Sanitation and water supply coverage thresholds associated with active trachoma: modeling cross-sectional data from 13 countries

Trachoma is the leading infectious cause of blindness. Previous association studies have primarily assessed household-level exposures, ignoring potential community-level protection from water and sanitation coverage in neighbouring houses. There is biological plausibility that increased community-level coverage of facial cleanliness and/or sanitation could reduce trachoma transmission, even to non-face washers or to those without access to sanitation.

This multi-country study investigating relationships between active trachoma and community-level coverage of sanitation and water is novel in concept and unprecedented in scale. The findings support the plausibility of community-level or herd protection from trachoma with increasing water and sanitation coverage. The results of this study suggest access to adequate water and sanitation can be important components in working towards the 2020 target of eliminating trachoma as a public health problem.