Overview and epidemiologic assessment of the current global tuberculosis situation with an emphasis on control in developing countries

Abstract

The global epidemiologic situation of tuberculosis is reviewed, with emphasis on the disappointing achievements in its control in developing countries over the last three decades. In developed countries where prevalence of tuberculosis is low, it will take at least 30-50 years to eliminate the disease because of exacerbation by individuals who acquire infection abroad. In developing countries, 2-3 million deaths will occur among the estimated 4 million new smear-positive and 4 million new smear-negative and extrapulmonary cases of tuberculosis. The low cure rate with standard chemotherapy is the chief reason for failure of tuberculosis control in developing countries. The basic chemotherapeutic regimen (streptomycin for 2 months then a combination of isoniazid and thiacetazone for 12 months) does not achieve a high cure rate in developing countries. Under routine conditions the cure rate is high (90%) with an inexpensive 8-month regimen consisting of 2 months of strictly supervised daily administration of isoniazid, rifampin, pyrazinamide, and streptomycin and then 6 months of self-administration of a tablet containing both isoniazid and thiacetazone. A substantial decrease in the risk of tuberculous infection in developing countries is essential because of the increase in number of AIDS patients with tuberculosis. Vaccination alone, at least with the present vaccine, cannot substantially influence the epidemiologic situation but should be continued for children when its use is justified for prevention.