8l8 MICROBIOLOGY OF DISEASES OF MAN AND DOMESTIC ANIMALS 



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 membrane, 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 com- 

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

 and yellowish-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 in 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 is 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 disin- 



* Prepared by F. C. Harrison. 



