360 VETERINARY HYGIENE 



development. It yields to treatment much more readily than 

 does the same disease in equines. It is the most common form of 

 mange in cows. Infection spreads very rapidly from one cow to 

 another on account of the close contact with which the animals 

 lie in their stalls. 



Sarcoptic Mange of the Dog. In marked contrast with the 

 bovine disease the canine parasite is very difficult to find, thus it 

 is probably often mistaken for eczema, an opinion with which 

 Fillers concurs. It is interesting to note that many so-called cases 

 of eczema are treated successfully with parasiticides. 



Sarcoptic Mange of the Pig is also common but does not call 

 for special mention. 



Notoedric Mange of the Cat may be mentioned here, as it is often 

 confused with sarcoptic mange; unlike that disease on the dog, 

 it can be diagnosed with comparative ease. 



PSOROPTIC MANGE. 



The Psoroptes communis is found on horses, cattle, sheep, goats 

 and rabbits. It does not pass to man, at least not to obtain lodg- 

 ment there. Psoroptic mange of the horse and sheep, the latter 

 being known as " sheep scab," are the only two of hygienic import- 

 ance in this country. Fillers suggests that these parasites may live 

 for a time on a horse without causing any clinical symptoms ; few 

 will disagree with this opinion, and it is important to keep the pos- 

 sibility in mind in connection with outbreaks, the orgin of which 

 may be difficult to trace. 



Psoroptic otacariasis is of common occurrence in the rabbit 

 and goat, and Henry* has stated that psoroptes are frequently 

 found in the ears of horses and sheep and also, but less frequently, 

 in the ears of donkeys and mules. 



He concludes that otacariasis is an important factor in the pre- 

 servation and propagation of psoroptic mange. Later, Craigf 

 made a point of examining the ears of sheep for acari, and found 

 psoroptes in the ears of a few sheep that had come from a flock 

 affected with sheep-scab. He therefore urges that, in dipping sheep, 

 care should be taken that the dip reaches the inner side of the ear. 



EQUINE SYMBIOTIC OR CHORIOPTIC MANGE. 



Symbiotic mange affects all the domestic animals, with the 

 exception of the pig. It is a very slow-spreading disease, and new 



*Rec. Med. Vet., XCIIL, Nos. 3-4, p. 41, 1917; through Vet. Rev., 1917, I., 260. 

 t Vet. Record, XXIX., p. 503. 



