98 Diseases of Poultry 



scatter the contagion constantly, however, and young tur- 

 keys, being more susceptible, contract a fatal form of the 

 disease and are nearly all destroyed by it. For this reason 

 it is very difficult to raise turkeys on or near grounds where 

 there are common fowls. 



Diagnosis. — The symptoms of blackhead are most fre- 

 quently seen in young turkeys, commonly called "poults," 

 which are from 2 weeks to 3 or 4 months old. When young 

 poults are infected experimentally by feeding them diseased 

 livers they usually die in about two or three weeks, but when 

 infected naturally they generally take in a smaller quantity 

 of contagion and live a longer time. 



The affected birds at first appear less lively than usual, 

 are not so active in searching for food, and when fed show a 

 diminished appetite. Diarrhea is a nearly constant symp- 

 tom, being due to the inflammation of the ceca. As the 

 disease progresses there is more dullness and weakness, the 

 wings and tail droop, and there is often the peculiar dis- 

 coloration of the head which led to the disease being called 

 "blackhead." There is increasing prostration and loss of 

 weight; the affected birds, instead of following their com- 

 panions, stand about in a listless manner, indisposed to 

 move and paying little attention to what occurs about them. 



The greater part of the affected poults die within three 

 or four months after hatching; but with some the disease 

 takes a more chronic form and does not cause death for a 

 year or more. Nearly all die sooner or later from the effects 

 of the disease, but in a small proportion of the cases there 

 is healing and recovery. 



The finding after death, in young turkeys, of the diseased 

 and thickened ceca, plugged with cheesy contents, together 

 with the yellowish or yellowish-green spots in the more or 

 less enlarged liver are suflJcient indications to warrant a 

 diagnosis of blackhead. 



