MICROBIAL DISEASES OF MAN AND ANIMALS. 615 



FOWL DIPHTHERIA.* 



This disease, popularly known as Roup, and in its later stages canker, 

 is characterized by a grayish-yellow fibrinous exudate, called a false mem- 

 brane, which forms upon the mucous membrane of the eyes, nasal 

 passage, mouth, pharynx and larynx. 



Roup, or fowl diphtheria, may be caused by a number of different 

 organisms, among them the well-known Ps. pyocyanea (green or blue pus 

 organism), B. cacosmus and other species which give rise to a complex 

 suppurative process. The pus formed is semi-solid, cheese. like and yellow- 

 ish-white in color without any tendency to become soft and liquid or to 

 perforate the surrounding skin. The organisms have a tendency to 

 penetrate the deeper layers of the mucous membrane or sub-mucous 

 tissues, and hence swabs or cultures taken from the false membranes 

 may not contain the causal microorganisms which are retained in the 

 depths of the tissues. Sections of membranes from affected fowls 

 show large numbers of pus cells, some regular masses, debris of epithelial 

 cells and bacteria, and thus they differ from the diphtheritic membranes 

 of man. 



The organisms mentioned above have been isolated from affected 

 fowls, not only in America but also by Hauser in Europe. Several 

 investigators have described other bacteria producing false membranes, 

 and there are a few who think that coccidia are associated with the 

 disease. 



Both Ps. pyocyanea and B. cacosmus are able to produce false mem- 

 branes when inoculated into healthy birds, typical croupous and diph- 

 theritic membranes hi the mouth and eyes; tumors in the subcutaneous 

 tissues, the contents of which are firm, cheesy and yellowish- white ; 

 purulent conjunctivitis, blindness, purulent ophthalmia, and cheese-like 

 exudations in the bronchial tubes. These indications are identical with 

 the symptoms of "roup." 



The disease is of variable virulence, and is apt to become chronic, 

 especially in unhygienic surroundings, and in draughty, badly ventilated 

 damp houses. A common cold in a predisposing factor, and favors 

 the invasion of the organisms mentioned. 



Treatment of severe cases is useless, and demands too much time. 

 Diseased birds should be isolated and the buildings thoroughly disinfected. 



* Prepared by F. C. Harrison. 



