Dissertations / Theses on the topic 'AIDS (Disease) Cameroon Epidemiology'

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Cryptococcal meningitis (CM), caused by an encapsulated yeast is a leading cause of AIDS related opportunistic infection in adults in sub-Saharan Africa and a major driver of mortality, second to tuberculosis. We aimed at optimising the management of AIDS-related cryptococcal meningitis in Cameroon through interventional studies. As such, we designed and performed three studies on the role of cryptococcal antigen (CrAg) in CM diagnosis, contributed in a major phase III non-inferiority clinical trial for inductive treatment of CM in the African setting and analysed the trial participants’ tolerability of the antifungals used in the trial. We also contributed in a review on the long-term prognosis of CM and finally in an advocacy paper for CM to be recognised as a neglected tropical disease. In Cameroon, serum CrAg detection, a major risk factor for incident CM in AIDS patient is prevalent in 7.5% of patients initiating antiretroviral therapy (ART) at less than 100 CD4 cells/μL, of whom 45% have cerebrospinal fluid (CSF) evidence of asymptomatic CM. The new Biosynex CryptoPS test for CrAg detection is comparable to the IMMY lateral flow assay test and shows promise for correctly classifying patients with high serum CrAg titre, a predictor of confirmed CM. Post CrAg screening, enhanced adherence to ART and to fluconazole-based pre-emptive therapy to CrAg positive patients who present with no CM is effective in preventing incident CM within the first year of ART. In HIV patients presenting with symptoms of central nervous system disease, compared to Indian ink staining and/or culture of CSF, serum CrAg detection is highly presumptive of CM and CSF CrAg detection is diagnostic of first episode of CM. In African patients with confirmed CM, inductive therapy based on oral fluconazole-flucytosine combination or seven-day amphotericin B-flucytosine combination are as effective and more tolerated than standard fourteen-day amphotericin B-flucytosine combination. In spite advances in HIV care, mortality due to CM remains unacceptably high warranting CM to be recognised as a neglected tropical disease for which targeted resources need to be allocated to reduce HIV-related mortality. Overall, in Cameroon, putting in place of local pragmatic algorithms based on the availability of simple but highly performant diagnostic tools and sustainable recommended treatment are indispensable to decrease AIDS-associated CM-related morbidity and mortality

This study endeavoured to explore and describe the experiences of social workers in their intervention with HIV and AIDS clients within the Department of Clinical Services of the Ministry of Health in Botswana. The researcher undertook a qualitative research study, using an exploratory, descriptive and contextual design to explore these experiences as perceived by the social workers. The method of data collection included semi-structured face-to-face interviews, as this was deemed most appropriate to the nature of the study. Data analysis was undertaken according to the outline of Tesch (1990), as stated in Creswell (1994:155). The findings were reported as themes, sub-themes and categories emanating from the data-analysis process. In ensuring the trustworthiness of the findings, the researcher adhered to Guba’s (1981) model (in Krefting, 1991:251). The research findings were subjected to a literature control, and culminated in the compiling of the research report. The research findings centred around the following five themes: · experiences of intervention with HIV and AIDS clients; · challenges in HIV and AIDS intervention; · measures to alleviate challenges of HIV and AIDS intervention; · intervention strategies utilised by social workers; and · suggestions and advice to new social workers. The recommendations resulting from this research project proposed inter alia that social workers need to be trained in specific and specialised areas related to HIV and AIDS intervention in the health setting, and that the support structures and a holistic multidisciplinary service delivery approach need to be put in place to assist social workers to be able to meet the needs of the clients as well as their own needs. Key Words: participants, clients/patient, qualitative, HIV and AIDS, experiences, intervention, strategies.

Thesis (MSc)--University of Stellenbosch, 2007.
ENGLISH ABSTRACT: While research and population surveys in HIV/AIDS are well established in developed countries, Sub-Saharan Africa is still experiencing scarce HIV/AIDS information. Hence it depends on results obtained from models. Due to this dependence, it is important to understand the strengths and limitations of these models very well. In this study, a simple mathematical model is formulated and then extended to incorporate various features such as stages of HIV development, time delay in AIDS death occurrence, and risk groups. The analysis is neither purely mathematical nor does it concentrate on data but it is rather an exploratory approach, in which both mathematical methods and numerical simulations are used. It was found that the presence of stages leads to higher prevalence levels in a short term with an implication that the primary stage is the driver of the disease. Furthermore, it was found that time delay changed the mortality curves considerably, but it had less effect on the proportion of infectives. It was also shown that the characteristic behaviour of curves valid for most epidemics, namely that there is an initial increase, then a peak, and then a decrease occurs as a function of time, is possible in HIV only if low risk groups are present. It is concluded that reasonable or quality predictions from mathematical models are expected to require the inclusion of stages, risk groups, time delay, and other related properties with reasonable parameter values.
AFRIKAANSE OPSOMMING: Terwyl navorsing en bevolkingsopnames oor MIV/VIGS in ontwikkelde lande goed gevestig is, is daar in Afrika suid van die Sahara slegs beperkte inligting oor MIV/VIGS beskikbaar. Derhalwe moet daar van modelle gebruik gemaak word. Dit is weens hierdie feit noodsaaklik om die moontlikhede en beperkings van modelle goed te verstaan. In hierdie werk word ´n eenvoudige model voorgelˆe en dit word dan uitgebrei deur insluiting van aspekte soos stadiums van MIV outwikkeling, tydvertraging by VIGS-sterftes en risikogroepe in bevolkings. Die analise is beklemtoon nie die wiskundage vorme nie en ook nie die data nie. Dit is eerder ´n verkennende studie waarin beide wiskundige metodes en numeriese simula˙sie behandel word. Daar is bevind dat insluiting van stadiums op korttermyn tot ho¨er voorkoms vlakke aanleiding gee. Die gevolgtrekking is dat die primˆere stadium die siekte dryf. Verder is gevind dat die insluiting van tydvestraging wel die kurwe van sterfbegevalle sterk be¨ınvloed, maar dit het min invloed op die verhouding van aangestekte persone. Daar word getoon dat die kenmerkende gedrag van die meeste epidemi¨e, naamlik `n aanvanklike styging, `n piek en dan `n afname, in die geval van VIGS slegs voorkom as die bevolking dele bevat met lae risiko. Die algehele gevolgtrekking word gemaak dat vir goeie vooruitskattings met sinvolle parameters, op grond van wiskundige modelle, die insluiting van stadiums, risikogroepe en vertragings benodig word.

The first two official AIDS cases were diagnosed in South Africa in 1982. During the same period of the 1980s, the black/African population was experiencing an accelerated fertility decline, following a period of accelerated mortality decline. Demographers invoked the demographic transition theory to explain the observed mortality and fertility decline. According to the demographic transition theory, mortality and fertility rates would continue declining to low, post transitional levels with increasing modernization. The relatively higher prevalence of HIV/AIDS estimated among black/African South Africans is expected to alter their demographic transition. This research investigated the impact of HIV/AIDS on the demographic transition of black/Africans by 2021.

The Australian HIV Observational Database (AHOD) is a collaboration of hospitals, sexual health clinics and specialist general practices throughout Australia, established in April 1999. Core data variables collected include demographic data, immunological and virological markers, AIDS diagnosis, antiretroviral and prophylactic treatment and cause of death. The first electronic data transfer occurred in September 1999 followed by six monthly data transfers thereafter. All analyses included in this thesis are based on patients recruited to AHOD by March 2004. By March 2004, 2329 patients had been recruited to AHOD from 27 sites throughout Australia. Of these, 352 (15%) patients were recruited from non-metropolitan clinics. The majority of patients were male (94%), and infected with HIV through male homosexual contact (73%). Almost 90% of AHOD patients are antiretroviral treatment experience, and the majority of patients are receiving triple therapy as mandated by standard of care guidelines in Australia. Antiretroviral treatment use has changed in Australia reflecting changes in the availability of new treatment strategies and agents. The crude mortality rate was 1.58 per 100 person years, and of the 105 deaths, more than half died from HIV-unrelated deaths. The prevalence of HBV and HCV in AHOD was 4.8% and 10.9%, respectively. HIV disease progression in the era of highly active antiretroviral treatment (HAART) among AHOD patients is consistent with what has been reported in developed countries. Common factors associated with HIV disease progression were low CD4 cell count, high viral load and prior treatment with mono or double therapy at the time of commencing HAART. This was demonstrated in AHOD in terms of long-term CD4 cell response, the rate of changing combination antiretroviral therapy and factors predicting death. HBV and HCV coinfection is also relatively common in AHOD, similar to other developed country cohorts. Coinfection does not appear to be serious impediments to the treatment of HIV infected patients. However, HIV disease outcome following HAART does appear to be adversely affected by HIV/HCV coinfection but not in terms of HIV/HBV coinfection. Patients attending non-metropolitan sites were found to be similar to those attending metropolitan sites in terms of both immunological response and survival.

