IDPs in the country. Qualitative research using semi-structured interviews collected discursive data from 18 authorities and/or humanitarian actors and 29 IDPs in June 2021. The transcribed interviews were coded with N'vivo 11 software and analyzed thematically. RESULTS: Although respondents had a good knowledge of lockdown, isolation, and quarantine measures, the difference between these three concepts was not easily understood by either authorities/humanitarian actors or IDPs. Communication was one of the biggest challenges for humanitarian actors. The difficulties encountered by IDPs were economic (lack of financial resources), infrastructural (limited housing), and socio-cultural in the application of lockdown, isolation, and quarantine measures. As for adjustment measures, the health authorities developed a strategy for isolation and quarantine for the management of positive and suspected cases. The IDPs mentioned their commitment to compliance and awareness of lockdown measures as the main adjustment. CONCLUSION: Although there were no known cases of COVID-19 among the IDPs at the time of the study, tailored response plans were developed to facilitate the application of these measures in emergencies. The involvement of IDPs in the communication and sensitization process was necessary to facilitate their adherence to these different measures.

Landscape analysis of healthcare workforce and resilience actions in the Sahelian context of high security challenge areas: The case of Burkina Faso.

INTRODUCTION: Access to health services is a major challenge in developing countries in general, particularly those affected by insecurity. The availability of sufficient quantity and quality of equitably distributed healthcare workforce is a major obstacle, yet it is an essential pillar of an effective and efficient national health system. Burkina Faso, similar to other countries in the Sahel, has been affected by an unprecedented security crisis that has severely tested the functionality of health facilities and the availability of healthcare workforce. OBJECTIVE: To describe the landscape of healthcare workforce and to analyse the actions taken by the government and other stakeholders to improve the resilience of the system and the retention of healthcare workers in the context of major security challenges. METHODS: This is a transversal, descriptive and analytical study carried out in Burkina Faso in 2023 through a documentary review, analyses of databases collected from health districts and regional directorates, focus groups and a national triangulation workshop with key informants. RESULTS: The study shows that, with the closure and minimal functioning of certain health facilities in security-challenged areas, healthcare workforceare concentrated in the urban areas of regional and district capitals, to the detriment of rural areas. Some staff become in an irregular situation regarding the administration. To strengthen resilience to the crisis, the main solutions have been implemented: (i) enhancing the community platform with the recruitment of 15,000 community-based health volunteers, (ii) delegating tasks to community health agents, (iii) simplified approaches, (iv) advanced health posts and mobile clinics, (v) redeployment to the most stable structures, (vi) thinking about legislation in crisis situations. CONCLUSION: Community resilience through the delegation of tasks to community-based health workers and strengthening of the community health platform has helped ensure the continuity of care in insecure areas. However, the optimization of innovative and attractive strategies will further improve the retention and return of healthcare workers in rural areas affected.

Transition of adolescents living with HIV from pediatric to adult care, a retrospective 12-year Single Center Study from the Sahel Region in West-Africa.

ABSTRACTTransition is the next major hurdle in the field of HIV-infected youth, especially in sub-Saharan Africa. At St Camille Hospital in Ouagadougou, fully informed and compliant patients over 13-years-old were eligible for referral to the adult HIV/AIDS service, after completion of an individualized preparatory process. Transition consisted in at least two consecutive "joined-service" appointments in the respective facilities. We retrospectively compared immunological, clinical, and therapeutical data one year before transition, at transition and one year after transition. Between 2008 and 2019 73 patients (34 females, 39 males) were transitioned. All had been previously in pediatric care for at least 1 year and 66 were on HAART. Matched paired analysis of CD4 counts revealed a modest drop in CD4 cells over time (p < 0.05). Clinical data also showed strong fluctuation between WHO clinical stages over the three time points, with a clear trend towards increased severity especially post transfer. This large retrospective 12-year single-center experience from a Sahel country showed a 95.8% retention rate at one year. It demonstrates how a comprehensive plan, carefully implemented, can provide excellent retention, even in a low-resource setting. However, mild immunological decline was associated with a worrisome clinical deterioration, underlining the importance of assessing the latter after transition.

The genomic echoes of the last Green Sahara on the Fulani and Sahelian people.

