376 Diseases of Sheep, 



Cause. — While in one sense we know the cause of this 

 disease, as stated in the definition above, in another sense we 

 are ignorant of it, as the origin and life history of these 

 curious parasites are still a sealed book to us. The disease 

 prevails especially in low, damp situations ; on grounds sub- 

 ject to overflow, and grown with rank grass ; after heavy 

 rains, and in the autumn months. It has already been to 

 some extent discussed, in speaking of hoose in calves. 

 According to the best authorities, the disease is steadily 

 increasing, both in England and the United States. (See 

 highland Agric. Soc. Reports, 1878). 



. The worm itself is from one to three inches in length, 

 slender and whitish, like a thread, and while in sheep they 

 are mostly found in the bronchial tubes, in lambs they are 

 discovered in the lung tissue itself. When in the lungs of 

 sheep, they are not active, but folded in cysts. Often they 

 are matted together in masses or balls, which choke up the 

 passages they inhabit. 



Symptoms. — The presence of these worms does not always 

 cause inconvenience to the sheep. Occasionally prime, and 

 to all appearances perfectly healthy animals are killed, whose 

 lungs are found filled with them. In lambs, however, they 

 are a frequent cause of death. 



When lodged in the bowels, the symptoms are those of 

 dysentery, with fetid stools. There is much straining, and clots 

 of blood may be passed. When in the lungs, they cause irrita- 

 tion and inflammation, indicated by a husky cough, quickened 

 breathing, rubbing the nose on the ground, loss of appetite 

 and flesh, and exhaustion. These symptoms are clearly not 

 positive, and, indeed, the only unquestionable sign of the 

 presence of the worm is its discovery in the feces, or in the 

 mucus from the mouth and throat. The combination^ how- 

 ever, of a cough in a number of lambs, occurring often with 

 dysenteric symptoms, and under the conditions above men- 



