Tuberculosis management time: an alternative parameter for measuring the tuberculosis infectious pool.

OBJECTIVE: To demonstrate the application of TB management time as an alternative parameter to estimate the size of the tuberculosis infectious pool in West Gojjam Zone of Amhara Region, Ethiopia. METHODS: In this study, we used the TB management time, i.e. the number of days from start of cough until start of treatment, to determine the infectious period. Patients with sputum smear-positive and smear-negative pulmonary TB, retreatment and an estimated number of undetected cases were included. The infectious pool was then estimated as the annual number of infectious person days in a defined population. RESULTS: The TB management time of presently undiagnosed TB cases and sputum smear-positive patients contributed significantly to the infectious pool with 151,840 and 128,750 infectious person days per year, respectively. The total infectious pool including sputum smear-negative TB cases and retreatment patients in the study area was estimated at 325,410 person days or 15,447 person days per 100,000 population during the study year. CONCLUSION: Recording TB management time may be used to estimate the infectious pool of TB and to monitor programme performance in the community.