LECTURE XLIX. 

 STOMACH WORM (Sheep). 



One of the especially common and serious parasitic diseases 

 of sheep, and this means much, for the parasitic diseases of sheep 

 are the serious ones. This disease is very widespread and almost 

 universal. 



The parasite (Strongylus contortus) which causes this trouble 

 is a small threadlike worm, perhaps an inch in length and so 

 slender that they must be looked for carefully or one is liable to 

 miss them. The individual worms are somewhat twisted and are 

 found in the fourth stomach. Frequently they are in motion. If 

 they are present in great numbers as is frequently the case, the 

 portion of the stomach contents next to the mucous membrane 

 ma}' seem to be fairly alive. The worms vary in color from dirty 

 white to reddish. 



Life history. — This is a permanent parasite, being present 

 in the stomach at all times of the year. The eggs pass out with 

 the feces and are afterwards taken in by other animals with the 

 water or food, particularly when in pasture. 



Symptoms. — There are no diagnostic symptoms by which this 

 disease can be distinguished from other internal parasitic diseases 

 of sheep. There is a gradually developing weakness and unthrift. 

 Lambs are affected more seriously than older sheep. These are 

 unthrifty during the late summer, and some die during the late 

 summer and fall. 



Treatment — The Bureau of Animal Industry has done some 

 careful experimenting in this line, and recommends coal tar creo- 

 sote as the most satisfactory treatment for this parasite. This 

 medicine is not expensive and is very easily obtained and pre- 

 pared. It is important to insist upon getting coal tar creosote, 

 not beach wood creosote which is ordinarly dispensed, the coal 

 tar creosote being cheaper and more satisfactory. It is given as 

 a one per cent solution ; that is, one ounce of the creosote to 99 

 ounces of water, in doses proportioned to the age and size of the 



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