514 



DISEASES OE CATTLE. 



vent cattle from infection with these parasites stray dogs, wolves, and 

 coyotes should be killed wherever found, and dogs too valuable to kill 

 should be kept free from tapeworms. As a precaution against infec- 

 tion with tapeworms, the viscera of cattle, sheep, or hogs should not 

 be fed to dogs unless cooked. 



Fig. 24.— Hydatids (Eahinococcus granulosus) in portion of hog's liver. 



Hydatids {Echinococcus granulosus) form tumors (fig. 24) of vary- 

 ing size (sometimes as large as 6 inches in diameter) in the liver, 

 lungs, and other organs. Their contents are liquid, 

 resembling water. The presence of these parasites 

 can not be detected in the living animal and there is 

 no medicinal treatment for them. Organs contain- 

 ing hydatids should be destroyed by burning in 

 order to prevent their being eaten by dogs. This is 

 especially important, as dogs infested with the tape- 

 worm stage of this parasite are a menace to human 

 beings on account of the danger of infecting them 

 with hydatids, which develop in man if the eggs of 

 the hydatid tapeworm are swallowed. 



Thin-necked bladder worms (Toznia hydatigena, 

 fig. 25) are most commonly found attached to the 

 mesentery and omentum. There is no medicinal treatment. 



Pig. 25.— Thin-necked 

 Madder worm (Tae- 

 nia hydatigena) 

 from abdominal 

 cavity of a steer. 



TAPEWORM CYSTS IN THE MUSCLES, BEEF MEASLES. 



Small tapeworm cysts {Toznia saginata), about the size of a pea, 

 found in the muscles of cattle (fig. 26) are the larvsa of the common 

 tapeworm of man. Cattle become infected from feed or water which 

 has been contaminated by the feces of persons harboring the adult 

 tapeworms, and human beings in turn become infected by eating raw 

 or rare beef infested with the larval stage (measly beef). 



