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published_or_final_version / Architecture / Master / Master of Architecture

Epidemiologists engage in the study of the distribution and determinants of health-related states or events in human populations. Eventually, they will apply that study to prevent and control problems and contingencies associated with the health of the population. Due to the spread of new pathogens and the emergence of new bio-terrorism threats, it has become imperative to develop new and expand existing techniques to equip public health providers with robust tools to predict and control health-related crises. In this dissertation, I explore the effects caused in the disease dynamics by the differences in individuals’ physiology and social/behavioral characteristics. Multiple computational and mathematical models were developed to quantify the effect of those factors on spatial and temporal variations of the disease epidemics. I developed statistical methods to measure the effects caused in the outbreak dynamics by the incorporation of heterogeneous demographics and social interactions to the individuals of the population. Specifically, I studied the relationship between demographics and the physiological characteristics of an individual when preparing for an infectious disease epidemic.

The possibilities of transmission of infectious synovitis were explored. Two types of tests, using mosquitoes as vectors, were employed. One type involved the feedings of mosquitoes on previously inoculated birds, then after a period of from zero to ninety-six hours refeeding the mosquitoes on assay birds. The second type of insect test comprised the feeding of mosquitoes on inoculated birds, then macerating and inoculating them into check birds at intervals of one to twenty-one days following feeding. Other experiments were conducted in which uninoculated birds were brought into close contact with inoculated chickens and their excrement. The observation of all tests indicated the absence of transmission of an infective titer of the infectious synovitis agent. These conclusions are drawn from tests using Aedes aegypti (Linn.) and Culex fatigans Wied., with methods and materials described. / Master of Science

Traditional Public Health decision-support can benefit from the Web and social media revolution. This dissertation presents approaches to mining social media benefiting public health epidemiology. Through discovery and analysis of trends in Influenza related blogs, a correlation to Centers for Disease Control and Prevention (CDC) influenza-like-illness patient reporting at sentinel health-care providers is verified. A second approach considers personal beliefs of vaccination in social media. A vaccine for human papillomavirus (HPV) was approved by the Food and Drug Administration in May 2006. The virus is present in nearly all cervical cancers and implicated in many throat and oral cancers. Results from automatic sentiment classification of HPV vaccination beliefs are presented which will enable more accurate prediction of the vaccine's population-level impact. Two epidemic models are introduced that embody the intimate social networks related to HPV transmission. Ultimately, aggregating these methodologies with epidemic and social network modeling facilitate effective development of strategies for targeted interventions.

