DEMODECIC MANGE. 643 



The primitive races of pigs resist the disease better than the 

 improved races. This mange can be conveyed to man and to other 

 animals. 



Symptoms. It usually commences about the head, ears, and eyes, 

 and extends to the quarters, internal surface of the thighs, etc. In the 

 early phases it is impossible to discover the little galleries under the 

 epidermis, but closely placed reddish papules may be seen. The active 

 proliferation of the epidermis, together with discharge, causes the for- 

 mation of dry crusts of a greyish-white, silvery tint, adherent while 

 still thin, easy to detach at a later stage, and sometimes f of an inch 

 in thickness. The skin becomes wrinkled, the bristles are shed or 

 loosened in their follicles, and are glued together in little bunches before 

 falling. As these patches extend over the whole surface of the body, the 

 animal appears to be bespattered with dry guano (Muller). 



Under the crusts the skin is rough, excoriated, and, about the 

 thorax and abdomen, is indurated, and sometimes measures 1 to 1^ 

 inches in thickness. In other parts, particularly at the base of the 

 ears, the papillae are hypertrophied ; they become as large as a pea, 

 or even a bean, and, lifting the crusts which cover them, assume the 

 appearance of the warts sometimes found on the cheeks of dogs or the 

 teats of cows. Sarcoptes may be found under these epidermic growths, 

 though in order to obtain them the skin must be scraped until it almost 

 bleeds. 



The dimensions of these parasites render them visible to the naked 

 eye. They are the largest variety of the sarcoptinse, the egg-bearing 

 female being half a millimetre in length. Guzzoni has found in the ears 

 specimens of smaller size. 



Mange in pigs develops slowly. When it affects the whole body, it 

 prevents fattening and causes loss of condition. 



Diagnosis. This is the only parasitic disease which affects the entire 

 surface of the body and presents these peculiar powdery crusts. 



Treatment. All the styes should first be carefully disinfected. 

 Treatment is commenced by vigorously scrubbing the animal with a 

 brush dipped in soap and water, and thus getting rid of the crusts as 

 far as possible. 



The animals are afterwards dressed with decoctions of tobacco, with 

 Helmerich's ointment, or the other mixtures above mentioned. 



DEMODECIC MANGE. 



This mange is produced by parasites of the family Demodecidae 

 {Demodex foUiculorum) , which live in the hair follicles and sebaceous 

 glands of several species of mammals. 



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