926 



Favus of Fowls. 



tlie comb or wattles with a white deposit. This gradually bo- 

 comes thicker, and generally in the course of several months 

 changes into a cracked crust completely covering the comb. 

 The crust mav be as much as 8 mm. thick and some parts of it 

 mav be dark colored (Fig. 137). Not infrequently isolated, 

 moid-like scales form which enlarge peripherally until they 

 reach the edge of the comb or wattle; they are only slightly 

 thickened, and more so at the periphery than in the middle, ])y 

 the development of scales. 



After a duration of several weeks, and sooner in young ani- 

 mals, the eruption involves the feathered skin of the head, and 

 rapidly passes on to the neck, the back, and finally to the skin 

 of the whole body. This requires several months. The skin 

 becomes thickened at small roundish places and covered with 

 thick scaly crusts (Fig. 137) which are especially strong around 

 the quills" and pass down into the feather follicles, whereupon 

 the feathers become loose and fall out. Later on the skin heals 

 in the center and ring-shaped spots develop as in herpes. The 

 roots of the feathers and especially the fine down are surrounded 

 by a white fungous mantle. 



Matruchot & Dassonville assert that coincidently with the affection of the 

 comb favus spots appear on the feathered parts of the body, especially on the 

 sides and about the opening of the cloaca. 



When the process has involved the feathered parts of the 

 skin, the emaciation of the animal becomes more and more strik- 

 ing. If the eruption attains a considerable extent the animals 

 disseminate a mouldy odor. 



Course. Favus of fowl often remains limited to the comb 

 and then heals spontaneously. Heim saw a severe case in which 

 the disease was extensive and the feathers had fallen out, and 

 which healed spontaneously after one month. But if the dis- 

 ease once passes on to the feathered portion of the skin it is 

 generally fatal, death l)eing preceded by cachexia and diarrhea. 

 In young fowls the prognosis is always more unfavorable than 

 in full grown ones. 



Besides the external characteristic form of the eruption, Schlegel very often 

 found hoarliko and even yellow cheesy deposits, nodules and ulcers in the upper 

 air passages and in the digestive organs, especially in the crop and small intestine, 

 and further isolated foci of necrotic inflammation in the bronchi and lungs. In 

 all these lesions the favus fungus could be demonstrated. 



Diagnosis. The occurrence of a mold-like layer on the 

 comb and wattles, the gradual spread of the attack, involving 

 the feathered skin, and' the contagious character of the disease 

 sufficiently indicate fowl favus. 



Treatment. Besides the remedies recommended in favus 

 of sucking animals (see page 923), painting with a 2 to 5% 



