188 DISEASES OF DOMESTICATED BIRDS 
ground should be encouraged. The knowledge that the house fly is 
the intermediate host of a chicken tapeworm suggests the advisability 
of combating that insect. It breeds commonly in bird or horse ma- 
nure and any decaying vegetable matter. These breeding places 
should be eliminated as far as possible besides using fly traps. 
ROUND WORMS 
General nature. Round worms or nematodes are common para- 
sites of the intestines and are capable of inflicting considerable 
damage. They are long, slender and thread-like in form. Mouth, 
alimentary canal and anus are present. The female worm is gener- 
ally larger than the male. 
Species of round worms. There are two principal species in 
fowls. Ascaridia (Heterakis) perspicillum occurs in the small in- 
testine. The male is 3 to 8 em. long, while the female is 6 to 12 cm. 
in length. The color of the body is yellowish white. They are often 
present in numbers sufficient to occlude the lumen of the intestine. 
The same species is found in the turkey and guinea-fowl. Heter- 
akis papillosa, a much smaller worm with white body, is very com- 
mon in the ceca. The male is from 7 to 13 mm. long while the fe- 
male varies from 10 to 15 mm. in length. This species is found 
also in the turkey, guinea-fowl, peafowl, and pheasant. Five other 
less important species, Heterakis lineata, H. brasiliensis, H. compar, 
H. compressa and H. differens have been reported by Neumann as 
occurring in fowls. This writer lists other nematodes of the intes- 
tine as follows: 
Pigeon: Heterakis columbe. 
Duck: Ascaris crassa, Heterakis dispar, H. vesicularis, H. 
lineata, Strongylus tenuis. 
Goose: Heterakis dispar, H. vesicularis, Strongylus tenuis, Tri- 
chosoma anatis. 
Life history of Ascaridia perspicillum. Eggs are deposited by 
the worms within the intestine and are expelled in the feces. The 
length of time worm eggs will remain alive in the droppings is not 
fully determined, but there is evidence that they are viable up to a 
year. The life cycle of the worm is completed by eggs gaining access 
to a fowl through contamingted feed or water. Ordinarily, eggs do 
not hatch until they are taken into the alimentary canal of a fowl. 
The worms require three to four weeks to develop into sexually ma- 
ture forms. 
