New evidence on adolescent sexual and reproductive health and rights from the West and Central African region.

The African Journal of Reproductive Health is pleased to publish these compendiums of original research in this special edition that document new findings in adolescent sexual and reproductive health and rights from the West and Central African region (WCA). While sub-Saharan Africa has some of the worst indicators of sexual and reproductive health and rights (SRHR) in the world, the indicators are more daunting in the WCA region. To date, the WCA is recognized to have the highest rates of unwanted pregnancy, unsafe abortion, and human immunodeficiency virus (HIV) and other sexually transmissible infections, as well as the lowest contraceptive prevalence rates among adolescents worldwide.1 Despite the high rate of adverse adolescent reproductive health outcomes in WCA, there has been limited documentations of the socio-cultural and economic circumstances that perpetuate these adverse consequences. There have also been no purposefully designed interventions that provide strong scientific evidence for developing strategies to reverse the trend.

Le Journal africain de la santé reproductive est heureux de publier ces recueils de recherches originales dans cette édition spéciale qui documentent les nouvelles découvertes sur la santé et les droits sexuels et reproductifs des adolescents de la région de l'Afrique de l'Ouest et du Centre (WCA). Alors que l'Afrique subsaharienne possède certains des pires indicateurs au monde en matière de santé et de droits sexuels et reproductifs (SDSR), les indicateurs sont plus intimidants dans la région AOC. À ce jour, l'AOC est reconnue pour avoir les taux les plus élevés de grossesses non désirées, d'avortements à risque, de virus de l'immunodéficience humaine (VIH) et d'autres infections sexuellement transmissibles, ainsi que les taux de prévalence contraceptive les plus faibles parmi les adolescents dans le monde.1 Malgré le taux élevé de En dépit des résultats négatifs en matière de santé reproductive des adolescents en AOC, il existe peu de documentation sur les circonstances socioculturelles et économiques qui perpétuent ces conséquences néfastes. Il n'y a pas non plus d'interventions spécialement conçues qui fournissent des preuves scientifiques solides pour élaborer des stratégies visant à inverser la tendance.

Gender and adolescent sexual and reproductive health and rights in West and Central Africa: New evidence and emerging gaps.

The West and Central Africa (WCA) region is a natural resource-rich, 24-country, contiguous area with a population of nearly 500 million people. The median age for the region is currently 18 years and approximately one-third of its population is aged between 10 and 24 years. If current demographic trends in the region persist, its population will reach 1.5 billion by 2050. At that time, WCA will not only have the largest number of young people globally, but it will also be the only part of the world whose population of young people will continue to increase1. Many countries in the region are also or have recently been involved in armed conflicts, which have devastated infrastructure, displaced people, stifled development, and more importantly, resulted in myriad deaths and morbidities.

La région de l'Afrique de l'Ouest et du Centre (AOC) est une zone contiguë de 24 pays riches en ressources naturelles et comptant près de 500 millions d'habitants. L'âge médian de la région est actuellement de 18 ans et environ un tiers de sa population est âgée de 10 à 24 ans. Si les tendances démographiques actuelles de la région persistent, la population de la région atteindra 1,5 milliard d'habitants d'ici 2050. À cette époque, l'AOC comptera non seulement le plus grand nombre de jeunes au monde, mais elle sera également la seule partie du monde dont la population de le nombre de jeunes va continuer à augmenter1. De nombreux pays de la région sont également ou ont été récemment impliqués dans des conflits armés, qui ont dévasté les infrastructures, déplacé les populations, étouffé le développement et, plus important encore, entraîné une myriade de morts et de morbidités.

Mapping of schistosome hybrids of the haematobium group in West and Central Africa.

Hybridization of parasitic species is an emerging health problem in the evolutionary profile of infectious disease, particularly within trematodes of the genus Schistosoma. Because the consequences of this hybridization are still relatively unknown, further studies are needed to clarify the epidemiology of the disease and the biology of hybrid schistosomes. In this article, we provide a detailed review of published results on schistosome hybrids of the haematobium group. Using a mapping approach, this review describes studies that have investigated hybridization in human (S. haematobium, S. guineensis, and S. intercalatum) and animal (S. bovis and S. curassoni) schistosome species in West Africa (Niger, Mali, Senegal, Côte d'Ivoire, Benin, Nigeria) and in Central Africa (Cameroon, Gabon, Democratic Republic of Congo), as well as their limitations linked to the underestimation of their distribution in Africa. This review provides information on studies that have highlighted hybrid species of the haematobium group and the regions where they have been found, notably in West and Central Africa.

