50 SWINE DISEASES 



in which they undergo various metamorphoses, finally 

 becoming sexually mature. They then leave the sub- 

 mucosa nodules and migrate into the lumen of the 

 intestine, where copulation occurs and the female later 

 ovulates in the same location. 



Lesions. The principal lesion is the submucous 

 nodules that occur in the large intestine. There may 

 be only a few nodules, or there may be many. These 

 nodules are inflammatory, caused by the presence of 

 the larvae. They are definitely circumscribed with a 

 fibrous capsule; the content of which is inflammatory 

 exudate that later becomes purulent, then caseous, and 

 may ultimately calcify. The nodules first cause a slight 

 hard, spherical elevation of the mucous membrane about 

 the size of millet seed, but they may later become as 

 large as a pea. In the later stages they assume a greenish- 

 gray cast due to the accumulation in them of pus. The 

 nodules frequently produce erosions and ulceration of 

 the intestinal mucosa, and they may persist and appear 

 as caseated incapsulated masses. The adult parasites 

 may be found free in the large intestine. They are 

 about three-fourths of an inch in length. 



Symptoms. The extent of invasion sufficient to 

 produce visible symptoms has not been determined, 

 but it is not uncommon to find a few nodules in the 

 intestine of swine that were slaughtered in packing 

 houses and were known to have been previously healthy. 

 The usual symptoms consist of a profuse and persistent 

 diarrhea, emaciation, weakness, and death in the intensely 

 infested animals. The disease is essentially chronic. 

 The course is from two to three months. 



Treatment. Because of the location of the offending 

 larvae, medication is of no avail. A small percentage 

 of the animals may be saved by dieting and treating 

 the symptoms as they arise. Prevention of further 

 spread of the disease should be the chief consideration. 



Trichocephalus Crenatus 



This parasite is not of common occurrence in America. 

 The worms are in shape similar to the old-fashioned 



