Targeted Active Case Finding In Household Contacts Of Smear Positive Tuberculosis Patients In A High Incidence Urban Setting

Background: This study assessed the additional role contributed by targeted active case finding in a setting where passive case finding strategy exists. Methods: This was a cross sectional hospital and community based survey, from 1st of May to 31st of August in Amana hospital and its catchment area in Ilala district Dar es Salaam region, Tanzania. Results: A total of 68 smear positive index cases were recruited in the passive case finding period whereby 390 of their household contacts were interviewed. Twenty out of the 390 (5.1%) contacts interviewed in the passive case finding period, reported to have cough which had lasted for two weeks or more at the day of the household visit. None of their symptomatic household contacts had been diagnosed with pulmonary tuberculosis at the time of the household interviews. A total of 74 smear positive index cases were recruited in the active case finding whereby 425 of their household contacts were interviewed. Eighteen out of 425 (4.2%) contacts reported to have had cough which lasted for two weeks or more. One of the two contacts was smear positive tuberculosis and one was smear negative. Overall, two contacts were diagnosed with pulmonary tuberculosis in the active case finding. This is a standardized prevalence of 471/100 000 (95% CI 82/100 000, 1879/100 000). Since the prevalence of TB by passive case finding was zero, the prevalence odds was undefined with an insignificant P-value. Conclusion: Due to the relatively low prevalence of tuberculosis it would be virtually impossible to interpret case detection findings based on statistical significances. Nevertheless, this study indicated that strengthening the current passive case finding system coupled with the introduction of active case finding, targeted to household contacts of infectious TB patients is likely to detect more tuberculosis cases than passive case finding alone.