THE DIGESTIVE SYSTEM 67 



The exact life cycle of the parasite is not known, but 

 general sanitary regulations are always in order and 

 will no doubt be of value in preventing or at least dimin- 

 ishing the extent of future infestations. 



Ascaridiasis 



An occasional ascarid migrates into the liver by way 

 of the hepatic duct. These parasites in this location 

 mechanically obstruct the outflow of bile and also pro- 

 duce sufficient local irritation to establish a catarrhal 

 inflammation of the hepatic duct, the gall bladder, or 

 the bile duct. 



Icterus, associated with digestive derangement, will 

 probably be the only evidence of the presence of this 

 parasite in any portion of the liver or its excretory duct. 



The location of the parasite prohibits the successful 

 use of therapeutic agents. The possibility of invasion 

 into any of the hepatic structures may be diminished by 

 frequent medication of the swine with agents previously 

 mentioned that will eliminate these parasites from the 

 bowel. Frequent cleaning, and removal of the excrement 

 from the pens, yards, or barns, will tend to diminish 

 infestation. 



Distomatosis 



This is a condition resulting from the invasion of the 

 liver by the Distoma hepaticum, Distoma Americanum, 

 or Distoma lanceolatum. All are commonly called flukes. 

 Distomatosis occurs most frequently in animals kept 

 upon low, marshy, or swampy lands. Swine raised in 

 the southern part of the United States are commonly 

 infested. The exact life cycle of these parasites has 

 been carefully worked out and may be obtained by 

 reference to works on parasites^, suffice here to say that 

 the ova are eliminated from the liver in the bile and 

 pass to the outside in the fecal matter. After several 

 changes the embryos are found upon vegetation which 

 is consumed by their hosts. They find their way up 

 the hepatic duct and on into the bile tubes within the 

 liver. 



