Abstract
1) The human leprosy bacillus was inoculated subcutaneously in 711 animals of 4 strains of black mouse (ICF, BK, C57BL, BTK), C3H and ddS, but proliferation of leprosy bacilli was not found.
2) Identification tests were carried out on 14 acid-fast bacilli which proliferated and these were found to be similar to the murine leprosy bacillus.
3) The Lepromin reaction was found to be the most simple and accurate for identification of the leprosy bacillus.
4) Contamination by acid-fast bacillus was investigated in 396 healthy, noninoculated mice and a high percentage, not only animals bred in the laboratory but obtained elsewhere, was found to be contaminated with the organism.
5) Inapparent infection by murine leprosy bacillus was found among the healthy mice. In other words, murine leprosy bacillus of mouse origin was discovered.
6) The acid-fast bacilli isolated in the present study are believed to originate from animals with inapparent murine leprosy infection.
7) Measures must be taken to prevent contamination by organisms such as these in conducting investigations in animals and the initial step following isolation of an organism should be to examine the Lepromin reaction.