The aim of this study was to establish a new understanding of the epidemiology of HIV/AIDS at the municipal level, but at the same time upholding the anonymity of the HIV infected and AIDS sufferers. Innovative research techniques such as the use of GIS (geographic information systems) as a research tool contributed to disclosing the patterns of the HIV pandemic in the Nelson Mandela Metropole that were not obvious or visible before. GIS involved geographic maps that detect the spatial relationship between HIV prevalence rates and vectors that drive the pandemic.

Thesis (MBA)--Stellenbosch University, 2004.
ENGLISH ABSTRACT: HIV/AIDS is one of the biggest challenges faced by many countries in this century. The rate of infection is rapidly increasing and more and more people are getting ill and dying from AIDS. Of all the people living with AIDS in the world, seven out of ten live in Sub-Saharan Africa. Namibia is one of the top five most HIV/AIDS affected countries in the world. There is therefore no question about the urgent need to accelerate actions to reduce prevalence, expand care and support and extend access to treatment. AIDS is eroding decades of progress made in extending life expectancy; thus hundreds of adults are dying young or in early middle age. The national strategic plan (2004) on HIV/AIDS indicated that the average life expectancy in Namibia is now 42 years, when it could have been 60 without AIDS. A 2003 study on the impact of HIV/AIDS on Windhoek indicated that the antenatal HIV/AIDS prevalence rate in Windhoek for 2002 was 27%, while the national prevalence rate was estimated at 22.3%. The prevalence rate for Windhoek is expected to reach its peak at 38% during 2005. Even though HIV/AIDS will have a diminishing effect on population growth, Windhoek's population is expected to continue growing, particular as a result of inward migration, but at a slower pace. Similarly, HIV/AIDS will have an abating effect on GDP growth as the virus will mainly affect the economic active and available labour force of the population and result in increased labour costs and skilled labour shortages. The impact on the informal sector is potentially more damaging than on the formal economic sector, as the majority of micro- enterprises and informal businesses are build around one individual. As the breadwinner dies, household income and expenditures levels deteriorate and increase poverty levels, because households within the city are very dependent on family structures to support their income levels. Informal settlements are also more volatile to HIV transmission and the majority of HIV infected individuals are likely to be found within these areas as the populations is poorer, crowded, has fewer social services facilities and is more likely migratory compared to those in affluent formal settlements. Considering that the incubation period of HIV/AIDS from infection to death takes about ten years, the real impact of current HIV infections in Windhoek will only be experienced during 2010. Health services will have to attend to a greater demand for curative services as well as to social care and support programs. Social welfare programmes will need to find ways of caring for a large population of HIV/AIDS orphans. Municipalities can playa critically important role in addressing HIV/AIDS at a local level as they are at the interface of community and government. They are ideally placed to playa coordinating and facilitating role that is needed to make sure that partnerships are built to bring prevention and care programmes to every community affected by AIDS. Therefore, in order to succeed in confronting HIV/AIDS, it is important to work closely with all levels of government as well as working with local partners in civil society that are fighting HIV/AIDS at the community level. By taking action against HIV/AIDS, municipalities are securing the future of their towns and communities.
AFRIKAANSE OPSOMMING: MIV/VIGS is een van die grootste uitdagings wat baie lande hierdie eeu in die gesig staar. Die koers van infeksie is vinnig aan die toeneem en al hoe meer mense word siek en sterf as gevolg van VIGS. Van al die mense wat met VIGS lewe in die wêreld, bly sewe uit tien in sub-Sahara Afrika. Namibië is een van die vyf mees MIV/VIGS geaffekteerde lande in die wêreld. Derhalwe is daar geen twyfel rakende die noodsaaklikheid om daadwerklike aksies te bewerkstellig om die voorkoms te verminder, sorg en ondersteuning te verhoog en toegang na behandeling uit te brei. VIGS vernietig dekades van groei behaal in die verlenging van lewensverwagting; dus sterf honderde volwassenes vroeg of gedurende hul middeljare. Die nasionale strategiese plan (2004) rakende MIV/VIGS toon dat die gemiddelde lewensverwagting in Namibië huidiglik 42 jaar is instede van 60 sonder VIGS. 'n Studie onderneem gedurende 2003, rakende die effek van MIV/VIGS in Windhoek, dui aan dat die voorgeboorte MIV/VIGS voorkoms koers 27% vir 2002 was, terwyl die nasionale voorkoms koers slegs 22.3% was. Daar word verwag dat die voorkoms koers vir Windhoek sy maksimum van 38% sal bereik gedurende 2005. Alhoewel MIV/VIGS 'n negatiewe effek op bevolkingsgroei groei gaan het, sal Windhoek se inwoners getalle steeds groei, alhoewel teen 'n stadiger koers, as gevolg van inwaartse migrasie. Terselfdertyd, gaan MIV/VIGS 'n verminderde effek het op die groei van die Bruto Binnelandse Produk (BBP), omdat die virus hoofsaaklik die ekonomiese aktiewe en beskikbare arbeidsmag van die bevolking affekteer wat as gevolg hiervan 'n verhoging in arbeidskoste en tekort aan geskoolde arbeid het. Die effek op die informele sektore is potensieel meer skadelik as op die formele ekonomiese faktore, aangesien die meeste klein en informele besighede rondom een persoon gebou is. lndien die broodwinner sterf, versleg die vlakke van huishoudelike inkomste en uitgawes wat lei tot verhoogde armoede, omdat huishoudings in die stad baie afhanklik is op familie strukture om hulle inkomste te ondersteun. Informele vestigings is meer kwesbaar in die oordrag van MIV en die meerderheid van die MIV geïnfekteerde individue word gewoonlik in hierdie areas aangetref omdat die bevolking armer is, meer persone huisves, minder welsyn dienste fasiliteite het en meer swerwend is in vergelyking met die meer welgestelde formele vestigings. As in ag geneem word dat die ontkiemings periode van MIV/VIGS vanaf infeksie tot en met sterfte omtrent tien jaar neem, sal die werklike effek van die huidige VIGS besmettings in Windhoek slegs ervaar word gedurende 2010. Gesondheidsdienste sal moet aandag skenk aan 'n groter aanvraag vir geneeslike dienste sowel as sosiale sorg en ondersteunings programme. Gemeenskaplike welsyn programme sal maniere moet vind om vir 'n groot populasie van MIV/VIGS weeskinders te sorg. Munisipaliteite kan 'n belangrike rol speel in die aanspreek van die MIV/VIGS epidemie op 'n plaaslike vlak omdat hulle die skakel is tussen die gemeenskap en die regering. Hulle is ideaal geplaas om 'n koordineerende en fasiliterende rol te speel wat nodig is om seker te maak dat vennootskappe gebou word om voorkomings en versorgings programme te lewer aan elke gemeenskap wat deur MIV/VIGS geraak word. Dus, om sukses te behaal in die bekamping van MIV/VIGS , is dit belangrik om nou saam te werk met alle vlakke van die regering sowel as met plaaslike vennote in die gemeenskap wat MIV/VIGS bekamp op gemeenskapsvlak. Deur aksie te neem teen MIV/VIGS , kan munisipaliteite die toekoms van hulle dorpe en gemeenskappe verseker.

