Pediatric Pulmonology, Supplement 26:53–54 (2004) Tuberculosis in the Developing World Heather J. Zar, MBBCh, PhD* Globally, tuberculosis is a major cause of morbidity and mortality, affecting almost a third of the worlds population and causing an estimated 2.6 million deaths annually. 1 In the year 2000, there were 8.2 million new TB cases worldwide; these occurred predominantly in the deve- loping world. 2 The highest incidence rates (around 300 per 100 000) occurred in sub-Saharan countries; Asian countries had approximately 60% of cases. 2 Twenty-two developing countries contain 80% of the global burden; many of these highest-burden countries are also experien- cing a dual epidemic of HIV. 1 Almost 98% of deaths from TB occur in developing countries. 2 The burden of TB in children in developing countries is often under appreciated and neglected; due to limited resources control programs have given priority to screen- ing for active infectious cases. However, childhood TB constitutes a large proportion of the TB caseload in devel- oping countries, contributing approximately 15 to 20% of all cases. 3 The World Health Organisation estimated that there were 1.3 million new TB cases and 450 000 deaths in children under 15 years of age in the year 1990. 4 In developing countries, children with TB tend to present at a more advanced stage of disease compared to children in the developed world. 5 The consequences of undiagnosed or untreated pediatric TB can be substantial as children are more likely to develop miliary or severe disease. Fur- thermore cases of childhood TB frequently reflect an undiagnosed adult infectious source case, thus the occur- rence of TB in children frequently indicates failure of TB control programs. DIAGNOSIS OF TB Diagnosis of TB in developing countries may be challenging particularly in areas of high HIV prevalence. In resource poor areas, sputum microscopy is the major way to diagnose TB and remains the most cost effective method available. 6 Although sputum smear examination for acid-fast bacilli can diagnose up to 60% of adult cases, poor access to microscopy and the paucibacillary nature of pulmonary TB in HIV-infected adults may reduce detection rates in developing countries. 7 Diagnosis of smear-negative cases has become increasingly proble- matic and urgent in high HIV-prevalence areas where clinical scoring systems, chest radiographic changes and skin testing may be less reliable. 7 In children, diagnosis of TB is notoriously difficult due to the paucibacillary nature of the disease, difficulty in obtaining specimens for culture and relatively low rate of bacteriological confirmation; diagnosis has relied pre- dominantly on clinical case definitions and chest radio- graphy. In developing countries, the difficulty of diagnosis has further been compounded by high rates of malnutri- tion and HIV, which may result in anergy and chronic pulmonary disease. Published diagnostic approaches and scoring systems for children lack diagnostic accuracy particularly for young, malnourished or HIV-infected children. 8 Simpler, cheaper, faster and more accurate diag- nostic methods for TB are urgently needed in developing countries. TB CONTROL Substantial progress has been made in the last decade in the global control of TB. Improved control of TB has been achieved through rapid expansion and adoption of the WHO directly observed treatment, short-course (DOTS) strategy to many countries including all 22 highest-burden countries, political commitment, improved funding and increased awareness and collaboration within the global community. 2,9 As a result, in developing countries in which effective control programs have been established, the prevalence of TB has been reduced by more than 15% annually and TB deaths by 80% in 3 years. 10 In addition, in countries in which DOTS has been implemented, the development and spread of drug resistance has been limited. 11 However, TB programmes in developing countries have been hampered by late presentation and diagnosis, treatment delays and low levels of adherence to therapy. 1 Moreover even in countries in which DOTS has been implemented, geo- graphical coverage has been incomplete and detection From the Department of School Adolescent and Child Health, University of Cape Town, South Africa. Address correspondence and reprint requests to Prof. Heather J. Zar, Department of School Adolescent and Child Health, Red Cross Children’s Hospital, University of Cape Town, 5th floor, ICH Building, Klipfontein Road, Cape Town, South Africa. E-mail hzars@ich.uct.ac.za ß 2004 Wiley-Liss, Inc. DOI 10.1002/ppul.70049