Multidrug resistant TB, TB control, and millennium development goals in Asia

Abstract

Tuberculosis is a major communicable disease, which has existed in the world for over two millennia. It affects people from all countries, more in some and less in others. The Asian countries have over 60% of the global TB burden. Specific treatment for tuberculosis was available only after the 1943 discovery of streptomycin. Many other anti-tuberculosis drugs have since been discovered and their efficacies established through controlled clinical trials. Table 1 presents a list of commonly used anti-tuberculosis drugs that are in use currently. Concerted efforts by researchers spread over the globe have provided us the scientific basis of treatment and management of TB patients through carefully conducted, controlled clinical trials in patients in different countries and settings. The World Health Organization was closely associated with most of those trials and has played a key role in the formulation of national tuberculosis programs in most countries adopting a uniform DOTS (Directly Observed Therapy, Short Course) strategy, which now forms the basis of TB control programs in 184 countries in the world (World Health Organization, 2007a). In the early introduction of chemotherapy, the incidence and prevalence of TB was high in many Asian countries. Mortality was high, diagnosis was delayed, and patients presented with advanced disease including some with acute fulminant tuberculosis, which often ended in death. Today, diagnosis is early, incidence and prevalence of tuberculosis have declined, most patients have access to drugs and are successfully treated, mortality has considerably reduced and very few patients present with acute fulminant TB. Currently available regimens under DOTS strategy include highly potent drugs of streptomycin (S), isoniazid (H), rifampicin (R), ethambutol (E), and pyrazinamide (Z), which form the sheet anchor of treatment programs in most countries. While the DOTS regimens have a potential of curing 100% of new cases in program conditions, a success rate of over 85% is acceptable. The DOTS strategy includes a strong political commitment, uninterrupted supply of anti-TB drugs of assured quality and administration of the drugs under direct observation, provision of diagnostic facilities for sputum smear examination, and standardized documentation and reporting systems. Nearly all Asian countries have adopted the DOTS strategy in their National TB Control Programs and have seen some decline in the incidence of TB in their countries since the introduction of DOTS (World Health Organization 2007a). © 2008 Springer US.