South African Population Research Articles

Decision tree analysis for age estimation in living individuals: integrating cervical and dental radiographic evaluations within a South African population.

Age estimation in living individuals around the age of 18years is medico-legally important in undocumented migrant cases and in countries like South Africa where many individuals are devoid of identification documents. Establishing whether an individual is younger than 18years largely influences the legal procedure that should be followed in dealing with an undocumented individual. The aim of this study was to combine dental third molar and anterior inferior apophysis ossification data for purposes of age estimation, by applying a decision tree analysis. A sample comprising of 871 black South African individuals (n = 446 males, 425 = females) with ages ranging between 15 and 24years was analyzed using panoramic and cephalometric radiographs. Variables related to the left upper and lower third molars and cervical vertebral ring apophysis ossification of C2, C3, and C4 vertebrae analyzed in previous studies were combined in a multifactorial approach. The data were analyzed using a pruned decision tree function for classification. Male and female groups were handled separately as a statistically significant difference was found between the sexes in the original studies. A test sample of 30 individuals was used to determine if this approach could be used with confidence in estimating age of living individuals. The outcomes obtained from the test sample indicated a close correlation between the actual ages (in years and months) and the predicted ages (in years only), demonstrating an average age difference of 0.47years between the corresponding values. This method showed that the application of decision tree analysis using the combination of third molar and cervical vertebral development is usable and potentially valuable in this application.

Biology and ecology of the African blackspot shark Carcharhinus humani on the east coast of South Africa

The African blackspot shark Carcharhinus humani (until now commonly known as Human’s whaler shark) is a small-sized requiem shark (family Carcharhinidae) found in tropical coastal waters of the western Indian Ocean as far south as Port St Johns on the east coast of South Africa. It was only recently recognised as being distinct from the blackspot shark C. sealei, which occurs elsewhere in the Indo-Pacific. This study utilised four datasets to investigate the movements, temporal and geographic distributions, life history and population status of this species in South African waters. The recapture of eight individuals of 294 that were tagged by shore anglers revealed an average distance moved of 33 km (range 1–192 km). Competitive shore anglers caught an average of 39 C. humani per annum along the entire KwaZulu-Natal (KZN) coast, with no marked trend in catch rate over time. Catches in the KZN bather protection programme were extremely low but included 30 pregnant females which displayed a highly seasonal pattern of embryo development. Sightings of C. humani on stereo baited remote underwater video systems (stereo-BRUVS) in the iSimangaliso Marine Protected Area were dominated by females (7.7:1) and were mostly in deeper water of 26–35 m. In all datasets most of the individuals were mature and were present year-round, but with a clear peak in summer and autumn, especially in the catches taken by shore anglers. Competitive shore-angling catch data were used to conduct a risk assessment for the South African population, and, based on values of probability of encounter, the sampled population satisfies the IUCN Red List criteria for Least Concern.

Correlation between CT volumetry and actual graft weight in living donor liver transplants in South Africa.

Liver transplantation is the definitive management for patients with end-stage liver disease. Preoperative computed tomography (CT) is used in living donor liver transplant (LDLT) for donor and graft selection as well as predicting graft weight. The aim of this study is to establish the relationship between estimated graft volume (EGV) and actual graft weight (AGW) and ascertain a correlation coefficient that will improve the accuracy of EGV in a South African population. The study included 117 LDLT between March 2013 and August 2022. Of these, 86 were left lateral (LL), 15 right lobe (R), 10 left lobe with caudate (LC), five left lobe (L) and one segment two (monosegment) grafts. Estimated graft volume and actual graft weight were compared using the Pearson coefficient and the relationship was illustrated with scatter plots. Estimated graft volume and AGW had a strong positive correlation with a Pearson correlation (R) of 0.95 (p < 0.001). The relationship was significantly linear with a correlation coefficient of 0.71. The mean EGV was significantly higher than that of AGW (388 mL ± 249 mL vs. 353 g ± 184 g) with overestimation in 61% of cases. Left lateral and R grafts were the most prevalent LDLT graft type, both having a strong linear correlation between EGV and AGW. Applying a correlation coefficient of 0.71 will improve the accuracy of CT volumetry graft weight predictions. A unique correlation coefficient will improve EGV accuracy, aiding in preoperative planning and mitigating post-operative complications in both donors and recipients.

