<p>The main purpose of the study was to assess and explore the knowledge of HIV/AIDS among secondary learners in rural Bergville district of KwaZulu-Natal. A stratified random sample of 100&nbsp / learners was selected from two secondary schools in the area. Data was collected using a questionnaire and interviews were scheduled with the teachers from the selected schools. The&nbsp / questionnaire was administered to a sample of 54 learners from school A and 46 from school B. The mean age was 16, with age range from 13-20. The participants were enrolled for grade&nbsp / 8-12 in both schools. Both qualitative and quantitative data on learners‟ knowledge and perception about HIV/AIDS, condom use and sexual issues including their attitudes towards people living with HIV/AIDS were collected in the questionnaire. Chi-square test was used for statistics purpose to test if the HIV knowledge of learners were associated with gender, culture and&nbsp / religion. Qualitative interviews with 9 teachers from both schools were conducted. The main purpose of the interviews was to investigate the management of HIV/AIDS in public schools in rural&nbsp / areas. Furthermore, to assess the learner‟s attitude towards HIV/AIDS education provided in schools. The results showed that the learners in Bergville district were more knowledgeable of&nbsp / HIV/AIDS through HIV/AIDS education in schools that had limited effect on gender, culture and religion. Quantitative findings presented, indicated no significant differences between those&nbsp / learners attending church and cultural activities that offer&nbsp / HIV/AIDS awareness programmes and those who do not with regard to the knowledge of HIV/AIDS. However, culture stood out to be associated with one item on the knowledge of whether school children can get HIV/AIDS (p-value = 0.04). On average, the level of knowledge of HIV/AIDS between female and male learners was similar. The major findings on both quantitative and qualitative findings confirmed that learners‟ knowledge levels were very high for modes of transmission and prevention of HIV/AIDS. Despite this knowledge, poor&nbsp / behavioural change among learners is a major setback thus increasing high risk of contracting HIV. Adequate knowledge about issues of cure, HIV testing and treatment was of concern in the findings in this study. Furthermore, data from qualitative interviews with the teachers highlighted the lack of multisectoral response to HIV/AIDS in Bergville rural communities which thus&nbsp / compromise the effectiveness in management of HIV/AIDS in schools. In summary, the study revealed some of the challenges faced by teachers and learners in regard to HIV/AIDS education.</p>

<p>A qualitative descriptive study approach was used to gather the required information. The sample for this study was drawn from an existing group of volunteers who participated in the vaccine trial at Mbeya Medical Research Centre in 2006-2007. A purposive sampling method was used to select respondents because they had had experience of being participants in a HIV vaccine trial. Twenty audio recorded in-depth interviews were conducted. The interviews were conducted at the clinic during their routine follow up visits. An open ended interview guideline was used to guide the discussion to elicit the required information from the respondents. The data was transcribed, translated and then analyzed by both content and thematic approach. Ethical procedures were observed, including getting permission from the local ethical committee in Mbeya region and participants were given an informed consent form to read and sign before starting the interview.</p>

<p>The global impact of the converging dual epidemics of tuberculosis (TB) and human immunodeficiency virus (HIV) is one of the major public health challenges of our time, because in many countries, human immunodeficiency virus (HIV) and mycobacterium tuberculosis (TB) are among the leading causes of morbidity and mortality. It is found that infection with HIV increases the risk of reactivating latent TB infection, and HIV-infected individuals who acquire new TB infections have high rates of disease progression. Research has shown that these two diseases are enormous public health burden, and unfortunately, not much has been done in terms of modeling the dynamics of HIV-TB co-infection at a population level. In this thesis, we study these models and design and analyze robust numerical methods to solve them. To proceed in this direction, first we study the sub-models and then the full model. The first sub-model describes the transmission dynamics of HIV that accounts for behavior change. The impact of HIV educational campaigns is also studied. Further, we explore the effects of behavior change and different responses of individuals to educational campaigns in a situation where individuals may not react immediately to these campaigns. This is done by considering a distributed time delay in the HIV sub-model. This leads to Hopf bifurcations around the endemic equilibria of the model. These bifurcations correspond to the existence of periodic solutions that oscillate around the equilibria at given thresholds. Further, we show how the delay can result in more HIV infections causing more increase in the HIV prevalence. Part of this study is then extended to study a co-infection model of HIV-TB. A thorough bifurcation analysis is carried out for this model. Robust numerical methods are then designed and analyzed for these models.&nbsp / Comparative numerical results are also provided for each model.</p>

