42 JOHNE^S DISEASE 



risk of infection; but as, apparently, no acid-fast 

 bacilli were at any time found in the faeces, and none 

 in the bowel wall at the post-mortem examination, it is 

 possible that the original diarrhoea was due to some 

 other cause, especially as the animal was a young one. 



B. Bang mentions that he has noticed that cows, after 

 showing symptoms of the disease (such as diarrhoea, 

 slight wasting, etc.), and then apparently recovering 

 for a while, die in the end of Johne's disease. We 

 have been unable to find any record of a case, where 

 the bacilli have been detected in the faeces, in which 

 the animal has been known to recover and to remain in 

 normal health for any considerable time afterwards. 

 It is highly probable that once the bacilli multiply to 

 any extent in the intestinal mucosa the animal will die 

 of the disease after a period of from three months to 

 two years, depending on the sex of the animal, its food 

 supply and hygienic management, and on the presence 

 or absence of other diseases, such as tuberculosis, etc. 



It may be assumed, therefore, that a prognosis of 

 recovery is not possible in any clinically affected 

 case. The possibility of treatment with a curative 

 vaccine, when the disease is discovered in a very early 

 stage by means of a diagnostic reagent, can only be 

 determined after a considerable number of experiments. 

 Nevertheless, our knowledge of allied diseases such as 

 tuberculosis leads us to believe that such treatment 

 might lead to recovery. 



Treatment. — Unfortunately, there is no specific treat- 

 ment for Johne's disease. We know of no drug that 

 will kill the bacillus in the pathological lesions or 

 neutralize the toxins which it produces. Moreover, 

 the risk that one diseased animal will infect others on 

 the farm is so great that by far the safest, and in the 

 end the cheapest, course is to kill all the infected 



