PhD, Faculty of Health Sciences, University of the Witwatersrand / HIV/AIDS continues to be one of the greatest health challenges which South Africa faces. The epidemic in children is closely linked to that in women, the prevalence of which continues to grow according to antenatal statistics from the South African Department of Health (DOH). HIV is known to invade the central nervous system at the time of infection, and causes widespead damage. In children, this leads to a well-researched condition known as HIV encephalopathy, which affects all areas of neurodevelopment. The effects of timely initiation of antiretroviral therapy on alleviating the impact of encephalopathy have been well described. Neurodevelopmental delay is a stage four disease indicator according to the World Health Organisation (WHO), and therefore is a criterion for initiation of Highly Active Antiretroviral Therapy (HAART). HAART is often only administered according to the virologic and immunologic status of a child, as standardised neurodevelopmental assessment tools are not widely available in South African clinics. When HAART initation is dependent on immunologic status, it is often too late to prevent encephalopahy. To date, the only means of prevention of this condition is early initation of HAART, which has not been widely available in South Africa. Stringent guidelines for the commencement of this therapy according to the WHO, and the South African Department of Health (DOH) have had to be followed, leading to late initiation of HAART, and widespread central nervous system encephalopathy. Studies which have been carried out in South African clinics have demonstrated the high prevalence of this condition. Once there is evidence of encephalopathy, children should be referred for assessments in all facets of development, and where necessary, for rehabilitation. A standardised developmental screening tool which is suitable for use in a developing country is therefore necessary in order to screen for neurodevelopmental delays to allow for further assessment and referral to rehabilitation services, as well as providing an additional assessment criterion for initiation of HAART. Paediatric HIV clinics in developing countries are understaffed, and children may be seen by junior staff or screened by nurses due to the high numbers of clinic attendees. This often results in neurodevelopment being inadequately assessed and children are therefore not referred for intervention services. A standardised screening tool, which The Development of a Screening Tool to Evaluate Infants who are HIV Positive could be administered by clinic staff in order to ensure correct and timely referral of children for further assessment and intervention is therefore necessary. This is of importance both locally and internationally where a screening tool, which has been developed specifically for this purpose, does not exist. The aim of this study was therefore to evaluate the agreement between the Bayley-III Screening Test and the Bayley Scales of Infant Development (3rd version) in a population of HIV positive infants in order to evaluate its appropriateness for use in South Africa. The Bayley Scales of Infant Development have long been considered the ‘gold standard’ in infant developmental assessment, which is why this tool was chosen to evaluate the Bayley-III Screening Test against. The developmental scores in each facet (cognitive, motor or language) were evaluated to determine which should be included in an assessment tool for this population. Further objectives for the study were to adapt the screening tool to the needs of the population, or to develop a new screening tool should the Bayley-III Screening Test not prove suitable for use in this population. In order to meet the aims and objectives, a cross-sectional study was conducted where 112 HIV positive infants between the ages of six and eighteen months were assessed using the Bayley-III Screening Test and the Bayley Scales of Infant Development (3rd version) (BSID III). The infants were stratified into four age groups namely 6-8 months, 9- 12 months, 13-16 months, and 17-18 months. Children were recruited from Harriet Shezi Children’s Clinic at Chris Hani Baragwanath Hospital in Soweto. The agreement between the Bayley-III Screening Test and the Bayley Scales of Infant Development (3rd version) was analysed using Kappa, for the overall group, and for each age group. Overall agreement between the tools was as follows: K=0.58 for the Cognitive facet, K=0.82 for the Expressive Communication facet, K=0.76 for the Receptive Communication facet, K=0.44 for the Fine Motor facet and K=0.57 for the Gross Motor facet. These values indicate that the Bayley-III Screening Test is therefore not acceptable for clinical use, as excellent agreement (k≥0.75) in all facets would be necessary for this purpose. A new screening tool therefore had to be developed. The infant’s developmental scores from the BSID III were analysed to determine which facets of development were most severely