THE DIGESTIVE SYSTEM 47 



.4 scan's Suum 



Ascarids are found in practically all hogs. They are 

 not blood suckers, but obtain their nutrition by direct 

 absorption. The pregnant female discharges her ova 

 in the intestine and they pass out with the feces, where 

 they hatch and, so far as known, pass through a portion 

 of their life cycle in decaying matter on the earth's 

 surface and later gain entrance to the animal body with 

 the food or drink. 



Lesions. These parasites are round, and pointed at 

 either end; they are white or pinkish- white in color and 

 vary from six inches to twelve inches in length. Usually 

 they are found in the small intestine, though they may 

 occur in the large intestine and even in the stomach. 

 They attach themselves to the mucous membrane by 

 means of papillae or membranous teeth, and produce 

 irritation to the mucous membrane as well as providing 

 an avenue of entrance for a variety of bacteria which may 

 produce inflammatory lesions and even necrosis and 

 ulceration. The entire mucous membrane adjacent to 

 the parasites is affected by a catarrhal inflammation. 

 Similar disturbances are observed in the mucous mem- 

 brane of the hepatic duct when it is infested. The 

 worms may form a mass that completely obstructs the 

 intestine, resulting in an engorgement of the intestine 

 anteriorly to the obstruction. Occasionally the intestine 

 may be perforated and the offending ascarids found 

 protruding into the peritoneal cavity, or they may 

 pass through the intestinal wall and some of the intes- 

 tinal content, and, escaping into the peritoneal cavity, 

 will produce a general peritonitis. 



Symptoms. Infestation with a limited number of 

 ascarids probably does not produce any noticeable 

 symptoms. The symptoms evidenced will vary and 

 depend upon the manner in which the parasites are 

 damaging their host. If the hepatic duct is obstructed, 

 there will be digestive disturbances, associated with 

 icterus. If the bowel is obstructed, there will be evidence 

 of obstruction colic. Perforation of the bowel will 



