INFECTIOUS DYSENTERY 169 



ACUTE INFECTIOUS DYSENTERY 



In the northern half of the United States horses are 

 the subjects of this disease. It is a hyper-acute, some- 

 times rapidly fatal, form of diarrhoea occurring most 

 frequently in young horses during the cold months of 

 the year. While the etiology of this disease is as yet 

 unknown, it is no doubt infectious in character, and is 

 transmissible. It occurs in an enzootic form and may 

 affect all the young horses in a series of stables. 



That it is not the result of errors in diet is easy to 

 demonstrate. It occurs in stables widely separated and 

 in which the feed and methods of feeding are not at all 

 similar. It affects young horses indiscriminately in a 

 stable or region, while the old horses fed on the same 

 feed and under the same conditions are not affected. 

 "When a case develops in a stable in a young horse, other 

 young horses in the stable can not be prevented from con- 

 tracting the disease, although the method of feeding 

 be changed immediately after the development and rec- 

 ognition of the first case. The earliest eases in an out- 

 break are usually the most severe. Towards the end 

 of an enzootic series of cases, only mild attacks are seen. 



Symptoms. There are no premonitory signs that are 

 noticeable. The horse may be attacked while idle or while 

 in harness at work. Suddenly a diarrhoea begins. The 

 evacuations are at first only a trifle more soft in con- 

 sistency than normal, but an evacuation is followed by 

 another every five or ten minutes. After three or four 

 evacuations have occurred thus, the feces that are passed 

 in following evacuations become more and more soft and 

 watery. At the end of an hour the evacuations are merely 

 water with a trace of feces in it. This liquid is passed 

 every five or ten or, at most, every twenty, minutes, and 

 spurts outward with considerable force. 



