PULLORUAI DISEASE 3 



History and Distribution of the Disease 



1. — When was puUorum disease discovered? This disease was first re- 

 ported late in the niiu'tccntli century. In 1899, Rettger isolated the causative 

 organism froin infected chicks. The organism was first named Bacterium pullorum 

 and the disease was designated bacillary white diarrhea. In 1925, the name of 

 the organism was changed to Salmonella pullontm. In 192S, the name bacillary 

 white diarrhea was changed to pullorum disease. 



2. — What is the geographical distribution of tlie disease? Heports of 

 the disease have come to our attention from England, continental Europe, 

 Asia, Africa, Australia, Canada, and approximately every state in the ITnited 

 States. ... . 



Nature and Dissemination of the Disease 



3. — What is the cause of pullorum disease? The cause is an infectious 

 agent, a microscopic organism known as Salmonella pullontm. 



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Photograph 1. — Salmonella pullorum, the Causative Organism of Pullorum Disease. 

 The cells were taken from a 24-hour plain agar culture. Magnified 1200 x. Refer to 

 question 3. (The author wishes to acknowledge his indebtedness to Dr. Theodore Soller, 

 Amherst College, for taking this photomicrograph.) 



4. — How does the disease affect adult birds? The disease usually mani- 

 fests itself in adults in a chronic form. Infected birds as a rule cannot be differ- 

 entiated from the non-infected by physical examination. While the organism 

 may localize in various parts of the body, it is most frequently found in the 

 ovary. Focal infections of this organism have been observed in the pericardial 

 sac, lungs, remnant yolk stalk, spleen, testicles, ovary, abdominal cysts, and 

 digital cushion of the foot. Frequently these focal infections break down, liberate 

 the organism into the blood stream, and cause death of the bird. This seems to 

 occur particularly when some debilitating process is present. Occasionally spor- 

 adic outbreaks of an acute form are observed in flocks and the disease pursues a 

 definite course, accompanied by a high mortality. 



