Page:Bergey's manual of determinative bacteriology.djvu/728

 cal with this species, although it is more difficult to cultivate (Dunkin and Balfour- Jones, Jour. Comp. Path., 48, 1935, 236). Source: Isolated from the intestinal mu- cous membrane of cattle suffering from chronic diarrhoea. Apparently an obligate parasite. Habitat: The cause of Johne's disease, a chronic diarrhea in cattle. Found in the in- testinal mucosa. 13. Mycobacterium leprae (Hansen, 1874) Lehmann and Neumann, 1896. (Bacil- lus leprae Hansen, Norsk. Mag. Laegevi- densk., 9, 1874, 1; also see Arch. f. path. Anat. u. Physiol., 79, 1879, 32; Nord. Med. Ark., 12, 1880, 1; and Quart. Jour. Micro. Sci., £0, 1880, 92; Lehmann and Neumann, Bakt. Diag., 1 Aufl., 2, 1896, 372). lep'rae. Gr. noun lepi-a leprosy; M.L. gen. noun leprae of leprosy. Common name: Leprosy bacillus or Han- sen's bacillus. Though not yet cultivated in vitro, these bacilli were the first to be recognized as a cause of human disease (Hansen, op. cit., 1874). The bacilli occur in enormous num- bers in lepromatous (nodular) cases of leprosy (Hansen's disease) and very sparsely in the tuberculoid or neural forms. Bacteriological identification depends on: (a) acid-fast staining and (b) failure of the organism to multiply in bacteriological media or in laboratory animals. Heated sus- pensions of the bacilli (obtained from nodules) produce a positive lepromin reac- tion in 75 to 97 per cent of normal persons and of tuberculoid cases of leprosy but usually produce no reaction in lepromatous individuals (Mitsuda: See Hayashi, Int. Jour. Leprosy, 1, 1933, 31-38). The failure of lepromatous persons to respond to injected leprosy bacilli constitutes a criterion for testing the validity of the acid-fast micro- organisms which can at times be recovered from leprous tissues by inoculation of bac- teriological media. Many organisms have been isolated from leprous tissues, some of which are acid-fast and which have been styled Mycobacterium leprae. The strains which have been ade- quately studied have proven to fall into the saprophytic groups. Hanks (Int. Jour. Lep- rosy, 9, 1941, 275) found that acid-fast cultures of this type were recoverable only from lesions located proximally with respect to open ulcers in the skin. Description of organisms seen in leprosy tissue from Hansen {op. cit., 1874, 1) and Topley and Wilson (Princip. Bact. and Im- mun.. London, 2nd ed., 1936, 316). Rods, 0.3 to 0.5 by 1.0 to 8.0 microns, with parallel sides and rounded ends, stain- ing evenly or at times beaded. When numer^ ous, as from lepromatous cases, they are generally arranged in clumps, rounded masses or in groups of bacilli side by side. Strongly acid-fast. Gram-positive. Pathogenicity: The communicability of leprosy from man to man is accepted (Rogers and Muir, Leprosy, 2nd ed., Balti- more, 1940, 260 pp.). Experimental trans- mission to humans or to animals has not been successful. Source: Found in human leprous lesions. In the lepromatous form of the disease, bacilli are so abundant as to produce stuffed-cell granulomas; in the tuberculoid and neural lesions they are rare. Habitat: Obligate parasite in man. Con- fined largely to the skin (especially to convex and exposed surfaces), testes and to peripheral nerves. Probably do not grow in the internal organs. 14. Mycobacterium lepraemurium Marchoux and Sorel, 1912. (Bacillus der Rattenlepra, Stefansky, Cent. f. Bakt., I Abt., Orig., 33, 1903, 481; Mycobacterium leprae murium (sic) Marchoux and Sorel, Ann. Inst. Past., 26, 1912, 700.) lep.rae.mu'ri.um. Gr. noun lepra leprosy; L. noun mus the mouse; L. gen. noun muris of the mouse; M.L. noun lepramuris leprosy of the mouse; M.L. gen. pi. noun lepraemu- rium of leprosy of mice. Common name: Rat leprosy bacillus. Rods, 3 to 5 microns in length, with slightly rounded ends. When stained, the cells often show an irregular appearance. Strongly acid-fast. Gram-positive. Like the human leprosy bacillus, this or- ganism has not been cultivated in vitro, but it can be passed experimentally through rats, mice and hamsters. Distinctive characters: The heat-killed