Parasites and Parasitic Diseases of Dogs 



part of the dog give rise to scratches, sores, and bleeding. Affected 

 dogs frequently whine or howl, and in severe cases may show epilepti- 

 form spasms, travel in a circle, or show other evidences of nervous dis- 

 turbances. More or less deafness may follow from the plugging of 

 the ears and from injuries to them. Bacterial complications may 

 follow, and inflammation of the middle and the inner ear and even of 

 the brain is said to occur in rare instances. The condition may be 

 diagnosed by carefully removing some of the material from the ears 

 and finding mites in it by examination with the naked eye, a hand 

 lens, or a microscope, or in earlier stages by recovering these mites 

 by carefully swabbing the region of the eardrum with 

 a pledget of cotton moistened with a bland oil, or by 

 examining the ears with a speculum or otoscope in a 

 good light with suitable illumination. 



Treatment. — Treatment for ear mange is not espe- 

 cially difficult. If the ear is full of detritus, this 

 should be removed with forceps or a swab, taking- 

 care not to injure the eardrum. The ear canal can 

 then be liberally swabbed with a cotton pledget 

 soaked in one of the following preparations : 1 per 

 cent carbolic acid or creosote in glycerin; 5 per cent 

 carbolic acid in olive oil or castor oil; 1 part carbon 

 tetrachloride and 3 parts castor oil ; or 1 part chloro- 

 form in 9 parts olive oil or castor oil. Eepeat treat- 

 ment dailv until the animal is cured. 



DEMODECTIC MANGE 



Fig. 4. — The de- 

 mode ctic 

 mange mite, 

 Demodex canis. 

 Female. Ven- 

 tral view. En- 

 larged. From 

 Hirst, 19 19. 

 (Micron meas- 

 urements: 

 Male, 220 to 

 250 long by 45 

 wide ; female, 

 180 to 300 long 

 by 45 to 55 

 wide.) 



Cause. — The mites, Demodex canis (synonym: 

 Demodex foUiculoruni var. canis) ^ responsible for 

 demodectic mange, differ materially in form from 

 those already described, being elongated, vermiform 

 objects (fig. 4). They are very small and can be 

 detected only by the aid of the microscope. The 

 diagnosis of demodectic mange (follicular mange or 

 red mange) may be made by finding the mites in 

 scrapings. The scrapings must be deep enough to 

 draw blood, as the mites live down in the hair follicles. 

 The scrapings may be macerated in caustic and ex- 

 amined, the procedure being as given for the diag- 

 Qosis of sarcoptic mange. 



Symptoms. — Demodectic mange may occur in dogs of all ages and 

 breeds, but appears to be more common in young animals and short- 

 haired breeds. The first evidence of demodectic mange, as a rule, 

 consists in the appearance of hairless spots, often somewhat red- 

 dened, these spots commonly occurring about the eyes or at the 

 elbows and hocks, though they may appear first in other places. 

 There is very little itching at this time, and though itching may be 

 more evident later there is usually less of it than in cases of sarcoptic 

 mange, and when present it is usually intermittent. As the disease 

 progresses the hairless areas become more extensive and redder, 

 though later the skin may be lead-gray in color. This is the so- 

 called depilatory stage of the disease (fig. 5). At this stage the 

 mites are increasing in the hair follicles and the visible skin changes 



