SWINE DISEASES AND THEIR CONTROL 197 



and the eggs are laid and passed out to be reconsumed 

 without an intermediate host. The distribution of this 

 worm is most extensive, and but few herds are entirely 

 free. They mostly inhabit the small intestines, but fre- 

 quently penetrate the gall duct, and even enter the liver. 

 A few worms do not cause serious results. When pres- 

 ent in quantity, they cause indigestion, liver diseases, 

 progressive emaciation and occasionally convulsions. 

 This is one of the most troublesome worms affecting 

 swine and must be provided against if serious damage 

 is to be avoided. 



The pin worm is a small white worm more commonly 

 inhabiting the large intestines. It is shaped similar to 

 the Ascaris, is white or grayish in color and about a 

 half inch in length. These worms never do serious dam- 

 age unless present in extremely large quantities, when 

 intestinal indigestion may result. 



Another less important intestinal worm is the whip 

 worm. They attach themselves to the wall of the intes- 

 tines and may give rise to irritations in this way. 



Trichinosis. This small round worm has the adult 

 stage in the intestinal tract and the larval stages in the 

 muscular tissues. It is supposed that the hogs become 

 infected by eating rats and slaughter-house offal con- 

 taining the cysts of the worm, growth to maturity taking 

 place in the intestines. Copulation and reproduction take 

 place to liberate numerous embryos which penetrate the 

 intestines and migrate to the various tissues. This dis- 

 ease is communicable to man, and care must be taken 

 not to eat infected pork. The medical measures are 

 about the same as those recommended for other intestinal 

 worms, but the preventive measures must be from a 



