492 



DIPHTHERIA IN FOWLS 



In fowls which die, the exudates are for the greater part 

 in the advanced stage, although fatal cases occur in which the 

 lesions are restricted to an abnormal quantity of a serous or 

 muco- purulent, more or less viscid, exudate in the conjunctiva 

 or nasal cavities. The best illustration of the diphtheritic 

 process is found in fowls killed for ex- 

 amination in the second stage of the 

 disease. The distribution of the lesions 

 shows that the conjunctiva is most fre- 

 quently affected. The exudate in the 

 nasal cavities is in some cases undoubt- 

 edly the result of the coagulation of the 

 liquid which has passed during the 

 course of the first stage from the con- 

 junctiva through the lachrymal duct into 

 the nares. In certain cases, however, 

 the lesions appear in the nares primarily. 

 In some cases the exudate appears in the 

 larynx and extends down into the 

 trachea. In these cases the fowls are 

 liable to die from suffocation. It occa- 

 sionally happens that the lesions are 

 restricted to the larynx and as the fowls 

 die suddenly the cause of death is not 

 suspected. Sections of the exudate with 

 subjacent tissues from the cornea and the 

 mouth, show that there is a cell infiltration into the mucosa 

 which destroys the epithelial layer and frequently the sub- 

 mucous tissues to a considerable depth. 



The fact should not be overlooked that the disease in the 

 eye is usually confined to the conjunctiva and the cornea, the 

 posterior portion remaining apparently normal. 



Mack in his work on thirty-three cases found 40 per cent 

 had lesions in the conjunctiva ; in 44 per cent the nasal 

 mucosa was affected ; in 41 per cent the mouth was involved 

 and in 33 per cent the suborbital sinuses were distended with 

 exudates. 



Fig. 117. A drawing 

 shelving areas of diph- 

 theritic exudate in the 

 throat of a pigeon. 



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