Objective: To describe the prevalence of pulmonary tuberculosis (TB) among household contacts of patients recently diagnosed as pulmonary TB.
Methods: Newly diagnosed pulmonary TB cases in 2006 were used as index cases for searching more active TB cases. All the household contacts were identified and examined with purified protein derivative, chest X-ray and sputum-smear for three times. The prevalence of active TB infection among household contacts was calculated and compared against demographic characteristics.
Results: A total of 1386 newly diagnosed active TB cases were reported and their 5392 household contacts were screened. The overall prevalence of active pulmonary TB among household contacts was 3.76%, but significantly higher in the age groups of <15 years or > or =55 years than the other age groups (chi2 = 15.381, P < 0.01). The rate of active pulmonary TB in household contacts was significantly associated with the amount of bacteria discharged from index cases (r = 0.998, P < 0.01). Through contact tracing, every 100 index cases could contribute in finding 15 more new active TB cases among household contacts.
Conclusion: Our results showed that this program could increase the identification of active pulmonary TB case through tracking down the household contacts of newly diagnosed TB cases.