Abstract
In 1903, in the first report of murine leprosy, Stefansky described the occurrence of two forms of the disease, glandular and musculo-cutaneous. Since then many investigators have observed natural murine leprosy on the basis of this classification.
With further progress, however, most workers are of the opinion that the glandular and musculo-cutaneous forms are merely early and late stages of the same disease.
The purpose of this experiment is to study in detail the classification of mouse leprosy.
As stated in previous reports (La Lepro, 26, 1957), remarkable differences were found between the various inbred strains of mice, when susceptibility to murine leprosy was studied for the purpose of selecting an adequate experimental mouse strain.
This author considered that mouse leprosy should be classified into two polar types, benign and malignant. The skin lesions of the former type, such as of C57BL/6, appeared early and were hard, small and sharply defined, whereas those of the latter type, such as of C3H, developed later, were soft and much larger, with a diffuse thickening appearance.
The variation in susceptibility to murine leprosy, the benign (with resistance) and the malignant (without resistance), is manifested in these two clinical characteristic features.
The course of malignant type is in general progressive, with fatal termination in appro-ximately 30 weeks. On the other hand, the disease may undergo gradual regression and sometimes spontaneous healing in the late stage of the benign type.
Moreover, it is of interest in immunological studies that the administration of BCG to mice, in which the disease occurs as the malignant type, is sometimes possible to convert the malignant type to the benign type.
Taking this fact into consideration, observation with a new classification may contribute to progress in murine leprosy research.
