Exploring the interaction between tuberculosis and antiretroviral treatment at a community level.
TB is the most common opportunistic infection and cause of death among individuals with AIDS, and it is therefore important to quantify what role, if any, interventions such as ART, may have in strengthening the TB control program.
The CIPRA Project 3 will study the impact of the introduction of ART on the prevalence and disease patterns of tuberculosis in a community with high TB and HIV rates, and in which the national TB control programme is well administered.
The HIV prevalence in the study community, Masiphumelele, is approximately 23%. Despite a well-run national TB program at this site, the community has experienced a 2.5 fold increase in TB notification rates in the past 10 years, reaching 1,468/100 000 in 2004. This is thought to be due to the increasing HIV prevalence rate in the community.
In order to determine the impact of Highly Active Antiretroviral Treatment (HAART) on TB prevalence, the study must begin by determining the baseline prevalence of TB and HIV in Masiphumelele. Therefore a cross-sectional community survey to estimate the prevalence of bacteriologically active tuberculosis and of HIV disease in a random sample of adults and children over 14 years of age, from the Masiphumelele township was performed in the first half of 2005. This study showed that there is a large burden of undiagnosed TB in the community, especially among HIV-infected individuals and an overall TB prevalence of approximately 2,518/100,000. While the TB programme is identifying 67% of TB among HIV negative patients, case finding of TB in HIV-infected patients is only 37%.
In Project 3B, surveillance of TB case notification rates in Masiphumelele will enable us to track changes in the prevalence of TB in the community over time. In addition to investigating the effect of highly active antiretroviral therapy on the pattern of TB transmission, we will also analyse the risk factors for transmission. We will utilise IS6110 fingerprinting on isolates of M tuberculosis, in order to identify and study various aspects relating to TB transmission.
