Sampling survey zones.

Upper right panel: the region in Africa from which samples were collected. Large panel: enlargement showing collection zones; samples were collected within or adjacent to the Odzala-Kokoua National Park in western RoC near the border with Gabon and the large panel indicates the details of the fecal sample collection zones: A and B2 are fecal sampling zones using closed loop survey or line transects (green line) and B1, C and D are sampling zones by reconnaissance walk survey (triangle shapes) as described in Materials and Methods. The blue line is the Mambili River. The diagnostically confirmed outbreak region (DCO) south and west of the river is in gray with dash lines and the no reported outbreak (NRO) region north and east of the river is in gray without dash line. The border of the Odzala-Kokoua National Park is identified by a dashed gray line.