lo Aug., 1908.] Diseases of the Skin. S^S 



There are many sub-classes of these causing various forms of mange 

 in different animals but a description of the mange caused by the above 

 groups in the horse and dog will serve to illustrate the nature of the disease 

 in other animals as well. 



Sarcoptic Mange. — This commences generally in the region of the 

 wdthers from which it may spread to all parts of the trunk. The punctures 

 of the j)arasite when it first attacks the skin cause an eruption of small 

 pimples filled with serum that soon dries up and forms a dry crust, which 

 scales off in the course of a few days leaving a raw moist surface. Before 

 this exfoliation occurs the female parasite has usually burrowed a canal 

 into the depths of the skin in which the eggs are laid. By the coalescence 

 of the primary pimple spots considerable areas may be affected, and when 

 the disease has tecome established the skin is thickened and thrown into 

 folds or wrinkles which are denuded of hair and are cO'vered wdth a thick 

 scurf. The itchiness is intense. 



Sarcoptic mange is very contagious, brief contact with infested clothing, 

 bedding, brushes and such like being sufficient to cause its transmission to 

 a healthy subject. The insect will live for about a month when removed 

 from the horse so that to be on the safe side an infected stable should 

 not be used for that length of time. 



Psoroptic Mange usually commences in either ' the mane or tail 

 spreading thence to the neck and jaws or thighs and quarters as the case 

 may be, but the spread is not rapid. Papules or blisters are first formed 

 amid the roots of the long hair. The bursting of these is accompanied 

 by a discharge of serum and pus which continues and maintains the moi.st- 

 ness of the affected parts by which this form of mange is distinguished 

 from the sarcoptic. The psoroptic insects do not burrow but remain on the 

 surface of the skin living on the exudation from the blisters. The skin 

 ultimately becomes covered with sores, thickened, wrinkled and devoid 

 of hair so that in the case of the tail being affected a "rat tail " results. 

 Psoroptic mange is by no means so quickly contagious as the sarcoptic 

 form. 



Symbiotic Mange is practically confined to the limbs, commencing 

 usually in the hollow of the pastern and rarely going higher than the knee 

 and hock. The hind limbs are more often affected than the fore and coarse 

 hairy-legged horses are more prone. There is at first great itchiness 

 manifested by stamping almost continuously. Later on cracks and sores 

 form and the skin becomes thickened and encrusted. Symbiotic mange 

 is much milder both in its local effects and its contagiousness than the 

 other two forms. 



Treatment. — None of the forms of mange shows any tendency to 

 spontaneous recovery. The predominant object in treatment is the de- 

 struction of the parasite both those living and those to be hatched from 

 the eggs, for it seems to be impossible to destroy the vitality of the eggs 

 by any known application that would not be dangerous to the horse. For 

 the latter purpose intermittent treatment is necessary at intervals of three 

 days for about a fortnight so as to cover the period of incubation or 

 hatching of the eggs, which is about ten days. 



Before applying any dressing the hair should be clipped (this is 

 especially necessary in long coated dogs) and the skin washed with strong 

 soap and water until the scabs and scurf are cleaned off. The use of a 

 scrubbing brush and currycomb mav be necessary to effect thorough removal 

 of the scurf but it is essential that it should be done, otherwise the dressing 



