Viral Vector Malaria Vaccines Induce High-Level T Cell and Antibody Responses in West African Children and Infants.

Heterologous prime-boosting with viral vectors encoding the pre-erythrocytic antigen thrombospondin-related adhesion protein fused to a multiple epitope string (ME-TRAP) induces CD8+ T cell-mediated immunity to malaria sporozoite challenge in European malaria-naive and Kenyan semi-immune adults. This approach has yet to be evaluated in children and infants. We assessed this vaccine strategy among 138 Gambian and Burkinabe children in four cohorts: 2- to 6-year olds in The Gambia, 5- to 17-month-olds in Burkina Faso, and 5- to 12-month-olds and 10-week-olds in The Gambia. We assessed induction of cellular immunity, taking into account the distinctive hematological status of young infants, and characterized the antibody response to vaccination. T cell responses peaked 7 days after boosting with modified vaccinia virus Ankara (MVA), with highest responses in infants aged 10 weeks at priming. Incorporating lymphocyte count into the calculation of T cell responses facilitated a more physiologically relevant comparison of cellular immunity across different age groups. Both CD8+ and CD4+ T cells secreted cytokines. Induced antibodies were up to 20-fold higher in all groups compared with Gambian and United Kingdom (UK) adults, with comparable or higher avidity. This immunization regimen elicited strong immune responses, particularly in young infants, supporting future evaluation of efficacy in this key target age group for a malaria vaccine

Higher gametocyte production and mosquito infectivity in chronic compared to incident Plasmodium falciparum infections.

Plasmodium falciparum gametocyte kinetics and infectivity may differ between chronic and incident infections. In the current study, we assess parasite kinetics and infectivity to mosquitoes among children (aged 5-10 years) from Burkina Faso with (a) incident infections following parasite clearance (n = 48) and (b) chronic asymptomatic infections (n = 60). In the incident infection cohort, 92% (44/48) of children develop symptoms within 35 days, compared to 23% (14/60) in the chronic cohort. All individuals with chronic infection carried gametocytes or developed them during follow-up, whereas only 35% (17/48) in the incident cohort produce gametocytes before becoming symptomatic and receiving treatment. Parasite multiplication rate (PMR) and the relative abundance of ap2-g and gexp-5 transcripts are positively associated with gametocyte production. Antibody responses are higher and PMR lower in chronic infections. The presence of symptoms and sexual stage immune responses are associated with reductions in gametocyte infectivity to mosquitoes. We observe that most incident infections require treatment before the density of mature gametocytes is sufficient to infect mosquitoes. In contrast, chronic, asymptomatic infections represent a significant source of mosquito infections. Our observations support the notion that malaria transmission reduction may be expedited by enhanced case management, involving both symptom-screening and infection detection

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

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

Vers une meilleure compréhension des facteurs d'attractivité et des impacts des IDE (investissements directs étrangers) en Afrique : proposition d'un modèle d'évaluation bidimensionnelle

L’Afrique est un continent aux nombreuses opportunités et un continent d’avenir. Autrefois délaissé, l’Afrique est aujourd’hui au cœur du développement. C’est ainsi qu’avec la mondialisation, les investissements directs étrangers n’ont pas cessé de croître, permettant ainsi à ce continent d’être l’un des principaux bénéficiaires de ces investissements. Avec l’ampleur grandissante des investissements directs étrangers (IDE), plusieurs auteurs se sont penchés sur les facteurs attractifs ainsi que sur les effets de ces IDE sur les pays d’accueil. Malgré la multitude d’études sur le sujet, très peu font référence à l’Afrique. L’objectif de cette recherche est d’analyser les facteurs d’attractivité et les impacts des IDE en Afrique, et ce, à travers une analyse multidimensionnelle (dimension économique et environnementale). On a procédé à une analyse économétrique basée sur des équations simultanées. En effet, cette analyse a permis d’observer des corrélations entre les investissements directs étrangers, la croissance économique, le capital humain, les ressources naturelles, l’ouverture au commerce extérieur ainsi que le transfert de technologie. On a également remarqué une corrélation entre les flux d’investissements directs étrangers et l’émission du dioxyde de carbone. Mots-clés : Investissements directs étrangers, attractivité, OLI, impacts, Afrique, croissance économique, environnement, CO2, pollution, équations simultanées.Africa is a continent with many opportunities and a future continent. Formerly abandoned, Africa is today at the heart of development. Thus, with globalization, foreign direct investment has continued to grow, enabling the continent to be one of the main beneficiaries of these foreign direct investments. With the growing magnitude of foreign direct investment (FDI), several authors have examined the attractive factors and the effects of these FDI on host countries. Despite the multitude of studies on the subject, very few refer to Africa. The objective of this research was to analyze the attractiveness factors and the impacts of FDI in Africa through a multidimensional analysis (economic and environmental dimension), an econometric analysis based on simultaneous equations was carried out. This analysis revealed correlations between foreign direct investment, economic growth, human capital, openness to foreign trade, and technology transfer. There was also a correlation between foreign direct investment flows and CO2 emissions. Key words: Foreign direct investment, attractiveness, OLI, impacts, Africa, economic growth, environment, CO2, pollution, simultaneous equations