O crescimento dos casos de Aids em pessoas de 50 anos a mais chama a atenÃÃo, principalmente na Ãltima dÃcada. Este estudo teve como objetivo descrever as caracterÃsticas epidemiolÃgicas de pessoas com 50 anos a mais vivendo com HIV/Aids no Estado do CearÃ. MÃtodo Realizou-se um estudo transversal, em um hospital de referÃncia terciÃria localizado em Fortaleza-CE, no perÃodo de setembro a novembro de 2008. Um questionÃrio semiestruturado foi aplicado a 200 pacientes com HIV/Aids, de 50 a 83 anos de idade. Foram comparadas as diferentes proporÃÃes, separadamente para homens e mulheres com (IC 95%). Utilizou-se o teste do Qui-quadrado, de Pearson, ou Exato, de Fisher, quando apropriado. Resultados. Do total, 72,5% dos pacientes eram homens com mÃdia de idade de 63,5 anos; 53,5% tinham menos de oito anos de estudo; 69,0% residiam em Fortaleza; 51,0% pertenciam ao âEstrato econÃmico D/Eâ, revelando as precÃrias condiÃÃes de vida materiais desta populaÃÃo. O sexo feminino predominou com as cores parda (74,5%) e preta (7,3%), nÃveis de instruÃÃo mais baixos e maiores proporÃÃes de viÃvas (51,5). As mulheres foram menos sexualmente ativas (22,0%) e somente uma (0,8%) relatou mais de um parceiro nos Ãltimos 12 meses. A atividade sexual diminuiu com a idade: 60,2% entre 50-59 anos e 42,8% entre aqueles com 70 anos e mais; 48,0% dos pacientes relataram mÃdia de seis relaÃÃes sexuais ao mÃs. Homens usaram mais preservativo em relaÃÃes casuais (96,5%), entre as mulheres o menor uso foi nas relaÃÃes fixas (80,0%). O sexo vaginal predominou com 70,0%; o sexo oral e anal foi pouco frequente entre as mulheres e 33,0% dos pacientes referiu sexo comercial em algum momento na vida. No conjunto da populaÃÃo masculina, 41,0% referiram contato sexual com outro homem; 52,5% descobriram o diagnÃstico entre 30 e 49 anos; 31,0% mostraram a mÃdia de 17 anos de diagnÃstico; 59,0% nunca fizeram o teste anti-HIV antes da infecÃÃo; 76,0% referiram aquisiÃÃo da doenÃa por via sexual, homens com parceiro desconhecido (44,1%) e mulheres com parceiro conhecido (69,1%); 17,0% nÃo tÃm ideia de como se deu a infecÃÃo. O uso de Ãlcool foi prevalente e de drogas injetÃveis foi raro. ConclusÃo. A anÃlise mostrou diferenÃas entre os sexos, diagnÃstico tardio, envelhecimento com a aids, alto uso de preservativo apÃs a infecÃÃo por HIV e pouca percepÃÃo em estar em situaÃÃo de risco. Estes achados remetem à necessidade de um programa voltado especificamente para esta populaÃÃo com 50 anos ou mais.

Thesis (DTech (Mechanical Engineering))--Cape Peninsula University of Technology, 2012
In this thesis, we investigate certain key aspects of mathematical modelling to explain the epidemiology of HIV/AIDS at the workplace and to assess the potential benefits of proposed control strategies. Deterministic models to investigate the effects of the transmission dynamics of HIV/AIDS on labour force productivity are formulated. The population is divided into mutually exclusive but exhaustive compartments and a system of differential equations is derived to describe the spread of the epidemic. The qualitative features of their equilibria are analyzed and conditions under which they are stable are provided. Sensitivity analysis of the reproductive number is carried out to determine the relative importance of model parameters to initial disease transmission. Results suggest that optimal control theory in conjunction with standard numerical procedures and cost effective analysis can be used to determine the best intervention strategies to curtail the burden HIV/AIDS is imposing on the human population, in particular to the global economy through infection of the most productive individuals. We utilise Pontryagin’s Maximum Principle to derive and then analyze numerically the conditions for optimal control of the disease with effective use of condoms, enlightenment/educational programs, treatment regime and screening of infectives. We study the potential impact on productivity of combinations of these conventional control measures against HIV. Our numerical results suggest that increased access to antiretroviral therapy (ART) could decrease not only the HIV prevalence but also increase productivity of the infected especially when coupled with prevention, enlightenment and screening efforts.

Thesis (PhD (Physics))--Stellenbosch University, 2009.
ENGLISH ABSTRACT: This dissertation investigates certain key aspects of mathematical modeling of HIV and TB epidemics in South Africa with particular emphasis on data from a single well-studied community. Data collected over a period of 15 years (1994 to 2009) in Masiphumelele, a township near Cape Town, South Africa are used to develop a community-level mathematical model of the local HIV-TB epidemic. The population is divided into six compartments and a system of di®erential equations is derived to describe the spread of the dual epidemic. Our numerical results suggest that increased access to antiretroviral therapy (ART) could decrease not only the HIV prevalence, but also the TB noti¯cation rate. We present a modeling framework for studying the statistical properties of °uctuations in models of any population of a similar size. Viewing the epidemic as a jump process, the method entails an expansion of a master equation in a small parameter; in this case in inverse powers of the square root of the population size. We derive two-time correlation functions to study the correlation between di®erent types of active TB events, and show how a temporal element could be added to the de¯nition of TB clusters, which are currently de¯ned solely by DNA type. We add age structure to the HIV-TB model in order to investigate the demographical impact of HIV-TB epidemics. Our analysis suggests that, contrary to general belief, HIV-positive cases are not making a substantial contribution to the spread of TB in Masiphumelele. We develop an age-structured model of the HIV-TB epidemic at a national level in order to study the potential impact of a proposed universal test and treat program for HIV on dual HIV-TB epidemics. Our simulations show that generalized ART could signi¯cantly reduce the TB noti¯cation rate and the TB-related mortality rate in the short term. The timescale of the impact of ART on HIV prevalence is likely to be longer. We study the potential impact of more conventional control measures against HIV. Guidance for possible future and/or additional interventions emerge naturally from the results. We advocate a reduction in intergenerational sex, based on our ¯nding that 1.5-2.5 standard deviation in the age di®erence between sexual partners is necessary to create and sustain a major HIV epidemic. A simulation framework is developed to help quantify variance in age-structured epidemic models. The expansion technique is generalized to derive a Fokker-Planck equation. Directions for future work, particularly in terms of developing methods to model °uctuations and validate mixing assumptions in epidemiological models, are identi¯ed.
AFRIKAANSE OPSOMMING: Hierdie proefskrif ondersoek aspekte van die wiskundige modelering van HIV en TB epi- demies in Suid Afrika en fokus ook op 'n spesi¯eke gemeenskap. Data wat oor 'n periode van 15 jaar ingesamel is (1994 tot 2009) in Masiphumelele, 'n woonbuurt naby Kaapstad, Suid Afrika word gebruik om 'n wiskundige model te skep wat HIV-TB in die gemeen- skap modeleer. Die populasie word in ses kompartemente verdeel en 'n stel di®erensiaal vergelykings word afgelei om die verspreiding van di¶e epidemies te ondersoek. Ons nu- meriese resultate toon aan dat verhoogde toegang tot antiretrovirale behandeling (ARB) die potensiaal het om HIV prevalensie die TB koers beduidend te laat daal. Ons ontwikkel 'n raamwerk waarmee die statistiese eienskappe van °uktuasies ondersoek kan word in enige populasie van dieselfde grootte. Die metode ontwikkel 'n meester vergelyking vir die on- derliggende geboorte-dood stogastiese proses en brei dit uit in terme van 'n klein parameter; in di¶e geval in inverse magte van die vierkantswortel van die populasie grootte. Die twee-tyd korrelasie funksies word afgelei, en word gebruik om die korrelasie tussen verskillende tipes van TB episodes te bestudeer, asook om te wys hoe 'n tydselement aan die de¯nisie van TB groeperings gegee kan word. Di¶e word tans slegs d.m.v DNA tipe geklassi¯seer. Ouderdom- struktuur word aan die model toegevoeg om die demogra¯ese impak van HIV-TB epidemies te bestudeer. Ons analise toon aan dat, anders as wat algemeen aanvaar word, maak HIV- positiewe gevalle nie 'n groot bydrae tot die verspreiding van TB in Masiphumelele nie. Ons ontwikkel 'n ouderdom-gestruktureerde model van HIV-TB op nasionale vlak en gebruik die model om die potensiÄele impak van 'n universele toets- en behandel strategie op die HIV-TB epidemies te ondersoek. Ons simulasies toon aan dat algemene ARB waarskynlik 'n groot impak op die TB aanmeldings koers asook die TB-verwante mortaliteits koers kan h^e binne 'n relatiewe kort tydperk. Die impak op HIV prevalensie sal eers oor 'n veel langer periode duidelik word. Ons ondersoek ook die moontlikheid van meer konvensionele beheermaa- treels. Ons ontmoedig tussengenerasie seksuale omgang, gegrond op ons bevinding dat 'n standaard afwyking van 1.5-2.5 in die ouderdoms verskil tussen seksuele vennote, nodig is om 'n HIV epidemie van stapel te stuur en te onderhou. Ons ontwikkel 'n simulasie raamwerk om variansie in ouderdomgestruktureerde modelle te benader. Die uitbreidingstegniek word veralgemeen om 'n Fokker-Planck vergelyking af te lei. Ons identi¯seer probleme in die on- twikkeling van metodes om interaksie patrone en °uktuasies te modeleer in epidemiologiese modelle as opgawe vir toekomstige werk.

