[Active epidemiologic surveillance of tuberculosis].

With 5,000 new active cases each year, tuberculosis in Chile remains as the most important communicable disease in the country. Since the type of control programs are linked to the epidemiologic situation as far as infection, morbidity and mortality are concerned, an effective surveillance system is needed, with analysis of the general data and an active search for other evidences which show the advantages and problems of the control programs. The number of active cases shows a downward trend with 66 new cases per 100,000 population in 1982 and 37 in 1992. nevertheless, in Santiago, comparing years 1991 and 1991, an increase of 4% in morbidity, 37% of mortality and 33% in the case fatality rate are observed. Morbidity rates are variable with highest numbers in the I Region of Tarapacá probably linked to the prevalent ethnic type of the population. One quarter out of total tuberculosis deaths depends on the late effects of the disease and three quarter are the consequences of recent active disease. People over 55 years of age represents 25% out of total new cases. Besides classical indicators it is important to consider the frequency and results of the practice of diagnostic laboratory tests; the antibiotic therapy resistance; the results of the treatment, analyzing cohorts of treated people; the importance of different infection factors; the evaluation of BCG immunization; the meaning of animal tuberculosis infection; the slowness in the beginning of treatment in new cases; the results of the screening of high risk population and the systematic analysis of each death due to tuberculosis.