Tuberculosis burden in China: a high prevalence of pulmonary tuberculosis in household contacts with and without symptoms
1 National Institute of Drug Dependence, Peking University, Beijing 100191, China
2 Takemi Program in International Health, Department of Global Health and Population, Harvard School of Public Health, Boston, MA, USA
3 National Center for Tuberculosis Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 100017, China
4 Center office, Beijing Tuberculosis and Thoracic Tumor Research Institute, Beijing 101149, China
5 Beijing Research Institute for Tuberculosis Control, Beijing 100035, China
6 Hunan institute for Tuberculosis Control, Changsha 410013, China
7 Jiangsu Center for Disease Control and Prevention, Nanjing 210009, China
8 Sichuan Center for Disease Control and Prevention, Chengdu 610041, China
9 Department of Environment health, Harvard School of Public Health, Boston, MA, USA
BMC Infectious Diseases 2014, 14:64 doi:10.1186/1471-2334-14-64Published: 6 February 2014
In the context of decreasing tuberculosis prevalence in China, we examined the effectiveness of screening household contacts of tuberculosis patients.
A tuberculosis survey was conducted in 2008. All 3,355 household contacts of notified tuberculosis cases were examined with a questionnaire interview, chest X-ray and three sputum smear tests. The effectiveness was examined by comparing the prevalence of pulmonary tuberculosis in household contacts with or without presenting clinical symptoms against the respective notification rates. Regression models were used to evaluate the factors associated with pulmonary tuberculosis.
Of the 3,355 household contacts, 92 members (2.7%) had pulmonary tuberculosis, among which 46 cases were asymptomatic. The prevalence of pulmonary tuberculosis and smear positive cases in household contacts without symptoms were 20 and 7 times higher than the notification rates in 2008, while those in household contacts with symptoms were 247 and 108 times higher than notification rates, respectively. The patients detected were mainly Index Cases’ spouses, sisters/brothers and those who were in contact with female Index Cases.
The present study provides convincing evidence that household contacts of notified tuberculosis cases are at higher risk of developing tuberculosis. Routine screening for household contacts without any symptoms is recommended for sustained tuberculosis control in China as well as in the world.