*Faculty of Health Sciences (ETDs)
Permanent URI for this community
Browse
Browsing *Faculty of Health Sciences (ETDs) by Type "Thesis"
Now showing 1 - 20 of 41
Results Per Page
Sort Options
Item A 5 year review of paediatric maxillofacial & oral surgery procedures performed at the Wits oral health centre(2021) Vally, M.Aim: To review paediatric maxillofacial and oral surgery procedures performed at the Wits Oral Health Centre (WOHC) over a 5-year-period. Materials and Methods: This was a retrospective record review study at WOHC, University of the Witwatersrand, Johannesburg. Records of paediatric patients who had treatment from 2013 to 2017 were included in the study. Data collected included the age of patients, gender, distribution of scope and type of treatment. Data was analysed and results presented as frequencies and percentages. Results: A total of 694 paediatric patients presented for treatment during the study period. There were more males (54.2%) than females (45.8%), and the majority of patients were in the 11-17-year age category. Oral surgery, treatment of pathoses and management of trauma were the most common procedures at 34%, 29% and 20.5% respectively. There was a statistically significant difference between the number of surgical procedures carried out under general anaesthetic and that under local anaesthetic (p < 0.001). The removal of third molars was more common than other oral surgical procedures. A high occurrence of paediatric trauma was observed in males aged between 11-17 years. Mandibular fractures, followed by dentoalveolar fractures, were the most common fracture types. The most commonly diagnosed pathological conditions were odontogenic cysts (23.15%), benign odontogenic tumours (22.31%) and fibro-osseous lesions (19.02%). Mucous extravasation cyst was the most common salivary gland pathology. Conclusion: Most oral and maxillofacial surgical procedures in paediatric patients are performed in the 11-17-year category. The removal of impacted 3 rd molars was the most common surgical procedure and the management of ameloblastomas appears to be the most common odontogenic tumour in this age group. Future studies are required to provide insight into the reasons, patterns and distribution of paediatric maxillofacial surgery. Results from such studies, especially prospective ones, will form the basis for design of educational campaigns and preventive strategies aimed particularly at the 11-17-year age groupItem A morphometric analysis of the growth of the immature and sub-adult human palate(2021) Onwochei-Bolum, Nkemakonam VincentPostnatal nutrition in humans is associated with advancement in the mode of feeding from the neonatal and infancy period of growth to adulthood. During the neonatal and infancy periods, the palate functions in suckling, tongue manipulation and swallowing, while in adulthood and with dental eruption, the palate participates in both mastication and in the production of sound. It is anticipated that the transition in the role of the palate due to alterations in its function over time will cause morphological changes. Thus, the aim of this study was to analyse alterations in the shape and dimensions of the human palate from birth through the stages of dental eruption to the complete emergence of the permanent dentition in the sub-adult stages of life. Crania from 72 South African individuals were sourced from the Raymond A. Dart Collection of Human Skeletons, School of Anatomical Sciences, Faculty of Health Sciences, University of the Witwatersrand. The sample was divided into three age groups to correspond with the age ranges of the eruption of the deciduous dentition (birth to 5 years of age), mixed dentition (6 to 12 years of age) and the permanent dentition (13 to 20 years of age) respectively. A series of 14 osteological landmarks were digitized across the oral surface of the palate using an Immersion MicroScribe G2 unit. Landmark data were converted to linear distances and the length, width and elevation of the palate were assessed in relation to the state of the dentition. Analysis included both quantitative (linear measurements) and qualitative (wireframes) methods. The length and width of the palate in the permanent dentition group was significantly larger when compared to the mixed and deciduous dentition groups. While elevation of the palatal dome in the permanent dentition group was significantly greater than that of the palate in the mixed dentition group, no further significant differences were observed. Thus, changes in the morphology of the palate appear to be progressive with dental eruption and development across the different states of the dentition. By establishing the nature of the changes in the functional environment of the palate during development and growth, abnormalities in the postnatal development of the palate could be diagnosed.Item Adverse childhood experiences and social and health outcomes in later life(2024) Naicker, Sara N.Background: Well-established literature points to early life experiences and childhood adversities setting the foundation for health and development and influencing life trajectories. Nurturing, responsive caregiving in a safe and stable environment is associated with healthy, productive lives throughout adulthood. On the other hand, adverse experiences in childhood are associated with poor health and wellbeing, risky behaviour and reduced human capital. How this adversity is measured and the context in which it is measured may provide insight into the relationship between adversity and outcomes over and above what has been found in high income countries. Aim: The overall aim of this study is to examine adverse childhood experiences (ACEs) in a South African birth cohort. Specific objectives of the study include: a) developing prospective and retrospective profiles of ACEs in the sample, b) establishing levels of agreement between these two profiles of ACEs, c) estimating the prevalence and clustering of ACEs in this population-based urban sample, d) examining the associations between exposure to ACEs and a range of physical and mental health and social outcomes, and e) understanding the role that recent stress plays in the relationship between exposure to ACEs and poor outcomes. Methods: This study uses a secondary analysis design using data from the longitudinal Birth to Thirty cohort. The cohort began in 1990 with the enrolment of 3,273 pregnant mothers and has followed the children born to these women for more than thirty years. The 10-item ACE Index developed by the CDC-Kaiser’s ACEs Study was expanded to include five additional ACEs common in the South African context – chronic unemployment, violence in the community, household death, parent death, and separation from parents. Prospective profiles of ACEs were collated from data collected over the first 18 years of the child’s life, initially reported by primary caregivers until age 11, then self-reported from ages 11 to 18. Retrospective profiles of ACEs were collected in young adulthood when the participants were 22 years old, along with an index of recent stressors. A series of human capital outcomes – those encompassing physical and mental health and psychosocial adjustment, were assessed at age 28. ACEs in the sample were conceptualized in three ways ‒ as single adversities, such as physical or sexual abuse, cumulative adversity in the form of the ACE score, and clusters of adversity determined by their patterning. Cohen’s kappa statistics and concordance rates were generated to establish the levels of agreement and consistency between prospective and retrospective reports of ACEs (timing) and between reports given by caregivers and children at age 11 (source). Descriptive statistics and latent class analysis were used to estimate the prevalence of ACEs and to explore the patterning of ACEs among participants. Logistic regression analysis explored associations between all three conceptualizations of ACEs and outcomes, disaggregated by sex. Mediation and moderation analyses were conducted to examine the influence of recent stress on mental health outcomes. Findings: Comparisons between prospective and retrospective reports of ACEs show that there is relatively low-to-moderate agreement between timing and sources of reports of ACEs. Agreement varies depending on the adversity in question – with greater levels for objective Naicker, S.N. 2023. Adverse Childhood Experiences and Social and Health Outcomes in Later Life experiences such as parental death and lower levels for subjective experiences such as chronic unemployment. Differences in agreement were partly due to prospective and retrospective reports identifying largely different groups of people; those who only report high exposure prospectively, those who only report high exposure retrospectively and those that overlap. Using either prospective or retrospective reports, the prevalence of ACEs in this sample were high, although there were significant decreases in prevalence from prospective reporting to retrospective reporting. ACEs tended to co-occur, and where one ACE was reported, the likelihood of others increased. Clusters of ACEs split distinctively into high-low:dysfunction abuse categories; with one group likely to have low exposure, another with high generalized exposure to all ACEs, a third with moderate exposure characterized by household dysfunction and a fourth with moderate exposure driven by emotional abuse and/or neglect. All three conceptualizations of ACEs were significantly associated with poorer outcomes. Single ACEs such as physical, sexual and emotional abuse, and exposure to intimate partner violence, were independently and strongly associated with poorer outcomes in adulthood. Increased exposure to ACEs, or cumulative adversity, was also linked to poorer outcomes in a graded manner, with the likelihood of experiencing poor outcomes increasing along with exposure. The clusters with high levels of exposure to ACEs and moderate levels of exposure driven by emotional abuse were most at risk for poor outcomes. There were significant differences in exposure to ACEs, outcomes and the associations between the two by sex. Associations also differed for prospective and retrospective reporting with the strength of association varying depending on the outcome in question. Recent stressors were found to play a confounding role in the relationship between ACEs exposure and poor outcomes. Although recent stressors had a different impact on those who reported high ACEs exposure prospectively versus those who reported high ACEs exposure retrospectively. The influence of recent stressors on the mental health of those who reported high exposure to ACEs prospectively supported a sensitization model. In contrast, the role of recent stressors on the mental health of those who reported high exposure to ACEs retrospectively supported a stress inoculation model. This suggests two potential pathways for risk. Conclusion: In combination and accumulation, it is demonstrated here that adverse experiences in childhood have an impact on health and wellbeing in adulthood. Specific individual ACEs can be teased out for their independent effect on outcomes, but the additive effects of multiple adversities lead to almost exponential increases in the risk for a myriad of negative physical and mental health and social outcomes. These findings provide important links from South Africa’s context of high levels of violence in all forms and multiple hardships that families with large burdens of care endure, with little support, to many of the human capital outcomes on which productive, healthy and happy lives depend. Born at the dawn of democracy, with anticipation for opportunity, many of the children in this cohort were raised in contexts of adversity that may have been experienced as normative in those settings. Regardless of whether these experiences leave enough of a mark to be recalled later in life, the strain of cumulative adversity has had persistent and serious effects on their mental health, their ability to finish school, find a job and stay out of trouble.Item An audit of the presence of coeliac disease associated human leukocyte antigen haplotypes in renal and bone marrow transplant donors and recipients from the South African National Blood Services(2021) Mrubata, Kitso-LesediIntroduction: Coeliac Disease (CD) is an autoimmune condition occurring in genetically predisposed individuals exposed to an environmental trigger. The Human Leukocyte Antigen (HLA) haplotypes HLA DQ2.5 and HLADQ8 bear the strongest association with CD, and 90 -95% of patients with CD bear these haplotypes. The absence of these haplotypes has high negative predictive value. The susceptibility of the South African population to CD has not been studied previously. Methods The South African National Blood Services database was used to analyse the prevalence of HLA DQ2.5 and DQ8 in potential donors and recipients of organ transplants. Results The overall prevalence