Cross-sectional studies of tuberculosis prevalence in Cambodia

Tuberculosis remains a major global health problem, with 8.6 million estimated incident cases and 1.3 million estimated deaths in 2012.1 Cambodia ranks second among the 22 countries with a high tuberculosis burden. Since the World Health Organization (WHO) adopted the DOTS (directly observed treatment, short-course) strategy in 1994,2 which is based on the passive detection of cases of smear-positive tuberculosis, this policy has been the foundation of global tuberculosis control. Cambodia’s national tuberculosis control programme introduced DOTS in hospitals in 1994 and decentralized it to primary care health centres between 1999 and 2004 with the technical support of WHO and the Japan International Cooperation Agency. To evaluate the impact of the national tuberculosis control programme in Cambodia, Cambodia conducted its first national tuberculosis prevalence survey in 2002 (hereafter referred to as the 2002 survey), during the early stage of DOTS decentralization. The results revealed a prevalence of smearpositive pulmonary tuberculosis of 362 cases per 100 000 people aged 10 years or older for (269 per 100 000 overall). For bacteriologically-positive (i.e. smear-positive tuberculosis case and/or smear-negative, culture-positive tuberculosis case) tuberculosis among individuals aged 10 years or older, the prevalence was shown to be 1208 per 100 000.3 In 2005, the year after DOTS became available at all health centres throughout the country (i.e. not just in the 141 tuberculosis units that existed already, primarily in hospitals), the rate of notification of new smear-positive tuberculosis cases peaked and subsequently stagnated for three years.4 In the following years treatment success rates were consistently above 90% thanks to the efforts of the national tuberculosis control programme.1 The question then is whether the prevalence of tuberculosis declined, and if so, by how much with respect to the first tuberculosis survey. To respond to these questions, the national tuberculosis control programme conducted a second national tuberculosis prevalence survey in 2010–2011(hereafter referred to as the 2011 survey). The objectives of the study presented here were to measure the current prevalence of smear-positive pulmonary tuberculosis and bacteriologically-positive pulmonary tuberculosis and to evaluate the change in tuberculosis prevalence in Cambodia between the 2002 and 2011 surveys.