TOG 



ORDER V. ACTINOMYCETALES 



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 



