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

 Verminous Pneumonea — Verminous Bronchitis. 



Plates XXIX to XXXVI. 



The Inng worms which cause disease in sheep in the United States be- 

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

 pulnionaUs, Diesing, the hair lung worm ; and Strongylus Jilaria, llud., 

 the tliread lung worm. The third si)ecies, which has been reported as 

 infesting sheep in Europe, is the hog hmg worm, iStronf/ylus 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 

 til at of Strongylns Jilaria, it will not be treated separately. 



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

 mechanical injuries the worms iutiict 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-pulmonaUs, 

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

 bronchioles and infundibuli, and causes disease in them primarily, 

 while Strongylns Jilaria, which penetrates only 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-pidmonalis is characterized by the 

 spongy 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 Strongly us Jilaria and S. paradoxus is char- 

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

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

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

 generally sinks in water, wliile pieces from the former disease float. If 

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



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