Burden of tuberculosis in underserved populations in South Africa: A systematic review and meta-analysis.

Identifying case-finding strategies to reduce tuberculosis (TB) incidence in high-burden countries requires better knowledge of the disease burden in key contributing populations and settings. To inform South Africa's National Tuberculosis Strategic Plan 2023-2028, we conducted a systematic review of active TB disease and latent TB infection (LTBI) prevalence and incidence in underserved populations, defined as those living in informal settlements, townships, or impoverished communities. We identified articles published from January 2010 to December 2023, assessed study quality, and conducted a meta-analysis to estimate pooled TB and LTBI prevalence stratified by HIV status. We calculated prevalence ratios for underserved populations compared to the overall South African population. The search yielded 726 unique citations. We identified 22 studies reporting TB prevalence (n = 12), TB incidence (n = 5), LTBI prevalence (n = 5), and/or LTBI incidence (n = 2) eligible for the review, including six high-quality studies. Meta-analysis demonstrated a high prevalence of TB disease among persons living without HIV (2.7% 95% CI 0.1 to 8.5%) and persons living with HIV (PLWH) (22.7%, 95% CI 15.8 to 30.4%), but heterogeneity was high (I2 = 95.5% and 92.3%, p-value<0.00). LTBI prevalence was high among persons living without HIV (44.8%, 95% 42.5 to 47%) with moderate heterogeneity (I2 = 14.6%, p-value = 0.31), and lower among PLWH (33%, 95% CI 22.6 to 44.4%) based on one study. Compared to the national average, underserved populations of persons living without HIV had a 4-fold higher TB prevalence and a 3.3-fold higher LTBI prevalence. Underserved PLWH had a 31-fold higher TB prevalence than the national average, but similar LTBI prevalence as measured in one study. Our findings illustrate that underserved populations in South Africa have a substantially higher TB and LTBI prevalence than the general population, making targeted TB interventions potentially beneficial. More research is needed to explore the heterogeneous TB epidemiology in South Africa.

Genetic etiology of autism spectrum disorder in the African population: a scoping review.

Autism spectrum disorder (ASD) is a neurodevelopmental disorder (NDD) characterized by significant impairments in social, communicative, and behavioral abilities. However, only a limited number of studies address the genetic basis of ASD in the African population. This study aims to document the genes associated with ASD in Africa and the techniques used to identify them. Additionally, genes identified elsewhere but not yet in Africa are also noted. Online databases such as Wiley Online Library, PubMed, and Africa Journal Online were used. The review was conducted using the keyword related to genetic and genomic ASD study in the African population. In this scoping review, 40 genetic studies on ASD in Africa were reviewed. The Egyptian and South African populations were the most studied, with 25 and 5 studies, respectively. Countries with fewer studies included Tunisia (4), East African countries (3), Libya (1), Nigeria (1), and Morocco (1). Some 61 genes responsible for ASD were identified in the African population: 26 were identified using a polymerase chain reaction (PCR)-based method, 22 were identified using sequencing technologies, and 12 genes and one de novo chromosomal aberration were identified through other techniques. No African study identified any ASD gene with genome-wide association studies (GWAS). Notably, at least 20 ASD risk genes reported in non-African countries were yet to be confirmed in Africa's population. There are insufficient genetic studies on ASD in the African population, with sample size being a major limitation in most genetic association studies, leading to inconclusive results. Thus, there is a need to conduct more studies with large sample sizes to identify other genes associated with ASD in Africa's population using high-throughput sequencing technology.

Processed food consumption and risk of non-communicable diseases (NCDs) in South Africa: evidence from Demographic and Health Survey (DHS) VII.

