Sero-Diagnosis and Allergic Reaction. 747 



Sero-Diagnosis and Allergic Reaction. Recent investiga- 

 tions permit tlie assumption that it will be possible to deter- 

 mine infection with the bacillus of 

 abortion by bacteriological methods 

 long before and after the abortion. If 

 these results are confirmed the com- 

 batting of the disease will appear con- 

 siderably more effective, as it will be 

 possible to prevent the introduction of 

 the virus by apparently healthy ani- 

 mals. 



1. Agglutination Test. Experiments in this 

 direction by MacFadyean & Stockman show that 

 cultures grown in serum-free media are agglu- 

 tinated by normal serum as a rule in a proportion 

 Fig. 127. Vaginal discharge o^ "o* higher than 1:25, whereas serum of infected 

 with baciin of abortion; carbol ^'O'ws, but which have not yet aborted, shows fre- 

 fuehsin. quently an agglutination vah\e of 1:100 or over. 



These results, however, were not sufficiently uniform 

 for utilization in practice. Better results were obtained by Holth with serum bouillon 

 cultures, or suspensions of such centrifugalized cultures, as 37 out of 39 samples 

 of serum from cows which had previously aborted gave an agglutination value 

 of over 100, mostly over 500, while seven specimens from healthy heifers and 

 cows failed to give an agglutination, even in dilutions of 1:50. Grinsted also 

 found that in infected cows the agglutination value, even several weeks before 

 abortion, rises to 1:300 and over, and after abortion it rises to 1:2000-4000, while 

 in healthy animals it does not exceed 1:300. 



2. Complement Fixation. IMacFadyean & Stockman obtained, although 

 not in all cases, distinct complement fixation (see p. 718) with sera from cows 

 which had already aborted, and a still more distinct reaction with sera of infected, 

 still pregnant cows, while Holth showed that the complement fixation test corre- 

 sponds with the results of the agglutination test. 



3. Allergic Reaction. MacFadyean & Stockman's experiments with the 

 preparation named "Abortin" which they prepared from 4-fi weeks' old glycerin 

 sugar bouillon cultures of the bacillus of abortion, in the same manner in which 

 tuberculin is obtained, showed that infected, as well as cows which had already 

 aborted respond after several hours, with few exceptions, to an intravenous or 

 subcutaneous administration of the preparation (5-10 ec), with a rise of tem- 

 perature to 40.5-41° C, and some also with organic sjTnptoms. 



Course. Infectious abortion often persists for years in 

 infected premises when proper measures for its suppression 

 are not taken. After the first case of abortion new cases 

 appear as a rule only after several weeks, then however they 

 follow each other in more rapid succession, and finally normal 

 births occur only exceptionally. After a time however the 

 cases of abortion again become more rare, as animals which 

 have already aborted once or twice again give birth at the 

 normal termination of pregnancy, and only the newly intro- 

 duced young cows or newly purchased animals from healthy 

 herds abort, until finally the disease dies out of its own accord 

 after several years. 



Prevention and Treatment. For suppressing the disease 

 after it has appeared in a herd, first of all the change of the 

 remaining apparently healthy female animals which have never 



