OBSERVATIONS ON AN OUTBREAK OF FAVUS^ 



By B. A. Beach and J. G. Halpin 

 College of Agriculture and the Agricultural Experiment Station of the University of 



Wisconsin 



INTRODUCTION 



Favus is a disease of the skin of animals, man, and poultry. In fowls 

 it begins as a white, scaly deposit on the unfeathered portions of the head 

 and may spread to the feathered parts of the skin, but never extends to 

 the internal organs. 



Schonlein in 1841 was the first accurately to describe the disease. 

 Other investigators have since recorded their observations. 



Favus is widespread, especially in chickens, which seem to be the most 

 susceptible of all poultry. In Wisconsin, to our knowledge, several severe 

 outbreaks have occurred in the last few years. 



CAUSE 



The cause of favus is a fungus which has been named Achorion Schon- 

 leinii after its discoverer. Some variations have been noted in the 

 appearance of the fungus that has been isolated by us. These were due 

 to the stain used and also to the condition of the culture when examined. 

 Young and actively growing cultures treated with methylene blue stain 

 deeply and fairly uniformly. In old, partially dry preparations stained 

 with methylene blue a limiting capsule may be seen. Internal to this 

 capsule is a central protoplasm which is more or less granular. The 

 spores are oblong in shape and are about 10 to 12 /^ long by 8 to 10 /z wide. 



The processes of growth and reproduction in single spores and groups of 

 two or three were determined by the use of the Barber method. 



There is seen during the first few hours a distension of the capsule fol- 

 lowed by elongation of the organism. This is probably what Ricketts ^ 

 refers to when he speaks of the club-shaped appearance. After 24 hours, 

 branching mycelia may be seen. They continue to grow for about 48 

 hours, when, if conditions are right, the hyphae break up into spores 

 beginning at the far end and advancing toward the parent mycelium. 

 These observations were made by flooding isolated spores with a drop of 

 naturally sterile horse serum. The preparations were incubated at 37° C. 

 except during observation. In all cases it took about 48 hours for the 

 cycle of growth to be completed — that is, for one spore to produce 

 daughter spores. The organism in its morphology and method of repro- 

 duction bears considerable resemblance to some of the oidia. 



> Published with the permission of the Director of the Wisconsin Agricultural Experiment Station. 

 2 Ricketts, Howard T. oidiomycosis (blastomycosis) op the skin and its fungi. In Jour. 

 Med. Research, v. 6 (n. s. v. i), no. 3, p. 373-547, pi. 22-33. 1901. Bibliography, pp. 538-544. 



Journal of Agricultural Research, Vol. XV, No. 7 



Washington, D. C. (415) Nov. 18, 1518 



px Key No. Wis. -14 



83816°— 18 4 