Thesis (MCur)--Stellenbosch University, 2011. / ENGLISH ABSTRACT: The impact of infant feeding practices in the prevention of mother-to-childtransmission of HIV raised concerns in the field of health services. Breast feeding adds an additional 15-30% risk of HIV transmission to the infant; therefore, mothers who are HIV-positive are in need of information regarding safe infant feeding. A descriptive design for this particular study was applied with a primary quantitative approach. A convenient sample of sixty (n=60) participants between the ages of 15 – 37 were taken from subjects that enrolled in the prevention of mother-to-child transmission (PMTCT) programme in Onandjokwe district. The sample formed 85% of the target population (N=71). A structured questionnaire with closed and openended questions was used and completed by the researcher. Ethical approval for the study was obtained from the Ethics Committee at the Faculty of Health Sciences, University of Stellenbosch. Permission to conduct the research was obtained from the Ministry of Health and Social Services, Namibia, and the Onandjokwe district Hospital. A pilot study was conducted that constituted 25% of the sample. Validity and reliability was insured by the pilot study and the consultation of an expert in HIV research and an expert in nursing research. The presentation of results was mostly descriptive in nature by using frequency tables and a pie chart. The results showed that all participants (n=60/100%) were offered HIV counselling and testing during antenatal care. Mothers who were HIV positive knew that there is a possibility that the baby might be infected through breast milk. Furthermore, the study found that 70% (n=42) of participants used breast feeding exclusively, 20% (n=12) used replacement feeding and 10% (n=6) used mixed feeding practices. It was concluded that pregnant women and mothers known to be HIV-infected should be informed of the infant feeding practice recommended by the national or subnational authority to improve HIV-free survival of HIV-exposed infants. This includes information about the risks and benefits of various infant feeding options based on local assessments and guidance in selecting the most suitable option for their own situation. / AFRIKAANSE OPSOMMING: Die invloed van voedingspraktyke vir babas by die voorkoming van moeder-na-kindoordrag van die menslike immuungebrekvirus (MIV) het kommer op die gebied van gesondheidsdienste laat ontstaan. Borsvoeding dra ’n addisionele 15–30% risiko van MIV-oordrag tot die baba by en daarom benodig moeders wat MIV-positief is inligting ten opsigte van veilige voeding van hulle babas. 'n Beskrywende ontwerp vir hierdie besondere studie is gebruik tesame met 'n primêr kwantitatiewe benadering. 'n Gerieflikheidsteekproef van sestig (n=60) deelnemers tussen die ouderdomme 15–37 jaar is gekies uit persone wat ingeskryf het vir die voorkoming van moeder-na-kind-oordrag (VMNKO) program in Onandjokwe-distrik. Die steekproef het 85% van die teikenpopulasie (N=71) uitgemaak. 'n Gestruktureerde vraelys met geslote en oop vrae is gebruik en deur die navorser voltooi. Etiese goedkeuring vir die studie is verkry van die Etiese Kommitee van die Fakulteit Gesondheidswetenskappe, Universiteit Stellenbosch. Toestemming om die navorsing te doen, is verkry van die Ministerie van Gesondheid en Maatskaplike Dienste, Namibië, en die Onandjokwe Distrikshospitaal. 'n Loodsstudie is onderneem wat 25% van die steekproef behels het. Geldigheid en betroubaarheid is verseker deur die loodsstudie en oorlegpleging met 'n kundige op die gebied van MIV-navorsing en 'n kundige in verpleegnavorsing. Die aanbieding van resultate was meestal deskriptief van aard deur van frekwensietabelle en 'n sektordiagram gebruik te maak. Die resultate het getoon dat MIV-berading en -toetsing gedurende voorgeboortesorg aan alle deelnemers (n=60/100%) aangebied is. Moeders wat MIV-positief is, het geweet dat daar 'n moontlikheid bestaan dat die baba moontlik deur moedersmelk geïnfekteer kan word. Verder het die studie bevind dat 70% (n=42) van deelnemers uitsluitlik borsvoeding gebruik, 20% (n=12) gebruik ’n vervanging vir moedersmelk en 10% (n=6) gebruik gemengde voedingspraktyke. Daar is tot die slotsom gekom dat swanger vroue en moeders van wie bekend is dat hulle MIV-geïnfekteer is, ingelig behoort te word oor die babavoedingspraktyk aanbeveel deur die nasionale of subnasionale owerheid vir die verbetering van MIVvrye oorlewing van babas wat aan die MIV blootgestel is. Dit sluit in inligting oor die risiko’s en voordele van verskeie babavoedingsopsies gebaseer op plaaslike assesserings en leiding ten opsigte van die kies van die geskikste opsie vir hulle eie situasie.

With a growing concern of an infectious diseases spreading in a population, epidemiology is becoming more important for the future of public health. In the past epidemiologist used existing data of an outbreak to help them determine how an infectious disease might spread in the future. Now with computational models, they able to analysis data produced by these models to help with prevention and intervention plans. This paper looks at the design, implementation, and analysis of a computational model based on the interactions of the population between individuals. The design of the working contact model looks closely at the SEIR model used as the foundation and the two timelines of a disease. The implementation of the contact model is reviewed while looking closely at data structures. The analysis of the experiments provide evidence this contact model can be used to help epidemiologist study the spread of an infectious disease based on the contact rate of individuals.

