Progress of trachoma mapping in mainland Tanzania: results of baseline surveys from 2012 to 2014

This paper reports on results of baseline trachoma prevalence surveys undertaken in 31 districts of mainland Tanzania in 2012-2014. In 2012 and 2013, 12 at-risk districts were selected based on proximity to known trachoma endemic districts, while in 2014, trachoma rapid assessments were undertaken, and 19 of 55 districts prioritised for baseline surveys.

A multi-stage cluster random sampling methodology was applied whereby 20 villages and 36 households per cluster were surveyed in each district. Only three districts had a prevalence of trachomatous inflammation follicular (TF) in 1 to 9-year-olds over the threshold at which WHO recommends mass distribution of azithromycin together with implementation of facial cleanliness and environmental improvement. By contrast, trichiasis was found to be a public health problem in many districts (20), therein calling for support for community-based trichiasis surgery.