Pathogenicity of cultivated murine leprosy bacilli of Hawaiian-Ogawa strain in mice. 4) Visceral lesions in mice produced by intraperitoneal infection.

The pathogenicity of two substrains (HO-R and HO-S) of cultivated murine leprosy bacilli was examined by intraperitoneal inoculation to various strains of mice (C3H, KK, BALA/c, DDD and C57BL/6). HO-R (Rough Form) was first isolated on 1% Ogawa's egg yolk medium from the leprous lesions produced by original Hawaiian strain (H bacilli). HO-S (Smooth Form) was dissociated in vitro during the 9th to 15th subculture of HO-R on the same kind of medium. In all the mice tested, intraperitoneal inoculation with HO-R bacilli produced progressively severe visceral lesions in the manner similar to H bacilli harvested from subcutaneous leproma. The only exception was, however in DDD strain of mice H bacilli produced only slight visceral lesions even in the later stage of infection. HO-S was much lower in the pathogenicity than the above two strains of murine leprosy bacilli. Visceral lesions produced by intraperitoneal inoculation with HO-S used to be very slight in all the strains of mice except BALB/c. BALB/c strain mice were highly susceptible to intraperitoneal as well as subcutaneous infection with HO-S. From the above observations, it is concluded that the characteristic features of pathogenicity of cultivated murine leprosy bacilli, such as mouse strain differences, are all the same regardless of infection route.