The world-wide increase in tuberculosis: how demographic changes, HIV infection and increasing numbers in poverty are increasing tuberculosis.

After more than a century of decline, in the mid 1980s tuberculosis began to increase in some developed countries. Health care workers were then forced to look to the developing world, where they found tuberculosis to be out of control, in many countries. It is now appreciated that tuberculosis is not only increasing globally but is likely to do so beyond the next decade for three principal reasons. First, demographically as the expected population increase will be greatest in areas of the world where tuberculosis is most prevalent, particularly middle Africa and South Asia. Secondly, the increase of HIV, which renders the host uniquely susceptible to tuberculosis, is occurring in the same areas of the world and is already causing an increase in tuberculosis case rates of up to tenfold. Thirdly, as more and more people are forced to live in poverty, where poor nutrition and crowded conditions lead to the spread of tuberculosis, the disease risk will be compounded. Sound medical management, particularly the use of the five components of directly observed therapy, will relieve the situation. But until world conditions of poverty and HIV spread are addressed, it is unlikely that tuberculosis can be controlled.