Tuberculosis

Tuberculosis is the leading infectious cause of death worldwide, being responsible for 3 million deaths annually. Among those aged over 5 years, tuberculosis kills more people than AIDS, malaria, diarrhoea, leprosy, and all other tropical diseases combined. The tragedy of this situation is that treating tuberculosis is one of the most effective and cost effective of all health interventions. The World Health Organisation has calculated that, unless urgent action is taken, the annual number of deaths could rise from 3 million to 4 million by the year 2004.1 We urgently need improvements in the implementation of existing strategies for tuberculosis control, with particular emphasis on early diagnosis and delivery of effective treatments. In addition, basic research is needed for the development of simple and rapid diagnostic tests, more effective vaccines, and new drugs. This article focuses on new scientific approaches to tuberculosis control that could soon be incorporated into routine practice. However, the impact of new approaches will be negligible if the wealthy Western nations fail to address the gross global inequities in healthcare provision,2 which account for the fact that 98% of deaths from tuberculosis occur in the poorer developing countries (fig 1).

So serious is the global threat of tuberculosis that, in 1993, the WHO took the unprecedented step of declaring this disease a global emergency.1 The problem is fuelled by the pandemic of HIV infection and AIDS and the emergence of drug and multidrug resistance. HIV infection renders a person infected by Mycobacterium tuberculosis much more likely to develop overt tuberculosis, and the evolution of the disease is considerably accelerated. At present, about 8-10% of all cases of tuberculosis worldwide are related to HIV infection, but the association is much more common in many African countries, often 20% or more.4

Drug resistance …