668 



DISEASES OF SWINE 



considerable amount of pus-like material, and as a result the lard 

 fat is ruined. It is not so common for the worm to invade the kid- 

 ney, although it has been my experience on the kiUing floors of our 

 large packing-houses that the kidney worm invades the kidney with 

 much greater frequency than is commonly stated by most author- 

 ities. 



Description. — The Stephanurus dentatum has a rounded body^ 

 which is slightly larger than a knitting needle and tapers at both 

 ends. The outer skin or covering of the worm is colorless and trans- 

 parent. The dark-colored intestinal tract shows through this 

 outer covering, and gives the worm a rather pecuhar, well-marked 

 mottled appearance. The parasites are divided into the male and 

 female sex. The male parasite is about 1 to 

 Ij inches long; the female, Ij to 1| inches. 

 Mode of Infestation. — This has never 

 been definitely worked out, but from the 

 location of the parasite it would seem very 

 likely that the eggs which are laid in the 

 region of the kidney and in the pelvis of 

 that organ pass down the small tubes lead- 

 ing from the kidney to the bladder, and 

 thence pass out with the urine to the 

 outer world. Here they become mingled 

 with the food and water of the animals, and 

 are taken into the stomach and digestive 

 apparatus. The parasite here hatches out 

 and the small worm which emerges from 

 the egg seems to have the power in some manner of working its 

 way out of the intestine and into the fat in the region of the kid- 

 neys, where it permanently locates. It here burrows and encysts 

 itself, and continues its further development, with laying of eggs 

 and often formation of abscesses. 



Symptoms. — Kidney worm is often present without producing 

 any noticeable symptoms. Its presence is rarely diagnosed in the 

 living animal. On postmortem examination in the packing-houses 

 it is very commonly found by United States Bureau of Animal 

 Industry officials in hogs that apparently are in perfect condition 

 during life. There are many stockmen who think that the pres- 



Fig. 93.— Stephanu- 

 rus dentatum (kidney 

 worm): a, Male; b, 

 female; c, caudal ex- 

 tremity; d, cephalic 

 extremity. (From 



Kaupp's Animal Para- 

 sites.) 



