PARASITES AND PARASITIC DISEASES OF HORSES 



41 



live on horses, and those of the horse, dog, and hog are known to 

 be readily transmissible to man. 



Sarcoptic mange of horses is contagious to all classes of horses 

 and is usually transmitted by direct contact with infested animals. 

 It may, however, be transmitted by other objects, such as currycombs, 

 blankets, or harness, or in stables or other premises. It is important 

 that mangy horses be isolated and all equipment kept separate until 

 the disease is eradicated. 



Apparently the disease spreads slowly during warm weather, 

 especially among horses on pasture, but it makes rapid headway in 

 horses closely confined or crowded together in small inclosures. 

 Exposure to cold, inclement weather, insufficient feed, or feed of poor 

 quality, or any other circumstances tending to lessen the vitality or 

 functional activities of horses hastens the spread and development of 

 mange. When the mites are active under favorable conditions the 



Figure 29. — A well-advanced case of sarcoptic roange 



lesions extend rapidly, and the entire body surface may become 

 involved in about six weeks. 



Although they do not propagate themselves except on the bodies 

 of animals, the mites as well as their eggs may retain their vitality 

 for a considerable time off the host animal. When exposed to sun- 

 light in dry places the sarcoptic mites live only a few days, but 

 in moist, protected places they may live three weeks or even longer. 

 Although it is difficult to infect horses experimentally from infested 

 premises, the possibility that the disease may be contracted from 

 such sources should not be overlooked. It is good sanitary practice 

 to clean and disinfect all stables and small inclosures which have 

 been occupied by mangy horses, also all currycombs, brushes, blan- 

 kets, and other objects used on such horses, before using them 

 for clean animals. Cleaning and disinfecting for sarcoptic mange 

 may be done in the same manner as for lice. 



Treatment. — On account of their burrowing habits, sarcoptic 

 mites are difficult to eradicate. The common dips, such as lime- 



