DISEASES DUE TO INTEENAL PARASITES. 213 



in the cavities of the heart and in the blood-vessels, and this goes 

 to prove the correctness of the above theory of migration. A 

 very large number of worms may be present in the lungs of a 

 single sheep and are also found infesting the intestines. This 

 M^ould account for the amount of infection and source of danger 

 a single diseased sheep may be to a pasture. 



Symptoms. 



These depend to a great extent as to whether the lungs 

 only are attacked, or v/hether the parasites are also present in the 

 intestinal canal. In the majority of cases the parasites are 

 present only in the lungs; in some cases both the lungs and . 

 alimentary canal contain the worms, and in a few exceptional 

 cases they are only present in the stomachs and intestinal canal. 

 As seen attacking the lung-tissue of lambs, they cause distressing 

 fits of coughing, difficulty in breathing, the affected animal fre- 

 quently rubbing its head against the ground. Symptoms of 

 anaemia (bloodlessness) soon become apparent. This is evi- 

 denced by a paleness of the mucous linings of the eye-lids, the 

 skin becomes dry and papery, the wool has a tendency to fall out, 

 the breathing becomes hurried, the animal loses strength and 

 sinks rapidly. When the parasites are present in the intestinal 

 canal as well as the lungs, purging is associated with the other 

 symptoms above mentioned. The animal has colicky pains, in- 

 tense thirst, and a tendency to dropsy. 



An examination of the mucus discharges of the nose and of 

 the faecal matter will frequently reveal the live parasites. 



The disease runs a course extending all the way from one 

 to four months, depending on the strength of the sheep and the 

 number of parasites gaining access to the system. If the symp- 

 toms are well marked at the outset, the disease is almost sure to 

 prove fatal unless the worms are few in number and the animal 



