Special intervention zones.

The Special Intervention Zones (SIZ) of the former Onchocerciasis Control Programme (OCP) were launched in December 2002, following the closure of the OCP, to sustain the momentum that had been gained for onchocerciasis control through Mectizan distribution and vector control. The donation of Mectizan in 1987 was fortuitous for the OCP, as vector control had become costly and ineffective in certain areas. Mectizan distribution benefitted the populations affected by onchocerciasis, who saw improvements to their health. When the SIZ were launched, Mectizan distribution became the primary strategy for onchocerciasis control. Good coverages with Mectizan mass treatments have been achieved and maintained in most of the SIZ, leading to dramatic reductions in both the prevalences and intensities of onchocercal infection. The control efforts in the SIZ in Sierra Leone and some areas of Ghana and Togo, however, need to be strengthened. Although the SIZ closed at the end of 2007, the Mectizan distributions will continue until 2012.