Nutrient-Dense African Indigenous Vegetables and Grains in the FAO Food Composition Table for Western Africa (WAFCT) Identified Using Nutrient-Rich Food (NRF) Scores.

Nutrient profiling (NP) models that assess nutrient density of foods can help remedy micronutrient deficiencies. We used NP methods to identify the most nutrient-rich foods in the 2019 FAO/INFOODS Western Africa Food Composition Table (WAFCT). The WAFCT had complete data for 909 foods. Three versions of the well-established Nutrient-Rich Food (NRF) model were used: (1) the original NRF9.3 based on 9 micronutrients (protein, fiber, calcium, iron, potassium, magnesium, vitamin A, vitamin C, and vitamin D); (2) a new NRF6.3 based on 6 priority micronutrients (iron, zinc, calcium, folate, vitamin A, vitamin B12); and (3) NRF 15.3, based on 15 nutrients to encourage (NRF6.3 nutrients + vitamin D, vitamin E, vitamin C, vitamin B1, vitamin B2, vitamin B3, vitamin B6, copper, and magnesium). Data analyses used one-way ANOVAs and independent t-tests, with significance at α = 0.05. Animal-source foods were rated higher by NRF6.3 priority micronutrient and NRF15.3 NP models than by the NRF9.3 model. African indigenous vegetables had higher protein content and higher nutrient density compared to non-indigenous vegetables, and African indigenous grains had higher nutrient density compared to non-indigenous grains. Though animal-source foods received some of the highest scores, NP models adapted to the West African context showed that African indigenous vegetables and grains were also nutrient rich. Indigenous foods could be important sources of priority micronutrients for the region.

West African Genetic Ancestry, Neighborhood Deprivation, and Prostate Cancer.

Importance: Racial disparities in prostate cancer are likely the result of complex relationships between both socioeconomic and environmental factors captured by the neighborhood environment and genetic factors, including West African genetic ancestry. However, few studies have examined the combined role of neighborhood environment and genetic ancestry in developing lethal prostate cancer. Objective: To examine the interactions between West African genetic ancestry and neighborhood deprivation in modifying prostate cancer risk and mortality. Design, Setting, and Participants: This case-control study was conducted in the Greater Baltimore area. Participants included men of African and European descent (617 cases with prostate cancer, 852 controls without prostate cancer) enrolled between January 2005 and January 2016. Follow-up was performed through December 31, 2020, using the National Death Index. Analysis was conducted from August 2023 to January 2024. Exposure: Included exposures were West African genetic ancestry, derived from large-scale genotyping, and neighborhood deprivation, defined using 2000 census-tract-level Neighborhood Deprivation Index (NDI) score. Main Outcomes and Measures: Outcomes of interest were prostate cancer and all-cause mortality. Results: Among a total of 1469 participants (mean [SD] age, 64.96 [7.95] years), there were 736 self-identified Black and 733 White men, and the mean (range) proportion of West African genetic ancestry was 0.27 (0.04-0.84) among participants residing in areas with low levels of deprivation and 0.48 (0.07-0.83) among participants residing in areas with high levels of deprivation. Multivariable logistic regression analysis revealed a significant multiplicative interaction of West African genetic ancestry and neighborhood deprivation with the odds of a prostate cancer diagnosis (P for interaction = .02). Among individuals living in neighborhoods with high NDI scores, West African genetic ancestry was associated with increased odds of a prostate cancer diagnosis (age-adjusted odds ratio [OR], 1.98; 95% CI, 1.23-3.19). In contrast, West African genetic ancestry was associated with reduced odds of this diagnosis among individuals residing in areas with medium to low levels of deprivation (age-adjusted OR, 0.22; 95% CI, 0.11-0.44). There was no significant multiplicative interaction between West African genetic ancestry and neighborhood deprivation for all-cause mortality (P for interaction = .44). The positive association of neighborhood deprivation with prostate cancer was independent of West African genetic ancestry (age- and West African ancestry-adjusted OR, 1,70; 95% CI, 1.50-1.94). Conclusions and Relevance: This case-control study of men with West African and European ancestry found that West African genetic ancestry was associated with increased odds of prostate cancer among males who resided in neighborhoods with high deprivation but lower odds in more affluent neighborhoods. Thus, neighborhood environments may play a critical role in defining how genetic ancestry modulates prostate cancer risk.