<p>Eligibility for antiretroviral therapy (ART) in HIV-infected patients is defined either by a cluster of differentiation antigen 4 (CD4) count of less than 200cells/mm3 or clinical diagnosis of WHO stage III and IV. Therefore, the decision to start ART becomes difficult when CD4 cell count is not available. With limited laboratory infrastructure, the decision to start ART is usually made based on clinical symptoms leading to late commencement of ART. This calls for alternative criteria to see if nail discoloration (ND) correlates with low CD4 count among untreated HIV infected patients. This will serve as a complementary screening tool for identifying asymptomatic ARV naive HIV patients with a CD4 cell count of less than 200cells/mm3 which signifies&nbsp / severe immunosuppression. Study Design and Setting: This was a quantitative cross-sectional descriptive and analytical study involving adult ART na&iuml / ve HIV infected patients in WHO stage I and II. Systematic sampling was used to select the participants from all adult ART na&iuml / ve HIV infected patients attending APIN clinic, located at the Jos University Teaching Hospital (JUTH), Jos, Nigeria. Data Collection: Face-to-face interviews, physical examination and relevant laboratory investigations with selected participants were conducted using a questionnaire guide. Questions on socio-demographic characteristics, clinical data, general physical examinations including finger nail examination and photographing with subsequent laboratory investigations including CD4 count and western blot were employed. Data Analysis: Variables were categorized and data analyzed using descriptive statistics including the frequency, percentage frequency / mean and standard deviation of continuous variables. Association between CD4 count of &le / 200cells/mm3 and ND was tested using the chisquare test with an alpha level of 0.05. Prevalence of ND, sensitivity, specificity, positive predictive and negative predictive values and accuracy of the screening test of ND was calculated. Results: 394 patients had their fingernails photographed and assessed. It was shown that distal banded and grey nails were the common types of ND seen with a prevalence of 38%. There was an association between CD4 count &le / 200cells/mm3 and ND (p&lt / 0.0001). CD4 count &le / 200cells/mm3 was a risk factor for developing ND (RR=2.3[1.8-3.6]). The association has a sensitivity of 78%, specificity of 55%, positive predictive value of 50%, and negative predictive value of 80% and accuracy of test 63%. Conclusion: With a significant association (p&lt / 0.0001) and a sensitivity of 78%, ND can be a useful clinical indicator of immune dysfunction mediated by HIV among patients in WHO stage I or II. ND can either be a clinical sign or a symptom in HIV patients with a CD4 of &le / 200cells/mm3 as seen in the study as the specificity and sensitivity of ND compared favourably with other WHO stage III diagnosis. Recommendations: Nail discoloration should complement CD4 count as an additional staging sign to help identify patients likely to benefit from ART especially in resource-limited settings. Finally, all patients with grey or distal banded should be on co-trimoxaxole prophylaxis in line with WHO /national guideline on the use of co-trimoxaxole for all HIV positive patients with a CD4 cell count of &le / 350cells/mm3.</p>

African-American and Latino men who have sex with men (MSM) bear a disproportionately large burden of the Human Immunodefiency Virus (HIV) epidemic in the United States. To further enhance HIV prevention efforts among men of color, a survey was conducted within New York City’s house ball community; a community largely comprised of racial and ethnic minority persons. Time-space sampling was adapted to recruit participants for the survey from venues frequented by members of the house ball community. Using logistic regression analysis, this study examined the effects of perceived stigma, enacted stigma, sense of community and self-esteem on unprotected anal intercourse (UAI) among a sub-sample of men in the survey. Both perceived and enacted stigma had a modest direct effect on engaging in UAI. The direct effect on UAI was significant even after controlling for covariates in the model. The magnitude of the effect on UAI did not vary by race/ethnicity or sexual identity. In addition, perceived and enacted stigma correlated negatively to both sense of community and self-esteem scores. Although sense of community did not buffer the effect of perceived or enacted stigma on UAI, both sense of community and self-esteem were protective against engaging in UAI. However, while the direct effect of sense of community on UAI remained after controlling for covariates in the model, the effect self-esteem had on UAI diminished after adding variables to the model. Further, self-esteem was negatively correlated with both perceived and enacted stigma, but it did not mediate perceived and enacted stigma’s effect on UAI. Implications for HIV prevention strategies given these findings are discussed. Implications include developing multilevel interventions, including structural interventions, to reduce the stigma that is perceived and experienced by men of color as well as building stronger communities for African American and Latino MSM.

