Prevalence of depigmentation of the shins: a simple and cheap way to screen for severe endemic onchocerciasis in Africa.

The prevalence of skin depigmentation in the pretibial region is closely correlated in the adult Congolese population with conventional indices (microfilarial index, mean microfilarial density, cyst index) for the evaluation of endemic onchocerciasis. Individuals over 15 years of age in endemic villages who had a microfilarial index of 80-90%, had a cystic index of 60-70% and a pretibial depigmentation index about 20% (30-40% for individuals aged > 50 years). Thus, in Africa, this new evaluation index offers a simple, noninvasive, quick and cheap way to identify areas where the level of endemic onchocerciasis is probably high and which are likely to benefit from an anti-onchocerciasis campaign.