Baobab Index

Land-use changes in West Africa are threatening wildlife viability, yet their impacts on species' genetic diversity and connectivity remain poorly understood. We investigated the environmental drivers of genetic diversity and functional connectivity in the Near Threatened Guinea baboon (Papio papio) by genotyping 243 non-invasively collected faecal samples across its range and applying a landscape genetics framework. We identified distinct genetic clusters, with Gambian populations exhibiting the lowest genetic diversity and highest inbreeding. Genetic diversity was positively associated with shrublands and forest-savannah mosaics, highlighting the importance of these habitats for maintaining viable populations. Rivers, grasslands, and shrublands facilitate functional connectivity and act as dispersal corridors, whereas large waterbodies and intensive croplands serve as strong barriers. Notably, habitats constituted by mosaics of forest and croplands provide more permeable barriers to movement than strict monocultures. Our results suggest that intensive agricultural land use can reduce functional connectivity, whereas heterogeneous natural habitats and riverine networks sustain it. To ensure the long-term survival of Guinea baboons, conservation strategies must prioritize preserving riverine corridors and habitat heterogeneity. Furthermore, replacing monoculture farming with agroecological practices like agroforestry is crucial to support landscape connectivity and mitigate the adverse effects of agricultural expansion.

Host genetic variation is a key determinant of malaria susceptibility, particularly in endemic regions where intense transmission has driven strong selective pressures on red blood cell-related genes. However, Senegalese and other African populations remain underrepresented in genomic studies, limiting population-specific inference. We analyzed malaria-related host genetic variants in 140 febrile patients from southern and south-eastern Senegal, focusing on key loci (ACKR1, Dantu blood group, HBB and G6PD) and on composite Multilocus Genotype Profiles (MGPs). We described the co-occurrence of the variants within individuals, allowing exploratory assessment of combined genetic architectures. We identified both well-established malaria-protective variants, including the Duffy-negative Fy(a-b-) phenotype (observed in all individuals), G6PD key variants (e.g., G202A with an allelic frequency of ~3%, A376G at ~40%, T968C at ~1%), and HBB variants (HbS at ~7% and HbC at ~1%), as well as some rare and less characterized polymorphisms. To the best of our knowledge, this study provides the first description in the Senegalese population of the Dantu variant (rs186873296) and the rare ACKR1 rs577808287 variant, each observed in 2 distinct individuals. Five major composite MGPs across the four loci were predominantly observed and together represented more than 75% of individuals. Excluding Duffy status, most of these profiles included at least one variant previously reported in the literature as malaria-protective, a pattern consistent with the hypothesis of malaria-driven balancing selection, despite the presence of potentially deleterious alleles. This study highlights substantial genetic heterogeneity in malaria-relevant host genes in Senegal and demonstrates the value of integrating composite genetic architectures into malaria research. These findings provide population-specific data that are critical for improving malaria risk assessment, clinical interpretation, and public health strategies in endemic regions. Moreover, the relatively high frequencies of some variants may reflect balancing selection, possibly partially driven by the adaptive benefits they confer in populations exposed to malaria.

