240 MASS. EXPERIMENT STATION BULLETIN 280 



A three-day conference for poultry disease laboratory workers of the Eastern 

 States was sponsored by this hxboratory. Thirteen states and two Canadian 

 Provinces were represented. PuUorum disease, coccidiosis, and infectious laryn- 

 gotracheitis were discussed. The purpose of this conference was to solve poultry 

 disease problems and to standardize and adopt uniform, sound methods which 

 will prove practical and effective in control or eradication. 



Pullcrum Disease Investigations. (H. \ an Roekel. K. L. Bullis, O. S. 

 Flint, and Miriam K. Clarke). 



1. Twenty hens negative to the tube agglutination test were allowed to 

 range on soil contaminated with droppings collected each week from reacting 

 hens. Two yards, approximately 8 x 12 feet, were used alternately for periods of 

 six weeks. At the end of the first six weeks, twelve birds were added to the 

 flock. All hens continued to be negative to the agglutination test. Twelve birds 

 died during the course of the investigation and at the end of 24 weeks, the re- 

 maining birds were necropsied. S. pullorum was not isolated from these 32 birds. 



2. Twenty-four non-reacting pullets (eight weeks old) from a pullorum 

 disease free flock were placed with twenty-four reacting pullets (nine to thirteen 

 weeks of age) from an infected flock. The two groups were kept together until 

 sexual maturity was attained. The non-reacting pullets remained negative for 

 111 days while in contact with the reactors, and for 70 days after the reactors 

 had been removed. 



3. Five hens and seven pullets negative to the tube agglutination test were 

 fed fresh eggs laid by pullorum-infected hens. All birds were fed a minimum of 

 30 feedings and one received as many as 65. Each bird received one egg per day 

 and was tested at frequent intervals. All birds were necropsied one month after 

 the last feeding with the exception of one which died of a septicemic form of the 

 disease 14 days after the last feeding. Two hens, including the fatal septicemic 

 case, became definitely infected as indicated by agglutinins in the blood stream 

 and the recovery of 5. pullorum at necropsy. In two pullets, agglutinins were 

 produced but 5. pullorum was not isolated. 



4. The testing of naturally and artificially infected chicks revealed that 

 agglutinins were first detected between the ages of three and four weeks. Among 

 chicks artificially infected and first tested at the age of four weeks, all infected 

 individuals were detected as reactors before twelve weeks of age. Some reactors 

 detected during this age interval later became negative. 5. pullorum was isolated 

 from chicks four to eight weeks old whose sera did not agglutinate pullorum 

 antigen. 



5. Pullorum infection was not established in pigeons when a suspension of 

 the organism was fed to two pigeons and instilled into the eyes of two others 

 for a period of six weeks. The birds were negative according to the tube agglu- 

 tination test and on necropsy S. pullorum was not isolated. Three additional 

 pigeons were inoculated intraperitoneally. Clinical manifestations of the disease 

 and agglutinin j)roduction were observed. The disappearance of agglutinins was 

 rai)id and on necropsj^ S. pullorum was not recovered. 



6. Sparrows appear to be susceptible to pullorum disease, as demonstrated 

 by subcutaneous and intraperitoneal inoculations, by instillation into the eye, 

 by forced feeding, and by exposure to contaminated feed and litter. Characteristic 

 gross lesions of pullorum infection were observed and 5. pullorum was recovered. 



7. Concentrated pullorum antigen stored at 8° C. was tested at frequent 

 intervals. The comparisons with freshly prepared antigens revealed that the 

 antigenic properties were not afTected at the age of 64 weeks. 



