VERMINOUS BRONCHITIS. 213 



Cause. — This disease is caused by a parasite which inhabits 

 the various cavities of the head which communicate with the nasal 

 chambers. 



Life history. — The mature fly resembles the well known bot 

 fly of the horse; is of a dirty yellow or grayish yellow color,. and 

 appears in the middle of the day from July to September. The 

 young larvae are deposited about the nostrils of the sheep, from 

 whence they crawl up into the various cavities of the head, in- 

 cluding the horn cores, and may even reach the brain substance. 

 They mature in about nine months. The developed grubs work 

 out, escaping from the nose during the spring, from March to 

 May. They then pass through another stage before the adult fly 

 appears, which occurs in six or seven weeks from the time the 

 grubs escape from the nose. 



Symptoms. — A nasal discharge appears during the spring. 

 The sheep sneeze, shake their heads, and rub tlieir noses ahd faces 

 against their feet or other objects; sometimes there are attacks of 

 vertigo and the walk may be unsteady or irregular; severe cases 

 develop convulsions and die. On examination post mortem, grubs 

 are found in the various openings and chambers of the head and 

 the mucous membrane lining these cavities is inflamed. 



Treatment. — Medical treatment under ordinary circumstan- 

 ces is not practical, and prevention is very difiicult to apply on 

 a large scale. Before the sheep are turned out in the morning 

 their noses may be smeared with tar or a mixture of tar, turpen- 

 tine and fish oil. They may be forced to take their salt out of 

 a large hole bored in a log or a plank, the tar being smeared arounci 

 the edges of the hole so that when the sheep take their salt they 

 get a little tar around the nose and mouth. 



CATARRH IN SHEEP. 



Cause. —Simple catarrh in sheep is usually due to cold rains, 

 imperfect ventilation and damp quarters, or undue exposure after 

 early shearing. In other words, simply a case of catching cold. 

 Many cases of catarrh are due to parasitic invasion of the nasal 

 chambers and head sinuses. However, these latter are not includ- 

 ed under simple catarrh. This disease is not contagious, although 

 many cases may appear simultaneously, due to common causes. 



Symptoms. - — The affected sheep are noticed to be sneezing, 

 with discharge from the nose and eyes, and sometimes coughing. 



