Table 3. Appearance of Infection in Flocks Previously Negative 



'Represents retests. 



Necropsy of Reacting Birds 



During the past year, 40 flock owners submitted 76 reacting birds (66 

 chickens and 10 turkeys) to the laboratory for necropsy. 



The causative organism of pullorum disease was isolated from 7 of the 

 66 chickens. In all but one case, the infected birds gave strong reactions. 

 The single case was a male which gave a low reaction with the tube test 

 and a negative reaction with the whole-blood test. The majority of these 

 reacting birds were classified in the doubtful or non-specific group. What 

 causes these reactions is not known and apparently it is not a local prob- 

 lem. 



Since such reactions are frequently indistinguishable from reactions ob- 

 tained in infected birds, one cannot regard such birds as negative unless 

 further examinations are carried out and reveal the absence of infection. 

 Neither should a flock be condemned as infected if only doubtful reactors 

 are detected that do not show conclusive evidence of infection. Flock 

 owners have been very cooperative in complying with requests from the 

 laboratory concerning this phase of the testing work. It is the policy 

 of the laboratory to extend every possible service to the flock owner in 

 order to arrive at an accurate flock diagnosis. 



The supplemental necropsy service of reacting birds during the past 

 year definitely identified fowl typhoid infection. The fowl typhoid car- 

 riers were detected in the routine testing with pullorum antigen. Through 

 the necropsy service, it was possible to determine that the reactors were 

 not infected with pullorum disease but with fowl typhoid. The fowl 

 typhoid infection was eliminated from the flock by retesting at 2 to 4 

 week intervals. 



