24 Oestrus Ovis. 



stand in the foreground of the clinical picture, while catarrhal 

 signs are absent. The differential diagnosis, however, meets 

 with great difficulties and becomes impossible when OEstrus 

 larvae situated high up lead to nervous symptoms, while symp- 

 toms of catarrhal affections of the mucosae are absent, as does 

 occur though in very rare cases. If larvae of CEstrus are 

 expelled with the nasal secretion, the diagnosis is always estab- 

 lished. The disease can be differentiated from lungAvorm dis- 

 ease by the absence of cough, by the occasional presence of 

 CT]strus larvae in the nasal secretion, while lung worms and 

 their ova are not found. 



Treatment. The only rational procedure consists in open- 

 ing up the affected cavities, removing the larvae that are present 

 and accessible with a pair of forceps and anesthetizing those re- 

 maining with appropriate irrigations. 



Trephining of the Frontal Sinuses. Since the laivfe are found preferably 

 in the frontal sinuses, these must be laid open in particular. Ziirn recommends 

 as the place of trephining the two upper, Moussu, however, the lower angles 

 formed by a line connecting the superciliary ridges with another line drawn at 

 right angles into the middle of the former line. If the condition does not improve 

 after trephining in this manner, it is advisable to remove the horns and thus to 

 lay open the cavities at their base. After the larva^ have been recovered from the 

 opened cavities, these must be irrigated with a fluid noxious to CEstrus larvae. Ser- 

 viceable fluids are: benzin diluted with water, oil of turpentine, 3<;/f carbolic acid, 

 9.5% alcohol, lime water, etc. None of these fluids will kill the very resistant larvae 

 (Fischer), but they will cause them to contract strongly, so that they will leave 

 their places of attachment and will be expelled from the nose by strong sneezing. 



This treatment, however, can hardly be carried out when 

 a large number of animals of a herd are affected and the 

 operative procedure will then perhaps be employed only on 

 the most valuable animals. The treatment sometimes does 

 not have the desired effect and most animals, especially in 

 the presence of severe cerebral symptoms, will, according to 

 Ziirn, remain sick and will succumb. Speedy killing of the 

 animals is therefore indicated if the affection is violent, if 

 trepanation cannot be carried out, or if, in spite of trepanation, 

 the s^^Ilptoms do not ameliorate. 



The insufflation into the nose of tobacco, snuff, heleborus, all of which cause 

 sneezing, the inhalation of irritating smoke, irrigation with various fluids (aside 

 from those already named, vinegar or salt water), is frequently recommended. 

 Considering the great resistance of the larvae and their place of location, one canno*. 

 expect much success from such procedures. 



Prophylaxis encounters very great difficulties. It is ad- 

 visal)le to destroy the larvae. Sheep flies may be driven out 

 of sheep stables temporarily by repeated fumigations. It also 

 appears advisable not to pasture sheep on hot summer days 

 in such locations where there are brushes and trees and to 

 exterminate brushes from sheep pastures. Local conditions, 

 however, usually prohibit the carrying out of such measures. 

 It is therefore recommended to apply, in places where sheep 



