352 The Diseases of Animals 



parasites and contagious diseases attack weak, debilitated 

 animals in preference to vigorous, healthy ones. 



GAPES IN FOWLS 



Gapes in chickens is due to the presence of a small 

 round-worm {Syngamus trachealis) in the trachea, or 

 wind-pipe. The female worm is about one-half an inch 

 long; the male, which is attached to the female, is less 

 than half as long. When the worms are found in the 

 trachea they are attached to the mucous membrane, 

 from which they obtain the blood that nourishes them. 

 After being detached, the male presents the appearance 

 of a smaller worm growing or branching from the larger. 



The worms are usually found in young, weak 

 chickens, but in some cases they attack strong birds. 

 The chickens contract the disease from food or water 

 containing the eggs, or "catch" it from diseased chick- 

 ens. It is said that angle worms from infested ground 

 often harbor the eggs or the young worms, and that 

 when these "foster parents" are fed to healthy chickens 

 they will transmit the disease. 



One of the first symptoms is sneezing, followed by 

 gaping and attempts to get rid of the worm in the 

 windpipe. In case there are many worms, or the swell- 

 ing and inflammation of the throat is severe, there is 

 often difficulty in breathing. If the irritation of the 

 throat continues, the chick becomes dull, weak and 

 stupid, and finally dies from exhaustiou or suffocation. 

 The gaping is so characteristic of this disease that there 

 is no difficulty in recognizing it. 