We aimed to analyse the association between processed food consumption and the risk of non-communicable diseases (NCDs) in South Africa. In this empirical study, we analysed nationally representative secondary data obtained from the South African Demographic and Health Survey (SADHS) VII. The survey included 13,288 occupied households, of which 11,083 were interviewed. In the interviewed households, 12,717 eligible adults aged 15 and older were identified and 10,336 were successfully interviewed. The study included four processed food groups (i.e. fried foods, takeaway foods/fast foods, salty snacks/packed chips, and processed meats) and eight NCDs (i.e. hypertension, cardiac arrest, cancer, stroke, hypercholesterolaemia, diabetes, chronic bronchitis, and asthma). As per the logistic regression results following adjustment, none of the disease states showed association with all four processed food groups. However, at least three processed food groups showed a significant positive association with hypertension, cardiac arrest, and diabetes. Two processed food groups showed significant positive association with stroke, and chronic bronchitis; one with hypercholesterolaemia and asthma; and cancer was not associated with any food groups. Processed meat and salted snacks/packed chips were each associated with five chronic conditions. In summary, we found that the consumption of any of the processed food groups increased the risk of NCDs in the South African population. Enabling policy and regulatory efforts in the production and distribution of processed foods, combined with improved awareness among the population need to be prioritised for immediate action. Facilitating the populations to choose traditional healthy diets would be a sustainable strategy for the prevention of NCDs.

A National Laboratory Perspective: The Impact of the Covid-19 Pandemic on the Management of Patients With Non-Communicable Disease in South Africa: Impact of COVID-19 on patients with noncommunicable diseases.

The aim of this study was to determine the impact of the COVID-19 pandemic on test requests for the diagnosis and routine care of patients with various non-communicable diseases (NCD) across South Africa (SA). A retrospective audit of laboratory test requests received from hospital outpatient departments and primary healthcare facilities across SA was performed. The following analytes were studied: glycated hemoglobin (HbA1c), lipids profiles, thyroid-stimulating hormone (TSH), and thyroxine (fT4), as well as triiodothyronine (fT3), serum protein electrophoresis (SPE), serum free light chains (SFLC), and prostate specific antigen (PSA); these tests were used as a proxy of NCD detection and follow-up. Requests received during the 3 waves of the pandemic were compared to requests received within the same period during 2017 - 2019. During the first wave, requests for all analytes were reduced, with the biggest reduction observed for SPE (- 37%); TSH (- 29%); fT4 (- 28%); and HbA1c (- 25%). Requests received from urban facilities showed a larger decrease compared to those from rural facilities. During the third wave there was an increase in requests for all analytes; the biggest increase observed was for fT3 (21%) and HbA1c (18%). The COVID-19 pandemic had a significant impact on the South African population receiving care in the public healthcare sector.

Extra-Governmental Relations as Response Strategy to Sustainable Development Goal 1 [poverty]: Lessons from A South African Municipality

South Africa is one of the many African countries that have displayed systemic weaknesses in their efforts realise the United Nations’ sustainable development goal (SDG) number one, which is about ending poverty in all its forms everywhere. According to the official data gleaned from World Bank (2014) and Statistics South Africa (2022), over 55 % of the South African population is currently living below the national poverty line. While government remain an important player in carrying the burden presented by this challenge, it does not mean other able stakeholders in society are exempted in the fight against poverty. With the understanding that poverty is more prevalent in rural settings, this study aimed to explore extra governmental relations as a drive for intensified rural development and poverty eradication in South Africa. The study was largely qualitative and used municipalities in Mopani region of Limpopo province, to argue for more involvement of external stakeholders like the business community and private sector in the promotion of the general welfare of communities in rural areas. As demonstrated in the paper, South Africa’s efforts to eradicate poverty can only materialise when there is intensified rural development drive that is supported by those in business sector, but this should also consider a number of conditioning factors that government, especially at local levels, has to create. The strength of this paper lies in its transdisciplinary nature, as it draws theoretical insights from both the field of development studies and public administration. Recommendations are offered towards the end of the paper.

Prevalence of and Risk Factors for Peripheral Artery Disease in Rural South Africa: A Cross-Sectional Analysis of the HAALSI Cohort.