La phaeoramulariose des agrumes (Pseudocercospora angolensis) attaque les agrumes en Afrique tropicale et constitue une menace pour les autres pays producteurs situés en zone tropicale. La lutte chimique est le seul moyen de lutte efficace contre cette maladie. Cependant, elle est couteuse et néfaste pour l'environnement. La mise en place de stratégies de lutte permettant de minimiser l'emploi de fongicides contre est donc nécessaire. La connaissance des facteurs de risque de la phaeoramulariose est une étape préliminaire à cette démarche. Le travail entrepris avait pour but de préciser, à l'aide d'une enquête et des expérimentations, les effets de certains facteurs sur le développement de la maladie. L'enquête a été effectuée dans 39 sites de production des agrumes au Cameroun. Elle a permis de recenser les facteurs pédoclimatiques et biologiques dans l'environnement des arbres et de retenir les plus importants dans l'épidémiologie. Les expérimentations sur 8 sites ont permis de confirmer et évaluer les paramètres retenus après l'enquête. L'altitude, le type de sol, l'espèce d'agrumes et le type de végétation ont été retenus comme principaux facteurs de développement de la maladie. Les relations entre ces facteurs et l'incidence de la maladie sont illustrées dans les arbres de segmentation. Les expérimentations ont confirmé la grande sensibilité des pomélos et orangers vis-à-vis P. angolensis. En revanche, les mandariniers et la lime Tahiti se sont avérés moins sensibles. L'incidence de la maladie augmente avec une élévation en altitude, une diminution de la température et de la pluviométrie. La texture du sol s'est avérée plus déterminante du niveau de la maladie que sa composition. Le rôle de l'ombrage s'est avéré déterminant sur l'incidence de la maladie. L'analyse de la structure spatiale de la maladie a permis de mettre en évidence une structure agrégée. La structure spatiale des sous populations de familles d'arbres d'une parcelle agroforestière était aussi agrégée. La dispersion de la phaeoramulariose au sein d'une telle parcelle entre les différents agrégats d'agrumes serait limitée. L'analyse de régression a permis de déceler des différences entre les paramètres contribuant au développement de la maladie sur pomélos, satsuma et orangers. La possibilité d'une conception des systèmes agroforestiers raisonnés pour diminuer la pression des bioagresseurs est envisagée
Phaeoramularia leaf and fruit spot disease of citrus (PLFSD) caused by Pseudocercospora angolensis attacks citrus in tropical Africa. It also constitutes a threat for the other producer countries located in tropical zone. Chemical treatment is the only method used for effective control of this disease. However, in addition to causing ecological problems, this method lies beyond the reach local smallholders. The development of ecologically friendly strategies to ensure effective protection of citrus is thus necessary. To this end, knowledge of PLFSD risk factors is pre-required. The purpose of this study was to specify, by means of a survey and experiments carried, the effects of certain biotic and abiotic factors on the development of the disease. The survey carried out in 39 production sites of Cameroon, targetted a collection of environmental and biological tree characteristics. Experiments on 8 sites enabled a confirmation and evaluation of suspected factors. A stepwise logistic regression analysis of survey data made it possible to target altitude, soil type, citrus species and vegetation type as main factors influencing disease development. Relations between these factors and disease incidence are illustrated in segmentation trees. Experiments confirmed the great sensitivity of grape fruit and orange trees, while tangerine and Tahiti lime trees were less sensitive. Disease incidence increased with a rise in altitude and a reduction in temperature and rainfall. Soil texture proved to be more determinant in disease development than its chemical composition. Experimentation showed that trees planted under shade are less affected than those located in sunshine. A spatial structure analysis of the disease made it possible to highlight an aggregate structure indicating small scale disease dispersion. An analysis of the spatial structure of an agro forestry farm showed an aggregate structure of the sub populations of constituent tree families. This structure suggested that the dispersion of PLFSD within such a farm would be limited between the various citrus aggregates. PLS regression analysis suggested that several of these parameters play a determinant role in contributing to the development of disease on grape fruit, orange and Satsuma mandarin trees. The development of integrated agro forest systems which enable a decrease of the pressure of pest and diseases is envisaged

Background: Women who inject drugs face vast disparities in health outcomes relative to their counterparts in the general population, most notably in HIV. Intimate partner violence (IPV) victimisation has a detrimental individual effect on women's HIV risk behaviour. Furthermore, IPV often co-occurs with substance use and poor mental health among women in high-income countries, but little is known about the cumulative and interactive effects of these conditions on women's HIV risk behaviour in low- and middle-income countries. This thesis applied an ecological approach guided primarily by syndemics theory to understand influences on women's HIV behavioural outcomes. It examined associations and mechanisms linking IPV, substance use, and depression, with HIV sexual and injecting risk outcomes in the first quantitative study of Indonesian women who inject drugs, the Women Speak Out study. Methods: This study combined community-based participatory approaches and extensive formative research with quantitative survey methods. 731 women, ≥18 years of age, and injecting illicit drugs in the preceding year were recruited using respondent-driven sampling (RDS) from urban settings in Greater Jakarta and Bandung, Indonesia. Network characteristics of the sample were assessed using the RDS software package for Stata 14. Data were analysed using multivariate logistic regressions, marginal effects models, and interaction analyses on the additive and multiplicative scales. The study was conducted in collaboration with the Indonesian Drug User Network. Results: Paper 1: Past-year IPV victimisation doubled the odds of engaging in one or more sexual HIV risk behaviours. Several covariates were associated with higher odds of sexual risk behaviour: HIV-positive status, non-injection crystal methamphetamine (crystal meth) use, low educational attainment, younger age, and being single. Co-occurrence of psychological, physical and/or injurious, and sexual forms of IPV had cumulative effects: sexual risk behaviour was reported by 62% of women who did not experience any form of IPV, but increased to 89% among those exposed to all three forms. Paper 2: Past-year IPV elevated women's odds of receptive syringe sharing. These effects remained after controlling for socio-demographic confounders. Two covariates, injecting illicit pharmaceuticals (vs heroin only) and housing instability and/or homelessness, remained associated with receptive syringe sharing in multivariate analyses. Paper 3: More than 1 in 4 women experienced concurrent IPV, depressive symptoms, and crystal meth use. All three exposures had independent negative effects on HIV sexual risk outcomes. The co-occurrence of all three factors produced a 4-fold increase in rates of survival sex work, 5-fold increase in STI symptomatology, and a 7-fold increase in inconsistent condom use. The joint effect of depressive symptoms and crystal meth use together was greater than the product of the estimated effects of each exposure alone on STI symptomatology, indicating an interaction on the multiplicative scale. Statistically-significant positive additive interaction was detected between IPV victimisation and crystal meth on inconsistent condom use; depression and crystal meth on STI symptomatology and on survival sex work; and IPV and depression on STI symptomatology and survival sex work. Conclusion: This thesis provides new evidence of the individual and cumulative effects of IPV, methamphetamine use, and depression on HIV risk outcomes among Indonesian women who inject drugs. The interaction analyses are the first to empirically test the assertion that these co-occurring conditions interact synergistically to increase drug-using women's HIV risk. This thesis furthers our understanding of how syndemics function within women who inject drugs to produce health disparities, and contributes to the problem theory for HIV risk behaviour in this population. The findings of this study have great public health significance and important implications for future longitudinal research, interventions, and policy.

