[The 69th annual meeting special lecture. Present situation of leprosy]

Many leprosy patients have deformity or disability owing to the characteristics of Mycobacterium leprae i.e. M. leprae affects skin and peripheral nerve. Optimum growth temperature of M. leprae was estimated by clinical manifestations and animal experiments, and it was concluded that the optimum temperature is 33 degrees C, and this characteristic of M. leprae may be one of the reason why M. leprae affects skin tissue. There was no reliable treatment of leprosy before 1943, but effectiveness of promin against leprosy was proven in 1943, and chemotherapy of leprosy was gradually improved especially since 1960 after the discovery of mouse footpad inoculation of M. leprae. In vitro cultivation technique of M. leprae is still unestablished, but susceptibility of ninebanded armadillo to M. leprae was discovered in 1970. Supply of M. leprae collected and purified from M. leprae infected armadillo tissue became available, then biochemistry, immunology and molecular biology of M. leprae was improved significantly. Ridley-Joppling's classification of leprosy i.e. two types (tuberculoid and lepromatous) and two groups (indeterminate and borderline) classification is being adopted at present. Rifampicin, DDS (dapsone) and clofazimine (lamprene) are widely used for chemotherapy of leprosy. WHO is recommending Multidrug Therapy (MDT) of leprosy i.e. administration of rifampicin and DDS for paucibacillary group, administration of rifampicin, DDS and clofazimine for multibacillary group. About 2.4 million leprosy patients are registered and under chemotherapy in the world at present, and about five hundred thousand new patients are being registered every year. Target of leprosy elimination by WHO is prevalence rate of leprosy should be less than one per ten thousand in every country.(ABSTRACT TRUNCATED AT 250 WORDS)