EPIDEMIOLOGICAL BASIS OF TUBERCULOSIS ERADICATION. 2. DYNAMICS OF TUBERCULOSIS MORBIDITY AND MORTALITY.

In most countries there have been signs in recent years of an accelerated decline in tuberculosis, but only the most superficial knowledge exists of what underlies the remarkable changes. It is therefore imperative to document the changing picture of tuberculosis by means of parameters that are not only descriptive but will also serve as guidelines for the development of methods to eradicate the disease.The authors describe the present system of tuberculosis reporting and control in Denmark, where the requisite conditions for obtaining meaningful statistics are, to a large extent, fulfilled, discussing its potentialities for depicting the forces behind the recent changes and pointing out its inherent deficiencies.The advantages of the Danish system, in which rates for the prevalence and incidence of respiratory tuberculosis are broken down into those for new cases and those for relapses, are stressed, as is the significance of the recently introduced practice of reporting cures and thus obtaining cure rates on a nation-wide scale.As an indicator of the lethal effect of tuberculosis in a country, the mortality rate suffers from several limitations, which will play an increasingly important role as the downward trend in tuberculosis continues. The authors suggest that a more objective measure than the specific mortality rate would be the so-called "lethality index" - an index based on all deaths occurring among persons with active tuberculosis, irrespective of whether they were attributed directly to the disease.