230 



THE HOESE IN HEALTH AND DISEASE 



MANGE 



Mange is a very contagious disease of the skin caused by- 

 infestation with a mange mite. Mites belong to the arachnida, 

 and are so minute that they are just visible to the naked eye. 

 They possess but four pairs of legs. There are three genera of 

 mange mites recognized as infesting the horse — viz., Sarcoptes, 

 Psoroptes, and Symbiotes. Of these, the Sarcoptes scabiei var. 

 equi is the most destructive (Fig. 64). It burrows tunnels or gal- 

 leries into the skin. 



Fig. 64. — Sarcoptes scabiei, var. equi, or mange mite. This mite burrows into 

 the deep layers of the sliin. (U. S. Department of Agriculture.) 



The symptoms of mange are intense itching, continuous rub- 

 bing, and the formation of scabs along the back and withers, where 

 the parasites lodge just beyond the reach of the mouth and tail 

 of the host. The irritation seems to be most marked during hot 

 nights. The hair drops out and the skin thickens, cracks, and 

 assumes a dead appearance. 



To positively diagnose mange, scrapings should be made from 

 the skin and examined under a microscope. By placing the scabs 

 on a warm, black background a strong hand lens is sufficient to 

 demonstrate their presence, but not their genera. 



