94 MASS. EXPERIMENT STATION BULLETIN 369 



3. Pasteurella and Pasteur ella-like Cultures {Avian Origin). Some physiologi- 

 cal characteristics and the pathogenicity of 61 such cultures were examined. The 

 typical Pasteurella cultures fermented mannite, produced indol, and were patho- 

 genic for rabbits, while the Pasteurella-like cultures were mannite- and indol- 

 negative and non-pathogenic for rabbits. Strains of the latter group did, however, 

 produce a disease condition in chickens which was represented largely by inflam- 

 mation and pus formation in the tissues in the region of the tibio-metatarsal 

 joints. Because of difficulties encountered in routine work in obtaining satis- 

 factory growth in carbohydrate media with Pasteurella cultures, 23 media were 

 tested. A medium containing 1.0 percent peptone, 0.3 percent meat extract, 

 0.5 pexcent sodium chloride, and LO percent of the desired carbohydrate was 

 the most satisfactory. 



4. Avian Encephalomyelitis. Investigations concerning avian encephalo- 

 myelitis ("epidemic tremor") have revealed that the disease is becoming a more 

 serious problem to the hatchery and baby chick industries. Field and laboratory 

 findings strongly suggest that the infective agent is transmitted through the egg 

 from the hen to the progeny. Transmission in the incubator through direct 

 contact is also suspected because the disease has spread among chicks through 

 direct contact during the brooder stage. 



The infective agent has been passed through 92 seiial passages in chicks. 

 Strain differences in susceptibility were observed among experimental chicks. 

 Turkey poults and ducklings were found to be susceptible to the disease upon 

 inoculation. White mice, rabbits, guinea pigs, mature pheasants, and sparrows 

 were found to be refractory. 



A more detailed report of these investigations was published in Veterinary 

 Medicine U (No. 12):754, 1939 (Contribution 355). 



5. Equine Encephalomyelitis Virus {Eastern Type). During the past year a 

 strain of equine encephalomyelitis virus (eastern type) was isolated from a 

 pheasant brain which was received from Dr. F. R. Beaudette, New Jersey Ag- 

 ricultural Experiment Station. This observation was made at the same time other 

 investigators discovered this infection among pheasants and pigeons in Connect- 

 icut and Massachusetts. These findings represent the first definite isolation 

 of the infective agent from naturally infected wild birds. Host susceptibility 

 experiments revealed that the English sparrow and purple grackle can be added 

 to the list of susceptible hosts, including man. The results of these investigations 

 were published in the Journal of American Veterinary Medical Association 94 

 (n. s. 47):466-468, 1939 (Contribution 344). 



6. Viability of S. pullorum. Viability studies, which are still in progress, 

 show that 5. pullorum has remained alive in a dry piece of cloth for a period of 

 seven years. The remarkable ability of a vegetative organism of the nature of 

 S. pullorum to remain viable over such a long period may give an insight into 

 some of the practical eradication and prevention problems of pullorum disease. 



7. Pullorum Disease in Turkeys. A study of pullorum reacting turkeys for a 

 period of approximately 18 months (including two laying seasons) has revealed 

 that the causative agent (5. pullorum) may be eliminated through the egg in two 

 successive laying seasons. Repeated agglutination tests, using the macroscopic 

 tube method, disclosed that infected turkeys may exhibit a variety of titres. 

 Among the 19 turkeys necropsied during the course of the experiment, 5. pul- 

 lorum was isolated from five. The agglutination titres of these five infected 

 turkeys at the time of necropsy were 1:10, 1:20, 1:40, 1:40, 1:640. Two of the 

 infected birds previously had exhibited a titre of less than 1:10. These observa- 

 tions should have a significant influence in combating the spread of pullorum 

 infection among turkeys and other poultry. 



