[Current data on the bacteriology of leprosy]

Microscopic examination and mouse foot-pad inoculation are the main tools in Mycobacterium leprae bacteriology. Microscopic examination enables to calculate bacteriological (IB) and morphological (IM) indexes. The former scores the density of acid-fast organisms in the lesions and the latter scores their viability since only solidly stained acid-fast organisms are likely to be alive. Mouse foot-pad inoculation provides the opportunity for studying the growth curve of M. leprae. Alterations of this growth curve under drug therapy enable to assess the antileprosy activity of drugs and to determine the drug sensitivity of organisms. Acquired and primary drug resistances to DDS are to date the most important events in the chemotherapy of leprosy. Researches are in progress on mice with congenitally reduced immunological capacity (nu/nu mice) and on antileprosy vaccination. Although no decisive advances have been obtained in these fields, researches in progress are promising.