12 



FARMERS BULLETIN 713. 



Fig. 8. — Sbcep tick (Mcloitlia- 

 !/U8 oriiiiiK). Male. Dorsal 

 view. mlarjied. ( From 

 Curtice, ISOO. ) 



A condition commonly known as summer sores exists among sheep 

 in some localities. - It appears as an irritating sore on the skin. The 

 she^p bite and scratch the affected parts until the wool is pulled out 

 and the skin becomes raw and bleeding. It 

 is differentiated from scab by the absence 

 of the scab mite, the character of the lesion, 

 and the fact that the skin is not thickened 

 in the characteristic manner. 



Inflammation of the sebaceous glands 

 may be mistaken for scab. There is severe 

 itching, the skin is red and sensitive, and 

 there is an excretion of a strong-smelling, 

 yellowish, viscid yolk. The skin does not 

 have the characteristic appearance of scab 

 and the mite is not present. 



In rain rot, a condition occurring in 

 rainy weather, an eruption may appear on 

 the skin which might be mistaken for scab. 

 There is, however, no parasite present, 

 itching is absent, and the trouble disappears when dry weather 

 comes. 



Shear cuts, sunburn, and the effects of alkali on the skin are con- 

 ditions found in sheep after shearing. They are easily differentiated 

 from common scab by the character 

 of the lesions and the absence of the 

 scab mites. 



CONTAGIOUSNESS OF SCAB. 



Sheep scab is exceedingly contagious 

 and is transmitted by direct contact 

 with animals or objects that are car- 

 riers of the mites. Although unable 

 to propagate except on sheep, the 

 mites may be harbored temporaril}^ by 

 animals other than sheep and may 

 live on goats for a long period. Con- 

 sequently, in the eradication of the 

 disease, goats belonging to a flock of 

 scabby sheep should be handled and treated in the same way as the 

 latter. Sheep scab spreads through a flock very rapidly, once it is 

 introduced. The contagion may be direct, by contact of one sheep 

 with another, or indirect, from tags of wool, fence jDOsts against 



Fig. 9. — Sheep foot louse (Hccmato- 

 pinus pcdaUs). Adult female and 

 egg, enlarged. (From Osborn, 

 189G.) 