affected, and therefore which facets should be included in a new screening tool. Gross motor function was demonstrated to be the area which was most severely affected, followed by cognitive function. A gross motor screening tool would therefore be suitable for use in this population, as no equipment would be necessary. Gross motor development is the most universally similar aspect of development, which is not completely dependent on cultural or socioeconomic factors which often have an influence on language and cognitive development. Item selection from the BSID III was undertaken to determine which items should be included in a brief screening tool. In each of the four age groups, item selection occurred as follows: Two items which discriminated the At-Risk, from Emerging and Competent groups (less than 20% in the At-Risk group, and 100% in the other groups) were selected. Two items, which discriminated between children in the ‘Emerging’ and ‘Competent’ categories on the BSID III were selected (0-5% of children who were At-Risk obtained credit, 30-50% of the Emerging group obtained credit, and 100% of the Competent group obtained credit). Lastly, two items were selected which discriminated the Competent group from the other two groups (100% or as high as possible in the Competent group, and 0% in the other groups). The new gross motor screening tool was assembled using the selected items, scoring was allocated, and it was tested against the scores obtained on the Gross Motor facet of the BSID III for the initial 112 infants. Agreement between the tools was analysed using Kappa, and refinements were made according to the discrepancies. This was done three times, until the Kappa value revealed excellent agreement between the tools (k = 0.87). A panel of experts was then invited to examine the new gross motor screening tool, and to comment on it, and further adjustments were made accordingly. Preliminary concurrent validity testing of the new gross motor screening tool was then carried out against the Gross Motor facet of the BSID III on 60 children, who were recruited from the Harriet Shezi Children’s Clinic at Chris Hani Baragwanath Hospital in Soweto. Statistical analysis revealed that the agreement between the BSID III and the new screening tool was excellent (k=0.85). The diagnostic properties of the new gross motor screening tool were as follows: sensitivity 97.4%, specificity 85.7%, positive predictive value 92.7%, and negative predictive value 94.7%. These values indicate that the statistical properties of the tool are excellent, and the tool will not be predisposed to underreferrals or over-referrals. Preliminary reliability testing was carried out on 15 children for test-retest/intrarater reliability and 15 children for interrater reliability. Interrater, test-retest and intrarater reliability were excellent (r=1, r=0.98, r=0.98 respectively). Further testing of reliablity and validity should be undertaken in order to establish these properties, and standardisation should also be carried out on healthy children. Given the need for an assessment tool of this nature in South Africa and other developing countries, and the statistical properties thus far, the tool may be used clinically for the purposes for which it was developed.

Background: Over 50% of HIV-infected children in South Africa have developmental delays. Early identification of affected children will lead to early intervention and favourable long-term outcome. Screening for developmental delay is not yet routine by many primary healthcare providers due to lack of locally available, rapid and sensitive screening tool s in busy Paediatric HIV clinics. A new screening tool was developed at the Red Cross War Memorial Children's Hospital (RCWMCH) for detecting moderate to severe global developmental delay among very young HIV infected children. The diagnostic accuracy and usefulness of the new tool was evaluated in this study. Objective: to validate the new RCWMCH developmental screening too l among HIV - infected South African children. Method: Forty-seven HIV-infected children in the age category 9-36 months attending the Infectious Disease Clinic (IDC) of the RCWMCH were screened using the new tool. Full developmental assessments of same children were performed using the Bayley Scale of Infant Development (BSID - III). Developmental Delay (global) was defined as composite scores 2 standard deviations below the mean in two or more developmental domains. Results: The sensitivity of the RCWMCH tool was 78.5%, specificity 54.6%, positive predictive value was 42.6%, and negative predictive value was 85. 7 %. Discussion: The RCWMCH screening tool was found to have sensitivity within the acceptable levels recommended for developmental screening tools. Its high negative predictive value will reduce unnecessary referrals for full developmental assessments in asymptomatic infants and toddlers. It is therefore recommended for screening for developmental delay among HIV-infected children from the age of 9 months to 3 years.

