THE MITES 117 



The disease finally becomes generalized, the skin everywhere ex- 

 hibiting the lesions in their various stages, and, with it all, exhaling a 

 disgusting odor. The pruritus increases, though it remains somewhat 

 intermittent, and at no time is as severe as in sarcoptic mange. With 

 the generalization of the malady its effect upon the whole animal or- 

 ganism is well established. The appetite is lost and emaciation ad- 

 vances, the subsequent marasmus leading to a fatal termination. 



Transmission. — Due to the intra-cutaneous location of the parasites, 

 follicular mange is not as contagious as other forms; furthermore a pre- 

 disposition is necessary for its development, and this is found in young 

 and short-haired animals. Adult dogs with healthy skins are rarely 

 attacked. 



Whether the dermatitis in follicular mange is primarily due to the 

 presence of the Demodex may be questioned. The assumption that this 

 mite is present in the hair follicles of all dogs needs the support of 

 further investigation. Accepting it from clinical observation as a proba- 

 bility — and with the predisposing factors of other forms of acariasis in 

 mind — there seems good reason to suppose that the mites, living, we 

 may say, as commensals, find in erythematous and eczematous skins 

 surroundings favoring their nutrition and more rapid multiplication, 

 thus bringing about the secondary severe dermatitis of folUcular mange, 

 the pyodermatitis resulting from subsequent intra-foUicular invasion 

 by pyogenic organisms. 



Auricular Mange of the Dog. — Otacariasis is of comparatively fre- 

 quent occurrence in dogs, by reason of its contagiousness, being most 

 often met with in hounds kept in packs. Symptoms of the presence of 

 the mites are frequent scratching and flapping of the ears, which may 

 be accompanied by whining and howling. Epileptiform seizures are 

 not infrequently an accompaniment, these especially likely to occur 

 when the animal is running. On examination the auditory canal is 

 found to contain an adherent, soot-colored powder and a fetid wax 

 which may be in sufficient abundance to produce deafness by obstruc- 

 tion of the canal and pressure upon the tympanum. An examination of 

 this material under magnification will reveal the Otodectes in large 

 numbers. 



Prognosis. — Otacariasis yields readily to treatment, but if neglected! 

 may have serious consequences. The animal may die during an attack 

 of convulsions or, if it survive, be rendered useless as a hunter. 



Mange of the Cat 



The cat may be affected with the two following forms of mange : 



1. Notoedric mange, due to Notoedres cati var. cati. 



2. Auricular mange, due to Otodectes cynotis. 



