A pilot study on the prevention of HIV related Tuberculosis in Zambia

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Mwinga, Alwyn G
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During the last decade there has been an increase in notification rates of tuberculosis in many developing countries the world over. Epidemiological evidence has linked this increase to the HIV epidemic in many of these countries, the mechanism of which is thought to be either reactivation of a distantly acquired latent infection or re-infection or progression from a recent infection. As a result of this association between HIV and tuberculosis attention has been drawn to the possibility for the use of preventive therapy as a means of reducing the incidence of tuberculosis in the HIV infected individual with a latent tuberculosis infection in developing countries with a high incidence of dual HIV/tuberculosis infection. To address this issue a randomised placebo controlled double blind trial of two intermittent regimens of tuberculosis preventive therapy with a study sample of about 1000 HIV positive individuals was proposed as a collaborative effort between the University of Zambia and the London School of Hygiene and Tropical Medicine. Prior to beginning this study a pilot study was carried out in order to assess the feasibility of recruiting and following up a cohort of HIV positive individuals in Lusaka.The pilot study and its findings are presented in this dissertation. At recruitment an assessment of Knowledge and Attitudes to HIV showed a high level of knowledge about HIV and its transmission. The recruitment of HIV infected patients occurred at a higher rate among those individuals already aware of their HIV status than those who were tested for the first time for the purpose of recruitment into the study suggesting that a voluntary testing centre would be a good recruitment site. Difficulty in excluding active tuberculosis was a major reason for non-enrolment into the study, however no active case of tuberculosis was diagnosed in these patients.Tuberculin testing at the time of the initial HIV test showed a much lower frequency of positive tuberculin responses in the HIV positive than the HIV negative subjects, indicating that tuberculin testing has limited usefulness as a means of identifying latent tuberculosis in areas with high rates of both tuberculosis and HIV. Many of the patients recruited did not return to the clinic for follow up. Some of the problems identified in the follow-up included difficulties in finding the patients within the community as a result of the wrong address being supplied, an inability to locate the given address in the residential areas and a tendency to easily move from one residential area to another. Thus it would be necessary to obtain very detailed information of the patient's residential address as well as that of their next of kin in order to ensure adequate follow-up. More frequent reviews and repeated counselling might also contribute to better follow-up of asymptomatic patients. Given the future impact that the interaction with HIV was expected to have on the tuberculosis situation in countries like Zambia it was considered important to conduct a study to determine the efficacy of tuberculosis preventive therapy in this setting. The various problems identified during the pilot study indicated that implementation of relevant measures to ensure maximum follow-up of the patients would be critical.
Tuberculosis -- Zambia , HIV (Virus) -- Zambia