260 DISEASES OF THE SKIN 



varieties of this mite occur in animals: (a) Psproptes com- 

 munis of the sheep, and horse and more rarely in cattle and 

 buffalo, (b) the Psoroptes caniculi of rabbits. 



Symbiotes or Scale-eating Mite. — This mite lives on the 

 surface of the skin and on scales of epithelium. In size it 

 stands between the Sarcoptes and the Psoroptes (0.3 to 0.5 

 mm.); The head is short, blunt, almost round, and the legs 

 long, provided with suckers. Two varieties belong to this 

 species: (a) Symbiotes communis of horses and cattle, and 

 (b) Symbiotes felis, canis, and cuniculi (cat, dog, rabbit). 



Mange of the Horse. — Forms. — On the skin of the horse 

 all three forms of mange mites appear. 



Sarcoptic Mange. — Definition. — This is the most important 

 form of mange of the horse. It attacks the skin of the body, 

 neck, and head, and can become general. 



Symptoms. — The symptoms are those of eczema (papules, 

 vesicles, crusts), accompanied by severe itching, which causes 

 the animal to rub, bite, and scratch itself, especially during 

 warm nights. It leads to alopecia, thickening, folding of the 

 skin, and in time to emaciation. Characteristic of mange is 

 the tendency for the eczema to spread and the transmissibility 

 to other horses and even to man. 



Diagnosis. — A positive diagnosis can be made only with 

 the microscope. As the mites are in tunnels under the 

 epidermis the scraping should be made deep enough to reach 

 them, and as a number of mites found are generally limited, 

 several slides should be examined before an opinion is 

 given. 



Prognosis. — In this form of mange the prognosis is always 

 doubtful, for unless circumscribed it may take several weeks 

 or months of persistent treatment to eradicate the mites. 



Treatment. — Success in treating sarcoptes mange lies not so 

 much in the agent used as it does in the thoroughness and 

 persistency in the application. The following agents are 

 recommended: Creolin (3 per cent.), creolin salve (1 to 25), 

 and creolin liniment, which consists of: 



I^ — Creolini et sapon viridi aa giv 



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