Population genomic evidence of a putative 'far-west' African cryptic taxon in the Anopheles gambiae complex.

The two main Afrotropical malaria vectors - Anopheles coluzzii and An. gambiae - are genetically distinct and reproductively isolated across West Africa. However, populations at the western extreme of their range are assigned as "intermediate" between the two species by whole genome sequence (WGS) data, and as hybrid forms by conventional molecular diagnostics. By exploiting WGS data from 1190 specimens collected across west Africa via the Anopheles gambiae 1000 Genomes network, we identified a putative taxon in the far-west (provisionally named Bissau molecular form), which did not arise by admixture but rather may have originated at the same time as the split between An. coluzzii and An. gambiae. Intriguingly, this taxon lacks insecticide resistance mechanisms commonly observed in the two main species. These findings lead to a change of perspective on malaria vector species in the far-west region with potential for epidemiological implications, and a new challenge for genetic-based mosquito control approaches.

Effectiveness of lifestyle interventions for glycaemic control among adults with type 2 diabetes in West Africa: a systematic review and meta-analysis protocol.

BACKGROUND: Lifestyle interventions are key to the control of diabetes and the prevention of complications, especially when used with pharmacological interventions. This protocol aims to review the effectiveness of lifestyle interventions in relation to nutrition and physical activity within the West African region. This systematic review and meta-analysis seeks to understand which interventions for lifestyle modification are implemented for the control of diabetes in West Africa at the individual and community level, what evidence is available on their effectiveness in improving glycaemic control and why these interventions were effective. METHODS: We will review randomised control trials and quasi-experimental designs on interventions relating to physical activity and nutrition in West Africa. Language will be restricted to English and French as these are the most widely spoken languages in the region. No other filters will be applied. Searching will involve four electronic databases - PubMed, Scopus, Africa Journals Online and Cairn.info using natural-language phrases plus reference/citation checking. Two reviewers will independently screen results according to titles and abstracts against the inclusion and exclusion criteria to identify eligible studies. Upon full-text review, all selected studies will be assessed using Cochrane's Collaboration tool for assessing the risk of bias of a study and the ROBINS-I tool before data extraction. Evidence will be synthesised narratively and statistically where appropriate. We will conduct a meta-analysis when the interventions and contexts are similar enough for pooling and compare the treatment effects of the interventions in rural to urban settings and short term to long term wherever possible. DISCUSSION: We anticipate finding a number of studies missed by previous reviews and providing evidence of the effectiveness of different nutrition and physical activity interventions within the context of West Africa. This knowledge will support practitioners and policymakers in the design of interventions that are fit for context and purpose within the West African region. SYSTEMATIC REVIEW REGISTRATION: This systematic review has been registered in the International Prospective Register for Systematic Reviews - PROSPERO, with registration number CRD42023435116. All amendments to this protocol during the process of the review will be explained accordingly.

Estimating the copepod biomass in the North West African upwelling system using a bi-frequency acoustic approach.

The Canary Current Large Marine Ecosystem (CCLME) is one of the most productive Large Marine Ecosystems worldwide. Assessing the abundance, biomass and distribution of zooplankton in the southern part of this system, off the coast of West Africa, remains challenging due to limited sampling efforts and data availability. However, zooplankton is of primary importance for pelagic ecosystem functioning. We applied an inversion method with combined analysis of acoustic and biological data for copepod discrimination using a bi-frequency (38 and 120 kHz) approach. Large copepods with equivalent spherical radii > 0.5 mm were identified using differences in the mean volume backscattering strength (MVBS). Regarding abundance measured by net sampling, copepods strongly dominated the zooplankton community and the large fraction account for 18%. This estimate correlated significantly with MVBS values that were obtained using an inverse algorithm. We confirmed the utility of using 38 kHz for large copepod detection. An epipelagic biomass of large copepod was estimated at 120-850 mg m-2 in March during upwelling season. It is worth noting that this estimation likely underestimates the true biomass due to inherent uncertainties associated with the measurement method. We recommend future investigations in the interest of using only nighttime data to improve the sampling pattern, particularly on the upper part of the water column (< 10 m) as well as on the shallow part of the continental shelf (< 20 m depth) not covered by fisheries vessel. Nevertheless, such high copepod biomass supports high fish production underlining the key role of copepod in the CCLME. Our results open the way to the analysis of the fluctuation and trend of copepod biomass, along with three decades of fisheries acoustics data available in the region. This helps to determine ecosystem changes, particularly under climate change, and to investigate the role of copepods in the southern CCLME carbon pump at the fine scale.

