In 1960, Shepard observed a limited multiplication of leprosy bacilli in the mouse foot pad. This limited multiplication type of infection has been confirmed by Rees and others. On the other hand, Waters and Niven reported that the limited multiplication, resembling that described by Shepard, had been achieved in the hamster ear and foot pad.
Such significant observations led us to an attempt to examine the fate of murine leprosy bacilli inoculated into the foot pads and ears of guinea-pigs.
At varing intervals, bacterial suspensions recovered from the tissues at the inoculation site were used for counting of the bacilli and for reverse transfer to mice to examine their multiplication and viability in the guinea-pigs. There was no evidence of multiplication of organisms in the ears and foot pads, and viability of organisms therein was remarkably diminished with time.

View full abstract

It is essential to study on the relation between macrophage and parasite in murine leprosy. However, in the previous experiments (Part 1) no finding could be obtained, concerning the macrophage-parasite relationship, although multiplication and viability of the bacilli were estimated by counting of the bacilli and reverse transfer. Therefore we have conducted the following experiment with regard to the macrophage-parasite relationship.
Guinea-pigs were subcutaneously inoculated in the back with suspension of murine leprosy bacilli. With intervals of 5 days, the subcutaneous conective tissues at the inoculation site were removed and spread on a glass slide and the behavior of the bacilli within mononuclears was examined. After 5 days, elongation of the bacilli was observed in mononuclears, and 15 days later many enlarged mononuclears filled with the elongated bacilli appeared at the site of inoculation. From the findings of this observation and of reverse transfer, it seemed that the growth patterns of murine leprosy bacilli subcutaneously inoculated into the guinea-pigs were identical with those in mice until 15 days after inoculation. But from then on infectivity of the bacilli in the guinea-pigs became remarkably reduced with time. After 30 days, non-leprous granuloma appeared at the inoculation site and the number of bacteria was significantly decreased.
Similar experiment; inoculation from Kirchner's medium back to the mouse, was performed to examine the viability of the in vitro cultured organisms. Elongation of the bacilli occurred in Kirchner's medium, but viability of the in vitro cultured bacilli was excessively reduced with time.
Based on these observations we have considered that macrophages of guinea-pigs play a role in multiplication of murine leprosy bacilli only in a short duration (about 15 days). It is desirable to prolong that short duration for evelopment of the study on transmission of murine leprosy to guinea-pigs, although no significant result was obtained in our attempts under present conditions.

View full abstract

The multiplication of M. leprae in the foot-pads of mice had been recognized in 1965, as reported by C.C. Shepard. The remark of this multiplication, however, must be due to the counting of acid-fast bacillary number in the tissue of foot-pad. If guinea pigs are used for these experiments, the results of skin reaction will be used for the remark in the multiplication of M. leprae, because the skin reaction in the experimental infections with acid-fast bacilli can be observed only in guinea pigs. Therefore, the experimental inoculation of M. leprae into the foot-pad of guinea pigs has been investigated.
This multiplication in the foot-pads of guinea pigs was not recognized in the experimental inoculation of M. leprae, not only with the emulsion of leproma but also with the emulsion of mouse foot-pad tissue, contained M. leprae. In the skin reaction provoked by Dharmendra antigen, however, it was found that guinea pigs may be sensitized with M. leprae at 5 months after the inoculation.
The above results were discussed on the activity of phagocytosis of foot-pad tissue, and the phagocytosis in guinea pig was stronger than those of mouse.
It may be concluded from the results of this investigation that the successful transmission of M. leprae into the hind foot-pad of guinea pig could not be obtained unfortunately.

View full abstract

7 cases of avulsion fracture of calcaneum at the insertion of achilles tendon in the leprosy for last 6 years are reported, but there is no subcutaneous rupture of achilles tendon. These fractures were occured on walking without any appreciable trauma. The mechanism of development of the fracture is supposed to be pathologic fracture: it is logical to believe that the avulsion fracture demonstrated in the leprosy is related to the fact that powerful force of gastrocunemius muscle always acts on the calcaneum, which has had a slight atrophy because of disturbance of both sensory and motor nerve.

View full abstract

Primary and mouse-passaged strains were inoculated into the hind foot-pads of fowls, but it may be concluded from our results that the successful transmission of M. leprae could not be obtained unfortunately.
However, no cultivable acid-fast strain was isolated from a fowl, as a contaminant.

View full abstract