1 84 DISEASES OF SWINE 



confined to pigs, and in most cases the symptoms 

 are so mild that the character of the aihnent is not 

 suspected. A' spasmodic cough is the most promi- 

 nent symptom. Sometimes, regular coughing spells 

 come on when the animal begins moving about, after 

 it has been lying down. Unless the infection is 

 severe, difficult breathing does not occur, and there 

 is no noticeable check in the growth and thriftiness 

 of the pig. The latter symptoms are ' never as 

 marked as in lung-worm diseases of calves and 

 lambs. 



In well-cared-for pigs, the appetite remains good 

 and the pig gradually outgrows the disease. In 

 ■poorly cared-for and weak individuals, the outcome 

 is not so favorable, and they may become stunted 

 and the disease persist for a long time. Death 

 seldom occurs. 



The lung lesions are produced by the worms irri- 

 tating the lining membrane of the bronchial tubes, 

 causing it to become inflamed and increasing the 

 amount of mucus secretions. This mucus, to- 

 gether with the worms, may plug the small bronchi, 

 prevent the air from passing to the air cells, and 

 cause a lobular pneumonia. Healthy hogs that are 

 slaughtered in the abattoir are frequently infested 

 with lung worms; the lungs in such cases show but 

 little evidence of disease. 



Treatment. — This parasite is so widely distributed 

 that it is necessary to use all measures of precaution 

 possible in order to prevent infection. The yards 

 should be well drained, and all ponds and mud holes 



