42 CIRCULAR 14 8, U. S. DEPARTMENT OF AGRICULTURE 



horses be isolated and all equipment kept separate until the disease is 

 eradicated. 



Apparently the disease spreads slowly during warm weather, espe- 

 cially 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 lesions extend 

 rapidly, and the entire body surface may become involved in about six 

 w T eeks. 



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 sunlight 

 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, blankets, 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-sulphur, 

 nicotine, and coal-tar creosote, will kill sarcoptic mites if the dip can 

 be brought into direct contact with the parasites. This method, how- 

 ever, requires thorough, frequent, and persistent applications. From 

 four to six dippings, five to seven days apart, in lime-sulphur or nico- 

 tine solution will usually effect a cure in ordinary cases, especially if 

 all affected areas are soaked well with warm dip and scrubbed with a 

 brush just prior to the first dipping. Affected animals should be held 

 in the bath from two to three minutes. 



Two or more applications, a week apart, of unprocessed crude 

 petroleum will usually eradicate sacoptic mange, if treatment is applied 

 before the disease becomes chronic. Crude oils, however, often cause 

 the hair to come out and may blister the skin. Crude oil is not a 

 suitable dip for common use on horses, but it is of value in hand treat- 

 ment for holding mange in check during the winter months when the 

 temperature is too low for clipping. Crank-case drainings may be 

 substituted for crude petroleum, but such oils also cause loss of hair and 

 often blister the skin. 



Fumigation of many horses with sulphur dioxide has been recom- 

 mended by some European investigators. The Bureau of Animal 

 Industry has conducted some field tests with this method of treatment, 

 but the equipment and methods of application so far devised are too 

 complicated and expensive for general use except where large numbers 

 of horses are assembled for treatment under the supervision of a 

 veterinarian. Apparently this method of treatment has no distinct 

 advantage over dipping except that it can be used when the tempera- 

 ture is too low for dipping. In applying home treatment or fumi- 

 gating for mange the medicament has a better chance of reaching the 



