Fig. 3. The frothy mucus in the eye of this 

 Rhode Island Red is another sign of chronic 

 respiratory disease. 



Photo by Robert L. Coffin. 



fied in dead and live embryos and 

 cull chicks (four days or less in age) 

 obtained from commercial breeding 

 flocks affected with the disease. 

 These findings may appear sig- 

 nificant from the standpoint of the 

 dissemination of the disease, if in- 

 fected breeding flocks are used to 

 supply flock replacements or fertile 

 eggs for the production of live 

 vaccines for poultry. More evi- 

 dence must be obtained to establish 

 the fact that this disease can be 

 spread through the egg. 



Identification Difficult 



A positive identification of the 

 disease is difiicult. An accurate 

 diagnosis can be approached by ob- 

 taining an adequate flock history, 

 isolating the agent in embryos, and 

 reproducing the disease in chickens. 



It has been found that infectious 

 exudates from the tracheae and air 

 sacs of affected birds, when inocu- 

 lated into embryonating eggs, will 

 produce embryo mortality and 

 embryo lesions. The fact that the 

 lesions, in some instances, appear 

 specific for this agent is an aid in 

 its identification. 



When the infectious agent is in- 

 oculated into chickens or turkeys by 

 way of the sinus or trachea, a sinus- 

 itis usually follows, and frequently 

 a tracheitis is observed. Extensive 

 air sac infection is usually found in 

 inoculated chickens. These symp- 

 toms and lesions do not become evi- 

 dent for several days (7 to 14) after 

 inoculation with the agent. When 

 infectious material is inoculated into 



birds immune to infectious bron- 

 chitis and Newcastle disease, it has 

 been found that a definite diagnosis 

 of this disease can be obtained gen- 

 erally within two weeks. Since 

 these methods and observations 

 have helped greatly in the identi- 

 fication of the disease in commercial 

 flocks, the flock owner is able to 

 deal with this problem more in- 

 telligently. 



Streptomycin Effective 



During the past year it has also 

 been observed that the chronic 

 respiratory disease agent is inhibited 

 by some of the antibiotics. Strep- 

 tomycin has been effective in re- 

 ducing sinusitis in turkeys, whether 

 the infection was caused by the 

 turkey sinusitis or chronic respira- 

 tory disease agents. Further in- 

 vestigation is necessary to deter- 

 mine the true value of the various 

 antibiotics in practical control of 

 chronic respiratory disease out- 

 breaks. At the present time, dis- 

 posal of affected flocks appears to be 

 the only means of controlling the 

 disease. 



