282 Hog Cholera. 



pigs may be protected against an infection of cholera, and Stadie & 

 Kael)iger have obtained mostly good results in practice with his serum, 

 testing it upon 24 herds. 



In Germany a serum prepared by Gans is also in use, and Spitzer, Stock and 

 Pfeil obtained beneficial results from its application. 



Hutyra & Wetzl treat hogs weighing from 60-100 kg. which have 

 recovered from the disease, either with a single injection of 1000-1200 

 cc. or 2-3 injections of 500-600 cc, of fresh defibrinated blood from 

 slaughtered hogs affected with hog cholera. Ten days after the last 

 subcutaneous injection, and at intervals of 2 to 3 Aveeks afterwards, 

 they are bled from the tail, and finally they are bled to death. The 

 blood is used for immunizing purposes, either defibrinated, or it is 

 used after centrifugation as pure serum. Finding that the pre- 

 liminary tests gave favorable results, serum immunizations have been 

 employed regularly in Hungary since 1909, and on the whole with 

 satisfactory results. 



In the preliminary tests 285 hogs of five herds were injected once or twice 

 with 10 cc. of filtered serum, or 15 cc. of defibrinated blood, while 240 animals 

 were not injected. After placing the animals in badly infected stables, the losses 

 among the inoculated animals in the various herds amounted to 6.1 to 35.4%i, among 

 the hogs which were not inoculated 40 to 66%, the difference in favor of the inocu- 

 lated animals amounting to 20 to 60%. 



Up to October 15, 1909, reports from 106 farms, with a total of 10,661 

 apparently healthy hogs, gave the results of the serum treatment as follows: in 

 42 herds with 3,125 inoculations the disease was immediately checked; in 22 herds 

 with 3,754 inoculations the loss amounted to 1.9%, in 7 herds with 730 inoculations 

 the loss was 8.2%, in 14 herds with 1611 inoculations 15.7% succumbed, in the 

 remaining 21 herds the losses amounted to 23.7 to 57.6%. In 46 herds in which 

 4,189 animals were inoculated, 5,008 hogs not being given the treatment, 8.8% of the 

 inoculated animals died, and 30.9% of those which were not inoculated. The inocu- 

 lations were absolutely without results in only eight herds, with a total of 599 

 inoculated, and 659 non-inoculated animals. The losses in these cases amounted 

 to 63.8 and 57.9%, respectively. 



The treatment of animals which were already manifestly diseased (2,681 

 cases) was in only a few cases successful and then the animals improved very 

 rapidly and recovered. 



The recurrence of the disease in herds which had been treated previously 

 with the serum, and from which the disease had been eradicated, has up to May, 

 1910, been observed in only five instances. (The dose of serum was 10 cc. per 

 animal weighing from 20 to 40 kg.) 



Favorable results with the serum are also reported by Szuran, Szabo, Tokayer 

 and Marton, but Szuran an<lMarton failed to obtain good results in one herd 

 each where the majority of the animals were already affected. In one instance 

 the outbreak was abruptly checke<l by the immunization, but 55 days later the 

 disease recurred with great severity. 



2. Immunization with Immune Serum and Virulent Blood. 



(Simultaneous Metliod.) In the United States this method is 

 mostly used according to the procedure of Dorset, McBryde and 

 Niles, the animals beini^ injected subcutaneously ^vitli 20 cc. of 

 immune serum, and 1-2 cc. of virulent blood. This treatment 

 has also by our numerous observations been proven to confer 

 an active immunity upon the animals wliicli lasts at least six 

 months, and probably even a longer time. Nevertheless the 

 practical application of this method does not, at least for the 

 present, appear to be altogether without danger, as some of the 

 inoculated animals apparently become affected, and scatter 