Thesis (PhD)--Stellenbosch University, 2012. / Includes bibliography / ENGLISH ABSTRACT: Mycobacterium tuberculosis, the causative organism of tuberculosis (TB), is a major cause for mortality and morbidity world-wide with a death toll only second to HIV among infectious diseases. Drug resistance is widespread and cases of multiple drug resistant TB (MDR-TB) and extensively drug resistant TB (XDR-TB) have emerged in several countries. Drug treatment is problematic and new drugs are not developed rapidly enough to offset the rapid drug resistance mutation rate of M. tuberculosis. Simple and effective diagnostics are required to contain the spread of the disease as current routine diagnostics are not fulfilling this role. Additionally, current rapid TB diagnostics are out of reach to resource poor settings due to infrastructure, cost and skill requirements. Novel TB diagnostics are thus required that meet these requirements. Mycobacteriophages are phages that infect mycobacteria and could offer a viable and cost effective alternative rapid TB diagnostics. In this study, an affinity-tagged fluorescent reporter mycobacteriophage is described, which was engineered to act as a TB diagnostic. Its performance proved favourable and superior to current existing mycobacteriophage-based TB diagnostics. / AFRIKAANSE OPSOMMING: Mycobacterium tuberculosis, die organisme verantwoordelik vir tuberkulose (TB), is `n groot bron van mortaliteit en morbiditeit wêreldwyd en slegs HIV is verantwoordelik vir groter getalle sterftes as gevolg van n aansteeklike siekte. Middelweerstandigheid is algemeen en gevalle van meervoudigemiddelweerstandige tuberkulose (MDR-TB) en uiters weerstandige tuberkulose (XDR-TB) kom in verskeie lande voor. Antibiotika behandeling is problematies en nuwe anti-TB middels word nie vinnig genoeg ontwikkel om die antibiotika weerstandigheid mutasie spoed van M. tuberculosis te bekamp nie. Doeltreffende diagnostiese toetse word benodig om die verspreiding van die siekte te beheer en bestaande roetine diagnostiese toetse voldoen tans nie aan hierdie vereiste nie. Behalwe hiervoor, is huidige vinnige TB diagnostiese toetse buite bereik van arm instansies weens vereistes aan infrastruktuur, meegaande kostes en werknemervaardigheid. Nuwe TB diagnostiese toetse is dus nodig om aan hierdie vereistes te voldoen. Mikobacteriofaage is fage wat mikobacteria infekteer en kan moontlik 'n lewensvatbare en koste-effektiewe alternatief bied vir vinnige TB diagnostiese toetse. In hierdie studie word 'n affiniteitgekoppelde fluoreserende rapporteringsmikobakteriofaag beskryf wat ontwerp is om op te tree as `n nuwe vinnige TB diagnostiese toets. Die werking hiervan vertoon gunstige en beter resultate as die huidige, mikobacteriofaaggebaseerde TB-diagnostiese toetse.

South Africa‘s high prevalence of HIV/AIDS coupled with a high crime rate and incidence of sexual violence necessitated the enquiry and study into the role of criminal law to address the wilful transmission of HIV.1 This study shows that criminal law can be used to punish offenders for wrongdoing and therefore finds application in the wilful transmission of HIV.2 The study distinguishes the dividing line between the justifiable use of criminal law and where use of the criminal law becomes discriminatory in nature and counterproductive to public health measures. The United Nations (hereinafter referred to as the UN) laid down guiding principles for countries to adopt when using the criminal law and stated that countries should use existing criminal law offences to prosecute intentional HIV infections.3 The South African Law Commission (hereinafter referred to as the SALC) endorses this approach. South Africa‘s use of the criminal law, in response to harmful HIV behaviour is in line with the UN recommendations as it uses the existing common law offences to prosecute the wilful transmission of HIV, namely murder, attempted murder and assault. Drawing from the writer‘s comparative study in Chapter Six below, South Africa, members of the Zimbabwean parliament, Canada, as well as the American Bar Association have all concluded that the use of specific HIV-related legislation creates some a form of stigmatization towards people living with HIV and is therefore not warranted. This study shows that criminal law has a role to play in the wilful transmission of HIV; however the creation of HIV specific legislation is not recommended and existing criminal law offences should be used to address harmful HIV related behaviour. Such an approach is in line with the guiding principles laid down by the UN and SALC.

