Commentary: Back to basics--good news from a birthplace of DOTS

Abstract

XDR-TB is particularly alarming in the context of the HIV/AIDS pandemic. Early reports suggest a TB mortality rate of nearly 100% among people living with HIV/AIDS. 2,4 To make matters worse, while the emergence of XDR-TB was by no means unexpected, its intractability is exacerbated by a global response which is crippled by chronic lack of investment in public health, and specifically in TB control programs. In the face of these prevailing challenges, it is good news indeed to read the paper by Subramani et al. 5 which appears in this issue. The active community surveillance of different TB control measures in Tamil Nadu, India, which is unique in its longitudinal scope, provides important insights into the value of the WHO-recommended DOTS strategy. Although there is a large and growing body of evidence that supports the DOTS strategy, 6,7 the authors’ extensive community surveys over a 31-year period convincingly document the impact of a well-implemented DOTS program on TB prevalence in the community. This study, which benefited from a long-term public health investment in the understanding of the epidemiology of TB and the effects of TB control measures, has found that implementing a DOTS program accelerated the decline of prevalence in culture-positive TB, by nearly 6 times the pre-DOTS implementation rate. In fact, the 2.5 years of DOTS implementation in this small community accounted for one quarter of the decline in culture-prevalence TB over the entire 33-year period. Another key implication of these findings is the inference that in the presence of a well-functioning TB control program, monitoring case notifications can provide a reasonable approximation of TB epidemiology in the community. For anyone with experience in implementing a wellfunctioning DOTS program in settings with a low prevalence of HIV/AIDS and drug resistance, these findings—while they are perhaps more dramatic than one might have expected— make sense. What does not make sense is that it has taken so many governments, communities, non-governmental organizations, donors, academics, patients and activists so long to recognize the importance of the DOTS management system— and to demand that it be implemented in every community affected by TB. There are a number of important issues that should be considered when interpreting these study findings. The first is the significant public health investment and value of the study area. Although it was necessary to make some assumptions regarding the socioeconomic situation of the community over time, the implementation of the TB control program, and the long-term sustainability of the accelerated downward trend under DOTS, the study site has yielded valuable insights. Foresight, as well as a considerable, sustained investment, laid the foundation for this and future studies of TB control interventions. The study team and researchers deserve mention: their expertise in conducting meticulous, large-scale community surveys is rare, and this, in combination with a long-term approach, maximized the study teams’ potential. Public health authorities and donors would do well to consider lessons learned from this study regarding how to make the most with scarce research dollars when evaluating key public health interventions such as DOTS. Another key consideration is the significant, positive impact of the rifampin-based DOTS regimen in a study area with low levels of rifampin resistance. India, one of the birthplaces of