The objective of this thesis is to examine which socio-economic, structural and cultural factors may influence Indian women’s propensity to contract HIV and later their ability to access the relevant healthcare services for their condition. The research draws on two theoretical frameworks, the first being Barnett and Whiteside’s (2002) concept of social structural factors of disease transmission. Second, Anderson and Aday’s (1981) model of access examines how a variety of structural and resource-based factors, e.g. area of residence, can influence usage of healthcare facilities. Two stages of data analysis were undertaken, the first being secondary statistical analysis of the National Family Health Survey III. The survey provided state level estimates on the HIV sero-status of the general population in India and data on demographic and socio-economic determinants for family planning, nutrition, utilization of healthcare and emerging health issues. The second stage of analysis consisted of a set of qualitative interviews conducted in Andhra Pradesh, India. Thirty-three interviews were conducted with female sero-positive patients and ten with HIV-infected women who were providing social services to others with the same condition. Statistical results on social structural determinants of HIV transmission illustrated that Indian women who were formerly married (OR=5.27, CI=3.07-9.04), lived in higher prevalence states (OR=3.48, CI=2.19-5.54), had a low level of education (OR=2.27, CI=1.40-3.68) and were employed (OR=1.45, CI=0.96-2.18) had significantly (<.05) higher odds of being HIV-positive in comparison to those who were not. Findings in the qualitative phase of analysis were similar but participants’ narratives illustrated that their risk of contracting HIV begun before they even had the opportunity to seek a match as they seemed to live in communities with a high level of HIV prevalence. Many of the participants commented that there were factors outside of their sphere of control, e.g. lack of education, which resulted in them having a narrow choice of potential partners. Additionally, statistical results on female participants’ access to healthcare services indicated the vast majority of HIV-positive respondents were almost certainly not aware of their sero-status as they had not undertaken an HIV test prior to the survey. As the sample of female HIV infected respondents was relatively small, it was difficult to ascertain which social factors had an impact on these participants utilisation of HIV testing services. On the other hand, respondents’ narratives from the qualitative stage of research highlighted on social structural factors which could potentially influence WLHA’s continual utilisation of HIV-related healthcare services. It was found that participants experienced the most barriers to accessing healthcare facilities in the initial phases of their treatment. These barriers were mediated by the structure of healthcare services, culturally sanctioned medical practices (e.g. physicians refusal to inform the patient of their sero-status) and quality of services.

FundaÃÃo de Amparo à Pesquisa do Estado do CearÃ
CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior
A subnotificaÃÃo de casos de Aids representa um dos principais problemas enfrentados pela vigilÃncia epidemiolÃgica da Aids. Dessa forma este trabalho teve como objetivo, conhecer a subnotificaÃÃo dos casos de Aids em adultos no municÃpio de Fortaleza, nos anos de 2002 e 2003, aplicando o mÃtodo de captura e recaptura. Estimou-se ainda, a subnotificaÃÃo em dois hospitais de referÃncia para Aids, Hospital SÃo Josà â HSJ e Hospital Geral de Fortaleza â HGF. Nesse estudo foram utilizados dados secundÃrios do Sistema de InformaÃÃo de Agravo de NotificaÃÃo â Sinan, Sistema de Controle de Exames Laboratoriais - Siscel e Sistema de InformaÃÃes sobre Mortalidade - SIM, comparando os trÃs sistemas e considerando como notificados os casos confirmados no Sinan. Os casos foram emparelhados no Programa RecLink II. ApÃs o emparelhamento dos casos foram selecionados os elegÃveis para aplicaÃÃo do mÃtodo de captura e recaptura, utilizando os estimadores de Lincoln-Petersen e o de Chapman. A subnotificaÃÃo estimada para Fortaleza foi de 33,1%, e 14,1%, tendo como referÃncia o Sinan e comparando com as fontes Siscel e SIM, respectivamente. Para os hospitais S. Josà e HGF a subnotificaÃÃo foi de 5,4% e 90,5%, na mesma ordem, comparando o Sinan com o Siscel. Este trabalho demonstrou uma elevada subnotificaÃÃo de casos de Aids no municÃpio de Fortaleza nos anos de 2002 e 2003 e que a subnotificaÃÃo quando avaliada por fonte, comparando o Siscel com o Sinan, ela à mais de duas vezes superior à estimada quando comparada à das fontes SIM/Sinan, demonstrando ser o Siscel uma importante fonte de notificaÃÃo de casos de Aids. Quanto à subnotificaÃÃo nas duas unidades de SaÃde, observa-se um percentual bem mais elevado para o HGF. O Programa RecLink II mostrou ser uma opÃÃo simples para o reconhecimento dos casos nÃo notificados no Sinan e em relaÃÃo a tÃcnica de captura e recaptura, pode ser utilizada de forma simples e rÃpida e com baixo custo, comparando os sistemas dois a dois em pesquisas pontuais. Diante dos achados nesse estudo, recomenda-se que o Sinan-Aids seja comparado em periodicidade mensal, com todas as fontes de informaÃÃes disponÃveis que possam contribuir para reduÃÃo da subnotificaÃÃo de Aids
Underreporting is one of the major problems challenging epidemiologic AIDS surveillance. The objective of this study was to estimate the level of underreporting of AIDS in adults in Fortaleza in the period 2002-2003 using the capture-recapture method. In addition, the level of underreporting at two hospitals for AIDS referral (Hospital SÃo Josà â HSJ, and Hospital Geral de Fortaleza â HGF was estimated. The study relied on three secondary databases: SINAN (national disease surveillance), SISCEL (laboratory test control) and SIM (mortality information). The systems were compared and cases confirmed by SINAN were considered as reported. Cases from the two databases were paired using the software RecLink II. Subsequently cases eligible for the capture-recapture method were selected using the Lincoln-Petersen and Chapmam estimators. The levels of underreporting were estimated at 33.1% and 14.1% for SISCEL and SIM, respectively. Underreporting for SISCEL was 5.4% at HSJ and 90.5% at HGF. The study shows a considerable level of underreporting of AIDS cases in Fortaleza for the period 2002-2003 and suggests that SISCEL is an important source of AIDS reporting considering that it allowed to detect levels of underreporting more than twice the estimates derived from the sources SIM and SINAN. The level of underreporting was considerably higher at HF than at HSJ. The software RecLink II was shown to be a practical tool for identifying cases not reported to SINAN. The capture-recapture method is a simple, time-saving and inexpensive way to compare two systems when necessary. Considering the findings of the present study, SINAN-AIDS should be compared monthly with all relevant information systems in order to reduce levels of AIDS underreporting

The prevention of mother-to-child transmission is one of the most powerful tools in human immunodeficiency virus type 1 (HIV-1) prevention and has huge potential to improve both maternal and child health. In the absence of any preventative measures, infants born to and breastfed by their HIV-positive mothers have roughly a one-in-three chance of acquiring the infection themselves. HIV can be passed on from mother-to-child during pregnancy, during labor and delivery, and even after during breastfeeding. Intrapartum and neonatal single-dose nevirapine (sd-NVP) is the foundation of preventing mother-to-child transmission in lower resource settings where it has been used alone or as part of combination regimens. Both its simplicity and its long plasma half-life contribute to the success of sd-NVP based therapy. However, sd-NVP frequently results in HIV-1 viral resistance in mothers and children who become HIV infected despite prophylaxis. Sd-NVP leads to the development of non-nucleoside reverse transcriptase inhibitors (NNRTI) drug resistance, compromising the success of treatment of mother and child with subsequent antiretroviral combinations. Resistance to NNRTIs is particularly worrisome in lower resource settings since many subsequent regimens for maternal and infant antiretroviral therapy include a NNRTI drug.

"May 2004"
Includes bibliographical references (leaves 243-270)
xviii, 270 leaves : ill. (some col.), maps ; 30 cm.
Title page, contents and abstract only. The complete thesis in print form is available from the University Library.
Thesis (Ph.D.)--University of Adelaide, School of Social Sciences, Discipline of Geographical and Environmental Studies, 2004