Thesis (MPH.) -- University of Limpopo, 2021 / Introduction: HIV/AIDS remains a disease of public health importance and mother-to-child transmission (MTCT) is one of the major problems. Sub-Saharan Africa is the most severely affected region, accounting for more than 90 percent of paediatric HIV infections. Most of these infections occurred during pregnancy, delivery or breastfeeding making the prevention of mother-to-child transmission (PMTCT) a public health priority. Over the last few years, efforts have been made in Sub-Saharan countries to improve PMTCT and the success of prevention of mother‐to‐child transmission of HIV (PMTCT) is dependent upon high retention of mother‐infant pairs within the PMTCT cascade. Assessing the risk factors for MTCT will help to decrease child morbidity and mortality and strengthen PMTCT programs as there is dearth of evidence regarding factors determining MTCT HIV infection to infants born to HIV positive mothers. The purpose of this study was to investigate the determinants for the human Immunodeficiency Virus positivity rates in the Greater Letaba Municipality. The study objectives were to describe the demographic characteristics of mothers and babies who tested polymerase chain reaction test (PCR)-positive in the Greater Letaba Municipality during the two-year period from 2015 to 2016, in order to determine maternal and neonatal factors associated with high positive PCR; and to determine health system-related factors associated with a high positive PCR result. Methodology The current study followed a quantitative approach in which convenient and purposive sampling was used, focusing on records of infants born from HIV-positive women in all clinics at Greater Letaba Municipality were reviewed. All records of infants who were tested for HIV and the PCR results were positive from birth up to 12 months of age were retrospectively reviewed and for the health care workers, all nurses working as managers of a clinic were interviewed. The Statistical Package for the Social Sciences (SPSS) version 23 computer software and Stata 15 was used. for comparison of categorical variables was done using a Chi-Squared test, whereas continuous variables were compared using a t-test and P-value of <0.05 was considered significant. To determine maternal and neonatal factors associated with high positive PCR, Factor analysis was used with rotated factor loadings done using the Varimax method. Results: A total of 107 records were retrieved and audited. Fisher’s exact test was used to determine the relationship between selected variables, where p<0.05 was set as level of significance. The findings reveal that the number of infants exposed to HIV during pregnancy has steadily increased. The current study further indicates that health system factors such as unskilled or untrained NIM-ART nurses in the facilities is a contributory factor to infant’s positivity rate in Greater Letaba hospital. Equal proportions of both male and female babies were found to be PCR positive at 6 weeks. The study further revealed that the highest proportion of the mothers who gave birth to PCR positive babies for the reporting period were married mothers, in the age group 25-29 years (46.1%). The second largest proportion of mothers who gave birth to PCR positive babies were single mothers in the age group 25-29 years (38.4%). The results show that high PCR positivity can be attributed to about 5 main Factors namely: maternal antenatal history (22% contribution to total variance), maternal HIV care history (18% contribution to total variance), measures of adherence to treatment (17% contribution to total variance), maternal exposure to HIV (14% contribution to total variance) and lastly the ART regimen (12% contribution to total variance). Conclusion: The study findings revealed that there is still vertical transmission of HIV to infants and the prevalence of HIV among infants born from seropositive mothers despite the availability of the latest Prevention of Mother to Child Transmission (PMTCT) Guidelines in all health care facilities. Even though transmission is reduced to the meaningful number (< 5%), there are still appropriate measures that should be taken to reduce the transmission of HIV from mothers to infants. The delayed diagnosis, adherence to ART by mothers, infant ARV prophylaxis at birth and feeding practices contributed the vertical transmission of HIV to infants. Strengthening of the PMTCT of HIV programme, increasing antenatal HIV screening and linking it to care and treatment of HIV positive mothers to obtain zero infant HIV prevalence in the region. Infant prophylaxis and maternal PMTCT interventions should be provided to all exposed infants and mothers based on the guidelines by the health institutions. Nurse-initiated management of antiretroviral treatment (NIM-ART) training of professional nurses is being offered by the Department of Health in South Africa, but it does not yield positive results as far as the PMTCT is concerned. This may be due to shortage of staff, especially trained professional nurses (PN), as well as the workload. Key concepts: Infant and Human immune deficiency virus