LUNG- WORM DISEASES.-PAPER SKIN, HOOSE, HUSK. 

 Verminous Pneumonia— Verminous Bronchitis. 



Plates XXIX to XXXVI. 



The lung worms which cause disease in sheep in the TJnited States be- 

 long to two, perhaps three, different species. They are Strongylusovis- 

 pulmonalis, Diesing, the hair lung worm ; and Strongylus filaria, Rud., 

 the thread lung worm. The third species, which has been reported as 

 infesting sheep in Europe, is the hog lung worm, Stronpylus paradoxus, 

 an abundant species occurring in the lungs of swine in this country, 

 and while ithas never been credited as having been found in our sheep 

 it is to be looked for. As its size and the disease it causes is similar to 

 that of Strongylus filaria, it will not be treated separately. 



The diseases produced by these species of worms are caused by the 

 mechanical injuries the worms inflict on the delicate membranes of the 

 lungs and the clogging up of the air passages by them and the debris 

 which they produce. The two forms of disease produced depends on the 

 different size and habits of the two species. Strongylus ovis-pulmonalis, 

 being very small, penetrates the air passages to their endings in the 

 bronchioles and iufundibuli, and causes disease in them primarily, 

 while Strongylus filaria, which penetrates oidy into the bronchi, creates 

 a disturbance there which produces a solidification of the lung second- 

 arily. The general diagnosis of each disease is no easy matter. The 

 disease produced by Strongylus ovis-pulmonalis is characterized by the 

 spono-y feeling of the lung and the presence of nodules from the size of 

 a mustard seed to that of a pea scattered under the surface of the dor- 

 sum of the lung and at its posterior free edge. These may be connected 

 by agrayish, fleshy, intermediate portion of the lung into patches of con- 

 siderable size. The parasites can scarcely be seen by the unaided eye ; 

 but if small pieces of the affected lung or a tubercle be placed in a shal- 

 low dish of water and teased out with needles under a tripod lens, they 

 can'be readily seen. 



The disease produced by Stronglyus filaria and S. paradoxus is char- 

 acterized by the posterior portion usually, or some entire section of the 

 •iffected lung appearing as a solid, usually red, mass which has lost all 

 fits contained air and is in a state of hepatization. A piece cut out 

 j]y sinks in water, while pieces from the former disease float. If 

 ■ the latter disease the trachea is carefully slit open and the branches 



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