A research report submitted to the Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, in partial fulfilment of the requirements for the degree of MSc Epidemiology (Infectious Disease Epidemiology), Johannesburg, November 2017
Tuberculosis (TB) is a leading cause of death worldwide, causing more deaths than HIV/AIDS. A TB patient can have pulmonary or extrapulmonary TB or both. South Africa has a high incidence rate of TB, recording 834 cases per 100 000 population in 2015, compared to 142 per 100 000 globally. Loss to follow-up (LTFU) rates during TB treatment in South Africa have ranged from 7% to 30%. The factors associated with LTFU can be divided into four groups: socioeconomic factors, patient-related factors, treatment factors, and health system or programmatic factors. Socioeconomic factors include a lack of support and a low socioeconomic status. Patient related factors include substance abuse, beliefs and low TB knowledge, while treatment factors include side effects and a history of LTFU. Among health system or programmatic factors that contribute to LTFU are a poor relationship with the healthcare workers and large treatment programmes. Studies to determine the factors associated with LTFU in HIV-uninfected TB patients are few as most studies have focused on HIV/TB co-infected patients. Co-infected patients make up almost 60% of TB patients. The aim of this study was to determine the demographic and clinical factors associated with LTFU in HIV-uninfected TB patients who registered for TB treatment in Ekurhuleni North sub-district from 1st January 2011 to 30th June 2012. LTFU was defined as a lack of a documented treatment outcome among TB patients who should have completed TB treatment based on TB treatment start date. The study was a retrospective cohort study involving the secondary analysis of routine TB treatment data collected from 18 primary care clinics in Ekurhuleni North sub-district. The participants were described at the beginning of TB treatment using clinical and demographic data. The treatment duration and outcomes were also described. The burden of LTFU was determined. Univariate and multivariate logistic regression and Cox proportional hazards regression were used to determine the factors associated with LTFU. In addition, survival analysis was conducted to determine if there was a difference in the time to LTFU among HIV uninfected TB patients based on clinical and demographic factors. Sensitivity analysis of the multivariate logistic regression and Cox proportional hazards regression was carried out to compare the results obtained when follow-up was restricted to 8 months to those obtained for 12 months of follow-up. Sensitivity analysis was also conducted around the definition of LTFU. The impact on the results of multivariate logistic regression after assuming that participants who had a missing treatment outcome in the primary study were not lost to follow up was determined. Five hundred and fifteen participants were included in the analysis. The median age of the participants was 33 years (IQR: 26-47). Fifty-eight percent of the participants were male. Pulmonary TB was the most common form of TB among the participants. The rate of treatment success was 77.67% and that of LTFU was 17.28%. Of those lost to follow-up, 60 had a missing treatment outcome and 29 had default as an outcome in the primary study. The median length of treatment was 6.39 months (IQR: 5.67-7.44), and the median time to LTFU was 3.67 months (IQR: 1.54-6.33). Eighty-two percent of the participants had a documented change of treatment phase. Clinics with a high patient burden had a similar proportion of poor outcomes (death, LTFU and treatment failure) to clinics with low patient burdens. Significant differences in change of treatment phase and length of treatment were observed between those lost to follow up and those not lost to follow-up. LTFU took place throughout TB treatment, with a steady increase in the probability of LTFU over the first 6 months of follow-up. None of the factors investigated had a significant effect on time to LTFU. Following logistic regression and Cox proportional hazards regression analyses, none of the factors assessed were significantly associated with LTFU. Sensitivity analysis showed that censoring the participants at 8 months did not change the results of the logistic regression analysis. For Cox proportional hazards regression, female participants had a 5% lower risk of LTFU compared to male participants in the 12-month analysis. In the 8 month analysis, female participants had a 5% higher risk of LTFU. When participants with a missing treatment outcome were not considered lost to follow-up, sex was found to be significantly associated with LTFU. Female participants had a 66% lower risk of LTFU compared to male participants. A limitation of the use of secondary data in this study was that the study question asked in this study was different from the question that was asked in the primary study. As a result, the variables collected in the primary study were different from the variables required in this study. Information on socioeconomic status, residence type, comorbidities, treatment clinics and health system factors was not available. None of the factors investigated in this study were significantly associated with LTFU in HIV uninfected TB patients in Ekurhuleni North sub-district. The factors influencing LTFU in Ekurhuleni North may not have been investigated in this study. More studies need to be conducted with a wide range of variables in Ekurhuleni North to determine the factors that influence LTFU among HIV-uninfected TB patients.
XL2018

D.Phil.
This thesis presents an intervention programme that aims to facilitate anger-expression and takes psychosocial and immunological variables into account. The present research argues that if the effects of the programme are validated, similar programmes may yield similar benefits for other participants in future intervention programmes in a South African context. The nature, course and effects of the HIV disease are described and include specific processes and mechanisms of influence in physical, mental and social terms. Biological processes that result from immunological deficiencies causing AIDS are analyzed and an explication of disease progression is offered. Psychological and social aspects related to immune-system deterioration carry implications for patients and influence their prognosis. The research was conducted in the context of a biopsychosocial conceptualization and was aimed at reducing levels of anger and helping establish recourses in the patients to manage infection and disease, as well as improve or at least retard decrements in immunological functioning. The goal of this intervention programme was to reduce levels of anger, anxiety, depression and social isolation. This would in turn increase the participant's personal sense of self-control, self-efficacy and self-esteem. Changes in these factors would help retard the overall HIV disease progression. An intervention programme was tailored to address the specific needs of HIV- infected patients. The group intervention was focused in such a way that relevant psychological, behavioural and social aspects were addressed. The programme borrowed and used aspects of different models and reformulated an intervention that would best address the specific needs of the participants. It was possible to isolate specific problems and focus the intervention on these specific areas, such as depression, anger, social isolation and hopelessness. For example, it was possible to take into account the participants' low self-efficacy and problems related to a lack of interpersonal coping skills and develop the participants' confidence and assertiveness (Antoni, 1991)

South Africa has had one of the fastest growing HIV epidemics in the world and almost 30% of women attending public antenatal clinics (ANC) are currently infected with the virus. But as the epidemic is starting to level off and antiretroviral therapy (ART) is becoming increasingly available, few methods exist to determine the impact of ART or other interventions on the epidemic in South Africa. This thesis explores the epidemiology and dynamics of HIV infection and investigates the potential impact of ART. Methods Total and age-specific prevalence data are analysed in time and space and are used to investigate patterns of infection in men and women, urban and rural, and low and high risk populations. Dynamical models are developed to estimate incidence from age-specific prevalence and trends over time and are compared to laboratory-based estimates of recent HIV sero-conversion. Incidence is estimated in different populations in South Africa. A dynamical model is developed to estimate the impact of ART on the future course of the HIV epidemic. Results HIV prevalence varies geographically and by age, sex and race. The average female-tomale HIV prevalence ratio is 1.7 and prevalence peaks at an older age among men than women. The age at which prevalence peaks among women has increased from 23.0 to 26.5 years between 1995 and 2002. Four patterns of infection are identified: among pregnant women attending ANCs, among men and women in the general population, and among migrant workers. HIV incidence among ANC attendees peaked in the mid to late 1990s (at 6.6% per year nationally) with variation between provinces. Current estimates of HIV prevalence and incidence among the general population in South Africa (aged 15-49 year) are 18.8% and 2.4% per year, respectively. Age-specific incidence estimates from dynamical models and laboratory methods are in good agreement provided the window period for the laboratory method is increased. Over the next ten years the provision of ART could avert 1 to 1.5 million deaths depending on whether it is provided when the CD4 cell count falls to 200 or 350 cells/ul. By 2015 about 1.1 million people will be receiving ART but this will have little impact on the incidence of HIV and scaling up of prevention efforts remains urgent. Conclusions The thesis explores some of the determinants and patterns of HIV prevalence and incidence in South Africa in order to find better ways to manage the epidemic of HIV, monitor changes and evaluate progress in control efforts. In order to fight the epidemic we need to mobilize the best possible science in support of those people and communities affected by the epidemic.
Thesis (M.Med.)-University of KwaZulu-Natal, Durban, 2007.

This study’s purpose was to explore the knowledge, attitudes and perceptions regarding HIV/AIDS and condom use, and sexual behaviours among senior secondary school learners in Kumba, Cameroon using the Health Belief Model (HBM) as the theoretical framework. The ultimate goal was to determine how at risk learners were of contracting HIV/AIDS. A quantitative, non-experimental descriptive, explorative and correlational research design was adapted; using self-designed questionnaires for data collection. Respondents were sampled through proportionally stratified simple random sampling resulting in 480 (240 male and 240 female) grade 10 to grade 12 learners from two participating high schools. Descriptive and inferential statistics were calculated using the SPSS version 12 software program. Most learners were knowledgeable about HIV transmission; the prevention of HIV/AIDS; and sexual risk behaviours pertaining to HIV transmission. Learners also manifested positive attitudes towards PLWHA. Most learners did not perceive themselves to be at high risk of contracting HIV/AIDS. Up to 52,3% who were sexually active, only 30,0% used condoms consistently. The respondents knew about condoms, but had poor attitudes towards condom use. Most respondents received information on HIV/AIDS, condoms and sexuality from magazines/newspapers and teachers. The findings could assist policy makers, programme planners and educators in developing and implementing programmes to improve the health of adolescents. The perceived barriers to condom use and modifying factors should be addressed into consideration in designing any policy geared towards controlling risk exposure to HIV/AIDS among youths in Kumba, Cameroon.