of HLA DQ2.5 and HLA DQ8 was 19.8%. The prevalence was lower in Black subjects (15%) than Caucasians (28%). Mixed race (22%) and Indian (17%) subjects had intermediate prevalence. The was no significant difference between potential transplant donors and recipients. Conclusion The prevalence of HLA DQ2.5 and HLA DQ8 differed among South African study participants of different ethnicities and was lower than the reported world-wide prevalence of 30-40%.Item Biomarkers to predict Tuberculosis treatment response(2024) Boshielo, ItumelengTuberculosis (TB) is a chronic disease caused by Mycobacterium tuberculosis (Mtb). Despite the implementation of multifaceted TB prevention and control efforts, a significant number of people still die from TB. Consistent with this, an uptick in TB-related mortality was recently noted, which has been ascribed to the negative effects of Coronavirus disease-2019 (COVID-19) on TB programs. The complex life cycle of Mtb is largely due to the use of immune evasion mechanisms to establish initial infection, remain dormant in the host, and reactivate pathogenicity under favourable circumstances. The prolonged TB treatment regimen is necessitated by the slow response of bacterial populations to standard TB chemotherapy, a phenomenon that may be caused by persistent, drug-tolerant bacteria. Scientific literature has provided evidence for these types of bacterial populations in the form of Differentially Culturable Tubercle Bacilli (DCTB). It has been demonstrated that DCTB represent drug tolerant bacteria that appear to be cleared at slower rate than organisms detected by routine culture methods. However, it remains unclear if DCTB populations elicit different immune responses when compared to their conventionally culturable counterparts. Herein, we address this question by optimizing a laboratory model for the generation of DCTB in vitro and test the capacity of clinical isolates of Mtb from Lineage 2 (Beijing) and Lineage 4 (LAM) to adopt the DCTB state. Using the Most probable number (MPN) assay, in the presence of culture filtrate (CF) as a source of growth factors to resuscitate DCTB, and colony forming units, the amount of DCTB in our model was quantified. As demonstrated by the limited growth on agar plates and increased growth in liquid media supplemented with CF from an axenic culture of Mtb, our findings demonstrated that carbon starvation was able to generate DCTB from clinical Mtb strains. After generating these populations, we stimulated whole blood with DCTB and conventionally culturable populations and report on the stimulation of a select set of cytokines (IFN-γ, IL-4, IL-5, IL-6, IL-12p70 and TNF-α) using a Bead Array Multiplex Immunoassay. In comparison to H37Rv-DCTB and LAM-DCTB, Beijing-DCTB induced significantly reduced levels of IL-5 and TNF-α. When comparing cytokine production between culturable and DCTB populations, within a single strain, we noted that LAMDCTB was delayed in the production of IFN-γ whilst Beijing-DCTB was not able to induce production of this cytokine when compared to conventionally culturable counterparts. These data suggest that shifting to a non-replicating DCTB state does indeed affect the ability of clinical isolates to induce immune responses. Based on these observations, we next set out to determine if DCTB affects immune responses during treatment of Mtb infected individuals. In prior work, using a prospective observational cohort, we demonstrated a substantive heterogeneity in clearance of DCTB in individuals with drug susceptible TB. We were able to classify these response patterns into three broad groups including (I) participants who were able to clear DCTB within the first two weeks of treatment (treatment-responsive); (II) those with delayed ability to clear these organisms (delayed-responsive) and (III) a group of individuals where DCTB did not change substantively during treatment (non-responders). Given these stark differences in treatment response patterns, we hypothesized that the immune responses associated with these patterns would be substantively different. In the second component of this work, we set out identify immune biomarkers that predict an effective response of DCTB to TB treatment. To quantify cytokines, chemokines and growth factors in plasma from these groups, we used a 65-plex Luminex assay, with a broad selection of targets. Statistically significant differences between these groups were analysed using the Kruskal-Wallis test with Dunn’s multiple comparisons, with p<0.05 was considered as statistically significant. When compared to patients who had TB and HIV co-infection, the number of cytokines that may possibly be used to report on the effectiveness of TB treatment was significantly higher in Mtbonly infected patients. This suggests that HIV infection significantly reduces the number of cytokines that can be used to report on TB treatment response. The ROC analysis of I-TAC, G-CSF and VEGFA showed that these cytokines have a significant discriminatory power to distinguish treatmentresponsive and non-responsive patients from HCs using DCTB as the measure of treatment response. No unifying cytokine signature that predicted DCTB response in all groups was identified. Together, our results indicate that some inflammatory markers are elevated in individuals with TB that rapidly clear bacteria during treatment. Given that these responses are based on DCTB, which represent drug tolerant populations, these select cytokines may be useful in evaluating the effectiveness of novel shorter TB treatment regimens.Item Characterising skeletopathy in an animal model of Type 2 diabetes(2024) Dlamini, Gcwalisile FrancesType two diabetes (T2D) is a chronic, progressive heterogonous syndrome with a genetic and environmental origin. It is now recognized as an epidemic with a high morbidity and mortality rate. The endocrinology of type 2 diabetes (T2D) and its predisposing factors have been studied extensively, while diabetic skeletopathy has received negligible research. Previous studies report that fractures in T2D vary with specific sub regions in bones, therefore prompting our study to focus mainly on the femoral head and neck as well as the humerus head. Femoral neck fractures are the commonest, followed by the proximal femur, distal radius and proximal humerus. Susceptibility to fracture is a sequelae of poor bone remodeling. Poor bone remodeling is established at molecular and cellular levels. It depends on the activity of osteoblasts, osteocytes and osteoclasts, which are under the influence of TGF-β1, a pro-osteogenic cytokine, together with BMP3, an anti-osteogenic cytokine.T2D induced bone marrow adipocity and the accumulation of AGEs in cortical bone have also been implicated in increasing susceptibility to fracture. It is still unclear how T2D affects molecular and cellular elements that culminate in weaker bones observed in diabetic patients. In addition, it is debatable if T2D affects the skeleton at disease onset or later in the disease. Therefore, this study aimed to characterize T2D induced skeletopathy and related it to age, in the Zucker Diabetic Sprague Dawley (ZDSD) rat, using the femur and humerus. This study initially confirmed the diabetic state by monitoring animal weights, fasting blood glucose levels, and fasting oral glucose tolerance tests (OGTTs) every fortnight. Then triglyceride levels and quantified serum levels of osteoregulatory hormones such as insulin and osteocalcin were monitored. To assess oxidative stress, Malondialdehyde (MDA) serum levels were also determined by ELISA. Once diabetes was successfully induced, rats were grouped according to strain and age at termination. Termination age was at 20 weeks and 28 weeks . The Sprague Dawley (SD) rats were v the controls, while the Zucker Diabetic Sprague Dawley rats (ZDSD) were the experimental groups. These were designated as SD20WK (n=8) and ZDSD20WK (n=7) respectively. Another batch was designated as SD28WK (n=8), and ZDSD (n=15) that were terminated at 28 weeks of age. The latter were further divided into moderate diabetes (ZDSD28WK-MOD) (n=9) and severe diabetes (ZDSD28WK-SVD) groups (n=6). Bilateral humeri and femora were harvested then fixed in 10% buffered formalin. Right proximal femora and humeri were scanned using a 3D-μCT scanner (Nikon XTH 225L) to analyse trabecular morphometric parameters, cortical bone area and medullary canal area. Biomechanical strength was analyzed by three point bending tests using a universal tensile tester. Left proximal femora and humeri were processed for histology. Some sections were stained with Haematoxylin and Eosin (H&E) to assess normal histologic morphology and adipocyte quantification. Remnant sections were immunolabelled using the anti-TRAP and anti-ALP antibodies for osteocyte and osteoblast quantification respectively, to assess osteolysis and osteogenesis. Immunolocalization of AGEs, TGF-β1 and BMP3 was also conducted to investigate their role in diabetic skeletopathy. We found that diabetes affected osteoblastogenesis as measured by ALP positive cells and bone marrow adipocytes. TRAP positive osteocytes numbers were increased in the presence of T2D, suggesting an increased osteolysis. There was reduced TGFB1 expression with increased BMP3 expression. The number of AGEs immuno-positive cells as well as its extracellular expression was increased. Our finding suggest that osteoblast and osteocyte numbers are regulated by TGFβ1 and BMP3 in both bones, under the influence of AGEs. Our findings from osteometry, 3-point bending tests and Micro CT support that diabetes weakens bone. The diabetic effect results in lighter, shorter hollow bones that perform poorly under loading, as well as exhibit unfavourable trabeculae microarchitecture. Our findings confirm that T2D causes increased fragility in the proximal femur and humerus as well the mid-diaphysis. These perturbations occur early and late in the disease, and they are also exacerbated by the presence of hyperglycemia. vi We conclude that the ZDSD rat can be used as a translational model for diabetic skeletopItem Defining the development of gp120-gp41 interface directed broadly neutralizing antibodies in HIV-1 infection(2024) Hlatshwayo, Vincent NkosinathiA prophylactic HIV-1 vaccine will likely need to elicit broadly neutralizing antibodies (bNAbs) against conserved HIV-1 envelope epitopes such as the gp120-gp41 interface which includes the FP. The isolation of gp120-gp41 interface-, and FP-directed bNAbs from chronically HIVinfected donors has made this epitope an appealing vaccine target. Moreover, promising preclinical immunogenicity animal studies have shown the possibility of eliciting such responses in animals. However, little is known about the population prevalence or kinetics of gp120-gp41 interface responses, including FP-directed responses. Lastly, few FP-directed antibodies have been isolated from people living with HIV (PLWH), limiting our understanding of common developmental pathways that can be explored for vaccine purposes. Here, we first assessed the prevalence of bNAbs in participants previously enrolled in the CAPRISA 004 Tenofovir gel trial (CAP004). We show that in this cohort, only 12% of individuals developed breadth at three years post-infection, and that high viral load and low CD4 count were associated with bNAb development, as previously reported. ELISA screening showed that only 13% of individuals developed FP-directed responses at three years postinfection. Of the 13% (n=9), only two donors had broad plasma responses, including donor CAP312, whose plasma exhibited 64% neutralization breadth at three years post-infection. In CAP312, FP binding and heterologous neutralization against a multi-clade 22 virus panel appeared simultaneously, within one year (~ 50 weeks post-infection). Taken together, our findings suggest that gp120-gp41 interface- and FP-directed responses are infrequently elicited during infection. As few FP-specific bNAbs have been isolated to date, little is known about their shared features that could be exploited for eliciting FP-specific bNAbs by vaccination. We next isolated three FP-specific mAbs from donor CAP312 at three years post-infection; AIRU-F8, AIRU-G9 and AIRU-G4 with 64, 45 and 5% breadth, respectively. We showed that our mAbs, and previously isolated bNAbs PGT151 and ACS202 share gene usage and have a similar unusually long CDRH3, as a result of a conserved motif inherited from the germline IGHJ6*02 gene. Furthermore, we showed that CAP312 mAbs have even longer CDRH3s compared to PGT151 and ACS202 despite this shared motif. We also showed, using point mutants and glycan mutants that our FP-specific mAbs have a unique neutralization profile compared to published mAbs. Overall, these results suggest that FP-specific mAbs share structural and genetic features that could be explored further for lineage vaccine development. Lastly, we delineated the ontogeny of the gp120-gp41 interface-directed nAb CAP248-2B by tracing the