Abstract
The distribution of human loiasis in Western Nigeria has been examined. Blood samples were collected from school pupils in 95 villages from the various divisions and vegetation zones represented. Even though human loiasis is widely distributed in Western Nigeria, Ilesha, Ondo and Ijebu divisions are areas of high transmission level, whilst Oyo, Ibadan and Egba divisions are areas of low transmission level. The level of transmission in the savannah zones is significantly lower than in the rainforest and mangrove zones.