Bridging Gaps to Eliminate Tuberculosis | CDC EID

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Volume 17, Number 3–March 2011
Perspective
Bridging Implementation, Knowledge, and Ambition Gaps to Eliminate Tuberculosis in the United States and Globally
Kenneth G. Castro and Philip LoBue
Author affiliation: Centers for Disease Control and Prevention, Atlanta, Georgia, USA


Suggested citation for this article

Abstract
We reflect on remarkable accomplishments in global tuberculosis (TB) control and identify persistent obstacles to the successful elimination of TB from the United States and globally. One hundred and twenty nine years after Koch's discovery of the etiologic agent of TB, this health scourge continues to account for 9.4 million cases and 1.7 million deaths annually worldwide. Implementation of the Directly Observed Treatment Short-course strategy from 1995 through 2009 has saved 6 million lives. TB control is increasingly being achieved in countries with high-income economies, yet TB continues to plague persons living in countries with low-income and lower-middle–income economies. To accelerate progress against the global effects of disease caused by TB and achieve its elimination, we must bridge 3 key gaps in implementation, knowledge, and ambition.

As we commemorate World Tuberculosis (TB) Day, March 24, we pause to reflect on remarkable accomplishments in eliminating TB in the United States and other parts of the world and to identify persistent obstacles to its eventual elimination. World TB Day marks the day when, in 1882, Robert Koch delivered his lecture to the Physiologic Society of Berlin announcing the discovery of the tubercle bacillus as the etiologic agent of TB (1). At the time, TB was estimated to account for one fifth to one fourth of all deaths in Europe. One hundred twenty-nine years later, TB is increasingly under control in most countries with high-income economies (2) yet continues to afflict persons living in countries with low-income and lower-middle–income economies (3,4). The World Health Organization (WHO) reported an estimated 9.4 million incident TB cases and 1.7 million deaths in 2009. Existing evidence-based interventions for TB control that have been successfully implemented from 1995 through 2009 have saved 6 million lives and alleviated much human suffering (3). Yet, by 2009 only an estimated 63% of annual incident TB cases were being detected and reported; of these, 86% were successfully treated (3). To accelerate progress against the global effect of disease caused by TB and to achieve its elimination, we must bridge 3 key gaps in implementation, knowledge, and ambition.

Implementation Gap
In his 1963 lecture delivered at the Postgraduate Medical School in London, Wallace Fox observed that remarkable progress in the chemotherapy of TB had been achieved over the prior decade "in the technically advanced countries" (5). In contrast, he remarked that nonindustrialized countries "have derived very little benefit from the progress." Fox cited 2 reasons for this lack of progress: a shortage of medical resources and "little attempt to adapt present knowledge to their specific problems" (5). During Fendall's 1972 presentation at the Symposium on the Teaching of Teaching Tropical Medicine, an epitaph is suggested to describe medicine throughout the 20th century: "Brilliant in its scientific discoveries, superb in its technological breakthroughs, but woefully inept in its application of knowledge to those most in need" (6). Fendall further suggested "all that remains is the problem of translating what is current common knowledge and routine medical and health practice to the other two thirds of the world: the 'implementation gap' must be closed."

Globally, this implementation gap has been closing as a result of reliance on the evidence-based strategy for TB control, originally known as Directly Observed Treatment Short-course (DOTS). This strategy was initially based on diagnostic and treatment recommendations derived from randomized controlled trials, conducted largely by the British Medical Research Council (7) and the US Public Health Service, which established the efficacy and safety of drugs against TB (8). Additionally, the basic elements of the strategy were defined and field tested under mutual assistance programs between host countries and the International Union Against Tuberculosis and Lung Disease (9). The DOTS strategy was endorsed by consensus derived in technical advisory bodies and promulgated by WHO and the global Stop TB Partnership. Its widespread implementation has been more recently facilitated by resources from governments; the Global Fund for AIDS, Tuberculosis, and Malaria; and the President's Emergency Plan for AIDS Relief (10–12). Furthermore, TB control has been demonstrated to be among the most cost effective of health interventions (13).

The original DOTS strategy contained 5 basic elements: 1) secure political commitment with adequate and sustained financing; 2) ensure early case detection and diagnosis through quality-assured bacteriology; 3) provide standardized treatment with supervision and patient support; 4) ensure effective drug supply and management; and 5) monitor and evaluate performance and effects. This strategy has now been expanded to contain additional elements to confront other evolving needs, such as addressing HIV-associated TB, and multidrug-resistant and extensively drug-resistant TB; contributing to strengthening health systems; engaging all providers (public, voluntary, and private) and affected communities; promoting use of the International Standards for TB Care; and enabling and promoting research (14,15).

