DISEASES OF POULTRY. 41 



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and game birds in England.during- the last twenty -five 

 years ; and it has been estimated that it destroys, there, 

 half a million chickens annually, in addition to the 

 losses among game and other tirHs. It has, also, 

 caused serious losses in France for more than forty 

 years, and iihdoubtedly exists in many other countries. 

 In the United States, it has become one of the most 

 common and most troublesome diseases of young 

 chickens and young turkeys, but adult birds as a rule 

 do not suffer from it. A number of species of wild 

 birds are susceptible to this disease as well as the 

 domesticated birds. 



Causation. — The single cause of gapes is the para- 

 sitic worm hnowti as' the Syn£-amus irachealis. This 

 worm is represented, in Fig. 5, a being the male and d 

 the female. The two sexes are usually joined together 

 in a permanent manner by the union of the integuments, 

 as shown in the fig^ure. 



The syngamus is a small round worm, red in color, 

 and both the male and female are found attached by 

 their mouths to the mucous membrane of the bird's 

 trachea. The female is slightly more than one -half 

 inch in length, while the male is only one -fifth inch. 



They suck the blood of the bird, which forms their 

 nourishment, and, in doing this, set up considerable ir- 

 ritation and even inflammation. The large and vig- 

 orous birds are not seriously disturbed by. the presence 

 of this parasite, particularly if the worms are not very 

 numerous. Small and weak birds, however, are un- 

 able to successfully resist the combined effect of the 

 loss of blood, the inflammation of the trachea, and 

 the obstructed respiration. The strength is rapidly 

 lost, and the windpipe becomes obstructed until finally 

 the bird dies of exhaustion or asphyxia. 



