240 



PARASITES OF THE DOMESTIC ANIMALS 



Fig. 124 

 Ascaris lumbricoides, 

 with shell and albu- 

 rn i n o u s envelope 

 (copied from Braun's 

 "Animal Parasites of 

 Man"). 



which are generally 

 denticulate. The body 

 is white, firm, and elas- 

 tic. The males have 

 two spicules and numer- 

 ous papillae anterior and 

 posterior to the anus. 

 The vulva of the female 

 is situated toward the 

 Egg of anterior third of the 

 body. 



Length of female, 20- 

 25 cm. (8-10 inches); 

 male, 15-17 cm. (6-6 3/4 

 inches) . 



Eggs, oval, 60-75 microns long by 40-58 

 microns wide. The shell is mammillated. 



In its adult state this worm lives in the 

 intestines of the hog and sheep, and also of 

 man. 



The ascarid of the hog and sheep and 

 that of man so closely resemble each other 

 that a number of authors now consider 

 them as one species; others distinguish a 

 specific difference, claiming that the ascarid 

 of the pig differs from the human ascarid 

 in being thinner, having the longitudinal 

 strise closer, spicules less sharp, and ova 

 smaller. It would seem, however, that such 

 slight differences should be regarded as of 

 no more than varietal importance. 



Heavy invasions of these worms in the 

 intestines of hogs bring about the con- 

 ditions such as have alread,y been described 

 in aggravated intestinal helminthiasis. In 

 young pigs especially, there is general un- 

 thrift, and emaciation may become quite 

 advanced. There is usually a cough, and 

 this is likely to be accompanied by occa- 

 sional vomiting. The pig shows a pecu- 

 liar restlessness, wandering about without 

 apparent motive and emitting cries indica- 

 tive of colicky pains. The lumen of the 

 intestines may be obstructed by the 



Fig. 125. — - Aseari 

 coides, male at right, 

 left, natural size. 



i luml^ri- 

 female at 