Le programme d’alimentation scolaire La Cantine dans les écoles permet aussi aux enfants de découvrir de nouveaux aliments

L’objectif de cet article est d’identifier les croyances parentales sur les composantes d’un programme d’alimentation scolaire au Québec qui influencent leur fréquence d’utilisation. Cette recherche est quantitative et corrélationnelle. Les données proviennent des résultats de deux sondages (2020 et 2022) d’appréciation des composantes du programme La Cantine dans les écoles auprès des parents utilisateurs. Les résultats exposent une corrélation modérée-supérieure (0,404 avec un p < 0,01) entre la fréquence d’utilisation du programme et la découverte de nouveaux aliments. La découverte d’aliments que permettent les programmes de repas scolaires et l’influence de cette croyance parentale sur la commande de repas par les parents apparaissent comme un résultat novateur. Ainsi, l’envoi périodique du menu détaillé aux parents est une stratégie à poursuivre afin que ceux-ci puissent juger des aliments que leur enfant va découvrir, de l’équilibre des repas, de la variété du menu et des plats qui correspondent, selon eux, à ses préférences alimentaires. Des messages promotionnels aux parents quant à la variété des plats offerts et l’offre de repas équilibrés qui favorisent la découverte d’aliments sont des stratégies marketing à considérer pour augmenter la fréquence d’utilisation du programme.The goal of this article is to identify the parental beliefs on specific components of a school lunch program offered in Quebec, that have an influence on the frequency of use. This research is quantitative and correlative. Data is based on the results of two surveys (2020 and 2022) related to the appreciation of components of the “La Cantine dans les écoles” program viewed by parents using the service. Results show a moderate correlation (0.404, p < 0.01) between the frequency of use and the discovery of new food. The discovery of food via school lunch programs and the influence of this parental belief on the meal orders by the parents appear as innovative. Hence, sending a detailed menu periodically to the parents is a strategy to pursue so they may judge the food that their child will discover, the balanced meals, the variety of the menu and of the meals that correspond, according to them, to the child’s food preferences. Key promotional messages to the parents regarding the variety of dishes and the balanced meals offered, that both promote discovering food, are marketing strategies to consider to increase using lunch programs

Antibody response to Schistosoma haematobium and other helminth species in malaria-exposed populations from Burkina Faso

Infection with helminths in sub-Saharan Africa could modulate the immune response towards Plasmodium falciparum as well as susceptibility to malaria infection and disease. The aim of this study is to assess the antibody responses to helminths species in malaria-exposed populations from Burkina Faso. Plasma samples were collected in rural villages inhabited by Fulani, Mossi and Rimaibe communities, and IgG against parasitic helminths were measured by ELISA. The prevalence of IgG against antigens of Strongyloides stercoralis, Wuchereria bancrofti and Schistosoma haematobium (Soluble Egg Antigen, SEA) was 5%, 16% and 63% respectively, in line with estimates of infection prevalence in the region for the three parasites. Anti-SEA IgG prevalence was highest at 10-20 years of age, higher in males than females, and did not show differences between ethnic groups. However, the Fulani showed lower levels of anti-SEA IgG suggesting that lighter S. haematobium infections may occur in the ethnic group known for a marked lower susceptibility to P. falciparum. The present data support the use of serological methods for integrated surveillance of neglected tropical diseases such as soil-transmitted helminths, lymphatic filariasis and bilharzia. Furthermore, as helminth infections might promote downregulation of immune responses against intracellular pathogens, the observation of lower anti-SEA IgG levels in the malaria resistant Fulani population warrants further investigation into the immunological cross-talk between S. haematobium and P. falciparum in this geographical region