Genetic investigation of population structure in Atlantic chub mackerel, Scomber colias Gmelin, 1789 along the West African coast.

Sustainable management of transboundary fish stocks hinges on accurate delineation of population structure. Genetic analysis offers a powerful tool to identify potential subpopulations within a seemingly homogenous stock, facilitating the development of effective, coordinated management strategies across international borders. Along the West African coast, the Atlantic chub mackerel (Scomber colias) is a commercially important and ecologically significant species, yet little is known about its genetic population structure and connectivity. Currently, the stock is managed as a single unit in West African waters despite new research suggesting morphological and adaptive differences. Here, eight microsatellite loci were genotyped on 1,169 individuals distributed across 33 sampling sites from Morocco (27.39°N) to Namibia (22.21°S). Bayesian clustering analysis depicts one homogeneous population across the studied area with null overall differentiation (F ST = 0.0001ns), which suggests panmixia and aligns with the migratory potential of this species. This finding has significant implications for the effective conservation and management of S. colias within a wide scope of its distribution across West African waters from the South of Morocco to the North-Centre of Namibia and underscores the need for increased regional cooperation in fisheries management and conservation.

Can global health security frameworks measure One Health implementation in West Africa?A mixed-methods study.

BACKGROUND: The 2014 outbreak of the Ebola virus disease highlighted the importance of overhauling and transforming healthcare systems in West Africa to improve the ability of individual countries to deal with infectious diseases. As part of this effort, in November 2016 the West African Health Organization (WAHO) began the process of institutionalizing the One Health (OH) approach to health security across the Economic Community of West African States (ECOWAS). The lack of clear metrics and evaluation frameworks to measure the progress of OH implementation in West Africa has been reported as a challenge. Therefore, this study sought to assess and explore whether the existing metrics of global health security frameworks can measure the successful implementation of OH activities, evaluate the progress made since 2016, and identify key areas for improvement in the region. METHOD: The study employed predetermined keywords to select indicators from the International Health Regulations (IHR) Monitoring Frameworks, specifically the State Party Self-Assessment Annual Report (SPAR) and Joint External Evaluation (JEE), deemed relevant to the OH approach. In addition, the COVID-19 performance index scores (severity and recovery) for June 2022 were extracted from the Global COVID-19 Index (GCI). The GCI Recovery Index evaluated the major recovery parameters reported daily to indicate how a country performed on the path to recovery from the COVID-19 pandemic compared to other countries. National documents were also analyzed using categorical variables to assess the performance status of OH platforms across implementing countries. A quantitative analysis of these indicators was conducted and supplemented with qualitative data gathered through interviews with key stakeholders. Between March and April 2022, we conducted 18 key informant interviews with purposively selected representatives from regional governmental agencies and international multilateral agencies, including ECOWAS member states. Interviews were conducted online, transcribed, and analysed following the tenets of thematic analysis. RESULTS: Our quantitative analysis revealed no significant association between the implementation status of OH activities and any of the selected indicators from SPAR and JEE. The descriptive analysis of the JEE scores at the country level revealed that countries with existing OH platforms scored relatively higher on the selected JEE indicators than other countries in the pre-implementation stage. OH implementation status did not significantly affect COVID-19 recovery and severity indices. The qualitative findings with relevant stakeholders revealed noteworthy challenges related to insufficient human capacity, inadequate coordination, and a lack of government funding for the sustainability of OH initiatives. Nonetheless, countries in the ECOWAS region are making progress toward the integration of OH into their health security systems. CONCLUSION: Standardized metrics were used to assess the implementation and efficacy of OH systems in the ECOWAS region. Current indicators for monitoring global health security frameworks lack specificity and fail to comprehensively capture essential OH components, particularly at the sub-national level. To ensure consistency and effectiveness across countries, OH implementation metrics that align with global frameworks such as IHR should be developed.

Dietary diversity and associated factors among infants and young children in three West African countries.

