178 POULTRY DISEASES 



Three stages then follow: catarrhal, characterized by a 

 mucus, or mucopurulent, discharge; diphtheric, affecting the 

 mouth and throat and characterized by the formation of a 

 mem])rane on the surface which may be followed later by 

 sloughing (formation of a mass of dead tissue) ; and con- 

 junctival, affecting the eyes, and often causing a destruction of 

 the eyeball. 



General Symptoms. — In the early stages before much sec- 

 ondary infection takes place, there are no marked general 

 symptoms. Later marked general symptoms appear. The 

 birds show dullness, assume a sitting posture, Avings are held 

 pendant, plumage becomes rough and the patients show much 

 depression. The comb and wattles grow bluish-red in color, 

 later they are pale and cold. In the colder climates the dis- 

 ease often assumes a subacute or chronic form, while in 

 warmer climates the acute form is more often observed. Fre- 

 quently, however, the disease assumes the character of a 

 chronic catarrh. 



Diagnosis. — The disease usually makes its first appearance 

 in the fall of the year and often occurs as the cutaneous 

 form ; it may be overlooked, especially if the birds are on the 

 range. The mucous membrane form usually makes its ap- 

 pearance soon after housing for the winter. The sneezing, 

 mouth breathing, occluded nostrils, and an occasional in- 

 flamed eye, are significant especially when rapidly spreading 

 through the flock. Soon after, a few will refuse food and 

 appear depressed. 



It must also be suspected when similar symptoms appear 

 after adding new birds to a healthy flock or returned birds 

 from shows. 



A peculiar characteristic and offensive odor is associated 

 with this disease, and poultrymen familiar with it often rec- 

 ognize the disease from the odor alone. The same odor is 

 given off by cultures. 



Differential Diagnosis. — AVounds on the skin around the 

 head, usually pick inflicted, appear suspicious, but these heal 

 rapidly without extensive thickening. An injury to thc^ eye, 

 even though serious, will not cause the formation of the 

 characteristic yellow deposit. Difficvdr respiration is rarely 

 seen in more than one bird in a flock. Healthy Hocks and 

 those intended for exhibition purposes may be vaccinated to 

 establish immunitv. This has proved very satisfactory. The 

 immunity established will last for at least one year. 



Postmortem Appearance. — The toxin (poison) from the 

 areas of disease is very destructive, as the rapid emaciation 

 of the bird, following a severe attack, shows. T^pon examina- 



