Leprosy.

Leprosy is a unique infectious disease with a prolonged incubation period and a predilection for skin and nerves. The involvement of nerves by the primary infection as well as the immunologically mediated reversal reactions result in impairment of nerve function and severe disabilities. The introduction of the World Health Organization Multi Drug Therapy over the last two decades has produced dramatic changes in the management and control programmes of leprosy. A recent important contribution to the understanding of leprosy pathogenesis has been the elucidation of the molecular basis for the entry of Mycobacterium leprae into the Schwann cell and the peripheral nerve. Leprosy still remains the commonest cause of peripheral neuropathy in developing countries.