640 SCABIES SCAB — MANGE. 



The prognosis only becomes grave when the disease has been 

 neglected and the animals are greatly reduced in condition. When 

 recent, this form of mange can readily be cured by the application 

 of parasiticides. 



Treatment. As in dealing with all transmissible diseases, the 

 animals must be isolated and washed with soap, and the diseased 

 parts must be dressed with some parasiticide, such as sulphur oint- 

 ment. The best preparations are: Benzine and petroleum in equal 

 quantities ; concentrated solution of sulphuret of potassium (8 

 ounces to the quart) ; Helmerich's ointment ; diluted creolin solu- 

 tion ; decoctions of tobacco ; ointment of pentasulphuret of potassium, 

 and oil of cevadilla. 



One or two applications are generally sufficient to effect a cure, and 

 relapses are not likely to take place if the stable is disinfected. In 

 America the disease is common in the West and North- West, where 

 it is treated by the lime-and-sulphur bath recommended for sheep-scab 

 (which see). Large vats are constructed, and the oxen are lowered into 

 these by means of a wooden cage controlled by machinery, which is ope- 

 rated either by a small engine or more frequently by a horse. 



The food should be of good quality, for good general health plays 

 a great part in resisting parasitic invasions. 



CHORIOPTIC JIANGE. 



This disease has also been termed dermatophagic and symbiotic 

 mange. 



It was first described in 1835 by Kegelaar, and has been the sub- 

 ject of investigation by Hering, Gerlach, Delafond, and Megnin. 



Causation. It is produced by the Clwrioptcs hovis, and is transferred 

 with difficulty, even by co-habitation. 



Symptoms. This form of mange in the ox does not affect the same 

 parts as in other animals. In the horse, etc., it attacks the limbs, whilst 

 in the bovine species it is usually found at the base of the tail. It causes 

 slight itching. The diseased region becomes covered with numerous 

 little pellicles, the hairs gradually fall, crusts form, and the skin shows 

 deep cracks. When the disease is completely neglected, it may extend 

 to the loins, back, sides of the body and shoulders. It may also affect 

 the perineal region, the inner surface of the thighs, and in fact the whole 

 of the body if the animals are young and in poor condition. 



Diagnosis. At the outset it is difficult to distinguish between chori- 

 optic and psoroptic mange, and the use of the microscope is necessary. 

 On a superficial examination chorioptic mange may be mistaken for 

 phthiriasis when the latter attacks the posterior portions of the body, 



