GASTRd-ENTERITIS 121 



tract involved. From a clinical standpoint the following 

 forms occur: 



(a) Simple, (6) croupous, (c) mycotic, (d) toxic. 



Simple Gastro-enteritis. — Etiology.— The causes of simple 

 gastro-enteritis are in a general way the same as those of 

 gastro-intestinal catarrh, but acting more intensively (see 

 these). Food which is infected with bacteria or fungi or 

 damaged by improper harvesting; frost, or containing poison- 

 ous, irritant weeds; or good food injudiciously fed may, 

 therefore, be predisposing factors. Overexertion, especially 

 in very hot weather (horses at hard work, animals shipped 

 long distances by rail, etc.), predisposes by greatly lowering 

 resistance. Copious draughts of cold water, the body being 

 hot, act in much the same way. 



The exciting causes of gastro-enteritis are evidently 

 bacterial. Probably no one species, however, is a constant 

 cause. For some as j^et unknown reason microorganisms 

 which are regularly found in the digestive tract assume 

 pathogenic activity once the resistance of the patient is 

 reduced by dietary errors, overexertion, extreme heat, etc. 

 It may thus be caused by some of the colon bacillus group. 

 The Bacillus enteritidis, the necrosis bacillus and pus bacteria 

 seem to have been active in some cases. 



Animal parasites (Strongylus tetracanthus and Spiroptera 

 megastoma in horses, and Spiroptera strongylina in swine) 

 are justly accused. 



In the ox a traumatic gastritis results from foreign bodies 

 penetrating the walls of the stomach (see Traumatic Indiges- 

 tion of Ox). 



Certain irritant drugs (aloes, cantharides) can cause toxic 

 gastro-enteritis. 



Symptoms. — ^The symptoms of simple gastro-enteritis are 

 much more intensive than those of catarrh. While at times 

 they develop gradually, (follow catarrh) as a rule the onset 

 is sudden (six to ten hours). The principal sjonptom is 

 abdominal pain, which is continuous and generally severe. 

 Appetite for food is entirely absent, although water may be 

 taken at frequent intervals. In the early stages the bowels 

 are constipated and peristalsis suppressed. Later diarrhea 



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