Study design.
Eligibility and enrollment.
In November 2009, the peri-urban zones were screened to find children that met the following study eligibility criteria: 1) < 60 months of age, 2) lived in squatter or low-income rental housing, 3) received their primary drinking/household water from a non-municipal source, and 4) lived in a household that lacked access to a direct municipal sewer line. Enrollment was limited to one child per household. If more than one child < 60 months of age resided in a household the youngest child was selected