416 DISEASES OF CATTLE, SHEEP, GOATS, ETC. 



HORN FLY (HAEMATOBIA SERRATA). 



[See discussion of this parasite in chapter on "The animal parasites 



of cattle."] 



TICKS. 



['See discussion of these parasites in chapter on "The animal 

 parasites of cattle."] 



FLIES. 

 [See discussion of these parasites in chapter on "The animal 



parasites of cattle."] 

 RINGWORM (TINEA TONSURANS AND TINEA FAVOSA). 



Ringworm is an affection of the skin, due to a vegetable para- 

 site. Tinea tonsurans is due to the presence of a minute or micro- 

 scopic fungus the Trichophyton tonsurans. It affects the hair and 

 the epidermic layer of the skin, and is highly contagious, being 

 readily transmitted from one animal to Another. This fungus con- 

 sists of spores and filaments. The spores, being the most numerous, 

 are round, nucleated, and seldom vary much in size. They are very 

 abundant in the hair follicle. The filaments are articulated, waving, 

 and contain granules. This disease is productive of changes in the 

 root and shaft of the hair, rendering it brittle and easily broken off. 



Symptoms. This disease becomes manifest by the formation 

 of circular patches on the skin, which soon become denuded of 

 hair. The cuticular layer of the skin is slightly inflamed, and vesi- 

 cation with exudation occurs, followed by the formation of scaly, 

 brittle crusts. The patches appear silvery gray when incrusted, and 

 are mostly confined to the head and neck. It is a common disease 

 among young cattle in the winter and spring. Very early in the 

 development of the patches the hairs split, twist, and break off close 

 to the skin. This disease is attended with more or less itching. It is 

 communicable to man. 



Tinea favosa is due to another fungus, the Achorion schonlei- 

 nii. This enters the hair follicle and involves the cuticle surround- 

 ing it, small crusts form which increase in diameter and thickness 

 and then become elevated at their margin, forming a cup-shaped 

 scab, the favus cup, which gives the disease its distinctive character. 

 The number of these cups varies from a few to many hundreds. 

 The hairs involved become brittle and broken, fall off with the 

 crusts, leaving small bald patches. The crusts are of a pale or sul- 

 phur-yellow color at first ; as they grow older they turn darker, or to 

 a brown color. This form of ringworm has a peculiar odor, re- 

 sembling that of mice or musty straw. It is occasionally commu- 

 nicated to cattle by man, mice, cats, etc., all being subject to this 

 disease. 



Sanitary Measures and Treatment. The first and. most impor- 

 tant point in this connection is the early recognition of the disease, 

 so that preventive measures may be adopted before it spreads through 

 the herd, and possibly extends to other species of animals. An ani- 

 mal which is found to be suffering from ringworm ought at once to 

 be separated from the others and treated according to the directions 

 given below. We do not know that ringworm always originates by 



