Criterion for inclusion in onchocerciasis control programmes based on ivermectin distribution.

Data on onchocercal lymphatic and skin lesions from 45 communities located in the West African savanna were analysed to determine if the criterion for inclusion in ivermectin mass treatment based on risk of onchocercal blindness needs to be modified. Only 16 cases of elephantiasis were reported among 10,108 people examined. Other lymphatic lesions were almost exclusively found in people older than 30 years living in villages at risk of onchocercal blindness. Permanent skin lesions also affected older people and were 3 times more frequent in villages at risk of onchocercal blindness. Papular rash and pruritus affected younger people. No evidence was, therefore, found to change the criterion based on risk of onchocercal blindness presently in use in savanna areas.