Abstract
Attempts have been made to inoculate M. leprae intracerebrally in the adult mouse but there are no reports of intracerebral inoculation in the suckling mouse. The intracerebral inoculation method in suckling mice is recently being used in the isolation of some viruses and a study was carried out to see if M. leprae could be grown by this method. It was also believed that this would be a more appropriate method since it is known that the skin of the healthy mouse is contaminated by murine leprosy-like acid-fast bacilli. Suckling mice, 1-4 days after birth, were inoculated intracerebrally with bacterial suspension prepared from untreated leproma. The control group was inoculated with heat-killed bacterial suspension or left untreated.
The animals were sacrificed and examined 6 months-1 year after inoculation. Of 78 animals inoculated with the live bacillus, 14 showed an increase over the original count (2×105) and of these, over one-haf showed a 100 to 300-fold increase in the number of organisms. Numerous bacilli were found in site other than the brain such as the subcutaneous tissue, lymphglands and other organs. In the group inoculated with the heat-killed bacterial suspension, proliferation was found in 2 nd in the untreated group, acid-fast bacilli were found in brain of 8 of 15 animals. It would be difficult to believe that the isolated organism was the inoculated bacillus and it would be more rational to consider that contamination by murine leprosy-like acid-fast bacilli had taken place. The results suggest that M. leprae cannot be grown in the brain of suckling mice and by rearing the animals for a long time, contamination by murine leprosy-like acid-fast bacilli takes place.