Sustaining progress toward polio eradication requires not only effective vaccination but also a resilient laboratory network capable of timely poliovirus detection, confirmation, and genetic characterization. In the WHO African region, the African polio laboratory network provides essential virological support for eradication efforts; however, persistent circulating Vaccine-derived Polioviruses (cVDPVs) outbreaks and increasing demands of genomic surveillance continue to challenge laboratory capacity. Despite its critical role, evidence describing the operational performance, adaptive capacity, and evolution of regional polio laboratory network remains limited. This study evaluates the performance and operational experience of the African polio laboratory network in 2025, highlighting contributions to poliovirus detection, genomic surveillance, quality assurance, and outbreak response, while sharing lessons to inform regional public health systems. A retrospective secondary data analysis was conducted using laboratory surveillance and outbreak databases, supplemented by reviews of programmatic reports. Data were cleaned and harmonized prior to analysis. Descriptive analyses were performed to assess laboratory workload, timeliness indicators, genomic capacity, quality assurance performance, and operational challenges. Qualitative review of programmatic documents was conducted to identify contextual factors influencing performance. In 2025, 77,230 Acute Flaccid Paralysis (AFP) specimens were analyzed across 16 laboratories. Ninety-two percent of specimens met the timeliness target for virus isolation, and 94% met the target for PCR-ITD. Genomic sequencing confirmed 20 cVDPV outbreaks in 10 countries. The establishment of new sequencing laboratories in Uganda and Nigeria reduced turnaround times, and a 2025 expansion plan aimed to build sequencing capacity in 12 additional countries. All laboratories assessed in 2024 for virus isolation, PCR-ITD, and environmental surveillance exceeded quality assurance accreditation thresholds and were rated "Pass". The pilot implementation of Direct Detection Nanopore Sequencing (DDNS) techniques is expected to further strengthen genomic surveillance. Challenges remain, including stock out of essential supplies, uneven workloads, and infrastructure gaps. The African polio laboratory network has demonstrated sustained capacity, adaptability, and innovation in supporting polio eradication activities in the WHO African region. This study provides evidence on the importance of strengthening laboratory systems, expanding genomic capacity, and maintaining quality assurance mechanisms to support the final phase of polio eradication and broader public health surveillance.

Crimean-Congo Hemorrhagic Fever virus (CCHFV) is a zoonotic arbovirus of major public health, transmitted to humans and animals by ticks or animals infected. Although previous evidence of CCHFV circulation was reported in central and southeastern bioecological areas of Senegal, its spatial and temporal dynamics remain poorly understood. To investigate CCHFV activity, naïve sheep and goats were placed near human populations as sentinel herds in the areas from March 2021 to June 2024. Blood and tick samples were regularly collected from these animals. Sera were tested by ELISA for CCHFV antibodies, while ticks were screened by RT-PCR for CCHFV RNA. A total of 2,708 sera were tested and an overall seroconversion of 16.83% (95% CI: 14.46%-19.42%) was recorded. Variations in CCHFV infection rate (CCHFVIR) were no significant between central and southeastern zones, but highly significant between districts within each area. Goats were significantly more likely to be infected than sheep (OR = 1.47; 95% CI: 1.03-2.11; Between March 2021 to June 2024, animals tested negative for CCHFV antibodies were placed in proximity to human populations in central and southeastern bioecological areas of Senegal. Every 3 months, regular collections of serums and ticks were carried out from these animals for early detection of CCHFV activity. Sera were tested by ELISA for CCHFV antibodies, and ticks screened by RT‐PCR for CCHFV RNA. Results revealed a permanent circulation of CCHFV in both central and southeastern Senegal, particularly in dry season with multiple CCHF foci. The findings suggested that rainfall patterns, host species and geographic location are key factors in CCHFV transmission risk, and there is a critical need to raise awareness among high‐risk occupational groups (e.g., farmers, butchers, healthcare workers) about risk factors and preventive measures, such as using personal protective equipment and safe handling practices for animals and animal tissues.

Early-maturing maize is vital for strengthening food security across the drought-prone agro-ecologies of Sub-Saharan Africa (SSA). Advancing genetic gain in these environments requires a clear understanding of genetic diversity and population structure patterns to support parental selection and future genomic-assisted breeding efforts. The study aimed at assessing genetic diversity and population structure of a panel of early-maturing yellow and orange kernel maize inbred lines, classify the inbred lines into putative heterotic groups, and identify a core set of elite, genetically divergent lines suitable for use in hybrid breeding and long-term genetic improvement. A panel of 376 elite early-maturing yellow and orange maize inbred lines from four source populations were genotyped using the DArTag SNP markers. After quality filtering, 1,954 high-quality SNP markers retained exhibited moderate diversity with an average polymorphic information content (PIC) of 0.38 and minor allele frequency (MAF) of 0.28. Linkage disequilibrium analysis showed a mean r2 of 0.046, with rapid LD decay across the genome, indicating substantial historical recombination and suggesting potential utility of the panel for future association studies. The Admixture analysis and discriminant analysis of principal components (DAPC) consistently resolved the panel into two major subpopulations with overlapping membership. Phylogenetic clustering also resolved the panel into two broad molecular clusters corresponding to putative heterotic groups. Analysis of molecular variance (AMOVA) revealed that most genetic variation occurred within groups (86%), with moderate differentiation among groups (14%). A core set representing 20% of the collection was identified using an allelic-richness-based greedy algorithm, offering valuable insights to accelerate breakthrough hybrid development for SSA farming systems. The study provides a comprehensive genomic characterization of early-maturing maize germplasm, providing genomic insights that may support future hybrid development and germplasm management efforts for SSA maize breeding programs.

