Interventions for Tuberculosis Control and Elimination 2002
Interventions for Tuberculosis Control and Elimination 2002
Interventions for Tuberculosis Control and Elimination 2002
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Figure 2. Pathogenetically-based model of the epidemiology of tuberculosis. 1<br />
Reproduced from 9 by the permission of the publisher Urban & Vogel.<br />
transmission (figure 4). 11 Once identified, they should be quickly <strong>and</strong> permanently<br />
rendered non-infectious through chemotherapy. In the terminology<br />
used in this monograph, this approach is called “tuberculosis control”.<br />
Thus, tuberculosis control is the strategy aimed at reducing the incidence<br />
of tuberculous infection. This strategy also includes prophylactic treatment,<br />
defined as the provision of chemotherapy to persons exposed to, but not<br />
yet infected with M. tuberculosis.<br />
The second strategy aims at reducing the prevalence infection with<br />
M. tuberculosis. Because M. tuberculosis probably survives in a large<br />
proportion of persons <strong>for</strong> years following acquisition, tuberculosis will<br />
continue to emerge from the pool of persons who are already infected.<br />
A strategy to reduce the prevalence of infection in the community will<br />
be designated “tuberculosis elimination strategy” in the context of this<br />
monograph. Tuberculous infection is highly prevalent in virtually every<br />
country’s population, but varies demographically in important ways. 1<br />
To be epidemiologically effective, preventive chemotherapy to reduce<br />
the prevalence of infection must target groups that are both easily identifiable<br />
<strong>and</strong> that potentially contribute a large fraction of future morbidity.<br />
Vaccination with BCG varies somewhat from this concept, as it aims<br />
at reducing the risk of progression from infection to disease. Consequently,<br />
its effect is expected to be similar to that of the strategy to reduce the<br />
prevalence of infection.<br />
The options available to address the tuberculosis problem in a community<br />
will first aim at reducing the incidence of tuberculous infection<br />
(case-finding <strong>and</strong> treatment of the most infectious cases, supplemented by
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