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MASS. EXPERIMENT STATION BULLETIN No. 284 



6. — Are male birds affected? Yes. Males may contract the disease. The 

 percentage of reactors among tested males appears to be less than among tested 

 females. It is probable that the sex difference is not the only factor responsible 

 for the difference in the percentages of reactors. 



7. — Do males play a role in dissemination? Conclusive evidence is not 

 available to show that males spread the disease. Focal infections have been 

 observed in the testicles. Also, one might assume that the infected male could 

 eliminate the organism in the droppings, as occurs in diseased females. Further- 

 more, males might act as mechanical carriers in transmitting the organism from 

 the cloaca of an infected female to the cloaca of a non-infected female. 



r-^ , -4,. 



Photograph 5. — The heart on the left Is apparently normal and was removed from a 

 non-Infected hen. The heart on the right shows enlargement, thickening of the heart 

 sac, and roughened heart surface. S. pullorum was isolated from the pericardial fluid. 

 Refer to question 4. 



8. — What is a pullorum disease "carrier"? A "carrier" is an infected 

 bird that has not succumbed to the disease during chickhood or has become in- 

 fected before or during maturity. 



9. — How is the organism eliminated by adult birds? The organism 

 may be eliminated by means of the droppings (secretions and excretions from 

 the digestive, urinary, and reproductive tracts), by eggs, abrasions in the skin, 



