60 



PARASITOLOGY. 



where infested sheep have recently been kept; by 

 being shipped in cars not disinfected after using for 

 transportation of infested sheep; through shipping 

 centers, unless such centers are controlled by proper 

 quarantine regulations ; by the introduction of an 

 infested sheep into a bunch not infested; or, by being 

 driven over a trail recently followed by scabby 

 sheep. 



PsoROPTES Communis, variety Caprae (Capra — a goat). 



Produces scabies in goats in the same manner as 

 the Psoropt in sheep. 



Symbiotes Communis, variety Equi (Equus — horse). 



Syno7iym. — Foot-scab parasite. 



History. — Symbiotic scabies is not common. It 

 has been found in some parts of the old world, and 

 is more prevalent among coarse horses and those 

 that are poorly cared for. 



Description. — This mite is a trifle smaller than the 

 species of the two previous genera. The rostrum is 

 nearly as wide as long. 



Ani^nal hifested. — The horse. 



Condition Produced. — It produces scabies of the 

 legs, usually in the region of the fetlock and pastern 

 of the posterior extremity. In later stages the 

 scabby condition extends up the leg, possibly as high 

 as the body. The skin becomes thickened and rigid 

 and the legs swollen. Cracks may be formed in the 

 pastern region from which may be found a secre- 

 tion of a fetid nature. The parasites live in colonies 

 under the scab. 



Treattnejit. — Thoroughly scrub the affected parts 



