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Background Iron deficiency (ID) and malaria are common causes of ill-health and disability among children living in sub-Saharan Africa. Although iron is critical for the acquisition of humoral immunity, little is known about the effects of ID on antibody responses to Plasmodium falciparum malaria. Methods The study included 1794 Kenyan and Ugandan children aged 0–7 years. We measured biomarkers of iron and inflammation, and antibodies to P. falciparum antigens including apical merozoite antigen 1 (anti-AMA-1) and merozoite surface antigen 1 (anti-MSP-1) in cross-sectional and longitudinal studies. Results The overall prevalence of ID was 31%. ID was associated with lower anti-AMA-1 and anti-MSP-1 antibody levels in pooled analyses adjusted for age, sex, study site, inflammation, and P. falciparum parasitemia (adjusted mean difference on a log-transformed scale (β) −0.46; 95 confidence interval [CI], −.66, −.25 P  < .0001; β −0.33; 95 CI, −.50, −.16 P  < .0001, respectively). Additional covariates for malaria exposure index, previous malaria episodes, and time since last malaria episode were available for individual cohorts. Meta-analysis was used to allow for these adjustments giving β −0.34; −0.52, −0.16 for anti-AMA-1 antibodies and β −0.26; −0.41, −0.11 for anti-MSP-1 antibodies. Low transferrin saturation was similarly associated with reduced anti-AMA-1 antibody levels. Lower AMA-1 and MSP-1-specific antibody levels persisted over time in iron-deficient children. Conclusions Reduced levels of P. falciparum-specific antibodies in iron-deficient children might reflect impaired acquisition of immunity to malaria and/or reduced malaria exposure. Strategies to prevent and treat ID may influence antibody responses to malaria for children living in sub-Saharan Africa. [ABSTRACT FROM AUTHOR]

Chronic immune activation has been considered as the driving force for CD4+ T cell depletion in people infected with HIV-1. Interestingly, the normal immune profile of adult HIV-negative individuals living in Africa also exhibit chronic immune activation, reminiscent of that observed in HIV-1 infected individuals. It is characterized by increased levels of soluble immune activation markers, such as the cytokines interleukin (IL)-4, IL-10, TNF-α, and cellular activation markers including HLA-DR, CD-38, CCR5, coupled with reduced naïve and increased memory cells in CD4+ and CD8+ subsets. In addition, it is accompanied by low CD4+ T cell counts when compared to Europeans. There is also evidence that mononuclear cells from African infants secrete less innate cytokines than South and North Americans and Europeans in vitro. Chronic immune activation in Africans is linked to environmental factors such as parasitic infections and could be responsible for previously observed immune hypo-responsiveness to infections and vaccines. It is unclear whether the immunogenicity and effectiveness of anti-SARS-CoV-2 vaccines will also be reduced by similar mechanisms. A review of studies investigating this phenomenon is urgently required as they should inform the design and delivery for vaccines to be used in African populations. [ABSTRACT FROM AUTHOR]

Background: Iron deficiency (ID) is a major public health burden in African children and accurate prevalence estimates are important for effective nutritional interventions. However, ID may be incorrectly estimated in Africa because most measures of iron status are altered by inflammation and infections such as malaria. Through the current study, we have assessed different approaches to the prediction of iron status and estimated the burden of ID in African children.Methods: We assayed iron and inflammatory biomarkers in 4853 children aged 0-8 years from Kenya, Uganda, Burkina Faso, South Africa, and The Gambia. We described iron status and its relationship with age, sex, inflammation, and malaria parasitemia. We defined ID using the WHO guideline (ferritin < 12 μg/L or < 30 μg/L in the presence of inflammation in children < 5 years old or < 15 μg/L in children ≥ 5 years old). We compared this with a recently proposed gold standard, which uses regression-correction for ferritin levels based on the relationship between ferritin levels, inflammatory markers, and malaria. We further investigated the utility of other iron biomarkers in predicting ID using the inflammation and malaria regression-corrected estimate as a gold standard.Results: The prevalence of ID was highest at 1 year of age and in male infants. Inflammation and malaria parasitemia were associated with all iron biomarkers, although transferrin saturation was least affected. Overall prevalence of WHO-defined ID was 34% compared to 52% using the inflammation and malaria regression-corrected estimate. This unidentified burden of ID increased with age and was highest in countries with high prevalence of inflammation and malaria, where up to a quarter of iron-deficient children were misclassified as iron replete. Transferrin saturation < 11% most closely predicted the prevalence of ID according to the regression-correction gold standard.Conclusions: The prevalence of ID is underestimated in African children when defined using the WHO guidelines, especially in malaria-endemic populations, and the use of transferrin saturation may provide a more accurate approach. Further research is needed to identify the most accurate measures for determining the prevalence of ID in sub-Saharan Africa. [ABSTRACT FROM AUTHOR]

