In 1993, the World Health Organization declared tuberculosis (TB) a worldwide health emergency and sent healthcare workers around the world to try to stop its spread. The organization developed a program called DOTS, which stands for directly observed therapy, short course. DOTS therapy works by actually watching people take their TB drugs to make sure their therapy stays on course. The World Health Organization maintains that DOTS is the most effective way to control tuberculosis, but not everyone agrees. Researchers from Harvard University argue that the DOTS program has some holes in it.

What the researchers wanted to know: Is DOTS the most effective way to control tuberculosis?

What they did: The researchers examined TB infection rates, death rates, and statistics about what people are getting TB. They also looked back at other efforts to control epidemics, such as smallpox, that have been successful and compared those strategies to the DOTS strategy. They used all their data to evaluate whether or not DOTS is effective and to suggest other ways to control TB.

What they found: Since DOTS has been used, cases of TB have increased, especially in sub-Saharan Africa, where the prevalence of AIDS leads to more TB deaths, and in parts of eastern Europe, where drug resistant strains of the disease are common. DOTS, even where it is well implemented, has not stopped the TB epidemic in these areas. The DOTS program treats only people who have smear-positive TB, meaning that a sample of saliva or throat culture has in it bacteria visible under a microscope. However, only 44 percent of all TB cases are smear-positive, and though these people tend to be more infectious than others, they are not the only ones who can pass on the disease. The authors recommend a strategy aimed at preventing new cases of the disease in addition to the DOTS strategy of treating people who are infected.

What it means to you: Current estimates, from the World Health Organization, are that 2 billion people have latent TB infections and tens of millions more have active, infectious cases of the disease. Though it has been used for more than a decade, the DOTS strategy has not been successful everywhere and may need adjustment. There are drugs that can effectively treat TB most of the time; the key is figuring out how to best get those drugs out to those who need them.

Caveats: The authors argue that people who do not test positive using a smear test need to be treated for TB, but concede that the more general tests to diagnose TB are expensive and slow. In the absence of easy tests to diagnose TB, it is hard to know how to treat the disease in those people and prevent them from infecting others.

Find out more: General information about tuberculosis can be found through the Centers for Disease Control and Prevention.

Information about the World Health Organization's DOTS program

Read the article: Brewer, T.F. and Heymann, S.J. "To Control and Beyond: Moving Toward Eliminating the Global Tuberculosis Threat." Journal of Epidemiology and Community Health. October 2004, Vol. 58, No. 10, pp. 822-825.

Abstract online: http://jech.bmjjournals.com