Development of a suitable animal model of AIDS is much needed in AIDS research to study infection and pathogenesis as well as to evaluate methods of prevention and treatment of HIV infection. Small animals such as rodents are attractive candidates for AIDS research due to the availability of various inbred and genetically engineered strains, extensive knowledge or their immune system, especially in mice, and the relative ease of breeding and maintaining animal colonies. Transgenic small animal models carrying entire HIV genome or selected genes have been instrumental to understand functions of HIV genes in vivo and their role in HIV pathogenesis. The type of cells in which HIV genes are expressed seems to be an import prerequisite for the study of HIV gene functions in transgenic mice. Mice constitutively expressing the entire HIV-1 genome or HIV-1 nef gene in CD4 + T cells and in the cells of macrophage/dendritic lineage develop an AIDS-like disease very similar to AIDS disease in humans. Similarly, expression of Nef in adult mice, using inducible system, results in the AIDS-like disease. This disease is characterized by thymic atrophy, impaired thymocyte maturation, loss of CD4+ T cells, increased activation and turnover of T cells, which can occur in the absence of lymphypenia, and non-lymphoid organ disease involving the lungs and kidneys. Susceptibility of adult mice to the pathological effects of Nef suggests that the AIDS-like disease in the constitutively expressing Nef Tg mice is not due to developmental defects caused by early expression of Nef. This model highlights the important role of Nef in HIV-1 pathogenesis. The high similarity in the disease in these Tg mice with human AIDS strongly suggest that these mice are a relevant model to study AIDS. This study further evidence that mouse cells can support functions of Nef and these Tg mice represent a unique model to study Nef functions in vivo in the context of the primary immune system. Moreover, the inducible Nef Tg model has given us the ability to control the level and time of expression of Nef which was impossible to do in the previously reported constitutive Nef Tg mouse models. These mice will be useful to study immune reconstitution since Nef expression can be turned off after withdrawal from dox.

<p>A qualitative descriptive study approach was used to gather the required information. The sample for this study was drawn from an existing group of volunteers who participated in the vaccine trial at Mbeya Medical Research Centre in 2006-2007. A purposive sampling method was used to select respondents because they had had experience of being participants in a HIV vaccine trial. Twenty audio recorded in-depth interviews were conducted. The interviews were conducted at the clinic during their routine follow up visits. An open ended interview guideline was used to guide the discussion to elicit the required information from the respondents. The data was transcribed, translated and then analyzed by both content and thematic approach. Ethical procedures were observed, including getting permission from the local ethical committee in Mbeya region and participants were given an informed consent form to read and sign before starting the interview.</p>

<p>Antiretroviral regimens have side effects that can threaten adherence by patients resulting in evolution of viral resistance due to suboptimal drug levels. Studies have shown that drug adherence of at least 80% can result in viral load suppression. There is no literature on the association between the level of adherence to antiretroviral therapy and the degree of virological suppression in Namibia. The aim of the present study was to determine the therapeutic and virological outcomes in HIV/AIDS patients at 6 and 12 months after initiation of highly-active antiretroviral therapy (HAART) in an urban population in Namibia. The distribution of viral load results showed a low uptake (35%) of virological monitoring at 6 month time point and even lower (12%) at 12 months. A conservative viral load threshold for virological response is required in the Namibian setting. The current adherence level of &gt / 80% encourage increased ARV therapy rollout. Poor virological outcome was associated with self-reported adherence.</p>

<p>The global impact of the converging dual epidemics of tuberculosis (TB) and human immunodeficiency virus (HIV) is one of the major public health challenges of our time, because in many countries, human immunodeficiency virus (HIV) and mycobacterium tuberculosis (TB) are among the leading causes of morbidity and mortality. It is found that infection with HIV increases the risk of reactivating latent TB infection, and HIV-infected individuals who acquire new TB infections have high rates of disease progression. Research has shown that these two diseases are enormous public health burden, and unfortunately, not much has been done in terms of modeling the dynamics of HIV-TB co-infection at a population level. In this thesis, we study these models and design and analyze robust numerical methods to solve them. To proceed in this direction, first we study the sub-models and then the full model. The first sub-model describes the transmission dynamics of HIV that accounts for behavior change. The impact of HIV educational campaigns is also studied. Further, we explore the effects of behavior change and different responses of individuals to educational campaigns in a situation where individuals may not react immediately to these campaigns. This is done by considering a distributed time delay in the HIV sub-model. This leads to Hopf bifurcations around the endemic equilibria of the model. These bifurcations correspond to the existence of periodic solutions that oscillate around the equilibria at given thresholds. Further, we show how the delay can result in more HIV infections causing more increase in the HIV prevalence. Part of this study is then extended to study a co-infection model of HIV-TB. A thorough bifurcation analysis is carried out for this model. Robust numerical methods are then designed and analyzed for these models.&nbsp / Comparative numerical results are also provided for each model.</p>

There is a growing interest in the dynamics of the co-infection of these two diseases. In this thesis, firstly we focus on studying the effect of a distributed delay representing the incubation period for the malaria parasite in the mosquito vector to possibly reduce the initial transmission and prevalence of malaria. This model can be regarded as a generalization of SEI models (with a class for the latently infected mosquitoes) and SI models with a discrete delay for the incubation period in mosquitoes. We study the possibility of occurrence of backward bifurcation. We then extend these ideas to study a full model of HIV and malaria co-infection. To get further inside into the dynamics of the model, we use the geometric singular perturbation theory to couple the fast and slow models from the full model. Finally, since the governing models are very complex, they cannot be solved analytically and hence we develop and analyze a special class of numerical methods to solve them.