168 SWINE PRACTICE 



PARASITES 



The principal pulmonary parasite is the Metastrongylus apri, which 

 has been described under bronchial disorders and ascaridiasis. 



Echinococcosis pulmonum is a common disease of swine. This 

 condition is caused by the larval form of Taenia echinococeus. The 

 cysts of pulmonary echinococeus are the same as those occurring in 

 the liver. 



Distomiasis, or invasion of the lung with flukes or Distoma, occurs 

 but is not common in swine. 



Pulmonary stephanurosis has also been observed, but is rare. 



Parasitic nodules, the supposed results of invasion of some unknown 

 parasite, are occasionally noted by veterinary inspectors, but there 

 is little significance in such invasion as the lung is not edible, accord- 

 ing to the meat-inspection regulations in the United States. 



Pleura 



Disease conditions of the pleura of swine are rarely recognized 

 clinically, though some eases of pleuro-pneumonia may be determined 

 by a clinical examination. Pathologic conditions of the pleura are 

 occasionally observed by veterinary inspectors in the carcasses of 

 swine that are slaughtered. 



HYDROTHOBAX 



Hydrothorax is a condition resulting from the accumulation in 

 the thoracic cavity of excessive quantities of serous fluid. It is of 

 rather rare occurrence in swine. 



Etiology. — Obstructed outflow of blood from the vena cava, with 

 engorgement, is the principal cause of hydrothorax. Chronic dis- 

 ease of the cardiac valves and chronic pneumonia are the most 

 common causes of obstruction of the outflow of venous blood from 

 the vena cava. Tumors, abscesses, and malformed thorax may also 

 be responsible for the causation of pneumo-thorax. 



Lesions. — Accumulation of varying quantities of a pale yellow 

 fluid in the thorax is the characteristic lesion, and in addition the 

 primary lesions in the heart or lung are usually evident. The 

 accumulated fluid will compress the lung. 



Symptoms. — It is not possible in the beginning to detect any 

 particular symptoms. Those produced by the accumulated fluid are 

 frequently so overshadowed by the primary condition that it is' not 



