Studies on Murine Leprosy Bacillus

During the primary isolation of murine leprosy bacillus, rapid growing mycobateria were sometimes isolated from the tissues of mice in experimental murine leprosy. To know whether these rapid growers exert any effect on the murine leprosy bacillus or whether they exist under an influence of the disease, the following experiment was per-formed using 10 animals for each grup:Group Intravenous Injection of Bacilli (Inoculum: 0.1mg per mouse)I. the supposed Hawaiian strain of murine leprosy bacillus, singlyII. strain Hll of the rapid grower, singlyIII. the supposed Hawaiian and strain Hll, concurrentlyThe animals were killed 3, 5, 6, and 7.5 months after. Gross involovement and spleen weight per gram of boyd weight were recorded at necropsy. The spleen, liver, lungs, and kidneys were removed aseptically and submitted to cultivation for re-isolating each of the bacilli inoculated. The results were shown in Tables 1 and 2. An in vivo effect of the strain Hll on the supposed Hawaiian strain was estimated by comparison bet-ween Groups I and III, and the reverse effect by comparison between Groups II and III. It may be summarized that (i) a somewhat growth-inhibtory effect of strain Hll on the supposed murine leprosy bacillus was noticed in the spleen and the liver but obscure in the lungs and the kidneys; (ii) in the spleen the Hawaiian strain was slightly growth-promoting, seemingly, at first but later growth-inhibitory against the strain of the rapid grower. There were no marked tendency in the liver, lungs and kidneys.