Southern Africa Research Articles

Dynamics of resting metabolic rate and innate immune response in malaria-infected Eurasian siskins

Abstract Avian malaria, caused by parasites of the genus Plasmodium, is prevalent among wild bird populations worldwide and can have significant impact on avian health and populations. With the rise in global temperatures due to climate change, concerns have arisen about the spread of southern malaria species, that potentially can affect previously unexposed bird populations. We studied juvenile siskins infected with two distinct malaria parasites: Plasmodium relictum (SGS1 lineage) and P. ashfordi (GRW2 lineage). While the former is common in the Northern Palearctic, the latter is primarily found in Central and Southern Africa. We assessed the impact of these infections on siskins’ physiological well-being using resting metabolic rate (RMR) and interleukin-6 (IL-6) levels. Changes in RMR reflect the energetic cost of disease, while IL-6 serves as a one of the inflammatory cytokines in the innate immune system’s response to infection. Our experimental findings reveal distinct outcomes during the acute phase of SGS1 and GRW2 infections. Infection with SGS1 was marked by reduced RMR and IL-6 levels in siskins. A similar IL-6 pattern was observed in the GRW2 group initially, though it was not sustained. Additionally, GRW2-infected siskins showed distinct RMR dynamics compared to SGS1-infected birds. Our study did not conclusively demonstrate that tropical malaria has more severe effects on siskins. However, similarities with previous studies with SGS1 infected birds and variations in disease progression between the two experimental groups underscore the complexity of host-parasite interactions in avian malaria infections.

Regional to large‐scale mechanisms controlling intraseasonal variability of low‐level clouds in Western Equatorial Africa

AbstractThe intraseasonal variability (ISV) of the stratiform cloud cover over Western Equatorial Africa (WEA) is analysed during the dry season (June–September, JJAS 1971–2019). Each JJAS daily sequence of a regional‐scale index of the stratiform cloud cover could be assimilated as a red‐noise process, without any significant recurrent periodicities. At local scale, cloudier conditions than usual are preceded by and synchronised with sustained easterly wind and warm anomalies near the top (850 hPa) and above the stratiform cloud deck, indicating higher stability. Anomalous easterlies or northeasterlies bring also anomalously moist air from either the Congo Basin or the West‐African rainbelt region to WEA. At low levels (<850 hPa), there is a clear switch between antecedent warm easterlies and synchronous cool and dry westerlies from the cold‐tongue area over the equatorial Atlantic. This switch may reflect a negative feedback loop, operating on a short time‐scale (i.e., ˜3–5 days) and involving low‐level thermal and geopotential gradients, zonal winds between the cold‐tongue area and the Congo Basin, as well as the deep convection over the latter region. Kelvin waves appear to be a possible trigger of this loop, which could be sustained internally. Another main process operates at longer time‐scales (i.e., ˜6–10 days) and involves a near‐standing Rossby wave over the South Atlantic and adjacent southern Africa. A ridge over the central South Atlantic and downstream trough over southern Africa lead to an overall strengthening of the St. Helena high, and increased thermal and geopotential gradients between the southeast South Atlantic and southern Africa. The ridge–trough couple is also related to an anomalous warming over equatorial Africa in the middle troposphere associated with increased lower‐tropospheric stability over WEA a few days later. All these mechanisms contribute to the knowledge regarding the intraseasonal atmospheric variations over equatorial Africa during boreal summer.

Changes in access to household handwashing facility and hygiene practice in Kanyama peri-urban, Zambia – a repeated cross-sectional study

ABSTRACT Hand hygiene is an essential behaviour that significantly enhances public health, especially in resource-limited settings with inadequate water supply and sanitation services. However, hand hygiene practices and access to facilities remain a challenge. We aimed to assess handwashing facilities and practice of hand hygiene in a peri-urban community of Zambia – Southern Africa. A repeated cross-sectional survey was conducted in Lusaka in 2018 and 2022 on 318households for both surveys. Data were collected using a Water Sanitation and Hygiene (WASH) questionnaire and checklist on household and handwashing facility characteristics, participants’ sociodemographic characteristics and methods of hand hygiene practice. Descriptive analysis, chi-square and logistic regression tests were used to analyse the data. Households without handwashing facilities increased by 20%, while those with handwashing facilities with soap and water reduced from 14% to 0%. Using soap and water was higher in 2018 than 2022 (p ≤ 0.05). The chances of handwashing with soap and water were reduced in males, those over 40 years old, married/living with a partner, and employed. The study revealed a decline in access to handwashing facilities and hygiene practices, indicating the need for strategies to enhance hand hygiene in peri-urban areas and individuals of all demographics.

