PARASITIC DISEASES. 173 



5. Liver Rot. 



Distomatosis. 



This is a disease of deadly importance in low- 

 lying countries but is not common to the sheep 

 raising sections of the west. 

 The sheep is naturally an in- 

 habitant of high altitudes; 

 this factor is in its favor, 

 since to a large extent it 

 keeps it away from noxious 

 parasites to which it is so 



susceptible. DISTOMA HEPATICUM. 



Feeders who prepare the 

 best mutton for market, and c. ventral sucker. 

 who buy western lambs that ' 



ey8 



-, T PIT" "Pathology.") 



have never lost a feed and 



that have spent their lives at an altitude of from 

 three to ten thousand feet above sea level, will 

 sustain me in making this statement. 



Liver rot is due to the Distoma hepaticum or 

 Fasciola hepaticum; commonly called the liver- 

 fluke. 



The life history of the fluke is an interesting 

 one, and may be briefly given as follows : The 

 feces of infected animals contain the embryos 

 which mature in about six weeks under favorable 

 conditions. They then bore their way into the 

 bodies of fresh-water snails, and after passing 

 through certain cycles, emerge as cysts. When 

 these are taken in by sheep in either food or 

 water, they undergo a further development and 

 migrate into the bile duct and on into the liver. 



