Leprosy is the clinical manifestation of chronic infection with Mycobacterium leprae, an intracellular parasite with a predilection for skin and nerves. Disabilities and mutilations associated with this disease, which are attributable primarily to nerve involvement, have made leprosy among the most feared and stigmatizing of all diseases. It is still widespread in the warmer regions of the globe, including southern Europe, southern USA and most of the developing countries. Though widespread, the distribution of the disease in endemic regions is sparse (a prevalence rate of 1 per 1000 is high) and predominantly rural, for reasons which are not understood, but which add to the difficulty of providing effective disease control.