Primary dapsone resistance in leprosy

20 carefully selected untreated patients of bacilliferous leprosy were investigated for primary dapsone resistance by foot pad inoculation. Mice were fed on 0.001 g% and 0.01 g% of dapsone during the period of study. Mice in the control group were given normal rodent feed only. Animals were sacrificed from 6 month onwards at 6 week intervals upto 9 months. In two animals the growth of M. leprae was not inhibited by 0.001 g% concentration of dapsone in diet, but was completely inhibited by 0.01 g% of dapsone.