THE TURKEY IMPORTANT IN THE SPREAD OF GAPEWORMS. H 



worms observed by the writer in chickens 14 days after infection 

 has been 17 mm. Usually the length attained in this period is less, 

 commonly being 12 to 14 mm. The longest gapeworm observed by 

 the writer in chickens measured 21 mm. in length. This was found 

 in an old, debilitated chicken, mentioned on page 6, which had been 

 infested for an unknown period. Some of the gapeworms present in 

 an adult turkey 19 days after infection measured nearly 30 mm. in 

 length, and worms measuring 24 mm. were common. In natural cases 

 of infestation gapeworms in turkeys have been found commonly to 

 measure 30 to 40 mm. in length, and have been found as long as 

 50 mm. The measurements given are those of mature females that 

 had begun oviposition or that contained eggs ready to be deposited. 



HOW TO AVOID LOSSES IN CHICKENS. 



From what has been determined as to the frequent occurrence of 

 gapeworms in turkeys, the susceptibility of old as well as young 

 turkeys to gapeworm infection, the diminishing susceptibility of 

 chickens to infection as they grow older, and the rarity of gape- 

 worms among adult chickens, it would seem that the chief element in 

 the spread and maintenance of gapeworm infection, leaving infested 

 soil out of consideration, is the turkey. The eggs of the gapeworm 

 are scattered over the soil in the feces of infested turkeys. Later 

 some of these eggs or the larvae that have hatched from them are 

 picked up again by the turkeys and more egg-producing worms de- 

 velop in them to add to the number of those already present. Thus 

 the stock of young worms in the soil and adult worms in the turkeys 

 is maintained. Meanwhile young chickens may also pick up gape- 

 worm eggs or larval worms from the ground where the eggs have 

 been distributed by the turkeys, with the result that they soon show 

 symptoms of gapes. As chickens young enough to be readily sus- 

 ceptible to infection with gapeworms usually die from gapes soon 

 after they begin to show symptoms of the disease they are not 

 likely to add much to the infection already in the soil. Older 

 chickens likewise do not scatter much infection because the eggs and 

 larval worms that they pick up either do not develop on account of 

 the diminished susceptibility of the chickens or, if the worms do 

 succeed in developing to egg-producing maturity, they are unlikely 

 to survive for more than brief periods. Chickens, therefore, may be 

 considered to play a small part, compared with turkeys, in infecting 

 the soil with gapeworms, and to be of minor importance as reservoirs 

 of infection. By keeping turkeys away from young chickens and 

 providing the latter with runs where there have been no turkeys 

 within a year or two and where, if used previously by young chickens, 

 there have been no cases of gapes in recent years, the danger of losses 



