Primary dapsone-resistant leprosy in Cebu, Philippines.

A survey of the prevalence of primary dapsone-resistant leprosy in Cebu, Philippines, has yielded an estimate of 3.6 per 100. Fifty-three of 55 patients proved to have M. leprae fully susceptible to dapsone. The organisms of two patients multiplied in mice administered the minimal effective dose of dapsone; and those of one of these patients also multiplied in mice administered dapsone in a 10-fold larger dose.