evolutionary pathways utilising longitudinal samples from 11-281 weeks postinfection (wpi). CAP248-2B interacts with the HIV-1 Env trimer through a long light chain CDRL3 that inserts into the viral membrane, and a heavy chain CDRH1 32ED33 motif that interacts with gp41. We showed that the unusually long light chain CDRL3 and the heavy chain 32ED33 motif are functionally redundant against heterologous viruses. We also showed that affinity maturation mutations in this lineage selected a lineage with limited heterologous neutralization breadth. In summary, these findings support further research into gp120-gp41- and FP-specific responses in multiple cohorts. Furthermore, future studies should aim to elucidate mechanisms governing the development of these responses so that productive developmental pathways can be identified and exploited for vaccine design.Item Determinant of metabolic syndrome and its cardiovascular complications among people of African ancestry(2024) Eluwole, Omotayo AlabaCardiovascular disease is now a leading cause of death globally. However, metabolic syndrome is an extremely critical healthcare issue worldwide due to progressive increase in obesity and its related factors. Obesity is strongly associated with insulin resistance and other components of metabolic syndrome. There is discrepancy in the use of parameters for the diagnostic criteria of metabolic syndrome due to genetic and environmental variability in different ethnicity. Body mass index and waist circumference (WC) are commonly used in the assessment of central obesity and abdominal obesity respectively. Fahed et al observed that waist circumference was employed because measurement was easy, however, waist circumference alone is inconclusive of abdominal adiposity and must be interpreted with body mass index. The two measurements (WC and BMI) have been documented to be strongly related to insulin resistance. (Fahed et al., 2022). However, there is controversial assessment of metabolic syndrome using either waist circumference (WC) or body mass index (BMI) or waist hip ratio (WHR) or combination of two measurements (Kassi et al., 2011; Fahed et al., 2022). Our study assessed the prevalence of metabolic syndrome among apparently healthy 1516 participants from African ancestry using seven established diagnostic criteria (NCEP-ATPIII- National Cholesterol Education Program Adult Treatment Panel III, WHO- World Health Organization, IDF-International Diabetes Federation, AHA/NHLBIAmerican Heart Association/National Heart, Lung and Blood Institute, EGIR - European Group for the study of Insulin Resistance, AACE- American Association of Clinical Endocrinology). The result revealed highest prevalence of metabolic syndrome when modified NCEP-ATPIII [National Cholesterol Education Program Adult Treatment Panel III (ATP III)] was considered. The predictive assessment of blood pressure and arterial stiffness may be useful in achieving early detection and prevention of target organ damage. This study further compared clinic blood pressure, ambulatory blood pressure and central pressure using conventional blood pressure monitor, Spacelabs 90207 (Spacelabs Inc., Redmond, Washington, USA) and applanation tonometry Sphygmocor device respectively. The findings revealed that central blood pressure and ambulatory blood pressure are more predictive of cardiovascular events among people of African ancestry. Our findings are pointers to cardiovascular risk in the study population. Additionally, this study provides new insights to the role of obesity in the perturbation of left ventricular geometry of people of African ancestry with metabolic syndrome; using quantitative and comprehensive evaluation of biochemical and echocardiographic profile. Aldosterone produced locally in adipose tissue, heart, kidney and vasculature increase the expression of cytokines and other fibrotic factors. Thus, role of the local renin angiotensin aldosterone system (RAAS) in the pathophysiology of atherosclerosis and cardio-renal fibrosis was evaluated in animal study. With high prevalence of metabolic syndrome and obesity in Africans, elevated aldosterone from diet may likely predispose African community to diastolic dysfunction; this may be a pointer to increased incidence of heart failure in groups of African ancestry. Hence, this study lends insights into the potential role of TRPM7; a novel non selective cation channel and chanzyme in aldosterone-induced cardiovascular fibrosis. This study concluded that modified NCEP-ATPIII has suitable components for the diagnosis of MS in people of African ancestry. Metabolic syndrome in people of African ancestry is strongly associated with factors such as sex, smoking and alcohol. Consequently, MS and other risk factors such as obesity, aldosterone and insulin resistance may lead to left diastolic dysfunction among individuals with MS. Experimentally, aldosterone-salt induced cardio-renal fibrosis, aggravated by TRPM7 might be the underlying pathogenesis of MS and its cardiovascular complications in Africans; thus suggests TRMP7 inhibitors has potential anti-fibrotic agents.Item Development of a multi-disease targeted next generation sequencing panel to study genetic aetiology of rasopathies(2024) Mudau, Maria MabyalwaWith Next Generation Sequencing (NGS), technologies it is now possible to screen a large number of genes simultaneously through massively parallel sequencing, significantly reducing costs and time generally associated with mutation screening. After an informal survey of the diagnostic needs of the clinicians in the Division of Human Genetics, National Health Laboratory Service (NHLS), it was established that the aetiology of genetic disorders called facial dysostoses, RASopathies and Cohesinopathies (FRASC) could be understood better using NGS. These are developmental disorders that are phenotypically different and are commonly referred to our genetic clinic, currently there is limited genetic testing for these conditions in South Africa. A NGS panel targeting genes associated with the FRASC disorders was designed and optimised. Upon successful optimisation the panel was then utilised to sequence samples from patients presenting with features suggestive of RASopathies. An overall detection rate of 56.6% (34/60) was obtained for all RASopathy patients sequenced in the current study. Detection rate of 46.7% (7/15) for neurofibromatosis type 1 (NF1) patients and 60% (27/45) for patients with non-NF1 RASopathies was obtained. No clinically significant variants were identified in 26 of the 60 patients (43.3%), two of the 26 had a VUS in the MAP2K1 gene. Seven patients of the panel negatives were successfully sequenced using whole exome sequencing (WES), one patient had a pathogenic variant and the rest had variants of uncertain significance identified. This is the first report profiling mutations and clinical features in patients with RASopathies as a whole in South Africa, compared to a study focusing on NS patients only. The detection rates obtained were comparable to other international studies using NGS, except for detection rate of LZTR1 and BRAF1 gene variants observed in Noonan syndrome patients. The (35/60) 58.3% (panel and WES) of patients with a disease causing variant identified in this study now have a molecular confirmation that they previously did not have. Our results show that a targeted panel could be an effective first-line diagnostic testing for RASopathies in SA. The development of the multi-disease targeted panel in the current study has contributed to the design of the 500 gene inherited disease NGS targeted panel (IDP) that is currently being utilised in our facility for diagnostic testing of various monogenic disorders.Item The effect of a scissor skills program on bilateral fine motor skills in preschool children in South Africa including skill improvement, equivalence, transferability of skills and skill retention(University of the Witwatersrand, Johannesburg, 2010-01-27T12:43:24Z) Ratcliffe, IngridThe purpose of this study was to assess the improvement of scissor skills after a graded scissor skills program in preschool children in South Africa (SA). A bilateral fine motor skills assessment tool was developed for use in this research. This task-based assessment included every day activities required at school as well as personal management items. This research phase included the development of the test items and test instructions, scoring as well as validity and reliability testing of the assessment. A suitable scissor skills program was then developed for Grade 0 children in South Africa. The program was validated by a pilot study and also by a focus group of occupational therapists. Some changes were made to the picture selection, the grading of the program, as well as to teacher instructions on how to present the program before it was finalised and ready for use in the implementation phase of the research study. The implementation phase of the study included the individual assessment of 149 learners (mean age of 5 years 6 months), from three different schools in South Africa. The main aim was to establish the effectiveness of the scissor skills program by measuring skill improvement, transferability of skills and skill retention. A further aim was to compare the difference of skill levels of learners from various socio-economic backgrounds in South Africa. The results showed statistically significant improvement in scissor skills in all groups from the three different schools, as well as an ability to retain the learnt skills. Participants from lower socio-economic backgrounds demonstrated the least skill initially but made the greatest gains during the program, at times decreasing the gap between themselves and other participants. It was concluded that children benefited from a graded scissor skills program, which allowed them to improve and retain their scissor skills but improvement did not transfer to other fine motor tasks.Item Effect of boophone disticha on the behaviour and hippocampal neuroanatomy in a BALB/c mouse model(2024) Xhakaza, Nkosiphendule KhuthazelaniDepression is one of the most common neuropsychiatric disorders and is associated with dysfunction of the neuroendocrine system and alterations in specific brain proteins. Boophone disticha (BD) is an indigenous psychoactive bulb that belongs to the Amaryllidacae family, which is widely used in Southern Africa to treat depression, with scientific evidence of potent antidepressant-like effects. The present study examined the antidepressant effects of BD and its mechanisms of action by measuring some behavioural parameters in the elevated plus maze, light dark box, open field forced swimming, brain content of corticosterone, brain derived neurotropic factor (BDNF), and neuroblast differentiation in the hippocampus of Balb/c mice exposed to the five-day repeated forced swim stress (5dRFSS) and 28 days chronic restraint stress. Male Balb/c mice were subjected to the 5dRFSS and 28 days chronic restraint protocols to induce depressivelike behaviour (decreased swimming, increased floating, decreased open arm entry, decreased time spent in the open arms and decreased head dips in the elevated plus maze test, increased time in dark box in the light dark box test, reduced frequency of rearing and increased time on the sides of the open field in the open field test), and treated with distilled water, fluoxetine and BD. Three weeks Boophone disticha treatment (10mg/kg/p.o) significantly attenuated both the 5dRFSS and chronic restraint-induced behavioural abnormalities and the elevated brain tissue corticosterone levels observed in stressed mice. Additionally, 5dRFSS exposure significantly decreased the number of neuroblasts in the hippocampus and BDNF levels in the brain of Balb/c mice, while fluoxetine and BD treatment attenuated these changes. In the chronic restraint stressed mice, similar effects of BD treatment were observed after 21 days of treatment, however, the levels of corticosterone were not different in control and stressed animals, probably due to habituation to stress. In both 5dRFSS and chronic restraint stress, the antidepressant effects of BD were comparable to those of fluoxetine, but unlike fluoxetine, BD did not show any anxiogenic effects, suggesting better pharmacological functions. It is important to note that in chronic restraint stress mice, it appeared that animals seemed to have habituated to stressful conditions, demonstrated in part by brain tissue levels of corticosterone that were not elevated in stressed animals treated with distilled water. However, BDNF levels remained significantly low in stressed animals treated with distilled water, suggesting that the effect of chronic stress in this parameter were not reversed when animals habituated. In conclusion, our study shows that BD exerted antidepressant-like effects in both 5dRFSS and chronic restraint stress mice, mediated in part by normalizing brain corticosterone and BDNF levels. Due to