The prevalence and the incidence are two primary epidemiological parameters in infectious disease modelling. The incidence is also closely related to the force of infection or the hazard of infection in survival analysis terms. The two measures carry the same information about a disease because they measure the rate at which new infections occur. The disease prevalence gives the proportion of infected individuals in the population at a given time, while the incidence is the rate of new infections. The thesis discusses methods for estimating HIV prevalence, incidence rates and the force of infection, against age and time, using cross-sectional seroprevalence data for pregnant women attending antenatal clinics. The data was collected on women aged 12 to 47 in rural KwaZulu-Natal for each of the years 2001 to 2006. The generalized linear model for binomial response is used extensively. First the logistic regression model is used to estimate annual HIV prevalence by age. It was found that the estimated prevalence for each year increases with age, to peaks of between 36% and 57% in the mid to late twenties, before declining steadily toward the forties. Fitted prevalence for 2001 is lower than for the other years across all ages. Several models for estimating the force of infection are discussed and applied. The fitted force of infection rises with age to a peak of 0.074 at age 15, and then decreases toward higher ages. The force of infection measures the potential risk of infection per individual per unit time. A proportional hazards model of the age to infection is applied to the data, and shows that additional variables such as partner’s age and the number of previous pregnancies do have a significant effect on the infection hazard. Studies for estimating incidence from multiple prevalence surveys are reviewed. The relative inclusion rate (RIR), accounting for the fact that the probability of inclusion in a prevalence sample depends on the individual’s HIV status, and its role in incidence estimation is discussed as a possible future approach of extending the current work.
Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2011.

