62 SWINE PLAGUE 



In case of coexistence of hog cholera and swine plague a 

 bacteriological examination is necessar}' to determine the pres- 

 ence of the two diseases owing to the possibility of an accom- 

 panying or terminal pneumonia with hog cholera. The ques- 

 tion has arisen as to whether the presence of B. septicaeviiae 

 hemorrhagicae in the hepatized lung constitutes a diagnosis of 

 swine plague. As understood at the present time it would 

 seem that the presence of this species of bacteria would indi- 

 cate the nature of the disease. It must be remembered, how- 

 ever, that bacteria not readily distinguishable from the swine- 

 plague organism exists in the normal upper air passages from 

 whence it could be brought into the diseased lung and in such 

 a case it might appear as a secondary element only, or it might 

 have been primarily the cause of the lesions. It is not im- 

 probable that epizootics may start from these sporadic cases, 

 although conclusive proof of this is still wanting. It seems, 

 however, that the presence of this organism in the lung tissue 

 of a sporadic case should be considered in the light of the dis- 

 tribution of these organisms and not necessarily as the starting 

 of an epizootic. 



§ 51. Prevention. Recent investigations show that out- 

 breaks of swine plague are much more extensive than hereto- 

 fore supposed. The present knowledge of this disease indi- 

 cates, that the adoption of measures for its prevention is quite 

 as important as for hog cholera. In general the measures to 

 be adopted and followed, and the rules to be observed in the 

 prevention of epizootic swine plague are practically the same as 

 those for the prevention of hog cholera. It will be seen 

 from the comparison of the two species of bacteria that the 

 bacillus of hog cholera is a more hardy organism than that of 

 swine plague, Thus the swine-plague bacterium is destroyed 

 more rapidly by drying and will live a much shorter time in 

 the soil. However, the channels through which it maj- gain 

 access to a herd are practically the same, and every precaution 

 suggested in reference to hog cholera, is applicable to swine 

 plague. It is believed that the time during which a field, hog 

 yard or pen should be kept free from swine after the appear- 

 ance of the disease can, with safety, be shorter after swine 



