Psoroptes have only been found about the eye, where the disturbance they produce is comparatively trifling.
SARCOPTIC MANGE.
This disease was noticed in 1818 in goats imported into France from Thibet.
Henderson published the history of a Persian goat which conveyed sarcoptic mange to men and horses. In 1851 Walraff noticed an epizootic mange which attacked the goats in the Prattigau valley of Switzerland, which was transmitted to men and sheep and which exhibited the clinical characters of sarcoptic mange.
Causation. This disease is due to the presence of Sarcoptes scabiei (v. capræ).
It sometimes occurs in an epizootic form, as Walraff’s observations show, but it seems specially to attack goats in Asia and Africa.
This mange may be transmitted by the goat to sheep, in which animals it attacks the head and muzzle; it is particularly contagious in sheep having coarse, dry fleeces.
Similarly sarcoptic mange of sheep may be conveyed to the goat, in which animal it extends all over the body.
Symptoms. This mange causes intense itching. It first attacks the head and ears, then the trunk, belly, udder, and limbs. If the disease is neglected it becomes generalised very rapidly, and the animals waste away and die in a very short time.
At the commencement little crusts, which discharge a viscous liquid, are found about the head. The goats rub themselves raw, and, as in facial mange of sheep, there appear dry, scaly, branlike patches. After a time the diseased area extends, the wool falls, and the skin becomes dry, thick and wrinkled. The appearance is exactly like that of sarcoptic mange in sheep, the lower part of the head being seldom invaded. The animals lose condition, waste and die of exhaustion.