The burden of peripheral artery disease (PAD) is increasing in low- and middle-income countries. Existing literature from sub-Saharan Africa is limited and lacks population-representative estimates. We estimated the burden and risk factor profile of PAD for a rural South African population. We used data from 1883 participants from a rural, low-incomecohort of South African adults aged 40 to 69 years with available ankle-brachial index measurements. We defined clinical PAD as ankle-brachial index ≤0.90 or >1.40, and borderline PAD as ankle-brachial index >0.90 and ≤1.00. We compared the distribution of sociodemographic variables, biomarkers, and comorbidities across PAD classifications. To identify associated factors, we calculated unadjusted and age-sex-adjusted prevalence ratios (PRs) with log-binomial models. Overall, 6.6% (95% CI, 5.6-7.7) of the sample met the diagnostic criteria for clinical PAD, while 44.7% (95% CI, 42.4-47.0) met the diagnostic criteria for borderline PAD. Age (PR: 1.9 [95% CI, 1.2-3.1] for ages 50-59 years compared with 40-49 years; PR: 2.5 [95% CI, 1.5-4.0] for ages 60-69 years compared with 40-49 years); diagnosed hypertension (PR: 1.53 [95% CI, 1.08-2.17]); and C-reactive protein (PR: 1.08 [95% CI, 1.03-1.12]) were associated with increased prevalence of clinical PAD. All other examined factors were not significantly associated with clinical PAD. We found high PAD prevalence for younger age groups compared with previous research and a lack of statistical evidence for the influence of traditional risk factors for this rural, low-income population. Future research should focus on identifying the underlying risk factors for PAD in this setting. South African policymakers and clinicians should consider expanded screening for early PAD detection in rural areas.

Integrated sun protection advice for the South African population.

Exposure to solar ultraviolet radiation (UVR) is associated with several cutaneous adverse effects. However, to the best of our knowledge, in South Africa there are no formal guidelines on sun protection. A group of South African dermatologists and researchers convened over the course of 1 year to deliberate on integrated advice for sun protection among the multi-ethnic South African population. For people with light skin and those with genetic skin disorders (e.g., oculocutaneous albinism), sun protection was identified as critical to prevent sunburn, skin cancer, and photoaging. The evidence is less clear for people with medium and darker skin types, especially the latter, in whom melanin may confer a degree of protection against some parts of the solar spectrum. Recent studies have demonstrated that visible light can cause pigmentary changes in individuals with darker skin types in particular. Sun protection for people of all skin colors is beneficial to protect against photoaging and ocular damage. Herein sun protection advice is suggested for South Africans of all skin colors to reduce morbidity and mortality from sun exposure, particularly relating to skin cancer. Several knowledge gaps are identified as future research priorities.

Content validity of the modified Barthel Index for stroke patients in an African country

Background: The Barthel Index is considered the global gold standard for assessing performance in activities of daily living (ADL) tasks, but there has been little research undertaken on this outcome measure for a stroke population in a low to middle income country. The study aimed to determine the content validity of the modified Barthel Index (MBI) for assessing the ADL of stroke patients in an African country. Method: A mixed methods design using the nominal group technique was utilised. The study sample consisted of occupational therapists (n=11) and physiotherapists (n=4) with four or more years' experience working in the field of adult neurorehabilitation in South Africa. Each of the four focus groups analysed the content validity of the MBI using five questions based on the Table of Specifications methodology. Data analysis followed van Breda's steps to analysing multi-group nominal group technique to establish themes arising from each question and were presented according to final rank scores. Results: The findings highlighted aspects of content validity of the MBI related to language, clarity, content completeness and appropriateness that require revision. Conclusion: This study provides recommendations for the revision of the MBI to improve its content validity for the South African stroke population. IMPLICATIONS FOR PRACTICE • Methodology can be replicated in other multi-cultural and language countries. • Training on administration of the MBI can overcome barriers related to language and item clarity where English is ahealthcare worker's second language. • The MBI is currently most suited to environments with water and sanitation infrastructure. • A future study implementing recommendations for revision of the MBI for the African stroke populations is suggested.