some degree of habituation in chronic stress model, caution should be exercised when evaluation effects of treatment in different parameters to evaluate antistress effects of tested agents, particularly levels of corticosterone. Furthermore, the persistent low levels of BDNF suggest that habituation of animals to chronic stress is due to normalising levels of corticosterone but not BDNF. The above occurrence could suggest that recovery from chronic stress without antidepressant treatment could alleviate other behavioural symptoms but not cognitive impairment which is influenced in part by BDNF levels.Item Estimating and predicting HIV risk using statistical and machine learning methods: a case study using the 2005 to 2015 Zimbabwe demographic health survey data(2024) Makota, Rutendo Beauty BirriBackground: The 90–90–90 targets were launched by the Joint United Nations Programme on HIV/AIDS (UNAIDS) and partners with the aim to diagnose 90% of all HIV-positive persons, provide antiretroviral therapy (ART) for 90% of those diagnosed, and achieve viral suppression for 90% of those treated by 2020. In Zimbabwe, a population-based survey in 2016 reported that 74.2% of people living with HIV (PLHIV) aged 15–64 years knew their HIV status. Among the PLHIV who knew their status, 86.8% self-reported current use of Antiretroviral treatment (ART), with 86.5% of those who self-reported being virally suppressed. For these 90–90–90 targets to be met, prevalence and incidence rate estimates are crucial in understanding the current status of the HIV epidemic and determining whether the trends are improving to achieve the 2030 target. Ultimately, this will contribute to the achievement of Sustainable Development Goals 3 (SDG 3) and the broader goal of promoting sustainable development and eradicating poverty worldwide by 2030. Using data from household surveys, this thesis provides a unique statistical approach for estimating the incidence and prevalence of the Human Immunodeficiency Virus (HIV). To properly assess the efficacy of focused public health interventions and to appropriately forecast the HIV-related burden placed on healthcare systems, a comprehensive assessment of HIV incidence is essential. Targeting certain age groups with a high risk of infection is necessary to increase the effectiveness of public health interventions. To jointly estimate age-and-timedependent HIV incidence and diagnosis rates, the methodological focus of this thesis was on developing a comprehensive statistical framework for age-dependent HIV incidence estimates. Additionally, the risk of HIV infection was also evaluated using interval censoring methods and machine learning. Finally, geospatial modelling techniques were also utilised to determine the spatial patterns of HIV incidence at district levels and identify hot spots for HIV risk to guide policy. The main aim of this thesis was to estimate and predict HIV risk using statistical and machine learning methods. Study objectives: The study objectives of this thesis were: 1. To determine the effect of several drivers/factors of HIV infection on survival time over a decade in Zimbabwe, using current status data. 2. To determine common risk factors of HIV positivity in Zimbabwe and the prediction capability of machine learning models. 3. To estimate HIV incidence using the catalytic and Farrington models and to test the validity of these estimates at the national and sub-national levels. 4. To estimate the age- and time-dependent prevalence and HIV Force-of-infection (FOI) using current status data by comparing parametric, semi-parametric and non-parametric models; and determining which models best fit the data. 5. To investigate the HIV incidence hotspots in Zimbabwe by using geographicallyweighted regression. Methods: We performed secondary data analysis on cross-sectional data collected from the Zimbabwe Demographic Health Survey (ZDHS) from 2005 to 2015. Datasets from three Zimbabwe Demographic Health Survey HIV test results and adult interviews were merged, and records without an HIV test result were excluded from the analysis. The outcome variable was HIV status. Survey and cluster-adjusted logistic regression were used to determine variables for use in survival analysis with HIV status as the outcome variable. Covariates found significant in the logistic regression were used in survival analysis to determine the factors associated with HIV infection over the ten years. The data for the survival analysis was modelled assuming age at survey imputation (Model 1) and interval-censoring (Model 2). To determine the risk of HIV infection using machine learning methods, the prediction model was fit by adopting 80% of the data for learning/training and 20% for testing/prediction. Resampling was done using the stratified 5-fold cross-validation procedure repeatedly. The best algorithm was the one with the highest F1 score, which was then used to identify individuals with a higher likelihood of HIV infection. Considering that the proportion of those HIV negative and positive was imbalance with a ratio of 4.2:1, we applied resampling methods to handle the class imbalance. We performed the Synthetic Minority Over-sampling Technique (SMOTE) to balance the classes. We evaluated two alternative methods for predicting HIV incidence in Zimbabwe between 2005 and 2015. We estimated HIV incidence from seroprevalence data using the catalytic and Farrington-2-parameter models. These models were validated at the micro and macro levels using community-based cohort incidence and empirical estimates from UNAIDS EPP/SPECTRUM, respectively. To ascertain the age-time effects of HIV risk, we estimated the age- and time-dependent HIV FOI using current status data. Five generalised additive models were explored, ranging from linear, semi-parametric, non-parametric and nonproportional hazards additive models. The Akaike Information Criteria was used to select the best model. The best model was then used to estimate the age- and time-dependent HIV prevalence and force-of-infection. The OLS model was fitted for each survey year to determine the global relationship between HIV incidence and the significant covariates. The Moran's I spatial autocorrelation method was used to assess the spatial independence of residuals. The Getis-Ord Gi* statistic was used for Hotspot Analysis, which identifies statistically significant hot and cold spots using a set of weighted features. Interpolation maps of HIV incidence were created using Empirical Bayesian Kriging to produce smooth surfaces of HIV incidence for visualisation and data generation at the district level. The Multiscale Geographically Weighted Regression method was used to see if the relationship between HIV incidence and covariates varied by district. The software used in the thesis analysis included R software, STATA, Python, ArcGIS and WinBugs. Results: Model goodness of fit test based on the Cox-Snell residuals against the cumulative hazard indicated that the model with interval censoring was the best. On the contrary, the Akaike Information Criterion (AIC) indicated that the normal survival model was the best. Factors associated with a high risk of HIV infection were being female, the number of sexual partners, and having had an STI in the past year prior to the survey. The machine learning model indicated that the XGBoost model had better performance compared to the other 5 models for both the original data and SMOTE processed data. Identical variablesfor both sexes throughout the three survey years for predicting HIV status were: total lifetime number of sex partners, cohabitation duration (grouped), number of household members, age of household head, times away from home in last 12 months, beating justified and religion. The two most influential variable for both males and females were total lifetime number of sex partners and cohabitation duration (grouped). According to these findings, the catalytic model estimated a higher HIV incidence rate than the Farrington model. Compared to cohort estimates, the estimates were within the observed 95% confidence interval, with 88% and 75% agreement for the catalytic and Farrington models, respectively. The limits of agreement observed in the Bland-Altman plot were narrow for all plots, indicating that our model estimates were comparable to cohort estimates. Compared to UNAIDS estimates, the catalytic model predicted a progressive increase in HIV incidence for males throughout all survey years. Without a doubt, HIV incidence declined with each subsequent survey year for all models. Based on birth year cohort-specific prevalence, the female HIV prevalence peaks at approximately 29 years of age and then declines. Between 15 and 30 years, males have a lower cohort-specific prevalence than females. Male cohort-specific prevalence decreases marginally between ages 33 and 39, then peaks at age 40. In all age categories, the cohort-specific FOI is greater in females than males. Moreover, the cohortspecific HIV FOI peaked at age 22 for females and age 40 for males. A 18-year age gap between the male and female HIV FOI peaks was observed. Throughout the decade covered by this study, the Tsholotsho district remained a 99 % confidence hotspot. The impact of STI, condom use and being married on HIV incidence has been strong in the Eastern parts of Zimbabwe with Mashonaland Central, Mashonaland East and Manicaland provinces. From our findings from the Multiscale Geographically Weighted Regression (MGWR), we observed that Matabeleland North’s HIV incidence rates are driven by wealth index, multiple sex partners, STI and females with older partners. Conclusions: The difference between the results from the Cox-Snell residuals graphical method and the model estimates and AIC value may be due to inadequate methods to test the goodness-of-fit of interval-censored data. We concluded that Model 2 with interval-censoring gave better estimates due to its consistency with the published results from the literature. Even though we consider the interval-censoring model as the superior model with regard to our specific data, the method had its own set of limitations. Programmes targeted at HIV testing could use the machine learning approach to identify high-risk individuals. In addition to other risk reduction techniques, machine learning may aid in identifying those who might require Pre-exposure prophylaxis. Based on our results, older men and younger women resembled patterns of higher HIV prevalence and force-of-infection than younger men and older women. This could be an indication of age-disparate sexual relationships. Therefore, HIV prevention programmes should be targeted more at younger females and older males. Lastly, to improve programmatic and policy decisions in the national HIV response, we recommend the triangulation of multiple methods for incidence estimation and interpretation of results. Multiple estimating approaches should be considered to reduce uncertainty in the estimations from various models. The study spread the message that various factors differ from district to district and over time. The study's findings could be useful to policymakersin terms of resource allocation in the context of public health programs. The findings of this study also highlight the importance of focusing on districts like Tsholotsho, which have consistently had a high HIV burden over time. The main strength of this study is dependent on the quality of the data obtained from the surveys. These data were derived from population-based surveys, which provide more reliable and robust data. Another strength of this study was that we did not restrict our analysis to one method; however, we had the opportunity to determine the risk and incidence of HIV by exploring different methodologies. However, the limited number of variables accessible to us for this study constituted one of its drawbacks. We could not determine the impact of variables including viral load, health care spending, HIV- risk groups, and other HIV-related interventions. Additionally, there were missing values in the data, which required making assumptions about their unpredictability and utilising imputation methods that are inherently flawed. Last but not least, a number of the variables were self-reported and, as a result, were vulnerable to recall bias and social desirability bias.Item Evaluation of antioxidant properties and neuroprotective effects of methanolic leaf extract of combretum molle in D-galactose-induced aging model of Sprague Dawley rats(2024) Fasemore, Thandi Mamorapelo DorothySeveral physical and biochemical changes in the body occur because of the biological process of aging. As part of natural aging, the brain encounters morphological and functional changes that affect dendritic trees and synapses, neurotransmission, circulation, and metabolism. The brain's high metabolism, elevated levels of lipids, and inadequate antioxidant defences make it susceptible to oxidative stress. A reducing sugar called