TEST FOR BACTERIUM PULLORUM INFECTION IN FOWLS. 



15 



In a field test on 231 birds made simultaneously with the agglutina- 

 tion test, the intradermal test at 38 hours failed to detect one case 

 reported positive to the other test. In a second flock of 50 birds in 

 which the two tests were compared, the intradermal test when read 

 at -1:6 hours failed to indicate one case that was detected by the agglu- 

 tination test. Another group of about 100 birds tested under un- 

 favorable conditions gave less satisfactory results. 



Forty-seven birds that had been tested by the agglutination method 

 by the Connecticut Agricultural Experiment Station in the field were 

 purchased for experiments with the intradermal test. Of these, 40 

 had given positive reactions to the agglutination test and 7 doubtful 

 reactions. There was complete agreement between the agglutination 

 test, the intradermal test, and autopsy findings in 70 per cent of the 

 cases. The agglutination test reported positive in 3 cases, or 7 per 

 cent, was not confirmed by the intradermal test nor by the autopsy 

 findings. The result of the intradermal test was negative in 2 cases, 

 or 5 per cent, when it was not confirmed by the positive agglutination 

 test and autopsy findings. Thus the percentage of absolute failures 

 of each test was small and very similar for both tests. 



Autopsy does not furnish an absolute standard for comparing the 

 accuracy of tests. Seventy -two per cent only of naturally infected 

 b)irds that had reacted to one or both tests were found on autopsy to 

 be unmistakably infected. 



The intradermal test detected the presence of infection in 4 of the 

 34 control birds injected in connection with the tests in the laboratory 

 on artificially and naturallj^ infected birds. 



In a field trial not made by the writers, 1,301 birds were tested 

 mtradermally and 78 reacted. Of these 70 reacted to the agglutina- 

 tion tests made subsequently. 



The intradermal test has already shown sufficient promise to war- 

 rant further extensive trials in the field in comparison with the 

 agglutination test. 



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