114 PARASITES OF THE DOMESTIC ANIMALS 



erate, and the skin becomes covered with fine, dry scales, later becoming 

 denuded, fissured, and scabby. 



It is but slightly contagious and, except in cases of extreme neglect, 

 has little tendency to spread upon the body. Where it seems to progress 

 beyond the limits usual to the choriopt, it should be determined whether 

 or not psoroptic scabies is coexisting with it — a condition which is 

 quite possible. If this is suspected, material from several affected 

 locations should be examined for recognition of the infecting species. 



Sarcoptic Mange of Cattle. — Mange of the ox due to Sarcoptes need 

 be no more than mentioned here. Probably in every case where it has 

 occurred it has been by transmission from animals more likely to har- 

 bor this species, as the horse or goat. In bovine animals the disease is 

 usually of short duration, showing less tendency to spread and yielding 

 more promptly to treatment than in the horse. It affects chiefly the 

 skin about the eyes and cheeks and may extend to the sides of the 

 neck. 



Mange of the Hog 



Two kinds of mange affect the hog. These are as follows: 



1. Sarcoptic mange, due to Sarcoptes scabiei var. suis. 



2. Follicular mange, due to Demodex folliculorum var. suis. 

 Sarcoptic Mange of the Hog. — Sarcoptic mange is considered to be 



the most common form in these animals. The infecting sarcopt is the 

 largest variety of the species and may be seen with the unaided eye as a 

 minute moving speck among the removed cutaneous debris. 



Symptoms. — The presence of the disease is first shown upon the 

 skin about the eyes and ears, from which points it spreads to the back 

 of the neck, withers, shoulders, and back, later, if unchecked, invading 

 the greater surface of the body. The pruritus is extremely severe and is 

 especially aggravated in animals subjected to the body heat of crowded 

 pens. With the extension of the itching nodules the bristles fall out, 

 and the skin becomes wrinkled and covered with brownish or dark 

 gray crusts. Within the folds the skin presents the morbid changes 

 usual to sarcoptic mange; it is fissured and bleeding and there may be 

 ulcerations. 



Yoimg pigs and those with a thick curly growth of hair suffer the 

 most. The condition retards development and fattening, and severe 

 cases may lead to general debility and death. 



Transmission. — Contagion is by contact of the animals with each 

 other, essentially facilitated when crowded together in pens or lots. 

 Because of the habit these animals have of rubbing their bodies, ob- 

 jects upon which infected hogs have scratched are especially a source of 

 transmission. 



This mange of the hog may be transmitted to man and to the dog and 



