•" ■• I ' 1 ANNUAL REPORT, 1932 ' ''' 57 



Several methods of vaccinating pullels and cockerels against infectious laryngo- 

 tracheitis have been studied, and the bursa of Fabricius appears to be the most 

 satisfactory site for inoculating birds with attenuated viruses. The immunity 

 produced by vaccination in the bursa of Fabricius is not lasting in all cases unless a 

 standard vaccine is used. As yet no simple, inexpensive process for standardizing 

 the vaccine for infectious laryngotracheitis has been discovered, and for this reason 

 no practical method for vaccinating birds on a large scale is recommended. 



Four spraying solutions recommended for infectious laryngotracheitis have been 

 tried out in the laboratory to determine their pharmacological action upon the 

 respiratory system. These sprays were not found specific for infectious laryngo- 

 tracheitis, since they did not destroy the virus in the tracheas of acute cases and 

 chronic carriers. 



A plan for the eraflication and control of infectious laryngotracheitis has been 

 worked out by laboratory studies and field tests and is recommended until a more 

 satisfactory way of handling the disease is discovered. The plan follows: ,, , 



The Massachusetts Plan for the Eradication and Control of 

 :i ;mi , I Infections Laryngotracheitis 



1. All birds on the premises that have had infectious laryngotracheitis or been 

 exposed to it should be condemned and disposed of at the end of the hatching sea- 

 son or at any other time most convenient to the owner for the expedient eradica- 

 tion of the disease. 



2. Incubators and brooders should be cleanerl, disinfected, and isolated some 

 distance from the condemned birds. 



3. Chicks that have not been exposed to infectious laryngotracheitis may be 

 kept for restocking, provided they are entirely separate from the condemned birds 

 and the premises occupied by them. 



4. All buildings occupied by the condemned birds should be thoroughly cleaned 

 and disinfected as soon as possible after they are vacated. 



5. The houses and yards after cleaning and disinfecting should be opened to 

 the air and sunshine and left vacant for two months or longer. 



6. Overalls and shoes worn around the condemned birds or on the premises 

 occupied by them should not be used in the houses, on the range, handling feed, or 

 in caring for chicks for re-stocking, unless laundered or thoroughly disinfected. 



7. Utensils and equipment used around the condemned birds or in cleaning and 

 disinfecting the premises occupied by them should not be used in the houses or on 

 the range where the chicks for re-stocking are kept unless said utensils and equip- 

 ment have been thoroughly cleaned and disinfected. 



8. Permitted Disinfectants should be used as directed for disinfecting all poul- 

 try houses, utensils, and equipment. 



9. New stock should be introduced only from absolutely clean flocks or from 

 the poultrymen's own hatchings which have been adequately protected from 

 infection. 



10. The subsequent re-ii.troduction of infectious laryngotracheitis should be 

 carefully guarded against. 



Twenty-seven poultrymen are known to have tried the plan as recommended 

 or some modification of it. Twenty-three of them succeeded in eradicating the 

 disease completely and four failed. The four failures were found to be due either 

 to improper cleaning and disinfection, or to the lack of sufficient airing and sun- 

 ning of the house and yards. , . 



Infectious Bronchitis. (C. S. Gibbs.) An epizootic of infectious bronchitis, 

 due to a streptococcus, has been found affecting a flock of hens and roosters. The 