This paper seeks to indentify the determinants of smallholder farmer's market participation decisions using a farm level approach. By opening the black box which conceals the complex mechanism guiding farmers' market participation decision, this paper's contribution resides on its ability to take account of the conditional nature of farmers' decision to participate in the market. The paper develops a farm level sequential market participation model while taking account of the conditional nature of farmer's decision to participate in the market. In fact, the paper argues that the farmer's decision to participate in the market of a certain crop is dependent on producing the crop. Therefore, failing to account for this may bias the results. From a policy implication standpoint, the highlights of the results suggest that providing affordable and easily accessible fertilizers will incentivize both greater market participation and market volume supplied of both cash and food crop types. [ABSTRACT FROM AUTHOR]

This essay examines the origins and evolution of the concepts of 'sovereignty as responsibility' and the 'responsibility to protect'. In particular, it considers the role and duty of states and how ideas of sovereignty have evolved since the modern nation-state was conceived by the European Treaty of Westphalia of 1648. It then examines the responsibility of states towards their own citizens and traces the development of the R2P norm in Africa as it has related to conflict prevention, management, and resolution since the end of the Cold War. The essay further considers the responsibilities of national democratic governments in Africa and beyond. Recent developments that have widened the scope and helped the acceptance and application of the concept of 'sovereignty as responsibility' are discussed, and the essay concludes with an examination of the accountability and enforcement challenges faced by R2P. [ABSTRACT FROM AUTHOR]

Harvesting of cowpea leaves for use as leaf vegetable has gained prominence in many parts of Africa and Asia. Little is known on effects of leaf harvesting on leaf and grain yields and profitability of cowpea-based cropping systems. This study sought to determine yields and profitability sole cowpea or cowpea-maize intercrop under different cowpea leaf harvesting initiation times. The study was conducted at Kenya National Dry land Research Center – Machakos using a Randomized Complete Block Design with cowpea grown as a monocrop or intercropped with maize. Leaf harvesting was initiated at 2, 3 or 4 weeks after cowpea emergence (WAE) and a control where no leaf harvesting was done. Initiating leaf harvesting at 3 and 4 WAE resulted in highest leaf and grain yields, respectively among leaf harvested cowpea. Overall, cowpea grain yields were highest in control treatment. Leaf vegetable and grain yields were lower in intercrop than in monocrop treatments. Maize yields in intercrop treatments were improved following harvesting of leaves of the companion cowpea. Initiating leaf harvesting at 3 and 4 WAE yielded highest returns in cowpea-maize intercrop and sole cowpea, respectively. Intercropping was on overall more profitable than sole cropping. [ABSTRACT FROM AUTHOR]

Sudan has been intermittently at war with itself since independence on June 1, 1956, with only ten years of precarious peace between 1972 and 1983. At the heart of the conflict is a crisis of national identity. Those who have been in control of the country define themselves as Arabs and also Muslims, and identify more with the Middle East than with black Africa, though they are essentially Arab-Africans. Their physical features are similar to other African groups in the region, and their cultures and even Islamic practices are an amalgam of Arab and Islamic culture with indigenous belief systems and cultures. The outcome of Sudan's struggles is difficult to predict. Three questions are worth probing: What is the conflict about? To what extent does the comprehensive peace agreement address the root causes of the conflict? What are the prospects for a truly comprehensive and lasting peace in the Sudan? [ABSTRACT FROM AUTHOR]

