Tuberculosis (TB) is a leading cause of death globally. Natural history studies show that young children are at particularly high risk of progression to active TB and severe, disseminated disease following infection. Despite this, high-quality regional and global surveillance data on the burden of childhood TB are lacking. We discuss the unique aspects of TB in children that make diagnosis and therefore surveillance challenging; the limitations of available surveillance data; other data which provide insights into the true burden of childhood TB. Improved surveillance is among the key research priorities identified for childhood TB, but progress to date has been slow. Recent advances in TB diagnostics, and standardized clinical diagnostic guidelines and case definitions, all provide opportunities for new strategies to improve surveillance. Better-quality data on the burden and trends of childhood TB will inform and improve both public health policy and clinical practice. 1. Introduction Three main challenges currently hamper efforts to control tuberculosis (TB) globally. Firstly, the ability to identify and diagnose cases remains suboptimal and is particularly poor among children and human-immunodeficiency-virus- (HIV-) infected individuals, with direct implications for the availability and quality of surveillance data in these groups. Secondly, there is a need for better (particularly shorter) treatment regimens to improve individual case management and to prevent and control the emergence and spread of drug resistant strains. Thirdly, the search is still on for better tuberculosis vaccines to provide more complete and longer-lasting protection against active TB. Success in all three areas is likely to be required to achieve the Stop TB goal to eliminate TB as a public health problem by 2050 [1, 2]. This paper addresses the first of these challenges and focuses on the need and potential strategies to improve diagnosis and thereby surveillance of childhood TB in low-resource, high-burden settings. In 2009 an estimated 9.4 million cases of TB occurred worldwide, equivalent to an annual global incidence of 137 per 100,000 population [3]. In the same year, 1.7 million deaths were attributed to tuberculosis [3]. TB remains second only to HIV as a leading infectious cause of death globally [4]. Global estimates of the causes of death among children have also been derived [5, 6], and the latest estimates based on data from 2008 are illustrated in Figure 1 [4]. Given the overwhelming burden of tuberculosis among the population as a whole and the
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