S8 



POULTRY DISEASES 



mon, having been found by the author in twenty-four out of 

 eighty-seven autopsies. 



Description. — This intestinal parasite is round in shape and 

 whitish-yellow to white in color, varying from one to two inches 

 in length. There are two sexes, male and female, the female being 

 considerably the larger. Fig. 36 shows the actual size of the 

 male and the female specimens from which this drawing was made. 

 Some few specimens are much larger than the ones shown. 



Life History. — The adult worms deposit large numbers of eggs 

 in the intestines of the infested fowl. These eggs are very minute, 

 microscopic in size and can be seen only when examined under a 

 high power microscope. They pass out of the intestine of the bird 

 with the droppings, are very resistant to dryness and ordinarilly 

 do not hatch until taken into the alimentary tract of another fowl. 

 There is some evidence that eggs may hatch in the droppings under 



38. 



Fig. 36. Fig. 37. Fig. 



Fig. 36. Ascaris Inflexa (Natural Size). 

 A, female; B, male. 



Fig. 37. Heterakis Papillosa (Natural Size). 



A, female; B, male. 



Fig. 38. Heterakis Papillosa, Head Extremity (Magnified). 



A, mouth parts; B, esophagus. 



certain conditions. Infestation is brought about by means of food 

 or drink, which has been contaminated with egg-laden droppings. 

 Thus one affected bird may infest an entire flock. The younger 

 worms are found toward the gizzard end of the bowel and the larger 

 ones farther down the small intestines. The development from 

 newly hatched larvae to full grown males and females is attained in 

 from three to four weeks. If infestation has lasted the required 

 length of time the droppings of an infested fowl will be seen to 

 harbor great numbers of tiny worm eggs. 



Symptoms of Iiifcslalion. — These parasites harm the host 

 by ingesting food during its digestion l)y the host, thus rob- 

 bing it to a certain extent. A few worms may produce no 

 noticeable effect upon tlie health of the bird, Imt if present 

 in large numbers they cause serious trou])le. It has been 

 found that the excrementitious (waste) matter given off by 

 these and other intestinal worms is poisonous. It is absor])ed 

 and has a deleterious constitutional eft'ect, similar to tliat of 