D-galactose (D-gal) causes a significant build-up of reactive oxygen species (ROS). Combretum molle (C.molle) is a plant rich in compounds that scavenge free radicals and is frequently used to cure a variety of human illnesses in African traditional medicine. This study investigated the potential impact of C.molle on rat brain aging brought on by D-galactose. Fifty adult male Sprague Dawley rats were treated for 90 days and were composed of 5 groups (n=10) as follows: I) Control group received saline and distilled water, II) C.molle only group received intragastric gavage of C.molle (500 mg/kg), III) D-gal only group received a subcutaneous injection of D-galactose (150 mg/kg), IV) CMD 90 group received D-galactose and C.molle simultaneously for 90 days, V) CMD 45 group received D-galactose for the first 45 days and C. molle for the remaining 45 days. The animals underwent behavioral evaluation post-treatment for a further period of 7 days twice a day. The rat’s cognitive function was evaluated through Novel object recognition and object location tests. The C.molle ’s neuroprotection was evaluated through levels of acetylcholinesterase (AchE), Acetylcholine (Ach), Brain Derived Neurotropic Factor (BDNF), and Tumor Necrosis Factor (TNF) alpha including the effects on adult neurogenesis through Ki-67 and doublecortin (DCX) immunohistochemistry. The oxidative stress level was measured through the evaluation of lipid peroxidation marker malondialdehyde (MDA), glutathione peroxidase (GSH-Px), glutathione (GSH), superoxide dismutase (SOD), and catalase (CAT) activity. The C.molle significantly attenuated the effects of D-galactose-induced changes in the hippocampus and cortex, ranging from cognitive capacity, and oxidative stress by increasing GSH, BDNF, Ach, GSH-Px, CAT, and SOD activity. Additionally, C. molle caused a decrease in the levels of MDA, TNF alpha, and AchE activity, and ameliorated reduced cell proliferation and neuroblast differentiation brought about by D-galactose.Item Examining the bidirectional relationship between comorbid depression and Type 2 diabetes: a managed healthcare perspective(2024) Naidoo, Lovina Asha CorrienIntroduction-Type 2 diabetes mellitus (T2DM) is common and has devastating outcomes for patients diagnosed with this disease. In Africa, the prevalence of T2DM is reaching epidemic proportions, especially in developing countries like Ghana, Nigeria and South Africa (SA). The financial burden of T2DM is seen in the public and private healthcare sectors in Africa. Major depressive disorder (MDD) frequently co-occurs as a discordant comorbidity with T2DM. MDD is an important component in the holistic management of T2DM care as the outcomes of both conditions are exacerbated by the presence of the other. T2DM patients are at high risk for cardiovascular (CV) morbidity and mortality. The comorbidity of MDD among these individuals is associated with poor diabetes-related cardiovascular disease (CVD) outcomes such as myocardial infarction, stroke and cardiac failure, because MDD is a highly prevalent risk factor for CVD and T2DM alike. Little is known of the prevalence of MDD as a comorbidity of T2DM in SA or if MDD is a risk factor for the onset of T2DM. It is also unclear whether the treatment of depressive disorders in T2DM would improve glycaemic control. While the association between depression and T2DM in America and Europe is established, understanding the relationship between these two non-communicable diseases (NCDs) is lacking in SA. The relationship between T2DM and associated co-morbidities, particularly MDD, is poorly acknowledged in chronic disease management practices in SA. The management of co-morbid conditions may influence managed healthcare costs and hospitalisation rates. Aim and objectives -This thesis investigated the bidirectional relationship between T2DM and comorbid MDD within a South African privately managed healthcare organisation. The objectives of the study were to estimate the comorbidity incidence, resource utilisation (medicine, services and hospital), assess the cost between two T2DM management funding models, the influence of MDD on glycaemia, blood pressure and lipid control (ABC guidelines) and finally identify the depressive symptom and CV risk profiles of patients with T2DM with or without MDD and those with MDD alone. Method -The thesis comprised four quantitative studies that analysed claims data from a privately funded healthcare insurer and electronic health records (EHR) from 2012 to 2019, and a cross-sectional survey from 2016 to 2019. The methodology in the first study was a retrospective descriptive analysis of 902 adult patients with T2DM in 2014. Patients were identified with T2DM and their comorbidities and categorised as those with concordant comorbidities (CC), and those with discordant comorbidities (DC). Hospital admissions of patients with T2DM, with MDD (T2DM+MDD) versus those without MDD (T2DM-MDD), were further analysed. The second study analysed the claims data of patients with T2DM and T2DM+MDD from 2012 to 2016. Annual healthcare costs were assessed between two funding models and categorised as in-hospital and out-of-hospital medicines and out-of-hospital services. Diabetes-related and other medicine-plus-services and hospitalisation costs between T2DM and T2DM+MDD were estimated In the third study, the cardiometabolic indices control of 1211 patients with T2DM+MDD, T2DMMDD and MDD only were measured using their EHR for the year 2019. Claims for lipid-lowering therapy, hypoglycaemic agents, antihypertensives and antidepressant selective-serotoninreuptake inhibitors (SSRI) were assessed between the study groups. Frequencies of patients achieving target glycated haemoglobin (HbA1c), systolic blood pressure (SBP) and low-densitylipoprotein (LDL-C) were compared between groups. A stepwise multivariate logistic regression analysis was performed to identify predictors of HbA1c and LDL-C control of the study groups. The fourth study conducted a cross-sectional survey of a random sample of members with T2DM+MDD, T2DM-MDD, MDD only, and a healthy control group between the years 2016 to 2019. The survey comprised a Patient Health Questionnaire-9 (PHQ-9) to assess possible depressive symptoms, and anthropometric measures (body mass index (BMI), family history of diabetes and/or heart disease, and smoking status as CV risk profiles). Findings- The first study revealed a high incidence of CV concordant comorbidities (hypertension )and hyperlipidaemia) in patients with T2DM+MDD, with MDD being the most prevalent discordant comorbidity of T2DM (17%). A higher percentage of patients with T2DM+MDD were admitted to 3 hospital (42%, p=0.004) compared with those with T2DM-MDD (30%). The number of overnight admissions was higher among the T2DM+MDD (76%, p=0.016) compared with T2DM-MDD (66%). The second study focused on health care costs and the funding models associated with managed care. The direct medical costs of patients with T2DM and T2DM+MDD registered with a medical scheme over a 5-year period between two funding models were estimated and compared: a capitation risk-sharing model (CM) versus a traditional fee-for-service (FFS) model. Of the identified T2DM patients, 64% were enrolled in CM in 2012 and this rose to 81% by 2016. The implementation of CM resulted in a significantly higher cost to the scheme ($1,095) compared to FFS ($296) in 2016 (p<0.0001). Forty-six T2DM patients in this study incurred hospitalisation costs of ≥ $24,243 for T2DM-related or other hospital admissions (non T2DM-related). The healthcare expenditure consumed by patients with T2DM and T2DM+MDD on a capitation model of care for diabetes was high compared to patients on FFS. While the diabetes-related treatment and management were similar between patients with T2DM+MDD and T2DM-MDD, other medicine and services, expenditure was significantly higher in the T2DM+MDD group, for example T2DM+MDD patients had a median expenditure of $1,414 in 2016 compared to a median of $614 in T2DM-MDD patients (p<0.0001). The third study assessed the HbA1c, SBP and LDL-C control target attainment (as per South African ABC guidelines) in patients with T2DM+MDD and T2DM-MDD and those with MDD alone. Only 13% of the patients in T2DM+MDD group and 7.1% in the T2DM-MDD group achieved ABC (HbA1c<7%, LDL-C<1.8mmol/l and SBP<140/90 mmHg) targets, despite hypoglycaemic, lipidlowering therapy and antihypertensive claims, indicating a possible risk for CVD in T2DM+MDD and T2DM-MDD patients. A higher proportion of patients with T2DM+MDD (56%) achieved an HbA1c target of <7% compared to the T2DM-MDD group (45%, p<0.05). Multiple regression analysis showed that HbA1c control was independently associated (p<0.001) with older age, claims for statins and having a history of MDD, after adjusting for claims for antihypertensive therapy, metformin, newer hypoglycaemic agents, sex, and interaction factor of newer hypoglycaemic agents and metformin. Only 24% of patients in both the T2DM+MDD and T2DMMDD groups reached the LDL-C target <1.8mmol/l. The predictors of LDL-C control between the T2DM+MDD and T2DM-MDD groups were older age (p<0.0001) and claiming statin therapy (p=0.001), after adjusting for antihypertensive therapy and metformin claims and sex The fourth study identified the depressive symptoms and CV risk factors (such as obesity, smoker status and family history of diabetes and heart disease) in individuals with T2DM+MDD, T2DMMDD or MDD alone compared to a healthy control. The PHQ-9 scores revealed that patients in all four groups were within a range of mild to moderate-severe depressive symptoms. The T2DM+MDD group had moderate-severe (PHQ-9≥10) depressive symptoms (58.8%) similar to the MDD group (54.2%, p=1.0) suggesting a poor response to antidepressants. Patients with T2DM-MDD had underlying unrecognized depressive symptoms: 20.5% had moderate-severe (PHQ-9≥10) depressive symptoms and 23.1% had mild (PHQ-9=5-9) depressive symptoms. Of concern was that 25% of the control (healthy) group recorded having moderate-severe (PHQ9≥10) depressive symptoms and 21.4% of having mild depressive (PHQ-9=5-9) symptoms. The majority of the T2DM+MDD group obese (76.5%) whereas 46.2% of the T2DM-MDD group were overweight. However, the control group, with no stated disease, were overweight (37.5%) or obese (30.4%). This study highlights the undetected MDD and high CV risk prevalent in this setting. Conclusion- Within this South African private managed healthcare setting, comorbidities associated in patients with T2DM, i.e. MDD and CVD, are managed discretely. High-risk individuals with T2DM increase costs and resource utilisation within the private managed healthcare setting. In summary, the relevance of the research was to increase awareness of the consequences of comorbidity of T2DM and MDD and encourage routine screening for depression in T2DM patients, and glycaemic screening among patients with MDD. Managed care programmes should consider a patient-centric approach to assist patients in engaging with their T2DM and comorbidities more effectively by listening to their difficulties in terms of medication compliance, offering regular glycaemic and lipid blood tests and encouraging healthier diet through visits to dieticians or nurse educators. Targeting primary healthcare as an intervention has the potential to reduce the hospitalisation burden by initially stabilizing patients with T2DM+MDD, providing cost-effective and appropriate medicine management (i.e. statins), improving attainment of ABC control targets and early screening for depression and non-invasive CV risk factors. Resource allocation for a coordinated care team that includes health professionals such as dieticians, endocrinologists, drug review utilisation (DUR) pharmacists, psychologists and nurse educators to treat patients with T2DM+MDD is indicated.Item Exploring healthcare user perspectives on utilisation of prevention of mother to child transmission (PMTCT) services in a high-mobility context in Johannesburg, South Africa(2024) Bisnauth, Melanie AnnIncluded in this thesis are four original papers. The first of four papers explored the impact of the Option B+ Prevention of Mother to Child Transmission (PMTCT) of human immunodeficiency virus (HIV) programme on the work of healthcare professionals and, investigated pregnant women living with HIV (WLWH) experiences with antiretroviral therapy (ART) for life, to gain insights in ways to better manage the programme. The first paper (Chapter 6) explored the views of both healthcare providers and user experiences with ART for life at the time the SA’s National Department of Health (NDoH) adopted World Health Organisation (WHO) 2013 guidelines on ARVs for HIV treatment and prevention in 2015. This included changes to PMTCT through Option B+ (now known as lifelong treatment). In 2015, little was known about the impact of these guidelines on the work of healthcare workers (HCWs) and no research at the time had focused on how these