Epidemiology of head and neck cancer in a Johannesburg Hospital: A file review

Background: There is little to no epidemiological data on the presentation of head and neck cancer (HNC) patients in South Africa. These data are important to ensure that local teaching, research and health services meet the needs of this population.Aim: To describe the epidemiological data of HNC patients using a record review from a tertiary level hospital in Johannesburg, South Africa.Setting: This study was piloted in a tertiary public hospital in Gauteng, South Africa.Methods: Sixty files between 2015 and 2021 were analysed quantitatively to describe the trends of HNC patients presenting to the hospital. This was a pilot study to review if this methodology can be used for future larger scale studies in South Africa.Results: Missing data were a significant finding as well as a limitation of the study. The most common form of HNC was laryngeal cancer, and African males were the predominant demographic. The most common comorbidities were smoking, hypertension and HIV/AIDS. The majority of patients presented with speech and swallowing difficulties and various complications that required multidisciplinary team management.Conclusion: All HNC patients need to undergo early screening to assess for speech and swallowing difficulties to prevent further complications.Contribution: The data derived from this study are novel and specific to the South African population. More studies of this nature are required to increase the availability of epidemiological data for this population, in order to inform evidence-based practices.

Stroke as the index presentation of traditional cardiovascular risk factors and Human Immunodeficiency Virus in a South African population

ObjectivesWe sought to identify what proportion of each cardiovascular risk factor and Human Immunodeficiency Virus (HIV) was first diagnosed at the time of stroke, compared to those that were diagnosed prior to the event, and to explore if this had any impact on the severity of stroke. MethodsAdult patients presenting with a new stroke to a quaternary hospital in Johannesburg between 2014 and 2017 were prospectively recruited. Patients were investigated for undiagnosed traditional cardiovascular risk factors (hypertension, diabetes mellitus, dyslipidaemia, atrial fibrillation, obesity and smoking), as well as HIV infection. Stroke severity was assessed using the National Institutes of Health Stroke Scale (NIHSS). Results346 patients were included. Stroke was the index presentation for at least one risk factor in 199 (57.5 %) patients. Dyslipidaemia was newly diagnosed in 76.0 % of all dyslipidaemics (95 out of 125). Newly-diagnosed dyslipidaemia was associated with a more severe neurological deficit (Median NIHSS of 12 (8-16) vs 7 (4-12), p=0.0007) and younger age on presentation (53 (44-63) years vs 62 (51-71) years, p=0.02) as compared to previously-diagnosed dyslipidaemia. ConclusionsMore than half of patients had previously undiagnosed modifiable risk factors at the time of their stroke. Dyslipidaemia was undiagnosed in a very high proportion, and this was associated with a higher stroke severity and younger age of presentation.

A systematic review of the implications for teaching, learning and assessment at South African universities after the Covid-19 pandemic

This paper presents the results of a systematic review of literature, reported in research journals, on the experiences of higher educational institutions regarding teaching, learning, and assessment during the Covid-19 pandemic. Different studies related to the Covid-19 pandemic have been conducted within the South African context, but there has not been a systematic review of these studies highlighting the lessons learned, how these lessons have affected education in higher education institutions (HEIs), and how these lessons can inform future planning. This study aims to summarise literature on teaching, learning and assessment in higher education institutions and to conceptualise possible guidelines for future planning. An analysis of 52 research articles revealed 7 implications for the lessons learnt from the pandemic for future teaching, learning and assessment (TLA) in South African HEIs (realisation of the affordances of technology for TLA, institutional changes related to online TLA during the pandemic, students’ experiences related to TLA, lecturer’s experiences related to TLA, the need for care, assessment related matters, approaches to teaching, learning and assessment) and several recommendations for how these lessons can be leveraged to help HEIs to prepare effectively for future catastrophic disruptions to education in South African HEIs. The discussion shows the digital divide that exists within the South African population and other contextual challenges faced by higher education institutions during the pandemic, and the different sacrifices by both institutions and students to survive the pandemic. Overall, the findings of this review provide valuable guidance for HEIs and stakeholders involved in TLA, offering insights on how to integrate the lessons learned from the pandemic into their future planning and strategies.

