950 Scabies. 



may rarely extend upwards to the scrotum or udder; with the 

 onset of spring it subsides spontaneously to a striking degree. 



Diagnosis. The comparatively large dermatocoptes mites 

 may be easily found, especially on the recently affected places, 

 under the damp crusts; while in older foci where the crusts 

 are hard and the skin under them has lost its elasticity, the 

 mites are only few. Prior treatment naturally makes the 

 demonstration of the mites difficult. For further data on the 

 demonstration of the mites see page 937. 



On account of the intense itching the disease might be mis- 

 taken for trembles, and the more so as in this disease the skin 

 may become eczematous in consequence of rubbing; yet the 

 other symptoms of the disease (terror, motor disturbances) and 

 the absence of mites on the inflamed skin ought to render the 

 ditferentiation possible in every case. Mites are also missed 

 in eczema which occurs after getting wet through or when out 

 in the open in the cool autumn time; it is much easier to heal 

 and is not accompanied by such intense itching. In certain 

 cases also the exclusion of sel)orrhea (socalled false scab, tal- 

 low mange) might present difficulties, because in this complaint 

 whitish yellow^ fatty scales or lamellag form, and later on the 

 wool liiay fall out, or at times the animals pull it out. In con- 

 trast to scab, however, the skin appears normal in seborrhea, 

 intense itching is absent, and the disease does not spread in the 

 flock, although the simultaneous affection of several animals is 

 quite possible if they are fed unsuital)ly. Itching also exists in 

 the presence of parasitic insects (Trichodectes, Melophagus) 

 or ticks, yet one can see these with the naked eye between the 

 hairs of wool, and the skin appears uninjured thereby. 



The shepherds often seek to make the scab of sheep imrecogiiizable to a 

 certain degree by the examining veterinary surgeon. The pleasure exhibited by 

 an affected animal on scratching is sought to be suppressed by pressing the sheep 

 to be examined between the thighs. By some remedies that may have been em- 

 ployed the discovery of the mites is remlered difficult, and perhaps a severe inflam- 

 mation of the skin may be produced, which on scratching is manifested rather by 

 signs of pain. Such applications (socalled grease spots, or grease plates) should 

 always awaken suspicion of scab and lead to a careful examination. 



The different forms of scab may easily be distinguished 

 from one another according to the parts of the body attacked, 

 quite apart from the fact that the dermatocoptic scab is far 

 more frequent than both other forms. 



Treatment and Prophylaxis. On account of its frequency 

 and economic importance, dermatocoptic scab is most frequent- 

 ly the object of treatment and is in itself cured easily enough, 

 but the carrying out of the treatment in practice is trouble- 

 some, since many animals must be treated at once and one must 

 be particular to protect the wool wherever possible. Since it 

 is not always possible in a scabby flock to separate the com- 