changes have affected adherence for the patients. Semistructured interviews were conducted with participants and revealed that work had become difficult to manage for all HCWs because of the need to strengthen indicators for tracking patients to decrease the PMTCT loss to follow-up (LTFU); there was inconsistency in delivery of counselling and support services and a need for communication across clinical departments of the hospital that both offered PMTCT services and had to provide care to the mothers and; a lack of compassion and understanding was existent amongst service providers. The overburdened healthcare environment had affected the overall views and experiences of pregnant WLWH going on ART for life. All patient participants (n=55) responded that they chose the fixed dose combination (FDC) pill for life to protect the health of the baby and felt ART for life could be stopped after giving birth, unaware of the long-term benefits for the mother. Although SA national women were interviewed at the time, RMMCH had provided PMTCT care to many migrants and their experiences needed to be heard. Further research was needed on how to strengthen the programme for long term scalability and sustainability for highly mobile WLWH to better adapt PMTCT programming within the healthcare system. Observations of the population of women accessing PMTCT at RMMCH indicated that many migrant WLWH were utilising the services and called for further investigation and lead into the next two phases of the research study. In addition, Paper 2 (Chapter 7) and Paper 3 (Chapter 8) data collection occurred during the COVID19 pandemic. Paper 2 (Chapter 7) investigated HCWs and their experiences in the provision of PMTCT services to WLWH, specifically migrants that were utilising services during the SARS-CoV-2 (COVID-19) pandemic in SA, to provide further insights on the programme. The COVID-19 pandemic resulted in SA taking preventative and precautionary measures to control the spread of infection, this inevitably proposed challenges to WLWH, especially migrant women by limiting population mobility with border closures and lockdown restrictions. Semi-structured interviews (n=12) conducted with healthcare iii providers across city, provincial, and national levels explored how COVID-19 impacted the healthcare system and affected highly mobile patients’ adherence and utilisation of PMTCT services. Findings revealed; a need for multi-month dispensing (MMD); fear of contracting COVID-19 leading to the disruption in the continuum of care; added stress to the already existent overburdened clinical environment; mistreatment and xenophobic attitudes towards the migrant HIV population and; three key areas for strengthening PMTCT programme sustainability for migrants. Paper 3 (Chapter 8) investigated the insights of migrant WLWH. Migrant typologies were not predetermined a priori. This research allowed for the different mobility typologies of migrant women utilising PMTCT services in a high mobility context of Johannesburg to first surface from the data. By analysing these experiences, it explored further into how belonging to a specific typology may have affected the health care received and their overall experience during the COVID-19 pandemic. Interviews with cross-border migrants (n=22) (individuals who move from one country to another) and internal migrants (n=18) (individuals who transcend borders within a country) revealed that women in cross-border migration patterns compared to interprovincial/intraregional mobility; expressed more fear to utilise services due to xenophobic attitudes from HCWs; were unable to receive ART interrupting adherence due to border closures and; relied on short message service (SMS) reminders to adhere to ART during the pandemic. All 40 women struggled to understand the importance of adherence due to the lack of infrastructure to properly educate them following social distancing protocols. COVID-19 amplified existing challenges for cross-border migrant women to utilise PMTCT services. Future pandemic preparedness should be addressed with differentiated service delivery (DSD) including MMD of ARVs, virtual educational care, and language sensitive information, responsive to the needs of mobile women and to assist in alleviating the burden on the healthcare system. The pandemics’ impact on the study timeline, key lessons learnt and, take away messages when conducting research during this unpredictable time are provided in Chapter 4 (Methods) and Chapter 9 (Discussion). It is important to include these reflections because of the impact it had on all participants and the entire PhD process. Paper 4 will be a future policy piece, drawn from Chapter 9, addressing the need for responsiveness from the SA government and NDoH. Chapter 9 brought together collectively the previous papers 1,2, and 3 and drew overall conclusions, recommendations, and a way forward for both policy and programme implementation. This chapter provided the principal findings of the overall thesis and in relation to other studies in the field, as well as implication for policy practice and research. Chapter 9 concludes with the recommendations for future research on WLWH, mobility typologies, service provision of PMTCT and future pandemic preparedness, and the vision for the South African PMTCT programme.Item Exploring the interplay of chemokine receptors ccr5 and cxcr6 in mechanisms of natural control in HIV-1- infected black South Africans(2024) Koor, Gemma WhitneyIn sub-Saharan Africa, HIV-1 is a significant cause of morbidity and mortality. However, research remains primarily focused on North American and European population groups, who have remarkably different genetic backgrounds to individuals from sub-Saharan Africa. HIV1 controllers represent a model of HIV-1 functional cure, with some individuals able to control viral replication, and some able to sustain immune function in the presence of high viral loads, both in the absence of antiretroviral therapy (ART). The chemokine receptors CCR5 and CXCR4 are the major coreceptors HIV-1 utilises to enter cells. The use of alternative coreceptors, such as the CXCR6 coreceptor, is thought to contribute to the lower pathogenicity exhibited by the HIV-2 and SIVsmm strains. Building on previous work conducted in our research unit on these two coreceptors in South African populations, this thesis firstly describes CCR5 genetic variants that associate with HIV-1 control or risk of progressive infection in black South Africans, and then explores constitutive expression levels of CCR5 and CXCR6 on various peripheral blood immune cell subsets in the absence of HIV-1 infection in ethnically divergent population groups. The effect of sex, age, and select CCR5 and CXCR6 single nucleotide polymorphisms (SNPs) on expression levels of these two receptors was also investigated. The CCR5 5’UTR and 3’UTR regions were PCR-amplified and sequenced from genomic DNA extracted from 145 ART-naive black South African individuals living with HIV-1 (71 HIV-1 controllers – 23 elite controllers, 37 viraemic controllers, 11 high viral load long-term nonprogressors and 74 progressors). Findings confirmed results from other studies in showing that the CCR5 HHE haplotype is deleterious for HIV-1 disease progression, and the HHA haplotype and HHA/HHC genotype associated with protection from HIV-1 disease progression. Novel haplotypes were characterised, both in the 3’UTR and spanning the CCR5 5’UTR and 3’UTR. Overall, findings suggest that two CCR5 promoter SNPs (-2459 G>A and -2135 T>C) and one CCR5 3’UTR SNP (+2919 T>G) may be key functional variants with regards to HIV-1 control in black South Africans. To gain further insight into the constitutive expression of CCR5 and CXCR6 on peripheral blood immune cells and explore the relationship between select genetic variants and expression, immunophenotyping by flow cytometry was conducted using whole blood from age- and sex-matched ethnically distinct South African HIV-uninfected individuals (17 black, 21 white). Expression levels of CCR5 and CXCR6 were assessed on CD4+ and CD8+ T cells, B cells, monocytes and NK cells, and their respective subsets. The effects of age and sex on expression levels of these two receptors was also investigated. Population-specific differences with regards to CCR5 expression on all cell types, except for B cells, were evident. Generally, black South Africans exhibited a lower expression level of CCR5 compared to white South Africans. CXCR6 expression only differed with regards to percentage of CXCR6-expressing cells, not CXCR6 density (numbers of cell surface receptors). Black individuals had a lower percentage of CXCR6-expressing CD8+ T cell subsets (naïve and effector memory) and a higher percentage of CXCR6-expressing CD14+CD16+ monocytes compared to white individuals. Overall, we found significant population-specific differences in expression levels of both CCR5 and CXCR6, multiple associations with cell activation (as measured by HLADR expression) and CCR5 and CXCR6 expression, and CCR5 and CXCR6 expression was positively significantly correlated on multiple cell subsets. Furthermore, both sex and age influenced CCR5 and CXCR6 expression, however results varied widely across the two population groups studied. Sex differences were only evident in white individuals; predominantly CXCR6 expression was increased in males compared to females. Age associations with CCR5 and CXCR6 expression were also primarily found in white individuals. Four CCR5-related SNPs that are associated with HIV-1 control in this or other studies (rs553615728 -4223 C>T SNP, rs1799987 −2459 G>A SNP, rs746492 +2919 T>G SNP and rs1015164 G>A SNP) were assessed for their potential association with CCR5 expression levels. The +2919 TG genotype significantly associated with a higher percentage of CCR5- expressing total CD8+ T cells, transitional memory and terminally differentiated CD8+ T cells compared to the GG genotype. The +2919 GG genotype associated with a lower percentage of CCR5-expressing B cells compared to the TT and TG+TT genotypes, however, only in white South Africans. The +2919 TG and TG+TT genotypes associated with significantly higher CCR5 density on all CD8+ T cell subsets, except for naïve CD8+ T cells, when compared to the GG genotype. When evaluating two CXCR6 genetic variants previously associated with HIV-1 viraemic control (rs2234355 G>A and rs2234358 G>T) in relation to CXCR6 expression, possession of the rs2234355 SNP GA genotype associated with lower CXCR6 expression on select CD4+ and CD8+ T cell subsets as well as on B cells, while possession of the rs2234358 SNP TT genotype associated with higher CXCR6 expression on multiple cell types, primarily in white South Africans. Possession of the -358TT/+355GA genotype combination associated with lower CXCR6 expression on select subsets of CD4+ T cells and monocytes. In summary, this study provides information on genetic variation in the CCR5 gene in a South African context, describes genetic variants associating with HIV-1 control in black South Africans, adds novel insight into constitutive CCR5 and CXCR6 expression levels on CD4+ and CD8+ T cells, B cells, monocytes and NK cells in HIV-1-uninfected black and white South Africans, and describes the potential associations of select genetic variants and expression. Black and white individuals differed in their baseline expression levels of CCR5 or CXCR6, which was partly driven by host genetic factors that were explored. This work highlights the importance of considering effects of ethnicity, age, and sex in any studies addressing any immune molecules in relation to differential HIV-1 outcomes of infection susceptibility/protection, disease progression, or HIV-1 virological control on antiretroviral therapy. Although conducted on small numbers of individuals, these variables clearly influenced constitutive expression of CCR5 and CXCR6, and further population-specific studies are warranted to gain further insights. Findings from this study have implications for risk of acquisition of HIV-1 infection and for disease progression in people living with HIV-1. Understanding the role of these molecules is important for informing strategies for both HIV1 prevention and HIV cure.Item Implementation of universal health coverage in South Africa: formative effects, perceived quality of healthcare and modelling of health service utilisation indicators in a national health insurance pilot district(2024) Mukudu, HillaryBackground- According to the World Health Organisation, member countries should attain universal health coverage by 2030. To achieve this goal, South Africa introduced the National Health Insurance programme in 2012. Since then, the first phase of the pilot programme has been implemented in Tshwane and ten other country districts. Historically, no other health system reform in South Africa has generated more interest than the National Health Insurance. This 15-year preliminary plan and pilot