170 DISEASES OF SWINE 



become irritated and inflamed, and obstruct the pass- 

 age of the food along the canal. The resulting 

 symptoms are those of acute or chronic indigestion, 

 and in young and poorly cared-for animals the 

 diseased condition is marked. Pigs are sometimes 

 very restless because of the irritation to the in- 

 testines, and may show other symptoms of a nervous 

 character. 



With proper care and feeding, pigs become strong 

 and healthy enough to throw off the parasites. In 

 thrifty hogs round worms are not found in large 

 numbers and cause no apparent harm to their host. 



THE THORN-HEADED WORM 



Echinorhynchus Gigas — Goeze 



Hogs are the only domestic animals that act as 

 hosts for the thorn-headed worm. The species found 

 in hpgs, in the adult stage, is a parasite of the small 

 intestine, sometimes of the large, and is usually 

 found fixed to the intestinal wall by means of its 

 hooked proboscis, from which the name thorn- 

 headed is derived. This parasite is not as common 

 as the round worm, and it is unusual to find more 

 than five or six of them in the intestines of any one 

 animal. It is frequently found associated with the 

 former, but is easily distinguished from ' it. How- 

 ever, the loss caused by it is no doubt large. 



Description.^The thom^headed worm is milky 

 white in color, irregularly wrinkled transversely, 

 and gradually tapering to a blunt point at the 

 posterior extremity. The general shape of the body 



