54 



CLINICAL DIAGNOSTICS. 



Mange (scabies) is a contagious dermatitis due to mites. The 

 principal manges are: 



a. Symbiotic mange (foot mange). Favorite seats: in the 

 horse, hind limbs, in the ox, root of tail. These mites live on the 

 skin, produce loss of hair, desquamation of epithelium, and intense 

 pruritis, causing the animal to stamp and kick continually. The 

 mites are 0.3 — 0.5 mm long, head broad. The legs, which are long, 

 are provided at their ends with bell-shaped suckers. 



b. Sarcoptic mange of fowls (Dermatoryctes mutans). It 

 affects the legs, causing "Scaly Feet." The lower, naked portions 

 of the legs become coated with calcarious, smeary or honey-like, 

 scaly, thick deposits. The mites are 0.2 — 0.5 mm long, legs 

 short, second pair well removed from first. U-shaped chitinous 

 shield behind head. 



c. Psoroptic mange. Seen in the horse, sheep and ox. Char- 

 acterized by great desquamation, the appearance of vesicles and 

 papules, the hair or wool agglutinated by crusts of dried exudate; 

 wool becomes tufted, falls out in patches, intense pruritis. The 

 psoroptes is the largest mange mite, 0.4 — 0.7 mm long; head long, 

 pointed, the three-jointed legs provided with tulip-shaped suckers. 



Fig. 12. 



■Stg.lS. 



Sarcoptcs scabiei. 



Ventral side. 



x 100 



Acarus 



folliculorum. 



x ISC 