Even hungrier for knowledge: A 10-year follow-up study on vulnerability to food insecurity amongst students at the University of KwaZulu-Natal

Research on the extent of food insecurity amongst the South African university student population has gained momentum over the past decade, and for good reason. Along with the multiple other challenges that South African university students face (e.g. funding shortfalls, limited access to student housing, high levels of failure and dropout, institutional bureaucracy, and oppressive colonial legacies), students being chronically hungry and unable to access safe and nutritious food on a regular basis remains a notable crisis. This article reports on a 10-year follow-up study on the extent of vulnerability to food insecurity amongst students registered at the University of ABC (UABC). Whereas data collected for the initial 2007–2009 study only targeted students from one of the five UABC campuses, the current study improved on the sampling strategy and collected data from 438 students registered across all five UABC campuses in 2018. Using the University Students Food Insecurity Questionnaire, as developed during the initial study and adapted from the Household Food Insecurity Access Scale, the findings from the current study suggest that 49% of the UABC student population experience serious to severe levels of vulnerability to food insecurity. This is more than double the reported levels of serious to severe vulnerability to food insecurity found in the initial study. This article reports on how and why food insecurity levels may have escalated unchecked over the past decade.

Area-level deprivation and individual-level socioeconomic correlates of the diabetes care cascade among black south africans in uMgungundlovu, KwaZulu-Natal, South Africa.

South Africa is experiencing a rapidly growing diabetes epidemic that threatens its healthcare system. Research on the determinants of diabetes in South Africa receives considerable attention due to the lifestyle changes accompanying South Africa's rapid urbanization since the fall of Apartheid. However, few studies have investigated how segments of the Black South African population, who continue to endure Apartheid's institutional discriminatory legacy, experience this transition. This paper explores the association between individual and area-level socioeconomic status and diabetes prevalence, awareness, treatment, and control within a sample of Black South Africans aged 45 years or older in three municipalities in KwaZulu-Natal. Cross-sectional data were collected on 3,685 participants from February 2017 to February 2018. Individual-level socioeconomic status was assessed with employment status and educational attainment. Area-level deprivation was measured using the most recent South African Multidimensional Poverty Index scores. Covariates included age, sex, BMI, and hypertension diagnosis. The prevalence of diabetes was 23% (n = 830). Of those, 769 were aware of their diagnosis, 629 were receiving treatment, and 404 had their diabetes controlled. Compared to those with no formal education, Black South Africans with some high school education had increased diabetes prevalence, and those who had completed high school had lower prevalence of treatment receipt. Employment status was negatively associated with diabetes prevalence. Black South Africans living in more deprived wards had lower diabetes prevalence, and those residing in wards that became more deprived from 2001 to 2011 had a higher prevalence diabetes, as well as diabetic control. Results from this study can assist policymakers and practitioners in identifying modifiable risk factors for diabetes among Black South Africans to intervene on. Potential community-based interventions include those focused on patient empowerment and linkages to care. Such interventions should act in concert with policy changes, such as expanding the existing sugar-sweetened beverage tax.

Kinderkinetics motor intervention framework for children with Developmental Coordination Disorder:

Developmental coordination disorder (DCD) is a motor coordination disorder that persists if intervention is not provided. Local guidelines are unavailable for intervention in children with probable DCD (p-DCD), and the aim of this study was to develop a motor intervention framework focusing specifically on the South African population within the scope of kinderkinetics, based on expert information, as a guideline for children with DCD or p-DCD. Twenty-nine kinderkinetics experts from South Africa participated in a three-round e-Delphi process. Round one obtained consensus and opinions from the experts by reviewing literature findings on intervention for children with DCD or p-DCD. Rounds two and three were based on answers and opinions provided in round one to determine an 80% agreement to accept the statement. Ten main elements formed the foundation for the motor intervention framework. The main focus areas of the framework were intervention planning, goal setting, intervention approaches, intervention apparatus, intervention delivery mode, additional role players, settings, dosage (time, duration, frequency and number of sessions), and evaluation. Understanding that the causes of DCD are heterogeneous was essential in finalising the framework. The research provided unique and collated feedback from kinderkinetics experts to develop a motor intervention framework for children with DCD or p-DCD within the scope of kinderkinetics in South Africa.