Bovine coronavirus presence in domestic bovine and antelopes sub-Saharan Africa: evidence from Namibia

BackgroundBovine coronavirus (BoCV) causes significant economic losses to cattle farming due to mortality in calves, reduced growth performances and milk production in feedlots and dairy cattle. Worldwide distribution of BoCV has been demonstrated, although knowledge of its epidemiology in Africa, especially in the sub-Saharan region, is limited.ResultsIn the present study, a total of 208 swab samples of wild ruminants and 435 bovines from different regions of Namibia were obtained and tested by a BoCV-specific qRT-PCR. Twenty-six bovine samples tested positive [26/435 (5.98%; 95CI: 3.94-8.64%)] while, among the wild ruminants, only Greater Kudu (Tragelaphus strepsiceros) were shown to be positive [13/52 (25.00%; 95CI: 14.03-38.95%)] of which 8 showed clinical signs. Analysis of partial nucleoprotein and spike protein gene sequences and comparison with international reference sequences demonstrated the existence of a unique Namibian clade, resulting from a single introduction event around 2010 followed by local evolution. Although the introduction source remains unknown, contact between bovine and wild animals appears likely.ConclusionsThe present study represents the first report of BoCV circulation in southern Africa, which showed a relatively high frequency and the ability of persisting and evolving locally in the absence of further foreign introductions. The implications for disease spread among domestic bovines and the potential impact on wildlife should encourage broader investigations on BoCV involving other African countries. Moreover, the Greater Kudu’s susceptibility to BoCV infection was also proven, further highlighting the host plasticity of this virus.

Multimarker genetic analyses of Gonimbrasia belina, the most harvested wild edible insect of mopane woodlands in Southern Africa, supports concerns over the sustainability of the species

Multimarker genetic analyses of Gonimbrasia belina, the most harvested wild edible insect of mopane woodlands in Southern Africa, supports concerns over the sustainability of the species

Fire weather severity in southern Africa is increasing faster and more extensively in the late than in the early dry season

Fire weather severity in southern Africa is increasing faster and more extensively in the late than in the early dry season

The association between 25-hydroxyvitamin D and parathyroid hormone in adolescents living with HIV in southern Africa: a cross sectional study.

Low vitamin D associated with high parathyroid hormone (PTH) is commonly reported in the context of HIV infection. We determined the association between total 25-hydroxyvitamin-D [25(OH)D] and PTH in adolescents living with HIV, in Zambia and Zimbabwe. Adolescents (11-19 years) perinatally-infected with HIV and established on antiretroviral therapy (ART) for ≥6 months were recruited into a cross-sectional study. Socio-demographic and clinical characteristics were recorded, anthropometry measured, and fasted serum concentrations of 1,25-dihydroxyvitamin-D (1,25(OH)2D), total 25(OH)D and intact PTH measured. The association between total 25(OH)D and PTH was examined using natural cubic spline regression modelling. 842 participants (female: 53.2%) with median age 15.5 (IQR:13.2-17.9) years were enrolled. Median ART duration was 9.8 [IQR:6.3-12.3] years and 165/841 (19.6%) had an HIV viral load >60copies/ml. Stunting (HAZ score<-2) and underweight (WAZ score<-2) were observed in 29.9% and 30.0% respectively. Three quarters (n=639) reported daily calcium intakes <150mg/day. The mean (SD) concentrations of total 25(OH)D and 1,25(OH)2D were 66.1(16.5) nmol/L and 210.6(70.4) pmol/L respectively, and median PTH level was 4.3 (IQR:3.3-5.5) pmol/L. There was an inverse non-linear relationship between total 25(OH)D and PTH, 25(OH)D levelling-off at 74.6nmol/L (95%CI: 74.5-75.2). Results were consistent in those taking tenofovir disoproxil fumarate (81.7%) and in those who were virally unsuppressed. In this population with extremely low habitual calcium intakes, the lack of association between 25(OH)D and PTH when 25(OH)D exceeded 75nmol/L, potentially suggests levels of 25(OH)D >75nmol/l may need to be achieved to improve bone health; investigation is needed in future research studies.