Providing children healthy diversified diets is important for their optimal growth and development. The high prevalence of under-nourishment during the critical early life period is of serious concern in West Africa. We assessed the level of dietary diversity and associated factors for children aged 6-23 months in Côte d'Ivoire, Niger and Senegal. Prior 24 h dietary intake was assessed for 3,528 children (Côte d'Ivoire: N = 118; Niger: N = 763; Senegal: N = 2,647) using the Diet Quality Questionnaire survey tool administered to primary caregivers. Cluster random sampling was conducted for urban and rural areas in Niger and Senegal and simple random sampling was used in Côte d'Ivoire, where only rural households were selected. Survey data were analyzed to determine children's intake of items from eight food groups: breast milk; grains, roots, tubers and plantains; pulses, nuts and seeds; dairy products; flesh foods; eggs; vitamin A-rich fruits and vegetables; and other fruits and vegetables. Minimum Dietary Diversity (MDD) was assessed based on the consumption of ≥5 of the 8 food groups. In all countries, the majority of children were ≥ 12 months of age and from rural households. Children from poor/very poor households ranged from 32.4 to 41.9%. MDD prevalence was 54.2% in Côte d'Ivoire, 33.3% in Niger and 30.8% in Senegal. In all three countries, children 12-23 months had significantly higher consumption of six of the food groups, compared to those 6-11 months, and children ≥12 months had a higher likelihood of MDD, compared to infants, in Niger (aOR = 4.25; 95% CI: 2.46, 7.36) and Senegal (aOR = 2.69; 95% CI: 2.15, 3.35). MDD prevalence was higher among children in urban, compared to rural, areas in Niger (p = 0.020) and Senegal (p < 0.001) and significantly higher in the wealthiest, compared to poorest, households. This study suggests most young children in Côte d'Ivoire, Niger and Senegal are not receiving an adequately diversified diet, with a reliance on starchy staples and lower intake of high-quality protein sources. Our results highlight socio-economic barriers to attaining dietary diversity in these settings and stress the urgent and continuing need for investments in strategies that support optimal complementary feeding practices.

Quantifying the risk of spillover reduction programs for human health.

Reducing spillover of zoonotic pathogens is an appealing approach to preventing human disease and minimizing the risk of future epidemics and pandemics. Although the immediate human health benefit of reducing spillover is clear, over time, spillover reduction could lead to counterintuitive negative consequences for human health. Here, we use mathematical models and computer simulations to explore the conditions under which unanticipated consequences of spillover reduction can occur in systems where the severity of disease increases with age at infection. Our results demonstrate that, because the average age at infection increases as spillover is reduced, programs that reduce spillover can actually increase population-level disease burden if the clinical severity of infection increases sufficiently rapidly with age. If, however, immunity wanes over time and reinfection is possible, our results reveal that negative health impacts of spillover reduction become substantially less likely. When our model is parameterized using published data on Lassa virus in West Africa, it predicts that negative health outcomes are possible, but likely to be restricted to a small subset of populations where spillover is unusually intense. Together, our results suggest that adverse consequences of spillover reduction programs are unlikely but that the public health gains observed immediately after spillover reduction may fade over time as the age structure of immunity gradually re-equilibrates to a reduced force of infection.

Quantification and characterization of microplastics ingested by mangrove oysters across West Africa.

Microplastic ingestion by marine organisms presents a challenge to both ecosystem functioning and human health. We characterized microplastic abundance, shape, size, and polymer types ingested by the West African mangrove oyster, Crassostrea tulipa (Lamarck, 1819) sampled from estuaries and lagoons from the Gambia, Sierra Leone, Ghana, Benin, and Nigeria using optical microscopy and Fourier transform infrared (FTIR) techniques. A total of 780 microplastics were isolated in the whole tissues of the 250 oysters (n = 50 oysters per country). The abundance and distribution of microplastics in the oysters followed the pattern: the Gambia > Ghana > Sierra Leone > Nigeria > Benin. The Tanbi wetlands in the Gambia recorded the highest average of 10.50 ± 6.69 per oyster while the Ouidah lagoon in Benin recorded the lowest average of 1.80 ± 1.90 per oyster. Overall, microplastic numbers varied significantly (p < 0.05) among the five countries. Microfibers, particularly those within 1001-5000 µm size, dominated the total microplastic count with a few fragments and films. No spherical microplastics were isolated in the oysters. In the Sierra Leone and Benin oysters, fragments and films were absent in the samples. Microplastic between the 1001 and 5000 µm size class dominated the counts, followed by 501-1000 µm, 101-500 µm, and 51-100 µm. Five polymer groups namely polyethylene, polyester, nylon, polypropylene, and polyamide were identified across the five countries, with polyethylene occurring in oysters from all five countries and polyester occurring in all but the oysters from Nigeria. This diversity of polymers suggests varied sources of microplastics ingested by the studied oysters. The absence of microspheres across the five supports findings from other studies that they are the least ingested and highly egested by the oysters.

