Fig 1.
Pre-stop MDA survey Phase 1—Defining the OTZs.
MDA, mass drug administration; OTZ, operational transmission zone.
Fig 2.
An example of establishing OTZs in Tchad.
(A) Identifying potential breeding sites. A map of breeding sites that require assessment developed from a desk assessment of information available—red circles represent a possible potential or active onchocerciasis breeding site areas (35 in total). (B) Defining the OTZ. Following the assessment of the breeding sites, further consideration of the historical and environmental information, 5 OTZ were defined (red lines). OTZ, operational transmission zone.
Fig 3.
Pre-stop MDA survey Phase 2—Carrying out an epidemiological survey.
MDA, mass drug administration.