Ethical issues surrounding the implementation of long-acting injectable antiretroviral therapy in sub-Saharan Africa.

This article discusses the ethical issues surrounding the integration of long-acting injectable antiretroviral therapy (LA-ART) in the programmatic management of human immunodeficiency virus (HIV). As the medical landscape evolves, implementing LA-ART introduces many ethical issues that should be considered for the success of scale-up in diverse settings. This article examines key issues such as bioethical concerns around the rollout of LA-ART, including regulatory requirements, a person's autonomy, informed consent, privacy and confidentiality; the societal implications of providing LA-ART, including the impact on stigma and discrimination; ethics around who receives LA-ART, financial accessibility, equitable access, inclusive decision-making and cultural sensitivity; and the ethics of providing an expensive intervention, including cost-effectiveness, supply chain sustainability and resource allocation. By critically analysing the ethical issues, we aim to guide policymakers and identify areas for further research. Our overarching aim is to ensure that the rights of people living with HIV are protected as implementors plan for the rollout of LA-ART with a focus on eastern and southern Africa. The utilization of LA-ART in resource-limited settings poses significant ethical challenges, necessitating careful consideration of autonomy, access and equity, stigma, discrimination, sustainability and treatment adherence.

Birds of greater Southern Africa

Birds of greater Southern Africa

A direct comparison of single-grain and multi-grain aliquot luminescence dating of feldspars from colluvial deposits in KwaZulu-Natal, South Africa

Abstract. The erosional landscape of the Jojosi dongas in KwaZulu-Natal, South Africa, exposes accretionary slope deposits that preserve important geological and archaeological information. This landscape was occupied by modern humans during the Stone Age for many thousands of years, as evidenced by the presence of numerous stone artefacts on the surface and interbedded within at least three phases of gully cut-and-fill deposits. A contextualisation of the artefacts and their role for human evolution in southern Africa, along with developing an understanding of the environmental conditions that shaped this inhabited landscape, is only made possible by establishing a robust chronological framework. Here, we use luminescence dating of feldspars to constrain the geochronological framework for the sequence of accretionary hillslope deposition at Jojosi at three sampling locations. Measurements of feldspar single grains show low luminescence sensitivity of the individual grains and a variable proportion of grains in saturation. Summing the luminescence signal of individual grains and creating synthetic aliquots enables us to study the effect of signal averaging on the luminescence sensitivity, signal saturation, and dose distributions. We then compare the results from individual grain measurements and synthetic aliquots to true multi-grain aliquots. To allow a quantification of the results, we apply four different dose models, including the Central Age Model (CAM), the Average Dose Model (ADM), BayLum, and a standardised growth curve (SGC) approach, using an averaged Ln/Tn value interpolated onto the SGC. Doses calculated for the different samples range from ∼ 80 to ∼ 800 Gy and contain 6 % to 67 % saturated grains. We evaluate the performance of the different dose models over this range in equivalent doses and relative number of saturated grains. On average, we find good agreement between the results obtained using the different dose models but observe that samples with a large number of saturated grains impact the consistency of the result. Overall, all dose models and data sets give consistent results below a saturated grain threshold of ∼ 15 %, corresponding to a dose of ∼ 120 Gy in this study. Finally, we favour BayLum for age calculations of the single-grain and multi-grain aliquot data sets, representing the opportunity to refine the chronology by including stratigraphic information in the age calculations. We are able to establish a chronology for the three sampled sections within the Jojosi dongas, constraining erosional and depositional processes from ∼ 100 to ∼ 700 ka, and human occupation of the area spanning from early marine isotope stage (MIS) 5 to late MIS 6.