This article presents guiding principles on internal displacement in Africa. The guiding principles address the specific needs of internally displaced persons worldwide. They identify rights and guarantees relevant to the protection of persons from forced displacement and to their protection and assistance during displacement as well as during return or resettlement and reintegration. For the purposes of these Principles, internally displaced persons are persons or groups of persons who have been forced or obliged to flee or to leave their homes or places of habitual residence, in particular as a result of or in order to avoid the effects of armed conflict, situations of generalized violence, violations of human rights or natural or human-made disasters, and who have not crossed an internationally recognized State border. These principles reflect and are consistent with international human rights law and international humanitarian law. They provide guidance to the Representative of the Secretary-General on internally displaced persons in carrying out his mandate, states when faced with the phenomenon of internal displacement, all other authorities, groups and persons in their relations with internally displaced persons and intergovernmental and non-governmental organizations when addressing internal displacement. These principles should be disseminated and applied as widely as possible.

Focuses on the problematics of tribalism, ethnicity, and national sovereignty in African contexts in efforts to build functional and productive African nation-states. Anatomy of identity; Conflict of identities; Perspectives from countries; Identity issues.

Focuses on the response of Africa toward United States foreign policy. Acceptance of primary responsibility for Africa's own situation; Resistance from further marginalization; Impact of Africa's moral responsibility on international cooperation towards pursuit of ideals for Africa.

Background: Ambient temperature is an important determinant of malaria transmission and suitability, affecting the life-cycle of the Plasmodium parasite and Anopheles vector. Early models predicted a thermal malaria transmission optimum of 31 °C, later revised to 25 °C using experimental data from mosquito and parasite biology. However, the link between ambient temperature and human malaria incidence remains poorly resolved. Methods: To evaluate the relationship between ambient temperature and malaria risk, 5833 febrile children (<18 years-old) with an acute, non-localizing febrile illness were enrolled from four heterogenous outpatient clinic sites in Kenya (Chulaimbo, Kisumu, Msambweni and Ukunda). Thick and thin blood smears were evaluated for the presence of malaria parasites. Daily temperature estimates were obtained from land logger data, and rainfall from National Oceanic and Atmospheric Administration (NOAA)'s Africa Rainfall Climatology (ARC) data. Thirty-day mean temperature and 30-day cumulative rainfall were estimated and each lagged by 30 days, relative to the febrile visit. A generalized linear mixed model was used to assess relationships between malaria smear positivity and predictors including temperature, rainfall, age, sex, mosquito exposure and socioeconomic status. Results: Malaria smear positivity varied between 42–83% across four clinic sites in western and coastal Kenya, with highest smear positivity in the rural, western site. The temperature ranges were cooler in the western sites and warmer in the coastal sites. In multivariate analysis controlling for socioeconomic status, age, sex, rainfall and bednet use, malaria smear positivity peaked near 25 °C at all four sites, as predicted a priori from an ecological model. Conclusions: This study provides direct field evidence of a unimodal relationship between ambient temperature and human malaria incidence with a peak in malaria transmission occurring at lower temperatures than previously recognized clinically. This nonlinear relationship with an intermediate optimal temperature implies that future climate warming could expand malaria incidence in cooler, highland regions while decreasing incidence in already warm regions with average temperatures above 25 °C. These findings support efforts to further understand the nonlinear association between ambient temperature and vector-borne diseases to better allocate resources and respond to disease threats in a future, warmer world. [ABSTRACT FROM AUTHOR]