received optimism and criticism depending on several factors. The pilot programme focusing on primary health care was implemented along with several other interventions. The components of the intervention included setting up: ward-based primary healthcare outreach teams, integrated school health programmes, district clinical specialist teams, centralised chronic medicine dispensing and distribution programmes, health patient registration systems, stock visibility systems, and contracting of private non-specialised (general) medical practitioners to provide services in public primary health care facilities. These interventions were envisaged to improve healthcare quality at the primary healthcare level and offset the burden of non-emergency (secondary) care at the hospital outpatient level. However, studies have yet to be done to determine population-level formative effects on primary and non-emergency secondary healthcare indicators, their relationships, and interdependencies. These data are needed to forecast and develop measures to meet the possible increase in health service utilisation. In addition, this information is essential to guide the possible scale-up of South Africa's National Health Insurance mechanism. Such guidance may be in setting benchmarks to monitor policy implementation, determine facility staffing, the package of health services, training needs, budget for medicines and consumables, and other resource allocation. Aim- Therefore, this study first aimed to determine the formative effects of implementing the Medical Practitioners' contracting of the National Health Insurance pilot program on primary healthcare utilisation indicators measured at both primary and non-emergency secondary levels of care. A comparison was made between Tshwane national health insurance pilot district and Ekurhuleni district, which is not a pilot district. Furthermore, the study aimed to determine the relationships between healthcare utilisation indicators and their interdependencies and then provide a forecast for 2025. Methods- This quasi-experimental and ecological study used selected primary health care and outpatient department indicators in the District Health Information System monthly reports between January 2010 and December 2019 for the Tshwane district and Ekurhuleni district. Thus, to determine the formative effects on primary healthcare utilisation indicators, the selected period was from June 2010 to May 2014. A total of 48-time periods (months), with 24 before (June 2010 to May 2012) and 24 after (June 2012 to May 2014) implementation of Medical Practitioners contracting of the National Health Insurance pilot programme. Similarly, June 2012 to May 2014 was the selected period to determine the effects on the perceived quality of care. A total of 24 months, with 12 before (June 2012 to May 2013) and 12 after (June 2013 to May 2014) implementation of the Medical Practitioners' contracting of the National Health Insurance pilot programme. To determine the relationship and interdependence between Primary Health Care and Outpatient Department indicators and forecasts for 2025, 113 time periods (quarters) were selected. There were 28 quarters before and 84 quarters after implementing the National Health Insurance pilot programme. Similar methodological approaches were used to determine the effects of Medical Practitioners contracting in the National Health Insurance pilot programme on Primary Healthcare utilisation indicators and perceived healthcare quality. All study data types used in the thesis were continuous; thus, they were initially evaluated descriptively using means (standard deviations) and medians (interquartile ranges). The range was evaluated using minimum and maximum values. An Independent t-test assuming unequal variances was used to compare the means of Outpatient Department indicators in determining the effect of Medical Practitioners contracting in the National Health Insurance pilot programme on the perceived quality of healthcare. Single- and multiple-group (controlled) interrupted time series analysis was used to determine the effect of the National Health Insurance pilot project implementation on the utilisation of selected primary and non-emergency outpatient department indicators and perceived healthcare quality. A different methodological approach was used to determine the interdependencies and relationships between selected primary healthcare and non-emergency outpatient department indicators and their forecasts for 2025. Initially, data were evaluated descriptively using means (standard deviations) and medians (interquartile ranges) and the range was evaluated using minimum and maximum values. Prior to the development of the vector error correction model, several steps were taken. Firstly, a natural log transformation of all time series data was done to enhance additivity, linearity, and validity. Additionally, the level of lags at which variables were interconnected or endogenously obtained was determined due to the sensitivity of causality. Furthermore, the stationarity of time series data was determined using both graphical means and the Augmented Dick Fuller test to confirm the stability of each time series. Finally, cointegration was determined using the Johansen cointegration test to check for the correlation between two or more nonstationary series. After developing the Vector Error Correction Model, the Granger causality test was done to determine whether one series is helpful for forecasting another. Then the Vector Error Correction Model relationships between variables of selected primary healthcare and non-emergency outpatient department indicators were used to forecast the utilisation of both levels of services by 2025. Results- The findings showed changes in primary healthcare indicators measured at primary and nonemergency secondary levels before and after contracting private medical practitioners of the National Health Insurance pilot programme. The study also confirmed the influence of selected primary health care and outpatient department headcounts on each other by finding four cointegration relationships between the variables. There were differences between single-group and controlled interrupted time series analysis findings for Tshwane district and Ekurhuleni district considered independently and collectively on the utilisation of primary health care services. Thus, the positive impact observed in primary healthcare utilisation post-June 2012 is not attributable to the implementation of the Medical Practitioners' contracting of the National Health Insurance pilot programme. Conversely, there were similarities between single-group and controlled interrupted time series analysis findings for Tshwane district and Ekurhuleni district considered independently and collectively on the perceived quality of primary healthcare. In the interpretation of this finding, the similarities indicated that implementing the Medical Practitioners' contracting of the National Health Insurance pilot programme positively influenced the perception of a better quality of primary healthcare in the Tshwane district. Regarding primary healthcare indicators, there were differences between single-group and controlled interrupted time series analysis. Single-group interrupted time series analysis showed a 65% and 32% increase in the number of adults remaining on anti-retroviral therapy in Tshwane and Ekurhuleni districts, respectively (relative risk [RR]: 1.65; 95% confidence interval [CI]: 1.64–1.66; p < 0.0001 and RR: 1.32; 95% CI: 1.32–1.33; p < 0.0001, respectively). However, controlled interrupted time series analysis did not reveal any differences in any of the post-intervention parameters. Furthermore, single-group interrupted time series analysis showed a 2% and 6% increase in the number of clients seen by a professional nurse in the Tshwane and Ekurhuleni districts, respectively (RR: 1.02; 95% CI: 1.01–1.02; p < 0.0001 and RR: 1.06; 95% CI: 1.05–1.07; p < 0.0001, respectively). However, controlled interrupted time series analysis did not show any differences in any of the postintervention parameters. In addition, single-group interrupted time series analysis revealed that there was a 2% decrease and 1% increase in the primary healthcare headcounts for clients aged ≥5 years in Tshwane and Ekurhuleni district (RR: 0.98; 95% CI: 0.97–0.98; p < 0.0001 and RR: 1.01; 95% CI: 1.01–1.02; p < 0.0001, respectively). Similarly, there was a 2% decrease and a 5% increase in the total primary healthcare headcounts in the Tshwane district and Ekurhuleni districts, respectively (RR: 0.98; 95% CI: 0.97–0.98; p < 0.001 and RR: 1.05; 95% CI: 1.04–1.06, p < 0.0001, respectively). However, controlled interrupted time-series analysis revealed no difference in all parameters before and after intervention in terms of total primary healthcare headcounts and primary healthcare headcounts for clients aged ≥5 years. Regarding secondary non-emergency outpatient department headcounts, single-group and controlled interrupted time series analyses revealed similar findings. Despite these similarities, single-group interrupted time series analysis showed a disparate increase in the outpatient department not referred headcounts, which were lower in the Tshwane district (3 387 [95%CI 901, 5 873] [p = 0.010]) than in Ekurhuleni district (5 399 [95% CI: 1 889, 8 909] [p = 0.004]). Conversely, while there was no change in outpatient department referred headcounts in the Tshwane district, there was an increase in headcounts in the Ekurhuleni district (21 010 [95% CI: 5 407, 36 611] [p = 0.011]). Regarding the outpatient department not referred rate, there was a decrease in the Tshwane district (-1.7 [95% CI: -2.1 to -1.2] [p < 0.0001]), but not in the Ekurhuleni district. Controlled interrupted time series analysis showed differences in headcounts for outpatient department follow-up (24 382 [95% CI: 14 643, 34 121] [p < 0.0001]), the outpatient department not referred (529 [95% CI: 29, 1 029 [p = 0.038]), and outpatient department not referred rate (-1.8 [95% CI: -2.2 to -1.1] [p < 0.0001]) between Tshwane the reference district and Ekurhuleni district. Four common long-run trends were found in the relationships and dependencies between primary healthcare indicators measured at the primary healthcare level and the non-emergency secondary level of care needed to forecast future utilisation. First, a 10% increase in outpatient departments not referred headcounts resulted in a 42% (95% CI: 28-56, p < 0.0001) increase in new primary healthcare diabetes mellitus clients, 231% (95% CI: 156-307, p < 0.0001) increase in primary healthcare clients seen by a public medical practitioner, 37% (95% CI: 28-46, p < 0.0001) increase in primary healthcare clients on ART, and 615% (95% CI: 486- 742, p < 0.0001) increase in primary healthcare clients seen by a professional nurse. Second, a 10% increase in outpatient department referrals resulted in an 8% (95% CI: 3-12, p < 0.0001) increase in new primary healthcare diabetes mellitus clients, a 73% (95% CI: 51-95, p < 0.0001) increase in primary healthcare headcounts for clients seen by a medical professional, a 25% (95% CI: 23-28, p < 0.0001) increase in primary healthcare headcounts for clients on ART, and a 44% (95% CI: 4-71, p = 0.026) increase in primary healthcare headcounts for clients seen by a professional nurse. Third, a 10% increase in outpatient department follow-up headcounts resulted in a 12% (95% CI: 8-16, p < 0.0001) increase in primary healthcare headcounts for new diabetes mellitus, 67% (95% CI: 45-89, p < 0.0001) increase in primary healthcare headcounts for clients seen by public medical practitioners, 22% (95% CI: 19-24, p < 0.0001) increase in primary healthcare headcounts for clients on ART, and 155% (95% CI: 118-192, p < 0.0001) increase in primary healthcare headcounts for clients seen by a professional nurse. Fourth, a 10% increase in headcounts for total primary healthcare clients resulted in a 0.4% (95% CI: 0.1-0.8, p < 0.0001) decrease in primary healthcare headcounts for new diabetes clients. Based on these relationships and dependencies, the outpatient department follow-up headcounts would increase from 337 945 in the fourth quarter of 2019 to 534 412 (95% CI: 327 682–741 142) in the fourth quarter of 2025, while the total primary healthcare headcounts would only marginally decrease from 1 345 360 in the fourth quarter of 2019 to 1 166 619 (95% CI: 633 650–1 699 588) in the fourth quarter of 2025. Conclusion -The study findings suggested that improvements in primary health care indicators in National Health Insurance pilot districts could not be attributed to the implementation of contracting private medical practitioners but were likely a result of other co-interventions and transitions in the district. However, it might have resulted in an improved perception of quality of care at primary health care facilities, evidenced by a reduction in the self-referral rate for nonemergency hospital