Maternal Socioeconomic Status and the Initiation and Duration of Breastfeeding in Western Europe Versus Southern Africa: A Systematic Review—A Contribution from the ConcePTION Project

Breastfeeding is associated with many health benefits, while its prevalence is determined by numerous factors, including socioeconomic status (SES). SES is the position of an individual on the socioeconomic scale, using occupation, education, income, place of residence, and wealth as key indicators. Since its interrelationship with health is complex, world region-specific insights into the relevant socioeconomic inequalities impacting breastfeeding practices are crucial to effectively address these. The purpose of this systematic review is, therefore, to explore SES indicators affecting breastfeeding initiation and duration in two different United Nations-defined regions, Western Europe and Southern Africa to assess (dis)similarities, as these can guide region-specific, targeted interventions to improve practices. A systematic literature search was conducted across seven databases, of which 47 articles were included. The risk of bias was assessed, and outcome data related to SES as well as breastfeeding initiation and duration were collected. Higher education consistently leads to better breastfeeding initiation outcomes, but economic constraints and employment in informal sectors hinder breastfeeding practices in Southern Africa. In Western Europe, supportive working conditions and a migration background have a positive impact, while employment status and income show rather mixed effects. Community, regional, and religious factors play significant, ambiguous roles. In South Africa, food insecurity, the living environment, and geographic location complicate breastfeeding. This systematic review highlights the significant influence of SES on breastfeeding initiation and duration in Western Europe and Southern Africa, while the specific factors indeed vary between both regions. This systematic review therefore illustrates the relevance of region-specific SES factors, impacting breastfeeding practices. Addressing these barriers with region-specific, targeted approaches may result in substantial progress toward achieving global breastfeeding goals. Registration: PROSPERO (CRD42023473433).

On the Shoulders of Giants: The Specialist Surgeon Workforce in East, Central and Southern Africa.

On the Shoulders of Giants: The Specialist Surgeon Workforce in East, Central and Southern Africa.

Analysis of Severe and Relapse Risks of Imported Malaria in Five Provinces of China.

Although China has achieved malaria elimination certification, the risk of malaria transmission reintroduction due to imported malaria remains. We analyzed data on imported malaria cases collected from January 1, 2014 to December 31, 2021, using multivariable logistic regression analysis to identify the factors associated with severe and relapsing malaria. The odds of severe malaria were around 4-fold greater for patients who were initially diagnosed with a nonmalarial illness than for patients initially diagnosed with malaria. The risk of relapse from Plasmodium vivax or Plasmodium ovale varied depending on the regions of Africa where patients resided. Patients residing in western and southern Africa (compared with Central Africa) had a lower relative risk of relapse. In addition, treatment with primaquine provided protection against malaria relapse. Improving the timeliness of treatment of malaria patients could help reduce the severity of illness, and use of primaquine can mitigate the risk of relapse after treatment.

A new chemotype of Lippia javanica (Burm.f.) Spreng collected in the Masai Mara National Reserve (Kenya): the essential oil chemical composition of its aerial parts

The genus Lippia L., included within the Verbenaceae family, has a wide geographical distribution in Tropical and Subtropical South Africa and America. Lippia javanica (Burm.f.) Spreng is a woody, multi-stemmed shrubbery native to central, eastern and southern Africa. In this work the chemical composition of the aerial part of essential oil of a Kenyan accession of L. javanica, harvested in the Masai Mara National Reserve, never previously studied, was evaluated by GC-MS. Essential oil (Lj) was characterised by good amounts of esters (58.1%) with octyl acetate (33.7%), the main constituent of the oil, octyl butanoate (19.1%) and hexyl butanoate (4.6%) as principal metabolites. Monoterpene hydrocarbons (33.5%) were mainly represented by β-myrcene (30.6%). An update of the chemical composition of all the essential oils (EOs) of Lippia javanica, studied to date, clearly indicates that the accession subject of the present work can be considered a new chemotype.

Preventing Unintended Pregnancies and HIV Through Self-Care Interventions in East and Southern Africa: Findings From a Structured Review.

