THE COMMON DISEASES OF SWINE. 



'Q3 



VII. Measles and Trichina. 



Causes. — ^In swine measles is caused by a parasite (the bladier 

 worm) from eating the eggs of the tape worm of man (taenia solium) 

 in its food, just as trichina is caused by eating rats and mice or garbage 

 containing the germs of this parasite ; dogs, also, are well known to carry 

 and void the eggs of the tape-worm, and hence care should be taken that 

 swine do not eat their excrement. If the flesh of measly pork is eaten 

 by man, without its being most thoroughly cooked, he will be just as 

 surely infected with tape-worm as he would be with trichina if he ate 

 trichina-infected pork. Hence, it is never safe to eat measly pork, since 

 there is always danger that some of the cysts may escape death in 

 cooking. 



The tape-worm is a flat-bodied worm, made up of small segments or 

 joints from a quarter to a half inch in length, joined end to end, with a 

 depression between them. When full grown, the worm is from one inch 

 to one hundred feet long. One end is narrow, being the head, which* is 

 globular and furnished with circular, sucking discs and a proboscis or 

 snout, encircled by a row of booklets. From the broad end the segments 

 become detached and are expelled when ripe. These little segments may 

 be seen wriggling along over the grass, vegetables and grounfl , and, as 

 they go, they deposit innumerable quantities of eggs, which are taken up 

 by grazing animals, especially the hog. It is estimated that a single tap© 

 worm lays upwards of 25,000,000 eggs. An egg taken into the stomach 

 of a hog opens and hatches an ovoid, six-hooked embryo, which bores 

 its way through the tissues till it finds a tissue congenial to its nature ; 

 and there it encysts itself and lies an 

 indefinite length of time till, perhaps, 

 it is eaten by a person, who becomes 

 a host for the tape- worm, which is 

 developed very soon and causes intes- 

 tinal pain, emaciation, nervous irrita- 

 bility, convulsions and, often, death. 



The cysticercus cellulosa is the hydatid or bladder worm, that forms 

 the measles in pigs ; it becomes encysted in the mus- 

 cles, liver, brain, mucous and serous membr^ines, etc. 



How to know it. — Measly pork is known by the 

 tysts, some of which are nearly the size of a grain 

 of barley, distributed through the muscular and 

 ftther tissues. In the living hog, when infected, 

 there will be found small, watery pimples of a pink or red color, just 

 under the skin. There will also be weakness of the hind parts and gen- 

 eral lack of health. 



HEAD OF T^NIA SOLIUM. 

 Magnified, (Cobbold.) 



CYSTICERCUS CEtLU' 



LOSA. — Magnified. 



