DOTS Show the Way to Tackle the Toughest TB

New research has shown for the first time that the spread of multi drug-resistant tuberculosis (TB) can be halted through a well executed standard treatment program.


Bacterial fingerprinting techniques used to track disease transmission in a southern Mexico community revealed that all categories of tuberculosis were controlled when the directly observed therapy (DOTS) strategy was used.


DOTS is the strategic approach which has been used to treat more than 17 million people since its adoption by the World Health Organization in 1991. It is based on; political commitment, accurate diagnosis, standardized drug treatment and monitoring of treatment results. But until now its ability to control the infectious disease in areas afflicted by multi-drug resistant strains had not been rigorously tested.


TB still kills 2 million people a year -- one death every 15 seconds -- and there are growing levels of multi-drug resistance in Africa and Europe.


This latest study, which comes just a week after World TB Day, was conducted by an international team of researchers from Mexicos National Institutes and Stanford University, and is published in this weeks edition of The Lancet. It shows that despite a moderate level of multi-drug resistant TB, the DOTS program interrupted disease transmission in the Orizaba Health Jurisdiction, Veracruz.


At the beginning of the study in 1995, 22 percent of previously untreated patients were carrying drug-resistant strains and 6.7 percent had multi-drug resistance. By 200, only 7.8 percent had drug-resistant strains and there were no cases of MDR-TB.


The researchers, who were funded by the Wellcome Trust, The Howard Hughes Medical Institute and the U.S. National Institute of Allergy and Infectious Diseases, also found that the rate of pulmonary TB among their 436 patients fell by 54 percent from 42 to 19 per 100,000 of the population. Despite DOTS, however, 12 percent of those with MDR tuberculosis died.


Dr. Alfredo Ponce de Leon from Mexicos National Institute of Medical Sciences and Nutrition, said, The spread of multi-drug resistant TB is potentially devastating. Our study is great news for the world -- in many settings implementing standard TB control can prevent this spread. However, it also amplifies the tragic fact that fewer than half of the worlds TB cases have access to this basic care.


Dr. Peter Small from Stanford University commented, Our data show that DOTS is an essential public health intervention. But even with this program the number of people dying from multi-drug resistant TB remains unacceptable, highlighting the desperate need for new tools to save the lives of the hundreds of thousands of people who are suffering from it.