Heterogeneity of distribution of tuberculosis in Sheka Zone, Ethiopia: drivers and temporal trends

Objective: To describe the distribution of tuberculosis (TB) and its drivers in Sheka Zone, a geographically remote region of Ethiopia. Methods: We collected data on TB patients treated from 2010 to 2014 in the Sheka Zone. Predictors of TB incidence were determined using a multivariate generalised linear regression model. Results: We found significant spatial autocorrelation of TB incidence by kebele (the smallest administrative geographical subdivision in Ethiopia) (Moran's I = 0.3, P < 0.001). The average TB incidence per kebele ranged from 0 to 453 per 100 000 population per year, and was significantly associated with average TB incidence across adjacent kebeles, TB incidence in the same kebele in the previous year and health facility availability. Each increment in TB incidence by 10/100 000/year in adjacent kebeles or in a previous year was associated with an increase in TB incidence of respectively 3.0 and 5.5/100 000/year. Availability of a health centre was associated with an increase in TB incidence of 84.3/100 000. Conclusions: TB incidence in rural Ethiopia is highly heterogeneous, showing significant spatial autocorrelation. Both local transmission and access to health care are likely contributors to this pattern. Identification of local hotspots may assist in developing and optimising effective prevention and control strategies