Global situation of TB and its control

Abstract

Tuberculosis occupies 4th place among major causes of death, and the number of new cases is estimated at 7.25 million in 1997, and 99% of TB deaths and 95% of new TB cases are seen in developing countries. TB had been brought under control in developed countries by applying modern TB control programme including chemotherapy, as basic health infrastructure was already well developed, and their economy can afford cost of control programme including TB drugs. The rapid decline of TB due to the success of TB control in developed countries had lowered the concern on TB, thus bought about the reduction in research grant for TB and difficulty in bringing up successors engaging in TB control. Similar trend was seen also in developing countries, where TB still remains one of most important health problems due to poor quality of the programme caused by poorly developed health infrastructure including man-power, budget and institutions. New obstacles which hinder the smooth implementation of TB control programme have appeared, and they are the rapid expansion of global population, the move of population, the impact of HIV epidemic on TB and the multi-drug-resistant TB (MDRTB). The growth of population automatically increases the number of TB cases and gives heavier burden for TB control. TB has moved from developing to developed countries with the move of the population, and currently approximately half of new TB cases in developed countries is occupied by foreign born patients. Among several opportunistic infections seen in AIDS cases, TB comes out first as the virulence of tubercle bacilli is much higher than the other germs causing opportunistic infections. The pathogenesis of TB changes markedly among HIV positives, and the incidence becomes much higher, and the time interval from the primary infection to the disease, and that from the detection of the disease to death without any effective treatment are shortened, and the fatality rate becomes much higher. Because of the atypical clinical picture, attenuated tuberculin sensitivity and high incidence of side-effects of TB drugs, in particular thiacetazone, clinical management of HIV positive TB is much more difficult than ordinary TB. MDRTB is produce by the bad quality of TB control, and by improving treatment completion rate as well as the cure rate, decline in the prevalence of drug resistance, both primary and acquired, could be expected together with the decline of TB itself. WHO has made a great challenge with TB after the nomination of Dr Kochi to chief medical officer, TUB in 1989. Currently, Global TB Programme (GTB) is promoting so-called DOTS strategy of TB control, consisting of the commitment of the government to give high priority to TB control, passive case-finding with sputum smear examination by microscopy, directly observed treatment by standardized short-course regimen of chemotherapy, well-organized logistics for TB drugs, and the provision of reporting and monitoring system of TB including the evaluation of treatment outcome by cohort analysis. Marked achievements have been obtained in several countries introduced DOTS strategy. Japan is asked to intensify its efforts in international cooperation in TB control.