介紹
愛滋病在中國男男性行為者中的流行持續增長，而新感染HIV的男男性行為者扮演著重要角色。本民族志研究採用了社會生態模式來探討與新感染HIV的男男性行為者中HIV二代傳播、心理健康、以及使用健康服務相關的問題。研究方法包括深入訪談、焦點小組訪談、非正式訪談和參與觀察。此外還採訪了志願者和醫護人員。資料分析採用主題內容分析法。
結果
在確診為HIV呈陽性後，大多數的男男性行為者經受過一定程度的心理及精神上的問題。與HIV相關的緊張性刺激影響著他們適應這個確診。HIV與一些重要的心理、社會和文化的條件呈現一種綜合流行。而大多數的男男性行為者通過自身的應變能力逐漸康復，其中一些人甚至體驗到某種程度的成長。人的應變能力是一種基於個人與環境互動的建構。
11名（占24.4%）HIV呈陽性的男男性行為者報告發生過無保護的肛交行為。基於性伴侶的不同類型，與無保護肛交行為相關的因素則有所不同。這些無保護的肛交行為往往同時伴隨著物質濫用、對風險的錯誤認識、以及消極的情緒或者心理和精神問題。阻礙無保護肛交行為發生的積極因素包括社會支援、自我保健、自我保護和志願服務。
自上而下的公共衛生服務傾向於控制和檢測而不是賦權于男男性行為人群，並且在很大程度上忽視了新感染HIV的男男性行為者的心理和精神健康、性健康、以及自我保健的能力。新感染HIV的男男性行為者的未滿足的需求已經被識別，且他們更願意到男男性行為人群的社區，尤其是感染者小組那裏去尋求服務和支援。但男男性行為人群的草根組織卻缺乏資金和技術的支持。
結論
新感染HIV的男男性行為者所遭遇的問題都植根於特定的個人際遇以及他們所生活的社會生態系統。是時候採取一種廣泛而綜合的“健康同志社區的觀點、促進自我保健的策略、以及具有文化敏感性和社會效能的措施來預防HIV的二代傳播以及促進新感染HIV的男男性行為者的社會福祉。人類行為的非線性的特徵要求愛滋病健康行為研究從強調生物行為的範式轉移到著重愛滋病的社會根源的範式中來。
Introduction
Newly diagnosed HIV positive men who have sex with men (NHIVMSM) play an important role in accelerating the high HIV prevalence in China. This ethnographic study, employing a modified social ecological model integrating concepts of adaptation, cognition, affect and action, investigated the inter-related issues on secondary HIV transmission, mental health and services utilization in this population. Methodologies included in-depth interviews, focus groups, informal interviews and participant observations. Moreover, information was also obtained from volunteers and health care workers. Thematic content analysis was performed.
Results
Most respondents commonly experienced psychological or mental health problems (e.g. depressive symptoms and anxiety) after their HIV diagnosis. HIV stressors, such as constraints of being HIV positive, limited information and knowledge of HIV/AIDS, ART and its side effects, associated co-morbidities and significant costs in health care, appeared to shape their adaptation to the diagnosis. Moreover, a syndemic was apparent among NHIVMSM and some influential psycho-social and cultural conditions, such as adversities in their migrants’ life, social suffering as MSM, cultural trauma, stigma and discrimination. Most respondents drew on a range of personal resilience strategies and some respondents testified to have achieved post-traumatic growth. Resilience was presented within a person-situation interactional construct.
Eleven (24.4%) respondents reported practicing unprotected anal intercourse (UAI). Several respondents reported their UAI had occurred in the first few months after their diagnosis when they suffered considerably from uncertainty, perceived stigma and identity struggles. Factors associated with UAI were based on differing partner types, such as fear of losing partners in a context of non-serostatus disclosure in lovers or stable partners, tongzhi (gay) sauna setting and moral judgment in casual partners, and poor economic status in commercial partners. UAI usually happened simultaneously in context of substance use, risk misconceptions, encountering negative emotion or mental health problems. Positive factors against UAI included social support, self-care, self-protection and volunteerism.
The current top-down public health services tended to operate on control and surveillance instead of empowering MSM. This approach largely ignored psychological and mental health, sexual health and self-care capacities among NHIVMSM, whose unmet needs were identified as preferring to obtain services and support from MSM and/or PLWH communities. However, current MSM organizations lacked funding and technical support. Health care providers operated with suboptimal care protocols, training and technical support. Coordination and collaborations among health care institutes and MSM communities were relatively weak. Tailored participatory health care is warranted, such as volunteerism, greater involvement of PLWH, health navigators and building supportive environment and services.
Conclusions
The problems of psychological and mental health, risky sexual behavior (UAI) and health services utilization that NHIVMSM encountered resulted from interactions between personal experiences and the social ecological systems they inhabited. Recommendation drawn include adopting a comprehensive and inclusive “healthy MSM community“ approach and a strategy of facilitating self-care to carry out culturally sensitive and socially effective measures to prevent secondary HIV transmission and to promote wellbeing among NHIVMSM. An emerging theoretical implication is that the nonlinearity of human behaviour requires paradigm shifting from a bio-behavioural emphasis to the social origin of HIV/AIDS.
Detailed summary in vernacular field only.
Detailed summary in vernacular field only.
Detailed summary in vernacular field only.
Detailed summary in vernacular field only.
Detailed summary in vernacular field only.
Detailed summary in vernacular field only.
Detailed summary in vernacular field only.
Detailed summary in vernacular field only.
Li, Haochu.
Thesis (Ph.D.)--Chinese University of Hong Kong, 2012.
Includes bibliographical references (leaves 425-457).
Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web.
Abstract also in Chinese; appendixes includes Chinese.
Abstract (English) --- p.iv
Abstract (Chinese) --- p.vii
Acknowledgements --- p.ix
Table of Contents --- p.xi
List of Tables and Figures --- p.xv
Glossary --- p.xvi
Abbreviation --- p.xviii
Chapter Chapter 1 --- Introduction --- p.1
Chapter 1.1 --- Background --- p.1
Chapter 1.1.1 --- High HIV prevalence and incidence among MSM in China --- p.1
Chapter 1.1.2 --- Social and cultural environment faced by HIV positive MSM --- p.3
Chapter 1.2 --- Sexual risk and secondary HIV transmission among HIV positive (and newly diagnosed) MSM --- p.7
Chapter 1.3 --- Psychological and mental health among HIV positive (and newly diagnosed) MSM --- p.10
Chapter 1.4 --- Health service utilization among HIV positive (and newly diagnosed) MSM --- p.13
Chapter 1.5 --- Exploring complexities of secondary HIV transmission through qualitative studies --- p.14
Chapter 1.6 --- Theories, concepts and the research framework --- p.15
Chapter 1.6.1 --- Conceptualization of adaptation in medical anthropology --- p.15
Chapter 1.6.2 --- The social ecological model --- p.17
Chapter 1.6.3 --- Cognitive adaptation and self-control --- p.19
Chapter 1.6.4 --- Emotion and motivation are influential in health behaviour --- p.21
Chapter 1.6.5 --- Action world and its role in health behaviour --- p.24
Chapter 1.6.6 --- Social control/social order --- p.26
Chapter 1.6.7 --- Stigma --- p.27
Chapter 1.6.8 --- Identity control --- p.29
Chapter 1.6.9 --- Research framework --- p.32
Chapter 1.7 --- Goals, objectives and research questions --- p.34
Chapter Chapter 2 --- Methodology --- p.38
Chapter 2.1. --- Entrée into the field --- p.38
Chapter 2.1.1 --- The start of the research --- p.38
Chapter 2.1.2 --- Pilot work --- p.39
Chapter 2.2 --- The participants --- p.43
Chapter 2.3 --- Data collection --- p.50
Chapter 2.4 --- Data analysis --- p.58
Chapter 2.5 --- Rigour --- p.62
Chapter 2.6 --- Reflexivity --- p.68
Chapter 2.7 --- Ethical considerations --- p.75
Chapter Chapter 3 --- Social circumstances and MSM communities in Shenzhen --- p.78
Chapter 3.1 --- Population and economic circumstances --- p.78
Chapter 3.2 --- Shifting political situation --- p.80
Chapter 3.3 --- A migrant society --- p.87
Chapter 3.4 --- Shenzhen Culture --- p.93
Chapter 3.5 --- MSM community and tongzhi subculture --- p.98
Chapter 3.6 --- The subgroup of HIV positive MSM --- p.113
Chapter 3.7 --- Public health implications --- p.117
Chapter Chapter 4 --- Health care system and services related to HIV case detection and follow up --- p.118
Chapter 4.1 --- Formal health care system --- p.118
Chapter 4.2 --- Health insurance --- p.125
Chapter 4.3 --- “Four Free and One Care“ policy --- p.126
Chapter 4.4 --- Informal health care --- p.127
Chapter 4.5 --- Services related to HIV case detection and follow up --- p.131
Chapter Chapter 5 --- Psychological and mental health --- p.142
Chapter 5.1 --- Negative mental health outcomes --- p.142
Chapter 5.1.1 --- Depressive symptoms --- p.142
Chapter 5.1.2 --- Anxiety symptoms --- p.146
Chapter 5.1.3 --- Factors associated with negative mental health outcome --- p.150
Chapter 5.1.3.1 --- Individual factors --- p.150
Chapter 5.1.3.2 --- Interpersonal factors --- p.157
Chapter 5.1.3.3 --- Cultural factors in community and family --- p.160
Chapter 5.1.3.4 --- Institutional and structural factors --- p.163
Chapter 5.2 --- Positive mental health outcomes --- p.166
Chapter 5.2.1 --- Integrating negative experiences and recovery --- p.166
Chapter 5.2.2 --- Resources for recovery --- p.169
Chapter 5.2.3 --- Back to normal functioning --- p.170
Chapter 5.2.4 --- Post-traumatic growth --- p.172
Chapter 5.2.5 --- Factors associated with positive mental health outcome --- p.175
Chapter 5.2.5.1 --- Individual factors --- p.175
Chapter 5.2.5.2 --- Interpersonal factor --- p.181
Chapter 5.2.5.3 --- Community-related factors --- p.184
Chapter 5.2.5.4 --- Institutional factors --- p.187
Chapter 5.3 --- Public health concern of suicidal ideation --- p.190
Chapter 5.4 --- Impacts of psychological and mental health --- p.194
Chapter 5.5 --- Summary of psychological and mental health in a modified socio-ecological mode --- p.195
Chapter 5.6 --- Discussion --- p.197
Chapter 5.6.1 --- The emerging of a syndemic in HIV and some psycho-social and cultural conditions --- p.197
Chapter 5.6.2 --- Powerful social and cultural factors associated with mental health --- p.200
Chapter 5.6.3 --- Resilience among newly diagnosed HIV positive MSM --- p.208
Chapter 5.6.4 --- Service implications --- p.213
Chapter Chapter 6 --- Sexual risk --- p.221
Chapter 6.1 --- Continued unprotected anal intercourse (UAI) after being diagnosed HIV positive --- p.221
Chapter 6.2 --- Changes in practising UAI during the study period --- p.222
Chapter 6.3 --- Factors associated with UAI with non-commercial sex partners --- p.224
Chapter 6.3.1 --- Individual factors --- p.225
Chapter 6.3.2 --- Interpersonal factors --- p.229
Chapter 6.3.3 --- Community-based factors --- p.231
Chapter 6.3.4 --- Institutional factors --- p.234
Chapter 6.4 --- UAI with commercial sex partners --- p.235
Chapter 6.5 --- Comparing factors associated with UAI among commercial and non-commercial partners --- p.238
Chapter 6.6 --- Reduced risky behaviour after diagnosis --- p.239
Chapter 6.7 --- Factors associated with condom use --- p.241
Chapter 6.7.1 --- Individual factors --- p.241
Chapter 6.7.2 --- Interpersonal factors --- p.246
Chapter 6.7.3 --- Community factors --- p.248
Chapter 6.8 --- Other special issues related to risky sexual behaviour --- p.250
Chapter 6.9 --- Summary of sexual risk in a modified socio-ecological model --- p.261
Chapter 6.10 --- Discussion --- p.263
Chapter 6.10.1 --- Prevalence of UAI --- p.263
Chapter 6.10.2 --- Partner types and UAI --- p.265
Chapter 6.10.2.1 --- Fear of losing partners in a context of non-serostatus disclosure --- p.266
Chapter 6.10.2.2 --- Anonymous sexual encounters and moral judgment --- p.267
Chapter 6.10.2.3 --- Economic barriers --- p.270
Chapter 6.10.2.4 --- Intrapersonal contexts --- p.271
Chapter 6.10.3 --- Critical views on some practices --- p.274
Chapter 6.10.4 --- Emerging positive experiences from Shenzhen --- p.276
Chapter 6.10.5 --- Service implications --- p.279
Chapter Chapter 7 --- Health service seeking --- p.285
Chapter 7.1 --- Problems identified in health service seeking --- p.285
Chapter 7.2 --- Processes of adaptation --- p.289
Chapter 7.3 --- Negative factors associated with health service seeking --- p.296
Chapter 7.3.1 --- Individual factors --- p.296
Chapter 7.3.2 --- Interpersonal factors --- p.302
Chapter 7.3.3 --- Community-based factors --- p.304
Chapter 7.3.4 --- Health care institution-based factors --- p.309
Chapter 7.4 --- Positive factors associated with health service seeking --- p.319
Chapter 7.4.1 --- Individual factors --- p.319
Chapter 7.4.2 --- Interpersonal factors --- p.321
Chapter 7.4.3 --- Community-based factors --- p.325
Chapter 7.4.4 --- Factors in the health care institutes--free services --- p.328
Chapter 7.5 --- Summary of health service seeking in a modified socio-ecological model --- p.329
Chapter 7.6 --- Discussion --- p.331
Chapter 7.6.1 --- Problems in health care institutes --- p.331
Chapter 7.6.1.1 --- The top-down approach -- controlling instead of community building --- p.331
Chapter 7.6.1.2 --- Problems among health care providers --- p.335
Chapter 7.6.2 --- Tailored participatory approach to health care and education for HIV positive MSM --- p.339
Chapter 7.6.3 --- Necessity for developing MSM communities --- p.342
Chapter 7.6.4 --- Service implications --- p.349
Chapter Chapter 8 --- Discussion and implications --- p.355
Chapter 8.1 --- The occurrences of UAI and its hidden meaning --- p.355
Chapter 8.2 --- Informing the future HIV epidemic among MSM in Shenzhen --- p.357
Chapter 8.3 --- Difficulties of controlling the HIV epidemic among MSM --- p.361
Chapter 8.4 --- New HIV prevention approach --- p.368
Chapter 8.5 --- Critiquing theories for recommended changes --- p.386
Chapter 8.6 --- Limitations of the study --- p.400
Chapter 8.7 --- Conclusion --- p.405
Appendix I to IX --- p.409
Bibliography --- p.425

Since the earliest reported cases of HIV/AIDS probably in 1959 in Africa, there has been a consistent progression in the new HIV/AIDS infection cases. In South Africa, Gauteng, records one of the highest HIV/AIDS prevalence rates in the country. The Department of Health (DOH) South Africa conducts ongoing studies on HIV/AIDS at provincial levels; these studies monitor the prevalence of HIV/AIDS amongst pregnant women attending antenatal clinics, as a tool for determining and monitoring the prevalence, trends, patterns and spread of the disease in the general population. This study analyses sentinel and spatial data collected from the (DOH) and Statistics South Africa (StatsSA) respectively, and depicts them in the form of spatial maps, and then critically analyses the spatial patterns that occur. The research findings would hopefully contribute to the overall knowledge of HIV/AIDS and provide framework and relevant literature for further investigation.
Geography
M.Sc. (Geography)

Indiana University-Purdue University Indianapolis (IUPUI)
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