outpatient departments. The study also confirmed the influence of selected primary healthcare and non-emergency outpatient department headcounts on each other by finding four common long-run trends of relationships. Based on these relationships and trends, outpatient department follow-up headcounts are forecasted to increase by two-thirds. Conversely, the total headcount for primary healthcare clients seen by a professional nurse will marginally decrease. Recommendations- Based on the study findings, the bidirectional referral between primary and non-emergency secondary levels of care in the Tshwane district should be strengthened to offset the burden of care at outpatient departments of district hospitals. Thus, the district health information system should include a down-referral indicator to monitor this activity. With the implementation of National Health Insurance, there is a need to improve the perception of quality of care at the primary healthcare level through appropriate training, recruitment, and placement of medical practitioners. Similarly, professional nurses, the core providers of primary healthcare services, should be supported and capacitated in line with the epidemiological transition.Item In vitro and in silico characterization of the anticholinesterase activity of select terpenoids against anopheles vectors(2024) Rants’o, Thankhoe AbramMalaria is a life-threatening plasmodial disease that is transmitted by female Anopheles mosquitoes. Major African malaria vectors include Anopheles arabiensis, An. funestus, An. gambiae and An. coluzzii. Malaria vector control programs have shown effectiveness in reducing the Anopheles populations. The main insecticide classes used in these interventions include pyrethroids, organochlorines, organophosphates, carbamates, and neonicotinoids. Nevertheless, the development of Anopheles resistance to these insecticide classes has greatly reduced the effectiveness of these interventions. A common resistance mechanism is through rapid detoxification of insecticides by overexpressed P450 monooxygenases. Although acetylcholinesterase (AChE) is a valid target in Anopheles vector, current anticholinesterase insecticides suffer from resistance and low selectivity between insect and mammal AChE targets. This indicates the urgent need to discover novel AChE inhibitors with higher affinity to Anopheles AChE compared to the mammal target, and less prone to resistance caused by the overexpressed monooxygenases. Identification of novel AChE inhibitors from natural sources and their potential to kill Anopheles during all its different life stages, presents a cost-effective approach. This PhD study aimed to identify such novel AChE inhibitors from essential oil sources and assess them for consistent activity against Anopheles species with hyperactive P450 monooxygenases. In this study, molecular differences between Anopheles and human AChEs were identified showing the opportunity to develop selective Anopheles AChE inhibitors. A novel approach was used to integrate the in silico and in vitro assays in assessing the Anopheles AChE inhibitory potential of select terpenoids and coupled these to the in vivo assays against different life stages of Anopheles. The terpenoids, farnesol, (-)-α-bisabolol, cisnerolidol, trans-nerolidol, and methyleugenol were identified as potent Anopheles AChE inhibitors and larvicidal agents with moderate adulticidal effects. Farnesol and (-)-α-bisabolol also displayed pupicidal activity, while methyleugenol inhibited the hatching of Anopheles eggs. Generally, farnesol and (-)-α-bisabolol were highly active across the Anopheles species, except in the strain with P450-based metabolic resistance. In contrast, the efficacy of cisnerolidol, trans-nerolidol, and methyleugenol was not affected by this resistance mechanism. This research suggests that cis-nerolidol, trans-nerolidol, and methyleugenol are potential candidates for further development as anticholinesterase bioinsecticides.Item Initial loss to follow up among tuberculosis patients: the role of Ward-Based Outreach Teams and short message service (SMS) technology(2024) Mwansa-Kambafwile, Judith Reegan MulubwaIntroduction: In South Africa, tuberculosis (TB) is still a serious public health problem with rates of initial loss to follow up (initial LTFU) varying between 14.9% and 22.5%. Poor clinician-patient communication resulting in lack of clarity on next steps, patients not prioritizing their healthcare and patients not knowing that their results are ready at the clinic are some reasons for initial LTFU. This PhD aimed to assess the effectiveness of Ward-based Outreach Teams (WBOTs) or Short Message Service (SMS) technology in reducing TB initial LTFU in Johannesburg, South Africa between 2018 and 2020. Methods: A mixed methods approach comprising two phases (formative and intervention) was employed. In the formative phase, secondary data were analyzed for frequency distributions to determine the rates of initial LTFU in the study area. In addition, in-depth interviews with WBOT Managers and with TB Program Managers were conducted to determine their perceived reasons for TB initial LTFU. In the intervention phase, two interventions (WBOTs/SMS technology) were tested using a 3 arm randomized controlled trial (RCT) comparing each of the interventions to standard of care (SOC). The WBOTs delivered paper slip reminders while SMS intervention entailed sending reminder SMS messages to patients as soon as TB results were available. Chi square statistics, Poisson regression and Kaplan-Meier estimates were used to analyze the data. The RCT was followed by in-depth interviews with WBOT members and with some of the trial participants who had tested TB positive and had received reminder messages. To identify themes in the qualitative studies, both inductive and deductive coding were used in the hybrid analytic approach. Results: From the formative phase, the TB initial LTFU among the 271 patients was found to be 22.5% and the overall time to treatment initiation was 9 days. Interviews with managers revealed that relocation and “shopping around” were the main patient related factors found as the reasons for initial LTFU. Health system related factors for initial LTFU were communication and staff rotations. In terms of TB related work, WBOTs screened household members for TB and referred them for TB testing. The services of the WBOT/TB programs which were found to be integrated were: referral of symptomatic patients for TB testing and adherence monitoring in patients already on TB treatment. There was minimal involvement of the WBOTs in the treatment initiation of patients diagnosed with TB. Findings from the trial were that 11% (314/2850) of the participants tested positive for TB. The 314 TB patients were assigned to one of the 3 arms (SOC=104, WBOTs=105, and SMS=105). Overall, 255 patients (81.2%) were initiated treatment across all study arms. More patients in the SMS arm were initiated TB treatment than in the SOC arm (92/105; 88% and 81/104; 78% respectively; P=0.062). Patients in the SMS arm also had a shorter time to treatment initiation than those in the SOC arm (4 days versus 8 days; P 8 days; P<0.001). A comparison of the WBOTs arm and the SOC arm showed similar proportions initiated on treatment (45/62; 73% and 44/61; 72% respectively) as well as similar times to treatment initiation. Findings from the post-trial interviews showed that delivery of the reminder paper slips by the WBOTs during the trial was something new, but possible to incorporate into their daily schedule. The patient interviews revealed that various emotions (happiness, fear, worry etc.) were experienced upon receipt of the reminder messages. Participants also reported that receiving the reminder message did influence their decision to go back to collect the results. Conclusion: Reminder messages to patients are beneficial in TB treatment initiation. National TB programs can use SMS messaging because it is an affordable and feasible method. Although implementation of the WBOTs intervention was suboptimal, findings show that with proper integration of TB and WBOT programs, WBOTs have the potential to contribute to improved treatment initiation.Item Integrated biological and behavioural assessment of human immunodeficiency virus and sexually transmitted infections among tertiary student men who have sex with men in Nairobi, Kenya: project bespoke(2024) Mwaniki, Samuel WaweruAims: The aims of this study were to: assess the appropriateness and acceptability of using respondent-driven sampling (RDS) as a strategy for recruiting tertiary student MSM (TSMSM) in a HIV/STIs bio-behavioural survey, estimate HIV/STIs prevalence and associated risk factors among TSMSM, explore experiences of TSMSM with access and use of health services, and assess healthcare providers’ (HCPs’) attitudes and perspectives towards care for TSMSM. Methods: The study was done in Nairobi, Kenya. During the first phase in September and October 2020, formative in-depth qualitative interviews were held with key personnel working in MSMfriendly health facilities (n=3), and TSMSM peer leaders (n=13), to assess the appropriateness and acceptability of using RDS to recruit TSMSM in a bio-behavioural survey. Subsequently, during the second phase in February and March 2021, six TSMSM selected from the 13 in the first phase, started off the RDS recruitment of another 242 TSMSM who participated in a cross-sectional biobehavioural survey to estimate HIV/STIs prevalence and associated risk factors. The survey was digitally self-administered on REDCap® platform. Participants received serological testing for HIV and Treponema pallidum, and pooled molecular testing for Chlamydia trachomatis, Mycoplasma genitalium, Neisseria gonorrhoeae, and Trichomonas vaginalis using urethral, anorectal and oropharyngeal samples. The third phase in September 2021 involved qualitative work to assess health access and delivery for TSMSM. In-depth interviews were held with TSMSM (n=22) purposely selected from the TSMSM (n=248) who participated in the biobehavioural survey. The interviews explored experiences of TSMSM with access and use of health services. During the same month, HCPs (n=36) took part in six focus group discussions to assess their attitudes and perspectives towards care for TSMSM. Qualitative data was analysed 2 thematically using NVivo v.11 (first phase) and v.12 (third phase), and quantitative data was analysed using Stata v.15 and RDS-Analyst v0.72 (second phase). Results: Formative qualitative work demonstrated that RDS was both appropriate and acceptable for recruiting TSMSM in the bio-behavioural survey. The median age of TSMSM who participated in the bio-behavioural survey was 21 years (interquartile range 20-22 years). RDS-adjusted prevalence of HIV, at least one of the five STIs, chlamydia, gonorrhea, Mycoplasma genitalium infection, trichomoniasis and latent syphilis were: 3.6%, 58.8%, 51.0%, 11.3%, 6.0%, 1.5% and 0.7%, respectively. Higher risk of HIV infection was independently associated with studying in private tertiary institutions, preferring a sex partner of any age, last sex partner being >25 years, meeting the last sex partner online and prevalent gonorrhea infection. Inconsistent condom use, and the last sex partner being a regular partner were independently associated with testing positive for at least one of the five STIs. From the qualitative work in the last phase, TSMSM vocalized experiences of prejudice, stigma and discrimination in public and institution-based health facilities, but felt they were equitably handled in community pharmacies, private and MSM-friendly health facilities. A majority of HCPs articulated positive attitudes towards care for TSMSM, while a minority expressed discomfort and displayed attitudes that likely reflected on their lived biases as it related to offering care and services to TSMSM. Conclusion: The demonstrated high HIV prevalence among TSMSM in Nairobi reflects the urgent need for tailored structural, biomedical and behavioural prevention interventions for this young key population. Structural interventions are required to address the environmental, social and economic factors that influence individual risk and protective behaviours in relation to HIV infection. Biomedical interventions such as pre-exposure prophylaxis are necessary to reduce the chances of transmission of HIV. The observed high prevalence of curable STIs calls for interventions to improve prevention, as well as prompt detection and treatment of these STIs. This is important because untreated STIs biologically potentiate the transmission and acquisition of HIV, and cause considerable morbidity on their own. Furthermore, there is a need for interventions that foster inclusive attitudes among, and improve the knowledge/skills of HCPs in tertiary institution-based health facilities, so as to make services more culturally competent, equitable and accessible for TSMSM.
- «
- 1 (current)
- 2
- 3
- »