To identify promising interventions targeting young people in East and Southern Africa through self-care practices, with a focus on prevention of unintended pregnancies and HIV and develop four evidence-based self-care models. A structured literature review was conducted followed by a consultation with key stakeholders and youth networks from Malawi, South Africa, Zambia and Zimbabwe. Of the 2,890 published articles identified, 464 were fully reviewed and 59 were included in the final analysis along with 48 pieces of grey literature. A total of 31 youths participated in the consultation sessions. Self-care interventions with high levels of feasibility, acceptability, and scalability included HIV self-testing, self-management of contraceptives, and self-awareness for improved and safer sex behaviours and sexual health. Key features of these interventions included the use of non-clinical environments, regular follow ups to reinforce practice, use of digital solutions, linkage to in person care, and participatory approaches involving young people from ideation to implementation. Self-care models that promote distribution, access, support through multiple mechanisms in non-clinical environments are more acceptable and more effective in reaching young people.

Profiling microplastics in a forgotten river system in Southern Africa

Microplastics have been studied in rivers worldwide with far-reaching implications for aquatic ecosystems. What is less understood is how microplastics distribute through rivers, as microplastics do not distribute ubiquitously through a river system. This study described the microplastic profile of the Nyl, Mogalakwena and Limpopo Rivers in South Africa. The study aimed to determine the driving environmental factors of microplastic distribution in a river system over multiple seasons. The study discovered relationships between flow and microplastics in sediment. This relationship allowed microplastics to have significantly (p < 0.05) different distributions over seasons. Seasons with reduced flow had higher mean microplastic abundances in water (1436 ± 4492 particles.m−3) and sediment (1710 ± 4951 particles.kg−1dw), which decreased in both water (59 ± 46 particles.m−3) and sediment (17 ± 11 particles.kg−1dw) during the high flow season. Although microplastic abundances decreased with increased flow, a more homogenous distribution was detected through the entire system in the high flow period. The results suggest that microplastics could become trapped and increase significantly during reduced flow but become more evenly distributed during high flow seasons. The microplastics had also become bioavailable, being found in benthic macroinvertebrates in the river system at varying concentrations with a mean of 29 ± 33 particles.g−1ww, which could not be related to environmental matrices. Significant differences (p < 0.05) were determined between microplastic polymers found in water compared to sediment in all seasons. The study is the first in this transboundary river system, which impacts multiple African nations and a RAMSAR accredited wetland of international importance.

Social Protection and HIV risk Factors among Youth in Southern Africa: An Analysis of Cross-sectional Population-based HIV Impact Assessment Surveys.

Poverty fuels risky sexual behaviors associated with HIV infection among youth. Interventions like cash transfers may mitigate HIV risk. We explored the role of broader social protection (including food, educational, and social transfers) in reducing HIV risk among 15-24-year-olds in Southern Africa. We analyzed Population-based HIV Impact Assessment surveys data from 31,317 youth in eSwatini, Lesotho, Malawi, Namibia, Zambia, and Zimbabwe (2015-2017). Using inverse probability-weighted multivariable logistic regression, we examined associations between types of social protection and condomless sex, multiple partnerships, and high-risk sexual behaviors. Food support was associated with reduced odds of condomless sex (OR 0.71 [95% CI 0.61-0.82]), multiple partnerships (0.77 [0.63-0.95]), and high-risk sex (0.70 [0.60-0.82]). Educational support was associated with reduced odds of condomless sex (0.57 [0.46-0.59]) and high-risk sex (0.59 [0.47-0.73]). Social transfers were associated with reduced odds of condomless sex (0.62 [0.54-0.70]) and high-risk sex (0.50 [0.44-0.56]). The benefits of social protection varied across countries. Educational support was associated with reduced odds of any HIV risk factors in eSwatini, Zambia, and Zimbabwe. However, the protective effect of social transfers was only observed in eSwatini, and the benefit of food support was only significant in Namibia. Furthermore, protective associations were more pronounced among females than males. This study underscores the potential of social protection to strengthen HIV prevention efforts by mitigating poverty-related risk factors, particularly for adolescent girls and young women in Southern Africa. The impact of specific programs appears context-dependent, highlighting the need for tailored interventions.

Prevalence and Determinants of Viral Suppression in Young People Living with HIV on Antiretroviral Therapy in Southern Africa: A Cross-Sectional Analysis of HIV Survey Data of 2020 and 2021.