The work described here details the experimental progress toward an improved means of HIV-1 diagnosis and an explanation of the experimental approaches taken to advance a previously developed HIV-1 reverse transcriptase detection assay using RNA aptamers for protein capture. After characterization of the identity and function of the aptamer samples to be used, we first set about clarifying the nature of the assay and pinning down sources of variability inherent in the original Aptamer Antibody Sandwich Assay (AASA) such that through the course of this work we might bring the assay to a point of high reproducibility. In doing so, we devised a set of criteria for data analysis and filtration and established a process to examine whether modifications to the method resulted in measurable improvement. Two new methods were tested in the hope that they might later be extended to our ultimate project goal of distinguishing binding affinity variations among HIV-1 reverse transcriptase protein and its mutant variants. Both method modifications involved the addition of a fluorescently labeled Cy5 probe to the immobilized aptamer construct. The addition of a fluorescent label to each printed aptamer allowed for detection of aptamer presence in addition to protein binding, essentially serving as a simple internal control for aptamer-protein binding. After optimizing the AASA aptamer construct and experimental procedure, the AASA was extended to a multiplexed array format. Using four groups of aptamers selected against two HIV-1 RT variants (wild-type and mutant 3) we tested the hypothesis that immobilized anti-HIV-1 aptamers might be capable of binding HIV-1 RT variants and regardless of their selective target. The experiments described here are the first example of these aptamers being used in a multiplexed array format, and the results are not only a clear exemplification of the capacity of RNA aptamers for detection in this novel, immobilized assay format, but also an indicator of the utility and flexibility of RNA aptamer functionality. The promising results described in these preliminary studies are the starting block from which several interesting aptamer-protein interaction and drug-competition studies have begun. / text

The prevalence of female adults and adolescents living with diagnosed HIV infection continues to rise. Latina women in the United States (US) are not only disproportionately affected by human immunodeficiency virus (HIV) infection, but also underutilize HIV prevention services, such as HIV testing. Data are limited on the differences in HIV risk among Latinas by country of birth, and opportunities still exist to prevent transmission of HIV and reduce HIV-related disparities. This dissertation describes the risk behaviors, testing behaviors, and test results among women tested for HIV at public sites in Florida. Additionally, it compares these characteristics by HIV testing site type among pregnant women. Multivariable logistic regression was used to estimate the adjusted odds ratios (AOR) and associated 95% confidence intervals for the outcome variables of risk behaviors, previous testing, and positive HIV test results. Of the total 209,954 records, 184,037 were from women not currently pregnant, of which 87,569 (45.6%) were among non-Hispanic Blacks (NHBs), 47,926 (26.0%) non-Hispanic Whites (NHWs), and 41,117 (22.3%) Latinas. Women who reported previous HIV testing had decreased odds of being Latina compared to NHW women (AOR 0.90; 95% confidence interval [CI] 0.87, 0.94), and testing event results indicate that foreign-born Latina women were significantly less likely to report partner risk (AOR 0.42; 95% CI: 0.40-0.54) than US-born Latina women. Of the 24,863 records of pregnant women, 10,199 (41.1%) were among Latinas, 6,796 (27.4%) were among NHB, and 6,631 (26.7%) were among NHW. The testing records indicated that Latina and NHB women had decreased odds of reporting partner risk than NHW women (Latina: AOR 0.20; 95% CI: 0.14-0.28; and NHB: AOR 0.14; 95% CI: 0.10-0.21), and records of women tested in prisons/jails had higher odds of reporting previous HIV testing compared to prenatal care sites (AOR 1.86; 95% CI: 1.03-3.39). Reported risk behaviors varied by race/ethnicity and Latina country of origin. Knowledge of these differences can enhance current testing and prevention strategies for women, and aid in targeting HIV prevention messaging, program decision-making, and allocation of resources, corresponding to the central approach of High Impact Prevention and the National HIV/AIDS Strategy.