. The diseases of poultry. DISEASKS OK 205 The birds occasionally peck at or scratch the affected parts with the beak. They do this most frequently at night and in warm weather. legs is a form of scabies or mange caused by the mite known as the Sarcoptes mutans. It ,s a strictly contagious disease although It does not spread rapidly from bird to bird, and there may be only a few noticeably affected birds in a flock. The Asiatic breeds are most susceptible to it, and many birds, even of these breeds, resist the attacks of the mites, and never show any symptoms. It att
. The diseases of poultry. DISEASKS OK 205 The birds occasionally peck at or scratch the affected parts with the beak. They do this most frequently at night and in warm weather. legs is a form of scabies or mange caused by the mite known as the Sarcoptes mutans. It ,s a strictly contagious disease although It does not spread rapidly from bird to bird, and there may be only a few noticeably affected birds in a flock. The Asiatic breeds are most susceptible to it, and many birds, even of these breeds, resist the attacks of the mites, and never show any symptoms. It attacks quite a variety of birds—fowls, turkeys, pheas- ants, partridges and cage birds, but has not been ob- served in ducks and geese. In the production of scaly legs, the Sarcoptes muians penetrates beneath the epidermic scales h'^^'V . •^...«.., . ' sLdieb dorsal surface; magnified 100 on the upper surface of the '*'^"^«*^''s- foot and the front of the shank, and bv burrowing there sets up an irritation which leads to a multiplication of the cells of the part, and an exudation of serum It IS by the union of these two products that the white powdery crust is formed, which raises the epidermic scales from their normal position. If the crusts are removed and the under surface examined with a lens they are found to contain a large number of depres- sions in each of which a female, egg-containing Sar- copt IS lodged. The larva-, males and younger females are found wandering beneath the crusts. The crust contains so many cavities that it has very much the. Fier. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Salmon, D. E. Washington, D. C. , G. E. Howard & co.
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