INFECTIOUS DISEASES 



311 



tious necrotic enteritis will be established in the not far distant fu- 

 ture. It seems probable that intestinal parasites are important pre- 

 disposing factors, probably because of injury to the intestinal mu- 

 cosa which provides a favorable field for action. The probable usual 

 method of entrance of the infection is in the feed or water, by way 

 of the digestive tract. 



Lesions. — The principal lesions of infectious necrotic enteritis oc- 

 cur in the mucous membrane of the intestine. In some cases the le- 

 sions indicate that the infection begins in the lymphoid tissue (Pey- 

 er's patches and solitary, follicles) of the intestinal mucosa near the 

 ileocecal valve. The lesions may be found in any portion of the di- 



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Pig. 92. DIPHTHERITIC ENTERITIS. A, gland I B, congested stroma vessel; 

 C, fibrinous exudate; D, organized fibrin in stroma. 



gestive tube including the stomach, but are usually more extensive in 

 the intestine. In the beginning the lymphoid areas become congested 

 and tumefied and later undergo necrosis. In other cases the lesions 

 are apparently not confined to the lymphoid tissue, but invade the 

 mucosa which becomes congested, tumefied and necrotic. When large 

 areas of the mucous membrane become involved the lesion appears as 

 a diphtheritic inflammation because of the adherent necrotic tissue. 

 In some cases the entire intestinal wall appears thickened and friable, 

 due to the ^ccumu^ted necrotic tissue, Some cases c^re observed in 



