664 DISEASES OF SWINE 



These little worms work their way out of the digestive apparatus of 

 the grubworm and bury themselves in small cysts in the abdominal 

 cavity of the worm. In rooting about the feed yards the hog un- 

 earths these worms and eats them very readily. When the worm 

 reaches the stomach of the hog and is digested, the larval thorn- 

 headed parasite is set free, and now commences its development in 

 the intestines of the pig. It does this quite rapidly, and in a few 

 weeks is fully mature and ready to commence over again its Ufe 

 cycle. 



Symptoms. — If the parasites be present in small numbers, say 

 one or two, no symptoms of importance may be produced. Where 

 several of them are found they undoubtedly result in considerable 

 harm. The worm buries itself in the wall of the bowel, and often 

 produces severe irritation, and may even cause an abscess to form. 

 On the outer surface of the bowel there may be a slight nodular 

 bulging over the point of attachment of the parasite, and an 

 inexperienced man might mistake these for lesions of tuber- 

 culosis. The mistake can easily be corrected by cutting into 

 one of the nodules, where the head of the worm will be found 

 buried. 



The thorn-headed worm does not remain attached to the one 

 spot, and very frequently lets go its hold on one spot to later attach 

 itself by a fresh bite in some other part of the bowel. In this 

 manner it very frequently causes a severe scattered inflammation 

 of the inner lining of the intestines, which may be so marked as to 

 be almost regarded as a true inflammation of the bowels. 



As a result of this irritation and the drain upon the system of 

 the affected animal well-marked constitutional symptoms are 

 seen. The pig becomes thin, loses appetite, often has irregular 

 periods of constipation, alternating with diarrhea. As a result of 

 the continued disturbance of digestion, the affected animal develops 

 quite severe nervous symptoms. These disturbances of the ner- 

 vous apparatus are much more marked with animals that suffer 

 from the echinorhynchus parasite than with any other form of 

 intestinal worm. These nervous symptoms are manifested by 

 marked restlessness, irritability, twitching of the muscles of the 

 head and neck, and often the development of convulsive seizures 

 resembUng those of epilepsy and eclampsia. When the nervous 



