Childhood Tuberculosis in Household Contacts of Newly Diagnosed TB Patients

Introduction: Childhood tuberculosis (TB), although estimated to account for a major proportion of the global TB disease burden, has a lower public health priority. Reliable research and surveillance data on childhood TB is limited in most regions of the world. This study was conducted to assess the burden of childhood TB among the household contacts of new TB patients in Karachi, Pakistan. Methods: A retrospective analysis of children (<15 years) who were household contacts of new adult TB patients presenting to Marie Adelaide Leprosy Center (MALC) clinics in Karachi during the period of 2008 to 2010 was conducted. Results: Of the household children contacts (n = 6613) screened, 317 were suspected and 121(1.8%) diagnosed with TB. These included 89 (73.6%) with pulmonary and 32 (26.4%) with extra-pulmonary disease. Smear positivity rate in pulmonary cases was 32.6%. Mean age of children diagnosed with TB was 11.7 (+/- 2.8) years. Within the child-contacts screened, disease was found to be significantly higher among females (2.3%) in comparison to males (1.2%) (p-value <0.01). The commonest relationship of source cases to diagnosed children was the mother (n = 51, 42.1%). The source case was a female for 66.1% (n = 76) of the children. Conclusion: A smear positivity rate of 32.6% amongst pulmonary cases suggests their potential to spread disease and emphasizes a need to review the contribution of children in transmission of TB within communities. Greater vulnerability of the female child and considerable role of mother in disease transmission highlights a need to increase focus on females in TB control programs in Pakistan.