Dapsone-resistant leprosy in Addis Ababa: a progress report.

Two hundred and twelve lepromatous patients, presenting with suspected dapsone-resistant leprosy in the 5-year period 1 973-77, were taken into trial treatment with dapsone. Clinically, 55% have been proven to be dapsone resistant and the remainder are continuing to respond to full dosage dapsone after 4·5 to 9 years. This clinical observation contrasts with results of the dapsone-sensitivity studies in mice which demonstrated in 86% of the 43 patients examined dapsone-resistant bacill i . The relevance of partial dapsone resistance, diagnosed in mouse foot-pad tests, is challenged and a modified definition of dapsone resistance is suggested . The annual incidence of proven dapsone-resistant leprosy over the period 1 973-77 was 1 ' 8%, resulting in a prevalence in 1 978 of 1 1 9 per 1 000 lepromatous cases on register in Addis Ababa.