In Silico Screening of Phytocompounds from West African Traditional Medicine and Molecular Docking Targeting Dengue Virus Protein NS2B/NS3.

Traditional medicine offers a wide range of application for in silico study techniques. This drug research and development strategy is embryonic in the West African context, particularly in Burkina Faso, which is increasingly faced with emerging diseases such as dengue fever. Circulation of the 4 serotypes of this virus has been documented in the country. This study aims to evaluate the therapeutic potential of phytocompounds contained in the West African pharmacopoeia against dengue virus NS2B/NS3 protein, using computational methods integrating several software packages and databases. Based on a literature review, we identified 191 molecules from 30 plants known for their antiviral effects. Five met the inclusion criteria for molecular docking: patulin from calotropis procera, resiniferonol from Euphorbia poissonii, Securinol A from Flueggea virosa, Shikimic acid and Methyl gallate from Terminalia macroptera. The best binding scores were observed between resiniferonol and the serotypes 1, 2 and 4 NS2B/NS3 protease, with binding energies of -7.4 Kcal/mol, -6.8 Kcal/mol and -7.3 Kcal/mol respectively; while the NS2B/NS3 protease of serotype 3 had the best affinity for securinol A (-7 Kcal/mol). This study points the way to further research in computer aided drug design field and calls for multidisciplinary collaboration to promote West African medicinal plants against health challenges.

The NS1 protein of contemporary West African Zika virus potentiates viral replication and reduces innate immune activation.

Mosquito-borne Zika virus (ZIKV) from sub-Saharan Africa has recently gained attention due to its epidemic potential and its capacity to be highly teratogenic. To improve our knowledge on currently circulating strains of African ZIKV, we conducted protein sequence alignment and identified contemporary West Africa NS1 (NS1CWA) protein as a highly conserved viral protein. Comparison of NS1CWA with the NS1 of the historical African ZIKV strain MR766 (NS1MR766), revealed seven amino acid substitutions. The effects of NS1 mutations on protein expression, virus replication, and innate immune activation were assessed in human cells using recombinant NS1 proteins and a chimeric viral clone MR766 with NS1CWA replacing NS1MR766. Our data indicated higher secretion efficiency of NS1CWA compared to NS1MR766 associated with a change in subcellular distribution. A chimeric MR766 virus with NS1CWA instead of authentic protein displayed a greater viral replication efficiency, leading to more pronounced cell death compared to parental virus. Enhanced viral growth was associated with reduced activation of innate immunity. Our data raise questions of the importance of NS1 protein in the pathogenicity of contemporary ZIKV from sub-Saharan Africa and point to differences within viral strains of African lineage.

An adjuvant formulation containing Toll-like Receptor 7 agonist stimulates protection against morbidity and mortality due to Anaplasma marginale in a highly endemic region of west Africa.

Efficient cattle production and provision of animal-sourced foods in much of Africa is constrained by vector-borne bacterial and protozoal diseases. Effective vaccines are not currently available for most of these infections resulting in a continuous disease burden that limits genetic improvement. We tested whether stimulation of innate immunity using the Toll-like Receptor (TLR) 7 agonist imiquimod, formulated with saponin and water-in-oil emulsion, would protect against morbidity and mortality due to Anaplasma marginale, a tick-borne pathogen of cattle highly endemic in west Africa. In Trial 1, haplotype matched Friesian x Sanga (F1) A. marginale negative calves were allocated to either the experimental group (n = 10) and injected with the synthetic TLR 7 agonist/saponin formulation or to an untreated control group (n = 10). TLR7 agonist/saponin injected calves responded with significantly elevated rectal temperature, enlarged regional lymph nodes, and elevated levels of IL-6 post-injection as compared to control group calves. All calves were then allowed to graze in pasture for natural exposure to tick transmission. All calves in both groups acquired A. marginale, consistent with the high transmission rate in the endemic region. The need for antibiotic treatment, using pre-existing criteria, was significantly lower in the experimental group (odds ratio for not requiring treatment was 9.3, p = 0.03) as compared to the control group. Despite treatment, 6/10 calves in the control group died, reflecting treatment failures that are typical of anaplasmosis in the acute phase, while mortality in the experimental group was 1/10 (odds ratio for survival was 13.5, p = 0.03). The trial was then repeated using 45 Friesian x Sanga calves per group. In Trial 2, the odds ratios for preventing the need for treatment and for mortality in the TLR7 agonist/saponin experimental group versus the control group were 5.6 (p = 0.0002) and 7.0 (p = 0.004), respectively, reproducing the findings of the initial trial. Together these findings demonstrate that innate immune stimulation using a TLR7 agonist formulated with saponin and water-in-oil emulsion provides significant protection against disease caused by tick borne A. marginale in highly susceptible cross-bred cattle, critically important for their potential to increase productivity for smallholder farmers in Africa.