The population history of the Sahara/Sahelian belt is understudied, despite previous work highlighting complex dynamics.1,2,3,4,5,6,7 The Sahelian Fulani, i.e., the largest nomadic pastoral population in the world,8 represent an interesting case because they show a non-negligible proportion of an Eurasian genetic component, usually explained by recent admixture with northern Africans.1,2,5,6,7,9,10,11,12 Nevertheless, their origins are largely unknown, although several hypotheses have been proposed, including a possible link to ancient peoples settled in the Sahara during its last humid phase (Green Sahara, 12,000-5,000 years before present [BP]).13,14,15 To shed light about the Fulani ancient genetic roots, we produced 23 high-coverage (30×) whole genomes from Fulani individuals from 8 Sahelian countries, plus 17 samples from other African groups and 3 from Europeans as controls, for a total of 43 new whole genomes. These data have been compared with 814 published modern whole genomes2,16,17,18 and with relevant published ancient sequences (> 1,800 samples).19 These analyses showed some evidence that the non-sub-Saharan genetic ancestry component of the Fulani might have also been shaped by older events,1,5,6 possibly tracing the Fulani origins to unsampled ancient Green Saharan population(s). The joint analysis of modern and ancient samples allowed us to shed light on the genetic ancestry composition of such ancient Saharans, suggesting a similarity with Late Neolithic Moroccans and possibly pointing to a link with the spread of cattle herding. We also identified two different Fulani clusters whose admixture pattern may be informative about the historical Fulani movements and their later involvement in the western African empires.

Climate change and sustainable agricultural growth in the sahel region: Mitigating or resilient policy response?

The aim of this study is to provide an empirical answer to the question of whether nexus exists between climate change and sustainable agricultural growth in nine (9) countries within the Sahel region between 1990 and 2020. The study utilized Panel ARDL and Pairwise Dumitrescu Hurlin Panel Causality Tests to arrive at the following conclusions; firstly, the climate change orchestrated by change in rainfall is a very prominent factor causing reduction in sustainable agricultural growth in the Sahel region. One way feedback relationship flows from sustainable agricultural growth to greenhouse gas emission. In the light of the above, this study recommends that, in addressing the adverse effects of change in rainfall on agricultural sustainability, the policymakers in the Sahel region in particular and Africa as a whole should embark on a policy mix by embanking on mitigating policy response towards ensuring sustainable agricultural production via irrigation which is the best mode of water provisions without causing negative spilliovers on the environment. Also, the policymakers should be proactive by embarking on policies and programs that would build the resilience and adaptation of the region ahead of the future adverse effects of agriculturally induced climatic change.

Unraveling phylogenetic relationships and species boundaries in the arid adapted Gerbillus rodents (Muridae: Gerbillinae) by RAD-seq data.

Gerbillus is one of the most speciose genera among rodents, with ca. 51 recognized species. Previous attempts to reconstruct the evolutionary history of Gerbillus mainly relied on the mitochondrial cyt-b marker as a source of phylogenetic information. In this study, we utilize RAD-seq genomic data from 37 specimens representing 11 species to reconstruct the phylogenetic tree for Gerbillus, applying concatenation and coalescence methods. We identified four highly supported clades corresponding to the traditionally recognized subgenera: Dipodillus, Gerbillus, Hendecapleura and Monodia. Only two uncertain branches were detected in the resulting trees, with one leading to diversification of the main lineages in the genus, recognized by quartet sampling analysis as uncertain due to possible introgression. We also examined species boundaries for four pairs of sister taxa, including potentially new species from Morocco, using SNAPP. The results strongly supported a speciation model in which all taxa are treated as separate species. The dating analyses confirmed the Plio-Pleistocene diversification of the genus, with the uncertain branch coinciding with the beginning of aridification of the Sahara at the the Plio-Pleistocene boundary. This study aligns well with the earlier analyses based on the cyt-b marker, reaffirming its suitability as an adequate marker for estimating genetic diversity in Gerbillus.

Higher diversity, denser stands and greater biomass in peri-urban forests than in adjacent agroforestry systems in Western Burkina Faso: implications for urban sustainability.

