QUESTIONS AND ANSWERS 157 



Infectious Diseases 



What tissue changes may be found in chronic glanders and farcy? 



Lesions are most frequently found on the respiratory mucous 

 membrane, in the lungs, lymph-glands, spleen and skin, and occur 

 in two forms, (1) as circumscribed nodules with the formation 

 of ulcers and cicatrices; and (2) as diffuse or infiltrated lesions. 



The nodules resemble somewhat the neoplasms of tuberculosis; 

 they show cell proliferation in nests in a fibrous stroma, varying 

 in size from a grain of sand upward; have a central degeneration 

 containing fatty debris ; open on the surface forming ulcers, showing 

 a grayish necrotic centre and surrounded by a ragged border ; cica- 

 trices may form. In the lungs the nodules give rise to a lobular 

 pneumonia, interlobular and peribronchial inflammation; the cen- 

 tral mass becomes yellowish and caseated from glandular and fatty 

 degeneration; the periphery may be bounded by a dense fibroid 

 envelope or show only an area of congestion. In the skin there 

 is an infiltration and proliferation of lymphoid cells which cause 

 an eruption of rounded papules that degenerate and soften and 

 form superficial ulcers (farcy). Sometimes the nodules undergo 

 fibroid degeneration and fail to ulcerate ; diffuse engorgements and 

 extensive swellings occur in the subcutaneous connective tissue, due 

 to infiltration of lymph ; hyperplasia of lymph-vessels. 



The regional lymphatic glands are always involved, showing 

 hypertrophy, congestion, serous infiltration and cell proliferation, 

 and often caseated centres. The spleen and liver may be the seat 

 of nodules. 



Describe the appearance of a typical nasal ulcer in glanders. 



At the first the ulcers are round, regular and smoothly bordered, 

 but later, as a result of progressive tissue destruction, they become 

 irregular with raised borders, ragged edges, pale-yellow, with a 

 lardaceous base covered with pus and detritus or, eventually, a 

 brownish crust. Larger ulcers are formed by the coalescence of 

 small ones. The shallow ulcers may heal without any visible 

 changes, but the deeper ones, after granulating, leave a radiating, 

 star-shaped cicatrix. 



What are the known lesions of rabies? 



Congestion of fauces, pharynx and larynx; cyanosis of the 

 mucous membrane of the mouth ; foreign bodies, but no food in the 

 stomach, and the mucous membrane of the latter is congested or 

 actively inflamed. The foregoing conditions are usually found in 

 all cases of rabies, but cannot be called specific of the disease. The 



Digitized by Microsoft® 



