INTESTINAL PARATUBEBCULOSIS 449 



diarrhea, anemia, cachexia, and death. It is due to an 

 acid-fast bacillus. 



Occurrence. — ^The disease was discovered in 1895 by 

 Johne and Frothingham in Germany. It is not uncommon 

 in the United States. Sporadic outbreaks and enzootics 

 have been reported from several states. England and the 

 continent of Europe are badly infected. In Switzerland and 

 Denmark it causes considerable losses. It is probably much 

 more prevalent than usually suspected, being confused with 

 other chronic enterites and bowel tuberculosis. 



Etiology. — An acid-fast bacillus resembling the tubercle 

 bacillus of avian type. The bacilli are found in the intestinal 

 mucous membrane, and in the mesenteric lymph glands. 

 The germ does not grow artificially unless cultivated on a 

 special medium. It is probably distinct from the tubercle 

 bacillus. (See Bacteriology.) 



Natmal Infection. — The causal organisms are eliminated 

 with the feces. They enter the body of a susceptible animal 

 via the digestive tract. The contagiousness of .Johne's disease 

 has been proved by feeding experiments and successful 

 transmission intravenously. This is further confirmed by 

 the practical observation, that when once introduced into a 

 herd it spreads. 



Necropsy. — ^The cadaver is usually emaciated. The lesions 

 are confined to the bowels and mesenteric lymph glands. 

 In typical cases the mucous membrane of the small intestines 

 and occasionally the colon and cecum is greatly thickened 

 (sometimes four-fold) and thrown into folds or convolu- 

 tions, some of them transverse, some longitudinal, giving the 

 bowel a corrugated appearance. Coating the affected mucosa 

 is a tiu-bid, grayish-yellow, slimy exudate which is readily 

 scraped off. The surface of the folds is usually smooth; the 

 crevices between ragged. Nodules and ulcers do not occur. 

 The mesenteric glands and Peyer's patches are somewhat 

 swollen. 



Symptoms. — ^As a rule, only adult cattle are affected, 



although occasionally it may attack yearlings or even younger 



animals. The disease develops gradually and may go on 



for a year and not be noticed. The most prominent symp- 



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