16 MASS. EXPERIMENT STATION BULLETIN 311 



since Hemophilus gallinarum (Eliot and Lewis, 1934) was isolated in cultures and 

 a virus indistinguishable from that producing infectious laryngotracheitis in 

 susceptible birds after filtration with Berkefeld V filters. Hemophilus gallinarum 

 and Streptococcus bronchitis (Gibbs, 1933a) were isolated from affected birds in 

 the other two outbreaks, and the disease reproduced in healthy laboratory stock 

 by instilling mixed suspensions of these microorganisms into the eyes and nostrils. 

 Preliminary experiments indicate that rhinosinusitis may be controlled by 

 autogenous vaccination, using the technique recommended for autogenous 

 vaccination in infectious laryngotracheitis. 



Infectious Bronchitis 



Two outbreaks of infectious bronchitis have been identified. One was in a 

 flock of brooder chickens and the other was in a flock of roosters which had been 

 housed by themselves. The disease did not appear to be especially serious in 

 either the chickens or adult birds, and finally disappeared without treatment. 

 Since infectious bronchitis appears to be relatively unimportant, and the location 

 of the symptoms in the bronchi and bronchioles is rather inaccessible, no curative 

 treatment is suggested for adult birds. However, the brooder should be thoroughly 

 cleaned before being used again when the disease appears in chickens. 



Chickenpox and Roup 



Four outbreaks of chickenpox complicated with roup appeared in this study 

 of field cases. These epizootics were in small chickens and rather difficult to 

 diagnose at first sight. However, upon close examination characteristic pustules 

 were found either on the edges of the beak or on the comb of some of the chickens, 

 and satisfactory diagnosis made. Since chickenpox is a cutaneous disease and 

 may be controlled by specific vaccination, these cases were not extensively studied. 



WHEN AND HOW TO VACCINATE FOR INFECTIOUS 

 LARYNGOTRACHEITIS 



The Massachusetts Plan for the Eradication and Control of Infectious Laryn- 

 gotracheitis (Gibbs, 1933c) is the most hopeful for the industry as a whole, 

 because it will eliminate not only infectious laryngotracheitis but all contact 

 diseases. This plan will never succeed unless the poultry associations get back 

 of it and put it across. There is no money in this plan for commercial firms as 

 there is in vaccines. Therefore commercial concerns will not put this plan into 

 operation, but some of them will be led into the manufacture and sale of vaccines. 

 There is undoubtedly a place for infectious laryngotracheitis vaccines for they 

 enable the poultryman, so unfortunate as to have an infected flock, to save his 

 birds until a more favorable time is reached for the complete eradication and 

 control of the disease by sanitary methods. 



Also it has been found (Gibbs, 1931b) that infectious laryngotracheitis is spread 

 by both acute cases and chronic carriers, and vaccination does not eliminate the 

 possibility of the spread of the disease from either of these sources, because 

 vaccination is nothing more than the inoculation of the mucous membrane of 

 the cloaca and bursa of Fabricius with the living virus and the symptoms and 

 lesions are confined to these organs rather than the larynx and trachea. In 