The advances achieved with DOTS from 1995 through 2009 include treating nearly 49 million persons and curing 41 million with TB, which was accompanied by a peak in global TB trends in 2004 followed by a relatively slow decline (3). These advances notwithstanding, TB continues to hold its dubious place as a leading infectious killer of young adults, and the disease preys on the most vulnerable persons in many parts of the globe (16). These populations are known to have difficulty in accessing available diagnostic tests and in obtaining curative short-course therapeutic regimens that require >6 months of multiple drugs to achieve the desired outcomes. Even when all countries of the world have adopted policies consistent with the DOTS strategy, a sizable proportion of estimated cases (≈37%) are undetected, and those infected are likely not receiving optimal treatment regimens. Efforts must now focus on tackling social determinants of illness associated with TB by expanding and facilitating access to impoverished persons in densely populated urban areas and remote villages.

In addition to partnering with all health providers (e.g., private, public, voluntary, traditional healers) to facilitate access to care, those concerned with public health must concentrate on subtleties such as optimizing the number of clinics or dispensaries offering diagnostic and therapeutic services, providing patient-convenient hours of operation, recognizing difficulties with distance and transportation, and minimizing out-of-pocket expenditures (including lost wages) for transportation, child care, and diagnostic services. An analysis from India has reported that 72% of TB patients who had a low standard of living (e.g., earning US $1–$2/d) first saw private providers and spent, on average, $145 before starting treatment with the Revised National TB Program, thus documenting the devastating economic toll incurred by poor persons with TB (17). Engagement of affected communities will also prove crucial to create educated consumers of services. Public communication campaigns will help educate persons about the signs and symptoms of TB, provide information about where to access quality services and drugs, alleviate stigma, and create the demand for these basic health services from all providers of care and government decision-makers.

Other scientific advances that have lagged behind in implementation include the use of universal genotyping of Mycobacterium tuberculosis clinical isolates as a way to understand and interrupt chains of recent and ongoing transmission and the use of universal drug susceptibility testing with liquid culture media that reduce turn-around times by several weeks (available in the United States since 1994) for timely surveillance of drug resistance trends and to guide optimal treatment regimens. Most recently, technologic advances have demonstrated the ability to rely on detection of bacterial DNA by PCR. The WHO policy recommendation to rely on Xpert MTB/RIF (Cepheid, Sunnyvale, CA, USA) for same-day diagnosis accentuates and magnifies this implementation gap (18).

A growing concern has to do with the gap in successfully addressing concurrent conditions associated with TB, such as HIV, diabetes, smoking, indoor air pollution, alcoholism, and malnutrition (16). This more holistic approach provides an ideal way to benefit both individual and public health, and secondarily to strengthen health systems. When modeled after the basic principles that underpin TB control, the combined interventions will provide platforms for planning, service delivery, analysis, accountability, and corrective actions.

In the zeal to bridge the implementation gap, we must avoid past false dichotomies. There are those who see the way forward as limited to securing investments and channeling all resources to expand access to available diagnostic services and curative drugs. Available tools are relatively blunt and limited, especially for effectively addressing HIV-associated TB and multidrug-resistant and extensively drug-resistant TB. In tackling urgent unmet needs, we must honestly acknowledge existing limitations and not ignore the need to bridge the immense knowledge gap in TB. Otherwise, we risk interventions that lack innovation, creativity, and do not keep pace with technological advances that could accelerate the path to elimination.

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Bridging Gaps to Eliminate Tuberculosis | CDC EID


Suggested Citation for this Article
Castro KG, LoBue P. Bridging implementation, knowledge, and ambition gaps to eliminate tuberculosis in the United States and globally. Emerg Infect Dis [serial on the Internet]. 2011 Mar [date cited]. http://www.cdc.gov/EID/content/17/3/337.htm
DOI: 10.3201/eid1703.110031


Comments to the Authors
Please use the form below to submit correspondence to the authors or contact them at the following address:

Kenneth G. Castro, Centers for Disease Control and Prevention, 1600 Clifton Rd NE, Mailstop E10, Atlanta, GA 30333, USA; email: kgc1@cdc.gov