Evolution and neutralization escape of the SARS-CoV-2 BA.2.86 subvariant

Omicron BA.2.86 subvariant differs from Omicron BA.2 as well as recently circulating variants by over 30 mutations in the spike protein alone. Here we report on the isolation of the live BA.2.86 subvariant from a diagnostic swab collected in South Africa which we tested for escape from neutralizing antibodies and viral replication properties in cell culture. We found that BA.2.86 does not have significantly more escape relative to Omicron XBB.1.5 from neutralizing immunity elicited by either Omicron XBB-family subvariant infection or from residual neutralizing immunity of recently collected sera from the South African population. BA.2.86 does have extensive escape relative to ancestral virus with the D614G substitution (B.1 lineage) when neutralized by sera from pre-Omicron vaccinated individuals and relative to Omicron BA.1 when neutralized by sera from Omicron BA.1 infected individuals. BA.2.86 and XBB.1.5 show similar viral infection dynamics in the VeroE6-TMPRSS2 and H1299-ACE2 cell lines. We also investigate the relationship of BA.2.86 to BA.2 sequences. The closest BA.2 sequences are BA.2 samples from Southern Africa circulating in early 2022. Similarly, many basal BA.2.86 sequences were sampled in Southern Africa. This suggests that BA.2.86 potentially evolved in this region, and that unobserved evolution led to escape from neutralizing antibodies similar in scale to recently circulating strains of SARS-CoV-2.

The Performance of Diagnostic Tests for Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) in the South African Population: A Scoping Review.

To determine the performance and reliability of diagnostic tests for the identification of SARS-CoV-2 infection in South Africa, we conducted a scoping review to identify published studies undertaken in the English language from March 2020 to August 2022 that evaluated the performance of antigen- and antibody-based diagnostic tests for SARS-CoV-2 in South Africa. We identified 17 relevant peer-reviewed articles; six reported on SARS-CoV-2 gene and/or antigen detection whilst 11 reported on antibody detection. Of the SARS-CoV-2 gene and/or antigen-based tests, sensitivity ranged from 40% to 100%, whilst for the antibody-based tests, sensitivity ranged from 13% to 100%. All tests evaluated were highly dependent on the stage of infection and the timing of sample collection. This scoping review demonstrated that no single SARS-CoV-2 gene and/or antigen- or antibody-based assay was sufficiently sensitive and specific simultaneously. The sensitivity of the tests was highly dependent on the timing of sample collection with respect to SARS-CoV-2 infection. In the case of SARS-CoV-2 gene and/or antigen detection, the earlier the collection of samples, the greater the sensitivity, while antibody detection tests showed better sensitivity using samples from later stages of infection.

Cerebrovascular disease is associated with memory function in the Health and Aging in Africa Longitudinal Study of an INDEPTH community in rural South Africa

AbstractBackgroundHealth and Aging in Africa Longitudinal Study of an INDEPTH community in South Africa (HAALSI) is a sister study to the US‐based Health and Retirement Study. The purpose of HAALSI is to characterize the social, economic, biological, physical, and mental health factors in a population‐representative cohort of older adults in a rural community in Agincourt, South Africa. Beginning in 2020, as part of an Alzheimer’s disease and related disorders (ADRD) substudy, we conducted neuropsychological evaluations and structural magnetic resonance imaging (MRI) in a subset of HAALSI participants. Here, we report preliminary observations on the relationship of white matter hyperintensity (WMH) volume, a marker of small vessel cerebrovascular disease, and hippocampal volume, a marker of neurodegeneration, on memory function in a group of substudy participants.MethodNinety‐nine HAALSI ADRD participants with available MRI scans and neuropsychological outcomes at time of analysis (mean ± SD; age = 70.3 ± 10.9, 87% with no formal education or some primary education) were included in these analyses. Participants received research‐grade, harmonized 1.5T MRI scanning at a private hospital and were evaluated with a battery of neuropsychological tests. Using in‐house developed software and FreeSurfer, respectively, we derived total WMH volume and total hippocampal volume. We examined the association of these variables with memory function, operationalized as the delayed recall score of the Logical Memory Test, adapted for context.ResultAdjusting for education level, increased WMH volume was associated with poorer performance on the Logical Memory Test (standardized β = ‐0.21, p&lt;0.05) but hippocampal volume was not (standardized β = 0.09, p = 0.41). Associations of these MRI markers with memory function did not interact with education level.ConclusionIn these preliminary analyses of older adults in a rural South African community, markers of small vessel cerebrovascular disease but not neurodegeneration are associated with poorer cognitive outcomes. Future work will examine the pathways that give rise to cognitive impairment and dementia in this rural South African population and track cognitive trajectories over time.