Infection of Laboratory Animals with Johne's Disease and Leprosy

Abstract

ACCORDING to Francis¹, “until recently it was generally accepted that laboratory animals had not been infected with Myco. leprœ or with Myco. johnei”. As regards the latter organism, in 1913 five out of, twenty-three rabbits, six out of forty mice and three out of twelve rats were successfully infected², the disease in three of the mice extending from the stomach to the rectum. In some situations even the muscular layer was invaded by the specific micro-organism, although the majority were found in the apices of the villi. The bacteria were grown on F. W. Twort's Myco. phlei egg medium or acclimatized to grow on ordinary glycerine-beef broth, although admittedly it would probably have been better to use naturally infected bovine gut. It was easier to infect by injection than by feeding, but by the latter method infection of the mesenteric glands was not at all difficult, although, of course, this does not mean that intestinal disease would have followed had the animals been allowed to survive.