Natural Infection. Anatomical Changes. 115 



fection probably results from the ingestion of infected food 

 and water through the uninjured mucous membrane of the 

 digestive tract. This mode of infection is indicated by the con- 

 stant swelling in the region of the throat and also by the 

 relatively frequent acute inflammation of the abomasum. On 

 the other hand, infection through the air passages is less prob- 

 able, as intratracheal injections of virulent material fail, in 

 most cases to produce the disease. A direct transmission from 

 animal to animal or a spreading over extensive territories is 

 not observed in the buffalo disease. 



In premises where the disease has appeared a^ccording to 

 the experience of Hungarian veterinarians hogs also frequently 

 become affected with symptoms of an acute pharyngitis and 

 general infection; in many cases this has been observed after 

 the ingestion of meat from buffaloes which had died from 

 Buffalo disease. In exceptional cases it may also occur that 

 hogs are first affected and the disease in buffaloes is observed 

 only later (Sequens). The disease does not spread to hogs 

 kept on other premises. 



Exceptionally the infection may be observed simultaneously 

 in buffalo and cattle probably as a- result of an infection with 

 the same virus (Betegh, Sequens, Sanfelice). 



Anatomical Changes. A serous infiltration of the sub- 

 cutaneous tissues in the region of the throat and trachea is 

 almost a constant lesion and more or less characteristic of 

 the disease. This may extend posteriorly reaching to the ster- 

 num. In the region of the swelling the perilaryngeal and peri- 

 tracheal loose connective tissue as well as that of the lig. ary- 

 epiglottica and of the frenum is saturated with a clear watery, 

 slightly yellow serous fluid. In rare cases the edema extends 

 on one side to the cheeks and on the other side also to the 

 mediastinum in which case the thoracic cavity sometimes con- 

 tains yellowish clear transudate (Gal). Occasionally the serous 

 fluid shows red coloration, and the infiltrated connective tissue 

 is studded with small hemorrhages. 



The other changes usually indicate in general a septic in- 

 fection. The mucous membrane of the air passages, especially 

 of the larynx and of the bronchi, shows a catarrhal swelling, 

 redness and occasionally punctiform or linear hemorrhages. 

 The lungs show a pronounced acute edema. The blood vessels 

 of the serous membranes are highly injected, the peritoneum 

 is sometimes covered with a fibrinous membrane. 



The mucous membrane of the abomasum appears highly 

 reddened and swollen, either over its entire surface or over 

 certain places, while in the intestines the catarrhal manifesta- 

 tions are less pronounced. The spleen is congested, but only 

 very slightly swollen or not at all. The liver and kidneys 

 usually show no changes. The lymph glands of the mesentery 

 as well as in other parts, manifest an acute swelling. 



