TWELFTH ANNUAL REPORT 



ON ERADICATION OF PULLORUM DISEASE IN 



MASSACHUSETTS 



1931-32 



By H. Van Roekel, K. L. Bullis, O. S. Flint and Miriam K. Clarkei 



INTRODUCTION 



In the eradication of pullorum disease, problems of great import have been 

 encountered. The progress in eradication is greatly assisted by removing the 

 various obstacles that impede our efforts. During the past few years, investiga- 

 tions have been made of some of these problems in order to bring about a more 

 comprehensive understanding of pullorum disease, which should enable one to 

 institute a more effective eradication program. 



These investigations and the testing results for the 1931-32 season are re- 

 ported in the following order: — 



1. Antigen Studies. 



2. Jellied Blood Samples. 



3. Non-Infected Females May Contract Pullorum Disease through Eating 



Fresh Eggs Laid by Infected Hens. 



4. Exposure of Pullorum Disease-Free Birds to Soil and Litter Contami- 



nated with Feces from Positive Reacting Birds. 



5. Dissemination of S. pullorum Infection Among Se.xuaUy Immature 



Females. 



6. Pathogenicity of S. pullorum in Relation to Aves Other Than Chickens. 



7. Agglutinins in Chicks. 



8. Avenues of Infection. 



9. Observations Concerning Diagnostic Tests for Pullorum Disease. 



10. Intensive Testing Versus Annual Testing in Pullorum Disease Eradica- 



tion. 



11. Testing Results for the 1931-32 Season. 



ANTIGEN STUDIES 



As the application of the agglutination test in control and eradication of 

 pullorum disease has become more and more general, numerous experiment sta- 

 tions and state laboratories have attempted to standardize their procedure with 

 the best methods. Their experience has resulted in certain practices becoming 

 estabhshed criteria in the treatment of cultures to be used for antigen and the 

 treatment of the antigen after it has been made. In 1931, "Standard Methods 

 of Diagnosis of Pullorum Disease in Barnyard Fowl" (69) were formulated and 

 are in the process of adoption by the Conference of Official State and Federal 

 Research Workers in Animal Diseases of America. The influence of two factors 

 in the preparation and handling of antigen have been studied during the past 

 two years; first, the effect of age upon the quality of concentrated and dilute 

 antigen stored at 8° C; and second, the danger that either too frequent transfer 

 of stock cultures or their storage at low temperature may cause them to produce 

 an inferior test fluid. 



^ Appreciation is extended to Dr. John B. Lentz, Head of the Department of Veterinary 

 Science, for administrative assistance and for suggestions made concerning this bulletin. 