Modelling Lassa virus dynamics in West African Mastomys natalensis and the impact of human activities.

Lassa fever is a West African rodent-borne viral haemorrhagic fever that kills thousands of people a year, with 100 000 to 300 000 people a year probably infected by Lassa virus (LASV). The main reservoir of LASV is the Natal multimammate mouse, Mastomys natalensis. There is reported asynchrony between peak infection in the rodent population and peak Lassa fever risk among people, probably owing to differing seasonal contact rates. Here, we developed a susceptible-infected-recovered ([Formula: see text])-based model of LASV dynamics in its rodent host, M. natalensis, with a persistently infected class and seasonal birthing to test the impact of changes to seasonal birthing in the future owing to climate and land use change. Our simulations suggest shifting rodent birthing timing and synchrony will alter the peak of viral prevalence, changing risk to people, with viral dynamics mainly stable in adults and varying in the young, but with more infected individuals. We calculate the time-average basic reproductive number, [Formula: see text], for this infectious disease system with periodic changes to population sizes owing to birthing using a time-average method and with a sensitivity analysis show four key parameters: carrying capacity, adult mortality, the transmission parameter among adults and additional disease-induced mortality impact the maintenance of LASV in M. natalensis most, with carrying capacity and adult mortality potentially changeable owing to human activities and interventions.

Impact of patrilocality on contrasting patterns of paternal and maternal heritage in Central-West Africa.

Despite their ancient past and high diversity, African populations are the least represented in human population genetic studies. In this study, uniparental markers (mtDNA and Y chromosome) were used to investigate the impact of sociocultural factors on the genetic diversity and inter-ethnolinguistic gene flow in the three major Nigerian groups: Hausa (n = 89), Yoruba (n = 135) and Igbo (n = 134). The results show a distinct history from the maternal and paternal perspectives. The three Nigerian groups present a similar substrate for mtDNA, but not for the Y chromosome. The two Niger-Congo groups, Yoruba and Igbo, are paternally genetically correlated with populations from the same ethnolinguistic affiliation. Meanwhile, the Hausa is paternally closer to other Afro-Asiatic populations and presented a high diversity of lineages from across Africa. When expanding the analyses to other African populations, it is observed that language did not act as a major barrier to female-mediated gene flow and that the differentiation of paternal lineages is better correlated with linguistic than geographic distances. The results obtained demonstrate the impact of patrilocality, a common and well-established practice in populations from Central-West Africa, in the preservation of the patrilineage gene pool and in the affirmation of identity between groups.

Re-Emergence of Rift Valley Fever Virus Lineage H in Senegal in 2022: In Vitro Characterization and Impact on Its Global Emergence in West Africa.

Rift Valley fever (RVF) is a re-emerging vector-borne zoonosis with a high public health and veterinary impact. In West Africa, many lineages were previously detected, but since 2020, lineage H from South Africa has been the main cause of the outbreaks. In this study, clinical samples collected through national surveillance were screened for RVF virus (RVFV) acute infection by RT-PCR and IgM ELISA tests. Sequencing, genome mapping and in vitro phenotypic characterization in mammal cells were performed on RT-PCR positive samples in comparison with other epidemic lineages (G and C). Four RVFV human cases were detected in Senegal and the sequence analyses revealed that the strains belonged to lineage H. The in vitro kinetics and genome mapping showed different replication efficiency profiles for the tested RVFV lineages and non-conservative mutations, which were more common to lineage G or specific to lineage H. Our findings showed the re-emergence of lineage H in Senegal in 2022, its high viral replication efficiency in vitro and support the findings that genetic diversity affects viral replication. This study gives new insights into the biological properties of lineage H and calls for deeper studies to better assess its potential to cause a future threat in Senegal.