934 Scabies. 



In the individual species of the domestic animals tlie following varieties of 

 mites occur. 



Ju the horse: Sarcoptes !-cabiei, Derniatocoptes coiiuiiunis, Dermatophagus 

 equi. The principal form of disease is tlie sarcoptic scab. 



In cattle: Sarcoptes (a])parently often only after transmission from other 

 animals), Derniatocoptes coninumis, Dermatophagus communis (bovis) ; — principal 

 form, dermatocoptic scab. 



In sheep: Sarcoptes squamiferus, Dermatocoi)tes communis, Dermatophagus 

 communis (ovis) ; — chief form, dermatocoptic scab. 



In the goat: Sarcoptes squamiferus, Derniatocoptes communis, Dermatophagus 

 communis (capra^) ; chief form, sarcoptic scab. 



In the dog: Sarcoptes squamiferus, Dermatophagus aurieularis (canis) ; chief 

 form, sarcoptic scab. 



In the cat: Sarcoptes minor, Dermatophagus aurieularis (felis) ; chief form, 

 sarcoptic scab. 



In the pig: Sarcoptes squamiferus. 



In the rabbit: Sarcoptes minor, Derniatocoptes and Dermatophagus cuniculi; — 

 chief form, sarcoptic scab. 



The tenacity of scab mites varies according to the different varieties. Ac- 

 cording to Gerlach the least resistant are the sarcoptes, which die in dry air in a few 

 days (the sarcoptic mites of the pig after a week | Brandl & Gmeiner]), and in damp 

 media only live a fortnight at the longest. The dermatocoiites mites remain alive 

 outside the animal body 4 to fi weeks, but longer in damp and dirty stables, and can 

 remain alive even in dry air for 10 to 14 days; Giinther succeeded in obtaining a 



positive result from inoculations of 

 mange scabs kept preserved for 8 

 weeks at room temperature. The 

 dermatophagus mites remain alive 

 for 10 days, and in damp warm 

 stables for .50 days. From the eggs 

 of mites the larvae "an develop even 

 after several weeks have elapsed. 



To the influence of certain 

 chemical substances the varieties of 

 iiMtes show a similar attitude as a 

 whole. They are destroyed immedi- 

 ately by pure or 10% creosote, liquid 

 carbolic acid, wood tar, Peruvian 

 balsam, 30% oil of chloroform, 

 bisulphide of carbon ; an almost 

 similar effect is produced after a few 

 ^. ^ .^ ^ , . , . ^ (2, 5 or 10) minutes by creolin, 



Fig. 141. Dermatophagus auncularis. On ^^ . ^^.^^^y^ saponatus or aqua 

 the left, egg-beanng feinale from the ab- <,,esolica, tincture of iodine, oil of 

 donimalside; on the right the same viewed turpentine and petroleum, 3 to 5% 

 from above. Magnif. 75. (After Megiiin.) eatery solution of carbolic acid, con- 

 centrated vinegar, ol. animate foetid, 

 2 to 3% cargolized oil, .5% salicylic oil and 20 7f' decoction of tobacco, while green 

 soap, sjjirit of sal ammoniac, gray mercury, 5 to 10%. decoction of tobacco, 0.5% 

 corrosive sublimate kill the mite after 1 to 2 or many hours. 



With reference to the derniatocoptes mites of sheep scab the investigations of 

 Brandl & Gmeiner show that the mites were killed immediately by chloroform and 

 carbon bisulphide, by 5% carbolic acid in 1 minute, by 2% water solution of liq. 

 cresoli sapon. in 2 minutes, by 2i/{>%. creolin water in % to 4 minutes, by 1% car- 

 bolic water in 4 minutes, by 3% carbolized oil and Peruvian balsam in 8 minutes, 

 by Lngol 's solution in 10 minutes, by tincture of iodine in 20 minutes, by petroleum 

 in 22 minutes, by 1% corrosive sublimate only in .50 minutes. In one hour they 

 are not killed by glycerine, rectified spirits, 20% tobacco decoction, 1% watery 

 arsenic solution, gray mercury, 10% corrosive sublimate ointment. Isolated 

 derniatocoptes mites ceased their movements definitely after direct eontact with 

 Frijhner's scab dip in 2^^ to 4 minutes, with Kaiser's dip in 3 minutes, with 

 Ziindel's in 5; but they remained active after an hour in Gerlach 's scab dip, in 

 arsenical baths, as well as in Walz 's dip. 



The infection occurs indirectly or hy the direct contact of 

 afrected animals Avith healthy ones, Avhereby either fnlly de- 

 veloped mites or tlieir larvae or eggs get on the healthy skin and 



