Ivermectin in onchocerciasis control in the forest zone of Cote d'Ivoire.

Ivermectin (Mectizan MK-933) is an efficient microfilaricidal drug used for mass treatment by the Onchocerciasis Control Programme (OCP) in the savanna zones of West Africa. Some populations of the forest zone of Côte d'Ivoire have very high microfilarial loads, so it was decided to treat some of these populations with ivermectin, in order to avoid an eventual reinfestation of the protected savanna areas. A pilot campaign was carried out in a small stream catchment area where onchocerciasis transmission is usually high. The whole population was treated orally with ivermectin (200 micrograms/kg of body weight), with the exception of children under 5 years of age, pregnant women and people who were ill. The results showed a very high efficiency of ivermectin in the treatment of onchocerciasis in the forest zone. The prevalence rate of microfilaria dropped from 60.1 to 33.2%. The community microfilarial load was reduced from 29.7 to 5.6 microfilariae per skin snip. To maintain this effect, the authors recommend regular treatment of all new comers into the area.