1973 Volume 42 Issue 4 Pages 210-217
It is important to clarify the source of natural infection of murine leprosy since we have found in previous experiment that murine leprosy bacillus is present in apparently healthy mice, an attempt was therefore made to isolate acid-fast organisms from the or-gans of fresh water fish bred and reared in pond closely related to earth and then in-oculate the organisms isolated to SPF (specific pathogen free) mice rearing under aseptic conditions in Vinyl-Isolator system.
For examination of bacilli in fish, stamp smears were prepared from liver, spleen, . kidney and gill. The slide was stained by Ziehl-Neelsen method, examined, closely under the microscope and organ showing bacilli was emulsified in Hanks solution, centrifuged lightly, and a small quantity of india ink added to supernatant, and a part of material prepared was inoculated subcutaneously into the back of SPF mice and the other of its was cultivated. The inoculated mouse carefully examined by method of spread prepara-tion from connective tissue surrounding the site of inoculation, marked by the india ink.
The organs of 3 carp and 280 goldfish were examined for the presence of acid-fast bacillus, and the bacilli were found in the organs from 3 goldfish. In 2 out of 6 primary inoculated mice (origin ; No. 243), though a leproma was not formed, there was pronounc-ed bacterial proliferation at site of injection, and then the material from subcutaneous tissue showing the proliferation of the bacilli was inoculated into next generation of SPF mice. Four of 6 animals in second generation showed bacterial proliferation and a mild leproma, and moreover 3 of 4 animals showed pulmonary lesion with leproma. All animals inoculated with material from second passaged mouse developed subcutaneous lepromata of murine leprosy in third generation (C3H mouse reared in conventional).
In the control, proliferation of acid-fast bacillus was not found in animals both groups in inoculated with heat-killed material and untreated, and there was no growth on the usual media for acid-fast bacteria at 33°C or 37°C.
As a result of the finding in this study, it was shown that acid-fast bacilli were found in organs of fish grown in fresh water pond and the typical leproma of murine leprosy was produced at site of inoculation in mice inoculated with living material. It seems that these findings are important in considering the origin of natural infection of the murine leprosy, but it is difficult to obtain the conclusion from only the present data because there are several questions at present time. It will be able to clarify the difficult problem according to development of culture technique of M. lepraemurium in the future.