Urban and peri-urban forests greatly contribute to the well-being of urban dwellers in West Africa. However, increasing urban densification and spatial expansion negatively affect the functioning of urban ecosystems. Therefore, highlighting the negative impacts of land use change on the ecological attributes of urban landscapes is fundamental for sustainable urban planning. This study aimed to assess the impacts of land use on woody species diversity, structure and carbon storage in peri-urban areas in Burkina Faso. Forest inventories were conducted in 167 plots across two peri-urban forests and their adjacent agroforestry systems. We found a total diversity of 91 woody species representing 69 genera and 26 families. Diversity indices were significantly higher (p-value < 0.0001) in the peri-urban forests than in the agroforestry systems, highlighting a negative impacts of land use on tree diversity. Besides, peri-urban forests had significantly lower tree diameter (15.749 ± 9.194 cm), but higher basal area (5.030 ± 4.407 m2. ha-1) and denser stands (317.308 ± 307.845 ind. ha-1) compared to the agroforestry systems. Tree aboveground biomass was significantly higher (p-value < 0.0001) in the peri-urban forests (18.198 ± 23.870 Mg. ha-1) than in the agroforestry systems (7.821 ± 6.544 Mg. ha-1). Multivariate analyses revealed that denser stands hold higher diversity in peri-urban areas, and that stand basal area mostly drives carbon storage than tree density and diversity. These findings highlight the potential of peri-urban forests to conserve plant biodiversity and mitigate climate change. The study advocates for a sustainable urban land use and planning.

Learning from history of natural disasters in the Sahel: a comprehensive analysis and lessons for future resilience.

One of the first environmental crises to attract interest in development initiatives and aid was the great drought of the 1970s in the Sahel. This study investigates the extent of damage caused by natural disasters from one of the most widely used databases-EM-DAT-with a sample size of 16 Sahelian countries over the period 1960-2020. These countries have been divided into three regions: Western Africa Sahel (WAS), Central Africa Sahel (CAS), and Eastern Africa Sahel (EAS). The analyses encompass four categories of natural hazards, namely, biological, climatological, hydrological, and meteorological. We used descriptive and test statistics to summarize the natural disaster records. Through this approach, we explore tendencies to identify the most frequently reported natural hazards; we examine their spatial distribution and evaluate their impacts in terms of socioeconomic damage and causalities. During the study period, a total of 1000 events were recorded in the database. The Western Africa Sahel (WAS) region had the highest number of disasters, with 476 events, followed by the Eastern Africa Sahel (EAS) region with 369 events. The most common hazards in the Sahel were hydrological (41.8%), mainly floods, and biological (39.5%) hazards. Approximately 300 million people in the Sahel were affected by natural hazards, with 59.17% in EAS, 36.48% in WAS, and 4.35% in CAS. Although droughts occurred less frequently (14%), they had a significant impact on the population, affecting 84% of those affected by natural hazards. In general, EAS experiences a higher impact from natural hazards, potentially influenced by the pastoral lifestyle of its population. However, WAS is also very vulnerable to natural hazards especially epidemics and nowadays floods. The uncontrolled urbanization in the area may contribute to this vulnerability.

Extremity injuries in the Sahelian conflict: lessons learned from a French Forward Surgical Team deployed in Gao, Mali.

PURPOSE: This study aimed to analyse extremity combat-related injuries (CRIs) and non-combat related injuries (NCRIs) treated in the French Forward Surgical Team deployed in Gao, Mali. PATIENTS AND METHODS: A retrospective study was conducted using the French surgical database OpEX (French Military Health Service) from January 2013 to August 2022. Patients operated on for an extremity injury less than one month old were included. RESULTS: During this period, 418 patients with a median age of 28 years [range 23-31 years] were included and totalized 525 extremity injuries. Among them, 190 (45.5%) sustained CRIs and 218 (54.5%) sustained NCRIs. Multiple upper extremity injuries and associated injuries were significantly more common in the CRIs group. The majority of NCRIs involved the hand. Debridement was the most common procedure in both groups. External fixation, primary amputation, debridement, delayed primary closure, vascular repair and fasciotomy were significantly predominant in the CRIs group. Internal fracture fixation and reduction under anaesthesia were statistically more frequent in the NCRIs group. The overall number of procedures and the overall number of surgical episodes were significantly higher in the CRIs group. CONCLUSION: CRIs were the most severe injuries and did not involve the upper and lower limbs separately. A sequential management was required with application of damage control orthopaedics followed by several procedures for reconstruction. NCRIs were predominant and mostly involved the hand among the French soldiers. This review supports the fact that any deployed orthopaedic surgeon should be trained in basic hand surgery and preferably have microsurgical skills. The management of local patients requires the execution of reconstructive surgery and therefore imposes the presence of adequate equipment.

