The tuberculosis epidemic in sub-Saharan Africa
During the past two decades there has been resurgence in TB, an infectious disease caused by a bacterium that generally affects patients’ lungs. Despite new strategies for controlling TB, the epidemic in sub-Saharan Africa continues to expand. This trend is reason for concern. There is an urgent need to understand the reasons TB control measures are failing and to develop innovative approaches to public health. The EU-funded TECOARTE (Epidemiology and control of tuberculosis in the antiretroviral therapy era: Towards a mathematical model for Cape Town, South Africa) initiative used a variety of epidemiological methods to describe the TB epidemic and its drivers in Cape Town. The researchers also measured the potential impact of different public health interventions on controlling the epidemic. They did this using state-of-the-art statistical techniques to perform an in-depth analysis of all TB cases in Cape Town during the past decade. From this data, researchers developed and validated a mathematical model of the local TB epidemic. The results show that the trajectory of TB incidence in Cape Town during the past century has been different to trajectories for London and New York. The introduction of chemotherapy did not reduce the TB epidemic in Cape Town, whereas it did in London and New York. Even before the HIV epidemic, TB rates were already at the same level as at the beginning of the century. The surge following the HIV epidemic led the life-time incidence of TB among Cape Town’s population to increase to more than 25 %. Over the last five years TB rates have declined, which could be due to increasing access to HIV treatment or to improved diagnosis of tuberculosis. The mathematical model’s projections showed that TB burden is linked to age structure of the population and to immune protection from TB infection. The most important finding from the research was that the burden of recurrent TB in Cape Town is very high. More than 30 % of TB patients develop additional episodes over a 12-year period. These findings from the TECOARTE initiative provide insights into how to improve TB control measures to ensure they are effective. They also help to explain TB trends in other parts of the world and how control measures might work there.
Keywords
Tuberculosis, South Africa, TB control measures, public health, TECOARTE
