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 exhaustion or suffocation. 
The gaping is so characteristic of this disease that there 
is no difficulty in recognizing it. 