Aeolian disaster risk evaluation in the African Sahel.

The Sahel is facing a serious environmental crisis due to aeolian disaster that has seriously affected the local development and survival of residents. Thus, evaluating the aeolian disaster risk levels and their variation in the Sahel is important. This study established an optimal model by evaluating the applicability of different models in the aeolian disaster risk determination in the Sahel. Using this model, the spatiotemporal changes in the risk subsystem of aeolian disaster (hazard, sensitivity, vulnerability, and restorability) and the aeolian disaster risk in the Sahel from 2000 to 2020 were analyzed. Based on this analysis, the impact of climate change and human activities on the aeolian disaster risk in the Sahel was evaluated. Results revealed that the variable fuzzy recognition (VFR) based on the aeolian disaster risk index (ADRI) model had the highest accuracy, reaching 89.72 %. The middle of the Sahel, located in the desert-grassland transition zone, exhibited a high hazard, sensitivity, and vulnerability, rendering it highly susceptible to aeolian disaster. The proportion of areas with very low and very high aeolian disaster risk levels decreased from 2000 to 2020, while those with low and high levels increased, and the change in moderate risk level areas remained relatively stable. Areas of low, moderate, and high risk are more sensitive to climate change and human activities and are subjected to greater pressure for change. Human activities were the main factor for the change of ADRI in the Sahel, accounting for 69.74 and 58.19 % of the increased and decreased areas of ADRI, respectively. This study evaluated the level of aeolian disaster risk in the Sahel and identified the main driving factors, providing a reference for Sahel countries to better implement the Green Great Wall (GGW) program in Africa, thereby mitigating the adverse effects of aeolian disaster.

Molecular drivers of insecticide resistance in the Sahelo-Sudanian populations of a major malaria vector Anopheles coluzzii.

BACKGROUND: Information on common markers of metabolic resistance in malaria vectors from countries sharing similar eco-climatic characteristics can facilitate coordination of malaria control. Here, we characterized populations of the major malaria vector Anopheles coluzzii from Sahel region, spanning four sub-Saharan African countries: Nigeria, Niger, Chad and Cameroon. RESULTS: Genome-wide transcriptional analysis identified major genes previously implicated in pyrethroid and/or cross-resistance to other insecticides, overexpressed across the Sahel, including CYP450s, glutathione S-transferases, carboxylesterases and cuticular proteins. Several, well-known markers of insecticide resistance were found in high frequencies-including in the voltage-gated sodium channel (V402L, I940T, L995F, I1527T and N1570Y), the acetylcholinesterase-1 gene (G280S) and the CYP4J5-L43F (which is fixed). High frequencies of the epidemiologically important chromosomal inversion polymorphisms, 2La, 2Rb and 2Rc, were observed (~80% for 2Rb and 2Rc). The 2La alternative arrangement is fixed across the Sahel. Low frequencies of these inversions (<10%) were observed in the fully insecticide susceptible laboratory colony of An. coluzzii (Ngoussou). Several of the most commonly overexpressed metabolic resistance genes sit in these three inversions. Two commonly overexpressed genes, GSTe2 and CYP6Z2, were functionally validated. Transgenic Drosophila melanogaster flies expressing GSTe2 exhibited extremely high DDT and permethrin resistance (mortalities <10% in 24h). Serial deletion of the 5' intergenic region, to identify putative nucleotide(s) associated with GSTe2 overexpression, revealed that simultaneous insertion of adenine nucleotide and a transition (T->C), between Forkhead box L1 and c-EST putative binding sites, were responsible for the high overexpression of GSTe2 in the resistant mosquitoes. Transgenic flies expressing CYP6Z2 exhibited marginal resistance towards 3-phenoxybenzylalcohol (a primary product of pyrethroid hydrolysis by carboxylesterases) and a type II pyrethroid, α-cypermethrin. However, significantly higher mortalities were observed in CYP6Z2 transgenic flies compared with controls, on exposure to the neonicotinoid, clothianidin. This suggests a possible bioactivation of clothianidin into a toxic intermediate, which may make it an ideal insecticide against populations of An. coluzzii overexpressing this P450. CONCLUSIONS: These findings will facilitate regional collaborations within the Sahel region and refine implementation strategies through re-focusing interventions, improving evidence-based, cross-border policies towards local and regional malaria pre-elimination.

