Study site. A. Map of Ecuador showing location of District of Quinindé, Esmeraldas Province (black oval) (Courtesy of The General Libraries, The University of Texas at Austin). The recruitment area for the cohort was defined by the geographic boundaries of this district. B. Map showing parishes the District of Quinindé including La Concordia. H-Hospital Padre Alberto Buffoni. C. Geographic location of households of cohort infants.