This study described the peculiarity of the clinical phenotypes and the pattern of reproductive hormones among women with PCOS in Nigerian populace.  A total of 90 consented volunteers consisting of 45 PCOS and 45 controls were recruited. The diagnosis of PCOS was established using the International PCOS guidelines 2018. Demographic, anthropometric, and clinicopathological data were obtained from each participant. Hormonal assay was done using the electrochemiluminescence (ECL) technology (Roche Diagnostics, Switzerland). Statistical analysis was done using the Statistical Package for the Social Sciences (SPSS) version 25.  Polycystic ovaries (PCO) are the most popular feature of PCOS, observed in more than 90% of PCOS subjects followed by oligomenorrhea (68 %), while hirsutism and acne were found in about 50% of the cases. The study shows 62 % of PCOS subjects had phenotype D, 52 % Phenotype C, 40 % Phenotype B, while 38 % had Phenotype A. Increased levels of Anti-Mullerian hormone (AMH), Testosterone, Prolactin, Luteinizing hormone (LH) and LH: FSH were observed in PCOS with median (95% Confidence interval) of 4.98(3.4-7.1), 32.5(19.75-53.0), 401.6(230.9-623.0), 9.23(5.4-16.6) and 2.03(1.48-3.58), respectively compared to control [1.43(0.8-2.4), 19.0(12.3-29.5), 252.2(196.3-337.0), 6.36(4.0-12.6) and 1.47(0.7-2.4), respectively] (p<0.05). The serum levels of follicle-stimulating hormone (FSH), estradiol, and sex hormone binding globulin (SHBG) were lower in PCOS with values of 5.21(3.6-5.9), 70.45(50.5-145.9) and 44.84(27.3-75.7), respectively compared to controls [6.0(4.4-7.9), 104.0(64.6-216.6) and 74.05(54.0-96.8), respectively] (P<0.05). FSH, LH:FSH, AMH, testosterone, estradiol, SHBG, and prolactin show significant odd ratio with risk analysis in PCOS (p<0.05). There existed a negative correlation between the hormones (Estradiol and AMH) and the PCOS phenotypes (estimated Spearman's rho were -.310 and -.348, respectively) (p<0.05). Phenotype D and C characterized by ovulatory dysfunction, polycystic ovary morphology and hyperandrogenism are the two predominant phenotypes of PCOS in our study population. This is accompanied by marked changes in hormonal pattern among PCOS subjects, particularly steroids and follicular hormones. Modulating this phenotype-hormonal interplay may support or improve PCOS management in the study population.

Traditional taxonomy is the foundation of biodiversity science with modern molecular techniques and integrated approaches now essential for advancing our understanding of ocean life. Without improved knowledge of marine biodiversity, it is impossible to address the biodiversity crisis or develop the fundamental science needed to assess, plan and manage marine biodiversity and maintain its many benefits. South Africa harbours exceptional marine biodiversity and has ongoing efforts to systematically list, map, monitor, assess and conserve this national asset. This review consolidates progress in taxonomic knowledge, species lists and molecular barcoding and identifies gaps for benthos-associated invertebrates, a group receiving the least taxonomic attention in the country. Building on previous efforts that revealed major capacity and knowledge gaps, this review updates the state of knowledge, providing a new and accessible baseline and evaluates progress over the past 27 years to guide the next phase of marine invertebrate biodiversity research. Taxonomic advances across 11 major phyla are presented, nine of which have received some level of dedicated revision at phylum, class or family level. Although the taxonomic crisis persists and progress is variable across groups, there has been an appreciable increase in species discovery over the last two decades with more than a thousand invertebrate species added to national lists. Key challenges that hamper efforts and enabling factors supporting progress are identified, with recommendations to consolidate and increase knowledge and capacity, accelerate marine biodiversity discovery and mapping, and address key gaps in our understanding of South Africa's marine invertebrate fauna.