A Population Genetic Perspective on Subsistence Systems in the Sahel/Savannah Belt of Africa and the Historical Role of Pastoralism.

This review focuses on the Sahel/Savannah belt, a large region of Africa where two alternative subsistence systems (pastoralism and agriculture), nowadays, interact. It is a long-standing question whether the pastoralists became isolated here from other populations after cattle began to spread into Africa (~8 thousand years ago, kya) or, rather, began to merge with other populations, such as agropastoralists, after the domestication of sorghum and pearl millet (~5 kya) and with the subsequent spread of agriculture. If we look at lactase persistence, a trait closely associated with pastoral lifestyle, we see that its variants in current pastoralists distinguish them from their farmer neighbours. Most other (mostly neutral) genetic polymorphisms do not, however, indicate such clear differentiation between these groups; they suggest a common origin and/or an extensive gene flow. Genetic affinity and ecological symbiosis between the two subsistence systems can help us better understand the population history of this African region. In this review, we show that genomic datasets of modern Sahel/Savannah belt populations properly collected in local populations can complement the still insufficient archaeological research of this region, especially when dealing with the prehistory of mobile populations with perishable material culture and therefore precarious archaeological visibility.

Present and Future Drinking Water Security and Its Impacts on Maternities: A Multi-Scale Assessment of Sudan.

Adequate access to drinking water for hydration and hygiene depends on many factors. We developed the Drinking Water Security Index (DWSI) to assess relative multifactorial drinking water security at different spatial and temporal scales. DWSI is a function of four key indicators of drinking water security: water quality, water accessibility, water continuity, and water availability. We built DWSI with a total of 10 variables and applied the new index in Sudan to assess historical and future drinking water security at state, local, and maternity levels. Analyses at the state level found that the Red Sea and River Nile states are most vulnerable, with the lowest DWSI for both historical and future periods. The 1 km2 pixel level analysis shows large differences in water security within the major states. Analyses at the maternity level showed that nearly 18.97 million people are affected by the 10% of maternities with the lowest DWSI, a number projected to increase by 60% by 2030. Current and future DWSI of maternities providing Emergency Obstetric and Newborn Care was assessed to identify those where urgent action is needed to ensure quality health care in water-secure conditions. This work provides useful information for stakeholders in the health and drinking water sectors in Sudan, to improve public health, reduce preventable mortality, and make the population more resilient to projected environmental changes.

Lake Chad vegetation cover and surface water variations in response to rainfall fluctuations under recent climate conditions (2000-2020).

Monitoring the evolution of the Sahelian environment is a major challenge because the great Sahelian droughts, marked by significant environmental consequences and social impacts, contributed, for example, to the drying up of Lake Chad. We combined remote sensing images with a water level database from the Hydroweb project to determine the response of Lake Chad vegetation cover and surface water variations to rainfall fluctuations in the Lake Chad watershed under recent climate conditions. The variance in lake surface water levels was determined by computing the monthly anomaly time series of surface water height and area from the Hydroweb datasets. The spatiotemporal variability of watershed rainfall and vegetation cover of Lake Chad was highlighted through multivariate statistical analysis. The spatial distribution of correlations between watershed rainfall and Lake Chad vegetation cover was investigated. The results show an increase in watershed rainfall, vegetation cover, and surface water area and height, as their slopes were all positive i.e., 5.1 10-4 (mm/day); 4.26 10-6 (ndvi unit/day); 1.2 10-3 (km2/day) and 6 10-5 (m/day), respectively. The rainfall variations in the watershed drive those of Lake Chad vegetation cover and surface water, as the rainfall trend was strongly and positively correlated with those of vegetation cover (0.79), surface water height (0.57), and area (0.53). The time lag between the watershed rainfall fluctuations and lake surface water variations corresponded to approximately ∼112 days. Between rainfall variations and vegetation cover changes, the spatial distribution of the time lag showed a response time of <16 days in the western shores of the lake and on both sides of the great barrier, about 16 days in the bare soils of the northern basin and the eastern part of the south basin, and >64 days in the marshlands of the southern basin. For the analysis of lakes around the world, this research provides a robust method that computes the spatiotemporal variances of their trends and seasonality and correlates these with the spatiotemporal variances of climate changes. The correlations obtained have strong potential for predicting future changes in lake surface water worldwide.

