THE TURKEY IMPORTANT IN THE SPREAD OF GAPEWORMS. 7 



harbored, respectively, 92, 75, and 36 pairs of gapeworms in their 

 tracheas, the females ranging in size from 4 to 11 mm. Besides the 

 worms in the trachea there were a few immature gapeworms in the 

 lungs of each chicken. 



Some of the same culture was fed on February 7 to three turkeys 

 nearly a year old. Nineteen days later one of the turkeys was 

 observed to be sick and was killed. There were no gapeworms found 

 in the lungs, but 483 pairs were present in the trachea, the females 

 averaging 24 mm. in length. The feces of the two remaining turkeys 

 were first examined 21 days after infection and at this time con- 

 tained large numbers of gapeworm eggs. The birds were coughing 

 and there was a brown crust on their bills, formed by the drying of 

 expectorated mucus. On March 17, 38 days after infection, these 

 two turkeys were still coughing, but the brown crust was no longer 

 present on their bills. On April 14, 66 days after infection, gape- 

 worm eggs were still present in the feces. April 29, one of the 

 turkeys which had been ailing was killed, the lungs and one bronchus 

 being found affected with a gangrenous necrosis. The trachea 

 contained 22 pairs of gapeworms, the females averaging 33 mm. in 

 length; also many broken pieces of dead worms were found. The 

 third turkey was kept alive. December 16, 10 months after infection, 

 an examination of the feces of this turkey failed to show gapeworm 

 eggs. 



In this experiment adult turkeys (nearly a year old) and young 

 chickens (8 weeks old) became heavily infested as the result of a 

 single feeding with gapeworm material, while chickens approaching 

 maturity (21 weeks old) that were fed repeatedly with gapeworm 

 material (including material from the same culture as that fed to 

 the turkeys and the young chickens) failed to become infested. Evi- 

 dently, therefore, adult turkeys and young chickens are much alike 

 in their susceptibility to gapeworm infection, and in this respect both 

 are quite different from adult chickens or chickens approaching 

 maturity. 



FACTORS IN THE SPREAD OF GAPEWORMS. 



From the results of the investigations briefly recorded above, it 

 would seem that turkeys are an important factor in the spread of the 

 gapeworm, and that adult chickens are relatively unimportant as 

 carriers of the parasite. In the perpetuation of gapeworms from year 

 to year on infested poultry farms the two chief factors appear to be 

 turkeys and contaminated soil. Whether guinea fowls are like turkeys 

 in commonly harboring gapeworms throughout life or whether they 

 are like chickens and tend to lose their susceptibility as they become 

 mature is uncertain. Little is known also as to the relation of pea- 

 fowls, ducks, geese, pigeons, and various wild birds to the spread of 



