Throughout the course of the disease the patients scratch and rub themselves, thus tearing off the crusts and causing bleeding and the formation of new crusts of a blackish hue. This form of scabies about the head may become complicated with conjunctivitis, the inflammation extending from the extremity of the eyelids to the conjunctiva. This arises from the fact that the membrane is frequently injured by the animal rubbing the parts. Conjunctivitis may be so intense as to lead to purulent ophthalmia and the loss of the eye.
Fig. 252.—Sarcoptic mange of the sheep, showing the appearance of the head.
Diagnosis. Sarcoptic mange in sheep cannot be mistaken for any other disease on account of its localisation.
Prognosis. The disease is not very dangerous, for it is easy to treat, though if left to itself it might in time become fatal.
Treatment. Preventive treatment consists in isolating diseased animals, cleansing and disinfecting the folds, and preventing the introduction of diseased animals into healthy flocks.
Curative treatment. When the disease is detected at an early stage anti-psoroptic remedies may be directly employed.
If, however, it is of old standing, the crusts must first be softened and removed by the use of fatty substances, such as vaseline or oil, before any curative treatment can be undertaken.
The crusts can be removed in from twenty-four to forty-eight hours by vigorous washing with soft soap and the application of anti-parasitic solutions. The omission to wash the parts causes drugs to lose much of their efficacy.
Helmerich’s ointment, oil of cade, mixtures of oil, benzine and petroleum, and 3 per cent. to 4 per cent. of tobacco juice, are the commonest and most efficacious applications.