From scenario to mounting risks: COVID-19's perils for development and supply security in the Sahel.

The African Sahel countries are inherently fragile, environmentally insecure and economically weak. This paper underscores the compounded impacts brought about by the COVID-19 pandemic on resource supply security and, hence, the long-term development of the region. It outlines the Sahel-specific COVID-19 scenario by firstly highlighting the underlying vulnerabilities and later linking the health sector outcomes to increased political instability and environmental insecurity, particularly the deterioration of food security. In this sense, this paper shows from a region-wide perspective how COVID-19 in the Sahel is associated with enlarged sociopolitical developmental perils. Lower remittance sent by expatriates, violent conflicts, increased cross-border terrorism and migration, discriminant mobility restrictions of people and goods, weak national healthcare infrastructures, bottlenecks in international aid, pressures on the education system and recent climate extremes are some revealing examples of aggravators of the impacts on the supply of vital resources, such as food. This paper also shows the importance of considering the close interlinks between health, food and political stability in the Sahel. There is a paramount need for more comprehensive approaches linking human health to other sectors, and for re-considering local sustainable agriculture. To avoid prolonged or recurrent humanitarian crises, the Sahel countries need to strengthen response capacities through public sector-led responses. Examples of these responses include reinforced national disaster programs for the vulnerable, support to sustainable agriculture and food markets, improved performance and communication of public sector relief, state-based cooperation, building of regional alliances and peacemaking efforts.

Molecular Epidemiology of Escherichia coli with Resistance against Third-Generation Cephalosporines Isolated from Deployed German Soldiers-A Retrospective Assessment after Deployments to the African Sahel Region and Other Sites between 2007 and 2016.

Colonization and infection with bacteria with acquired antibiotic resistance are among the risks for soldiers on international deployments. Enterobacterales with resistance against third-generation cephalosporines are amongst the most frequently imported microorganisms. To contribute to the scarcely available epidemiological knowledge on deployment-associated resistance migration, we assessed the molecular epidemiology of third-generation cephalosporine-resistant Escherichia coli isolated between 2007 and 2016 from German soldiers after deployments, with a particular focus on the African Sahel region. A total of 51 third-generation cephalosporine-resistant E. coli isolated from 51 military returnees from deployment collected during the assessment period between 2007 and 2016 were subjected to short-read next-generation sequencing analysis. Returnees from the Sahel region (Djibouti, Mali, South Sudan, Sudan, Sudan, and Uganda) comprised a proportion of 52.9% (27/51). Repeatedly isolated sequence types according to the Warwick University scheme from returnees from the Sahel region were ST38, ST131, and ST648, confirming previous epidemiological assessments from various sub-Saharan African regions. Locally prevalent resistance genes in isolates from returnees from the Sahel region associated with third-generation resistance were blaCTX-M-15, blaCTX-M-27, blaCTX-M-1, blaTEM-169, blaCTX-M-14, blaCTX-M-99-like, blaCTX-M-125, blaSHV-12, and blaDHA-1, while virulence genes were east1, sat, and tsh in declining order of frequency of occurrence each. In line with phenotypically observed high resistance rates for aminoglycosides and trimethoprim/sulfamethoxazole, multiple associated resistance genes were observed. A similar, slightly more diverse situation was recorded for the other deployment sites. In summary, this assessment provides first next-generation sequencing-based epidemiological data on third-generation cephalosporine-resistant E. coli imported by deployed German soldiers with a particular focus on deployments to the Sahel region, thus serving as a small sentinel. The detected sequence types are well in line with the results from previous epidemiological assessments in sub-Saharan Africa.