Young People Living with HIV (YPLHIV, 15-24 years) are an important demographic of Persons Living with HIV (PLHIV) globally and in Southern Africa. However, YPLHIV experience poor outcomes across the HIV diagnostic and treatment cascade due to multiple factors. We estimated the prevalence and determinants of HIV viral suppression in YPLHIV on antiretroviral therapy (ART) in selected Southern African countries. We used publicly available data from Malawi, Zimbabwe, Mozambique, Lesotho, and Eswatini collected during the Population-based HIV Impact Assessments (PHIAs) of 2020 to 2021. Weighted proportions, and 95% confidence intervals (CI) were computed to estimate the prevalence of viral suppression (< 1000c/ml) and bivariate and multivariate analyses were conducted to identify determinants of viral suppression. A total of 855 records of YPLHIV on ART were included in the analysis. The prevalence of viral suppression in YPLHIV on ART was 82.4% (95% CI: 76.7, 86.9). Residing in Mozambique and duration on ART were inversely associated with viral suppression; adjusted odds ratios (AORs) of 0.37 (95% CI: 0.14, 0.95), and 0.87 (95% CI: 0.80, 0.94), respectively. A negative result in the depression screen, being married/cohabitating, and ever switching an ART regimen were positively associated with viral suppression: AORs of 5.78 (95% CI: 2.21, 15.11), 3.72 (95% CI: 1.44, 9.63), and 3.44 (95% CI: 1.69, 7), respectively. YPLHIV had suboptimal viral suppression lower than the UNAIDS 95% targets and may benefit from further research and tailored interventions addressing modifiable factors associated with viral suppression such as depression.

The influence of ENSO-type on rainfall characteristics over southern Africa during the austral summer

Although the El Niño-Southern Oscillation (ENSO) is the leading mode of climate variability in southern Africa during the austral summer season, the impacts are nonlinear and not all events result in the expected impact. Limited work has been carried out to explore the role ENSO diversity plays in southern African climate, which this study aims to address. Here, the influence of El Niño diversity on rainfall characteristics and whether the impact evolves on sub-seasonal scales are examined. Two broad types of El Niño events, namely Eastern Pacific (EP) and Central Pacific (EP) events, are first determined by the location of the positive SST anomaly in the equatorial Pacific. For the 1950–2022 period, 9 EP El Niño events and 10 CP El Niño events are identified. Results show significant variability in ENSO impacts on a sub-seasonal scale across southern Africa during the summer half of the year (October-March). EP events affect rainfall throughout the summer, with the strongest impacts in the core months (Dec-Jan), characterized by less rainfall, more frequent dry spells and extended dry periods. EP events have a stronger relationship with various rainfall characteristics across most of southern Africa compared to CP events. Consequently, the likelihood of experiencing a significant summer rainfall deficit is higher during EP events. These findings indicate that traditional seasonal definitions, like JFM, or generalizing ENSO as a single type of event, may be inadequate in assessing ENSO-induced rainfall impacts from a seasonal forecasting perspective.

Amino acids, UPLC-MS phenolic metabolites and multivariate approach for elucidating the effect of two growing conditions on growth and yield attributes in okra pods and leaves

Okra is one of the highly nutritious indigenised food crops in Southern Africa. The study intended to evaluate plant growth, yield, amino acids, and untargeted or semi-targeted phenolic metabolites grown concurrently at greenhouse and micro-plot under open-field conditions. Yield and growth attributes: stem diameter, plant height, number of branches per plant, number of pods per plant, pod weight, pod length and pod diameter were higher in the micro-plot under open-field conditions. Sixteen amino acids were quantified and arginine, serine, glycine, aspartate, glutamate, alanine, proline, histidine, threonine, methionine, lysine, tyrosine, leucine, valine, and isoleucine were higher in leaf samples grown in micro-plots under open-field than greenhouse samples. UPLC-MS phenolic metabolites associated with the two growth conditions were quercetin 3-galactoside, succinyl adenosine, quercetin 3-lathyroside, isotan b and icariside F2b which were either highly upregulated or downregulated. Growth conditions can be used to manipulate the accumulation of free amino acids and phenolic metabolites.