PSOROPTIC MANGE— SHEEP SCAB. 621 



The ease with which the disease can be cured and the absence of para- 

 sites enable one to readily distinguish it from psoroptic mange (scab). 



^ Prognosis. The disease is not specially grave, so long as only a few 

 animals are affected, for it is hot difficult to cure by isolation, good 

 feeding, and proper external treatment ; but if scab appears in a flock, 

 the freedom with which the animals intermingle is such that all are 

 rapidly attacked, and the irritation produced at once checks their growth 

 and causes loss in condition. Many ewes give birth to small, feeble 

 lambs, which are almost certain to die, and in any case the wool is 

 considerably diminished in value. 



Delafond estimated that psoroptic mange formerly attacked one 

 thirty-fifth of all the sheep in France every year, causing damage to 

 the extent of five francs per head. At the present time, and since 

 proper sanitary laws have been instituted, it has become much less 

 common. 



During the bad season of the year the mortality is greater, and 

 may reach as much as from 40 to 50 per cent. In cases where 

 scab is accompanied by some other disease, such as distomatosis, it 

 may even rise to 80 per cent. 



The treatment is preventive and curative. PreventiYe treatment 

 consists in separating the healthy from the diseased animals and in 

 disinfecting the folds, sheds, etc. 



Curatiye treatment. The first point in this treatment consists in 

 improving the diseased animal's food both as to quality and quantity. 



It is to be ol)served that the parasite has more difficulty in living 

 on robust and -well-nourished animals. Moreover, observation shows 

 that transference from poor land to rich pastures is sometimes in 

 itself sufficient to bring about a spontaneous cure. Such, at least, 

 is the belief of the Spanish sheep farmers in Estramadura and of the 

 French shepherds. 



The shepherd can do a great deal to arrest the course of the disease. 

 If he is careful, zealous, intelligent and observant he will quickly note 

 the first indications of the disease and, by isolating the animals, check 

 its spread. 



The second point consists in shearing the diseased animals, and 

 this must be carried out at any season of the year. The money loss 

 is sometimes important, but must be met, for otherwise treatment is 

 impossible. In cases of localised scab, empyreumatic oil, oil of cade, 

 solutions of sulphuret of potassium, decoctions of black hellebore (water 

 1 quart, fresh rhizome 4 ounces or dry rhizome 2 ounces), de- 

 coction of tobacco and diluted tobacco juice (6 ounces in 1 quart 

 of water) have been recommended. Such local treatment, however, 

 is often useless, because incomplete. 