Background: A recombinant vesicular stomatitis virus vector expressing the Zaire Ebola virus glycoprotein (rVSVΔG-ZEBOV-GP) vaccine has been reported as safe, immunogenic, and highly protective in a ring vaccination trial. We aimed to identify transcriptomic immune response biomarker signatures induced by vaccination and associated signatures with its immunogenicity and reactogenicity to better understand the potential mechanisms of action of the vaccine., Methods: 354 healthy adult volunteers were vaccinated in randomised, double-blind, placebo-controlled trials in Europe (Geneva, Switzerland [November, 2014, to January, 2015]) and North America (USA [Dec 5, 2014, to June 23, 2015]), and dose-escalation trials in Africa (Lambaréné, Gabon [November, 2014, to January, 2015], and Kilifi, Kenya [December, 2014, to January, 2015]) using different doses of the recombinant vesicular stomatitis virus vector expressing the Zaire Ebola virus glycoprotein (rVSVΔG-ZEBOV-GP; 3 × 10 5 to 1 × 10 8 plaque-forming units [pfu]). Longitudinal transcriptomic responses (days 0, 1, 2, 3, 7, 14, and 28) were measured in whole blood using a targeted gene expression profiling platform (dual-colour reverse-transcriptase multiplex ligation-dependent probe amplification) focusing on 144 immune-related genes. The effect of time and dose on transcriptomic response was also assessed. Logistic regression with lasso regularisation was applied to identify host signatures with optimal discriminatory capability of vaccination at day 1 or day 7 versus baseline, whereas random-effects models and recursive feature elimination combined with regularised logistic regression were used to associate signatures with immunogenicity and reactogenicity., Findings: Our results indicated that perturbation of gene expression peaked on day 1 and returned to baseline levels between day 7 and day 28. The magnitude of the response was dose-dependent, with vaccinees receiving a high dose (≥9 × 10 6 pfu) of rVSVΔG-ZEBOV-GP exhibiting the largest amplitude. The most differentially expressed genes that were significantly upregulated following vaccination consisted of type I and II interferon-related genes and myeloid cell-associated markers, whereas T cell, natural killer cell, and cytotoxicity-associated genes were downregulated. A gene signature associated with immunogenicity (common to all four cohorts) was identified correlating gene expression profiles with ZEBOV-GP antibody titres and a gene signatures associated with reactogenicity (Geneva cohort) was identified correlating gene expression profiles with an adverse event (ie, arthritis)., Interpretation: Collectively, our results identify and cross-validate immune-related transcriptomic signatures induced by rVSVΔG-ZEBOV-GP vaccination in four cohorts of adult participants from different genetic and geographical backgrounds. These signatures will aid in the rational development, testing, and evaluation of novel vaccines and will allow evaluation of the effect of host factors such as age, co-infection, and comorbidity on responses to vaccines., Funding: Innovative Medicines Initiative 2 Joint Undertaking., Competing Interests: Declaration of interests TPM is an employee of NewLink Genetics Corporation. SD and ME are employees of Merck Sharp & Dohme. All other authors declare no competing interests., (Copyright © 2022 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 license. Published by Elsevier Ltd.. All rights reserved.)

Chronic immune activation has been considered as the driving force for CD4 + T cell depletion in people infected with HIV-1. Interestingly, the normal immune profile of adult HIV-negative individuals living in Africa also exhibit chronic immune activation, reminiscent of that observed in HIV-1 infected individuals. It is characterized by increased levels of soluble immune activation markers, such as the cytokines interleukin (IL)-4, IL-10, TNF-α, and cellular activation markers including HLA-DR, CD-38, CCR5, coupled with reduced naïve and increased memory cells in CD4 + and CD8 + subsets. In addition, it is accompanied by low CD4 + T cell counts when compared to Europeans. There is also evidence that mononuclear cells from African infants secrete less innate cytokines than South and North Americans and Europeans in vitro . Chronic immune activation in Africans is linked to environmental factors such as parasitic infections and could be responsible for previously observed immune hypo-responsiveness to infections and vaccines. It is unclear whether the immunogenicity and effectiveness of anti-SARS-CoV-2 vaccines will also be reduced by similar mechanisms. A review of studies investigating this phenomenon is urgently required as they should inform the design and delivery for vaccines to be used in African populations., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Wolday, Ndungu, Gómez-Pérez and de Wit.)

Malaria and iron deficiency (ID) are common and interrelated public health problems in African children. Observational data suggest that interrupting malaria transmission reduces the prevalence of ID 1 . To test the hypothesis that malaria might cause ID, we used sickle cell trait (HbAS, rs334 ), a genetic variant that confers specific protection against malaria 2 , as an instrumental variable in Mendelian randomization analyses. HbAS was associated with a 30% reduction in ID among children living in malaria-endemic countries in Africa (n = 7,453), but not among individuals living in malaria-free areas (n = 3,818). Genetically predicted malaria risk was associated with an odds ratio of 2.65 for ID per unit increase in the log incidence rate of malaria. This suggests that an intervention that halves the risk of malaria episodes would reduce the prevalence of ID in African children by 49%.