Retinal fundus images offer a non-invasive window into systemic aging. Here, we fine-tune a foundation model (RETFound) to predict chronological age from color fundus images in 71,343 participants from the UK Biobank, achieving a mean absolute error of 2.85 years. The resulting retinal age gap, i.e. the difference between predicted and chronological age, is associated with cardiometabolic traits, inflammation, cognitive performance, all-cause mortality, dementia, cancer, and incident cardiovascular disease. Genome-wide analyses identify genes related to longevity, metabolism, neurodegeneration, and age-related eye diseases. Sex-stratified models reveal consistent performance but divergent biological signatures: males have stronger links to metabolic syndrome, while in females, both model attention and genetics point to a greater involvement of retinal vasculature. Additional analyses indicate that retinal aging patterns in females vary across the menopausal transition, with postmenopausal females exhibiting higher retinal age gap values and clinical associations that more closely resemble those observed in males. Our study positions the retinal age gap as a biologically relevant and sex-specific phenotype associated with multiple aging-related diseases and outcomes beyond conventional risk factors, including chronological age.

Cancer genomic data sharing is a core pillar of precision oncology, underpinning reproducibility, scalability, and equity. The ability to discover, access, integrate, interpret, and reuse cancer 'omics data is a key determinant of precision oncology's value and benefit at scale. This work has been conducted as part of The Lancet Oncology Commission on Cancer Genomics and Precision Oncology to examine the practical data architecture required to support cancer genomics in research, clinical care, and health-system learning. We conclude that without robust data stewardship, including effective data sharing and global integration, the potential of cancer genomics will remain fragmented across projects, platforms, and jurisdictions. This disaggregation limits reproducibility, equity, patient benefit, and societal value. Healthcare systems must prioritise implementing fully efficient data ecosystems as a central challenge for precision oncology.

Delays in vaccination with the first/second dose of measles-containing vaccine (MCV1, MCV2) increases risk of measles transmission. MCV2 was added to Ethiopia's routine immunization schedule in 2019, administered at age 15 months. We describe age at measles vaccination and characteristics associated with timely vaccination following MCV2 introduction. A secondary analysis from a 2021 cross-sectional household survey of children aged 12-35 months in Oromia, Ethiopia was conducted. MCV vaccination status and age at vaccination were determined from the child's vaccination card. The cumulative card-confirmed vaccination coverage of MCV1 and MCV2 (among children 24-35 months) by age at vaccination was estimated. Among children who received MCV, vaccination timing was classified as early (MCV1: <9 months; MCV2: <15 months), timely (MCV1: 9 to <10 months; MCV2: 15 to <16 months), or delayed (MCV1: ≥10 months; MCV2: ≥16 months). Characteristics associated with timely MCV1 vaccination were analyzed using multivariate logistic regression, with urban/rural stratification. Overall, 651 children aged 12-35 months (MCV1) and a subset of 270 children aged 24-35 months (MCV2) were analyzed. Cumulative MCV1 coverage was 59.9% by age 9 months and 76.3% by age 12 months, and MCV2 was 33.0% by age 15 months and 44.8% by age 24 months. MCV coverage was generally higher in urban compared to rural areas. Among vaccinated children, the proportion receiving early, timely, and delayed doses was 30.1%, 44.5%, and 25.3% for MCV1, and 28.6%, 41.2%, and 30.3% for MCV2, respectively. Characteristics associated with timely MCV1 vaccination differed in urban and rural areas, but common themes included increased caregiver immunization awareness and service delivery aspects. Although most children who received MCV1 were vaccinated by 12 months, many received delayed doses. MCV2 coverage was low, irrespective of vaccination timing. Findings highlight the importance of routine catch-up vaccination policies and guidance, and the need for tailored strategies in urban and rural settings to improve MCV coverage and timely vaccination.