152 ANIMAL PARASITES IN THE STOMACH 



ROUND WORMS IN THE STOMACH OF THE 

 SHEEP. 



While several varieties of round worms affect the sheep 

 the principal one is the Strongylus contortus or twisted 

 palisade worm. This parasite is a brownish colored thread 

 worm; female 18 to 30 mm. long, male 10 to 20 mm. 



Life Cycle. — The life cycle of this parasite is not under- 

 stood. Probably the embryos are taken up on pastures 

 or perhaps in the sheep fold. From heavy invasions with 

 this parasite lambs become seriously diseased especially in 

 the spring and during wet simimers. It is probable that the 

 lambs become infested mainly around shade trees where 

 they gather during the heat of the day. On the open range, 

 in sandy or volcanic ash soil, sheep are rarely affected. 



Symptoms. — The symptoms in general are those of a 

 chronic gastro-intestinal catarrh leading to emaciation, 

 anemia, hydremia and death. The infested lambs begin 

 showing symptoms in July and August. They are noticed 

 hanging back from the rest of the flock, are weak, thin 

 and walk with a staggering gait. A cold, edematous swelling 

 develops beneath the lower jaw and the mucous membranes 

 and skin become pale, the latter parchment-like. As quite 

 commonly the lambs are also infested with lung worms the 

 symptoms of lung worm plague (see this) may also be 

 present. Death usually occurs from inanition in two weeks 

 to two months. On postmortem the abomasum of the 

 infested sheep will contain a large number of the small, 

 filiform, reddish parasites. 



Treatment. — ^Treatment is fairly successful. Cull out all 

 suspicious cases and place them in a separate enclosure. 

 The remainder of the flock should be placed on a well-drained 

 pasture in which there are no pools or stagnant water. The 

 lambs to be treated should be starved for twenty-four hours 

 but allowed water. Each lamb should be given gasoline 

 (Bss) in raw linseed oil (§ss) mixed with cow's milk (Biv). 

 The treatment should be repeated for three evenings in 

 succession allowing food several hours after giving the 

 medicine. It may be repeated in ten days. Copper sulphate 



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